Wind, Solar, Nuclear, and Electricity Storage

Posted on August 22, 2008
Posted By: Joseph Somsel
 
Advocates of intermittent alternate energy sources put enormous hopes in electricity storage development as a boon to the market acceptance of their technologies. It is recognized by anyone with an ounce of realism that the timing mismatch between God-given winds and sunbeams and the needs of man is one of the fundamental problems with alternative energy development. Advocates point to the expanded use of electric storage technologies as the fix.

So far, actual commercial installations of electric storage for the grid have used pumped storage exclusively, insofar as I’m aware. Battery facilities, super capacitors, compressed air storage, and flywheels have all been proposed and some even put on line for a while but none have shown commercial promise worthy of private investment. One could presuppose a micro-level storage device that would work only within the photovoltaic cell, like science fiction author Robert Heinlein did in “The Roads Must Roll” or maybe windmills with big wind-up springs inside, but for our purposes, we can confine our discussion to pumped storage at the grid level.

As most readers will remember, pumped storage is a type of hydroelectric development but with upper and lower reservoirs and hydroelectric turbine/generators that can run in reverse and serve as motor/pumps. To store electricity, megawatt-hours are consumed by the motors to drive the pumps which raise water from the lower reservoir to the upper. Energy is stored as potential energy in the water’s elevation difference. To deliver electricity, water in the upper reservoir is released back down the pipes through the pump impellers, now working as turbines, thereby driving the generators which used to act as motors during the storage phase. The released water is typically stored in the lower reservoir until the next storage phase. The highest differential between high and low reservoirs in the U.S. is the Helms pumped storage facility. This 1,050 MW capacity installation, located in the Sierra Nevada Mountains in Northern California has a 1,630 foot elevation difference between reservoirs connected through an underground equipment hall carved out of solid granite.

The Economics of Storage

Let’s look at a couple of the universal characteristics of energy storage technologies, including pumped storage, and how they affect the economics of storage. First, these installations are not free. While the variable operating costs (non-electrical) may be rather low on a per unit throughput basis and can be ignored in any first order analysis, the fixed capital costs are non-trivial and have to be allocated against each unit of delivered energy. Carving a huge underground hall out of granite with huge penstocks between artificial lakes ain’t cheap. The mortgage has to be paid and revenues from operation must recover the capital investment, with interest and profit.

Since the electrical demand for most human customers follows their waking hours, the demand on the grid falls off substantially late at night. Given the standard workweek, the weekends have typically lower demand than weekdays. That suggests that the upper reservoir is filled at night, when electricity prices are lowest and the stored power delivered to the grid during the day when electricity prices/costs are highest. The more megawatt-hours that are generated for sale, the lower the cost per megawatt-hour.

This is a simple function:

Cost per unit for fixed costs = (number of units sold per year) / (annual fixed costs)

Let’s make it look really mathematical by using letters to stand for the phrases:

Cf = T / M
Where:
Cf = unit costs for fixed expenditures T = Output in units sold per year M = annual fixed costs, ie the mortgage.

Another certain feature of any storage method, including pumped storage, is that it is not perfectly efficient. One has to put more electricity in than one can draw out. The motor/generators lose energy through heat and internal friction, the pump/turbines swirl water rather than move it, the penstocks offer friction to water flow through them. The list goes on and on but is comparable from any industrial use of power to move vast quantities of water. Batteries lose heat from internal resistance or make hydrogen bubbles. One thing every engineer has to learn is that NOTHING is perfect and never works as well as it does in the introductory textbooks.

With pumped storage, a good rule of thumb is that 4 units of electricity go in but only 3 come out for sale for a 75% cycle efficiency. An exceptional facility might see 80% (5 in and 4 out) but we’ll use the typical efficiency in our example calculations.

Variable cost per unit output = (price per input) / (efficiency)

Again, to make it look mathematical:

Cv = P / e
Where:
Cv = unit cost for variable costs
P = price of electricity bought as input
e = efficiency of output to input
If we combine the efficiency term and the fixed cost allocation term, our equation for the cost per unit output (Cp) looks like this:

Cost of product = fixed cost per unit output + variable cost per unit output

Or

Cp = Cf + Cv
Expanding:
Cp = (P / e) + (T / M)
So what does this cost equation tell us? If one wants the lowest delivered cost to the grid, one wants the lowest cost input and the maximum annual throughput. For the lowest cost input, can one really believe that solar or wind would be the best source of low cost power AT NIGHT, when one wants to charge the storage? Solar not only isn’t available except for a few hours around noon on days with little cloud cover, it also produces when grid demand is high and grid prices are relatively high so solar electric output would go directly to the customer unless the installed solar capacity is truly huge, some large fraction or multiple of peak grid demand. That way, solar wouldn’t be burdened with the inefficiencies of the storage.

Wind has the advantage that it can work at night or other off-peak times. However, the historical performance record in the U.S. doesn’t suggest that it preferentially does so. The U.S. Energy Information Agency’s records show that installed wind capacity only works at about 26% of its nameplate. The wind industry trade group would claim a higher number, maybe 30% or so, but either way, the wind blows when it will, not when we’d prefer it.

To achieve the maximum throughput is to lower the unit cost of storage since we spread those fixed costs over more output. If a storage facility costs a billion dollars but only produces one megawatt-hour for sale, that megawatt-hour will cost more than $1 billion. We have a strong economic incentive to keep the storage investment working every weekday. That means charging the facility with electricity every Sunday through Thursday night. Another crude way of looking at a 26% capacity factor for wind is that it works one day in four or six hours in 24. If we believe the wind advocates, that might look like one day in three or eight hours in 24 but either way, to use wind, we are trying to fit a narrow production window into a narrow recharge window. Like solar, production during peak load hours would be preferentially consumed at those higher prices rather than put into storage. Like solar, installed wind capacity would have to be some multiple of peak load to be justified as the preferred source for storage all the time.

Let’s do some examples to get a feel for the numbers. We’ll use price/cost in dollars per megawatt-hour (MWh).

Let’s say PV costs $100/MWh, wind costs $75/MWh, nuclear $70/MWh, the facility cost $1 billion and is financed at 8% for 30 years. Let’s assume it can deliver 1,000 MWh for six hours every weekday (200 days per year) and has a cycle efficiency of 75%.

We can posit several questions and answer them by cranking the above inputs through a simple spreadsheet (available on email request) using our equation. We’ll assume that the power input source is completely from one of our choices. We can ask, what would be the selling price for power from our pumped storage unit if the unit was utilized 100% of the 200 days per year and then 50% and 25% of the days, given supply limitations. An even more telling question is, what would be the selling price if the storage unit had the same capacity factor as the input power source?

Here are the results:

Output Costs Solar Wind Nuclear
full utilization $222 $188 $182
50% utilization $310 $277 $270
25% utilization $487 $454 $447
At source’s capacity factor $575 $395 $192

To give one a sense of current market reality, the early summer 2008 on-peak, “day ahead” prices for Houston, Texas are running about $120/MWh with off-peak “day ahead” costs lower at about $66/MWh. A baseload nuclear plant would sell into both time markets, hence covering a $70 levelized production cost and making a profit. The spot market peak there might run $300 to $450/MWh during the summer. Peaking power in East Texas is not from pumped storage but from natural gas-fired gas turbines with low capital costs but high fuel costs.

The conclusion is that economics of electricity storage favors not renewables but rather the cheapest and the most reliable input source. Since electric storage will never be 100% efficient and will never be free, the conclusions will differ only in degree. Building a pumped storage facility on a grid does not enhance the economics of renewables but decreases their attractiveness relative to more conventional technologies like large coal and nuclear. The only way to turn that around is for wind and solar to become both more reliable than nuclear and cheaper too.

In the real world, the analysis above is far too simplistic for investment decision making – call it a first order analysis. But for public policy thinking and for understanding the fundamental economics, it should disabuse even the most optimistic fan of renewables of any pipedreams that more storage would overturn the current economics. We can test our results by looking at existing pumped storage units. You’ll find that where someone has invested in a pumped storage facility, one will usually find a big coal plant or a nuke with good connections to it. I suspect it will be that way for a long time.

 
 
Authored By:
Joseph Somsel is a degreed nuclear engineer holding an MBA from California Polytechnic University. He has a broad work background in the nuclear power industry and in the overall electric utility business. This includes experience with architect/engineers, utilities, NSSS suppliers, and consulting firms. Current interests include the business end of electricity. He has also been involved in the entrepreneurial development of niche electrical generating sources in California and Colorado. His
 

Other Posts by: Joseph Somsel

Nuclear is Back in Business! - February 20, 2004
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Comments

August, 14 2008

david austin says

You speak of solar PV but not CSP solar thermal ... the only grid-worthy solar technology out there - the bulk of solar energy produced in the US (including private distributed sources) is in fact Thermal in nature, not PV. In fact PG&E is funding enough CSP to produce 3 GW of capacity within 5 years.

CSP has, perhaps, the only truly viable storage mechanism for massive amounts of energy: insulated heat in the form of molten salts, or steam in under-ground caverns underneath the solar fields. In fact, it is believed that storing half of the heat to be turned into electricity when its dark, may actually decrease the cost of the plants because the turbine demands are cut in half.

The molten salt method has already and is currently used in a small way to store heat in some facilities, to be used later, but the storage of steam in underground caverns is only theoretical, but apparently all the numbers look good, the caverns must be very deep, but dense earth isn't too bad of an insulator. I read somewhere that they'd expect to get something like 85% of the heat out of stored steam after 6-10 hours compared to using it directly. No expensive materials or fancy equipment either - just a deep hole in the ground.

The reason, however, you don't see these storage technologies being used is for the simple reason that when CSP is producing electricity is when it's at the greatest demand. What kind of brain-dead utility is going to save that juice for evening use when they're getting 3X more per kWh in the daytime?

But it does go to show that if massive CSP farms ended up providing the bulk of a region's energy, stretching that energy to meet evening use is entirely possible at a very reasonable cost - far exceeding the cost efficiencies of the other technologies listed in this article.

And that's very important, because if we are at peak oil then EV cars such as the Chevy Volt will all be recharging at night. I suspect in another 15-20 years evening electricity won't be as cheap as it is today.

It's also interesting to note a rumor that Johnson Controls, perhaps the largest LiPo4Fe battery maker is planning that in 10 years when these EV batteries will need replacement the old batteries will go into basements for consumers to sip electricity when it's cheap to use later in the daytime. Personally I don't think by then it will be worth it, as like I said, evening electricity will cost much more than it does today.

August, 16 2008

Joseph Somsel says

I explicitly EXCLUDED point-of-generation storage where the output costs to the grid at the bus bar include the cost of storage. For your example, a financial analysis of storage would depend on the specific technology.

Otherwise, any non-dispatchable generation should always sell into the spot market. A storage facility operator should be free to buy non-dispatchable MW-hr at the spot market but in the real world would want firm contracts with reliable suppliers like coal or nuclear.

A corrollary is that "alternatives" deserve only deeply discounted capacity payments based on real historical performance. For example, ERCOT only allocates capacity payments at less than 10% for wind in Texas. In addition, alternatives do not deserve "must run" status - let them sell at the real time auction price.

As to CSP solar thermal, their past record has been as PURPA machines. The Luz plants were supposed to get only 51% of their energy input from solar and 49% from "supplemental" natural gas. Special tax breaks made them go. Now, the new magic ingredient in project financing is "renewable mandates."

Advocates of alternative energy and their political allies will make us buy this stuff, no matter how much more it costs the ratepayers and the taxpayers. If your pet technologies and projects can make it in the free market (such as our grids are), then fine.

Don't get me started on "net metering" either!

August, 18 2008

Matt Fergus says

Joseph, I agree with the algebraic formulation of the cost of storage calculation you presented in your article.

In your followup comment 8/16, however, you argued alternative energy generators should be required to compete on a level playing field with traditional generators. While we've now clearly moved into value statements from mathematics, a similar argument could be made for traditional generators. By this I mean that traditional generators have historically largely avoided bearing the direct cost of their negative externality byproducts. Right or wrong, society is now adopting an increasingly negative view of the externalities of most traditional forms of generation. Through mechanisms such as carbon taxes, traditional generation sources are likely to become increasingly directly burdened with costs that are intended to represent these negative externalities.

Returning from a values discussion to your algebraic model, to the extent alternative energy sources avoid externalities that are explicitly costed in the future, the economics of your cost of storage calculation will begin to shift. While you likely see this point as self-evident, I suspect many readers would not.

August, 19 2008

Len Gould says

Joseph: I think you also miss the significance to unreliable renewables of real-time pricing of electricity to consumers combined with (I think) a fairly near-term advent of significant amounts of "free" storage in the form of vehicle batteries. All your points are correct only if one grants your stated limitations on storage technology to those you've discussed.

August, 19 2008

Jim Beyer says

It was pointed out to me that even simplistic smart metering applied to HVAC could easily make use of all bursts of intermittent power provided from wind/solar. Add to that the potential for PHEVs and advanced HVAC storage (via ice making) and no pumped storage will be necessary, even if renewables reach 20%.

Past that, it probably makes sense to tie additional renewable input in with increased PHEV presence. I'm not sure the intermittent renewables industry (solar/wind) realize how their long term viability is tied to the success of PHEVs.

August, 19 2008

Brad Bergman says

All you have done is reiterate the analysis that every utility and renewable energy advocate has already gone through to determine that pumped storage is not a useful applicaiton for wind or solar. Everbody in the industry already knows this, and I have heard of no one advocating the use of pumped storage for solar...ever. What pumped storage IS good for, like you pointed out, is taking excess (wasted) baseload capacity at night, and turning it into useful and valuable capacity during the day. Pumped storage is great for nuclear and coal, but we already knew that.

As an aside, I've been in SCE's pumped storage chamber at Big Creek and it's quite impressive. As a way to maximize your equations, SCE uses the same turbine for generating regular hydro electricity from rain and snowmelt as it uses to pump water backwards at night. This way thery're getting much more out of the capital investment than if they just used it for storage. I don't remeber ths exact numbers, but they pump about a quarter of the water back up the hill at night as comes down through the turbine during the day - and they use excess baseload power to do it.

August, 19 2008

Joseph Somsel says

Everyone in the utility business wants to integrate the customers into our control and management networks so that the customers change their lives to match our system needs and capabilities.

Funny, but few customers see it that way. Our customers expect the electric grid to serve THEIR needs, not the other way around. Plus, many of these alternate schemes push the capital investment from the grid to the consumers. That will go over big.

As to Mr. Bergman's complaint that "everyone knows" the economics of storage, I must assure him that this is NOT the case. Alternate energy advocates seem completely unaware of how the world works and the money flows, probably because it would bust their bubbles.

As to Mr. Fergus' issue with externalities, decades of experience with the concept shows it completely worthless since there is no sound method of calculation. If imposed by government fiat, any externality value is usually calculated for the effect that will result. Ergo, if you want to price coal out of the market, price CO2 so that your favorite technology can compete - you have no other methodology.

This article was submitted for posting on EnergyPulse but somehow wound up here.

August, 19 2008

Len Gould says

Joseph: "Our customers expect the electric grid to serve THEIR needs, not the other way around." -- Have you tried allowing customers to use their smart grid facilities to directly access those $0.012/kwh nighttime rates yet? I thought not.

August, 19 2008

Joseph Somsel says

Len,

I'm willing to allow opt-in for time-of-day metering for private residences. However, here in Northern California, the ratepayers are investing $1.7 billion for such meters, whether we want them or not. I'm skeptical of their acceptance by the customers but it looks like a fiat accompli at this point. Plus, the temptation for cross-subsidization looks rather easier to accomplish.

Remember the outrage at the programmable communicating thermostats this winter here in California? I don't think this augurs well for time-of-day schemes. How many electric bills are going to go DOWN?

Note that the article was moved to EnergyPulse today, 8-19-08.

August, 20 2008

Len Gould says

Joseph: California is in the unfortunate position of usually being on the bleeding edge of technology adoption, and results there shouldn't be taken as indicative (as Ontario regarding metering). These crude Time-Of-Use meters being deployed now are in no way capable of implementing a genuine realtime market as I suggested above, which would be capable of eliminating much of the need for storage.

August, 20 2008

Len Gould says

And which would, properly implemented, also definitely show noticeable savings for every customer, whether they actively exploit its functionallity (best case) or simply let it do what it can for them via smart appliances etc. (worst case).

August, 20 2008

Len Gould says

BTW, Joseph and others. Here's a good quote, attributed to James Lovelock, founder of the Gaia environmentalist movement.

"Opposition to nuclear energy is based on irrational fear fed by Hollywood-style fiction, the Green lobbies, and the media. … Even if they were right about its dangers - and they are not - its worldwide use as our main source of energy would pose an insignificant threat compared with the dangers of intolerable and lethal heat waves and sea levels rising to drown every coastal city of the world. We have no time to experiment with visionary energy sources; civilization is in imminent danger and has to use nuclear, the one safe, available energy source, now, or suffer the pain soon to be inflicted by our outraged planet." - From the London Independent – May, 2004

August, 20 2008

Joseph Somsel says

I inquired about a time-of-day (TOD) meter for my home in 1984 from our local utility. It was clear that there was no way to justify the cost of the meter. Of course, TOD meter costs have declined (I hope) in real terms.

The advantage of TOD metering is to shift load from peakers to base load generations. Only then can it reduce overall system costs which can be used to reduce individual customer costs.

An example I've used repeatedly is, would your wife put off doing laundry or doing a dishwater load until after dinner for 25 cents in electric savings? Mine wouldn't given her hectic day with two kids. She says she would since she's a liberal Democrat but it wouldn't last.

August, 20 2008

Jim Beyer says

Joseph,

Most of the TOD savings are expected to be from HVAC during peak critical times. That's about 30% of the demand (during those peaks) and thus the plum that everyone is trying to figure out how to grab.

August, 20 2008

Len Gould says

Joseph: Would she "put off" running the dishwasher if the only effort required was to press the "Autostart" button instead of the "Start Immediate" button on its front panel? Knowing that it would then stand and wait for prices to drop to a level which you have preset in your home controller (or until 4:30AM, whichever comes first)?

August, 22 2008

Todd McKissick says

Anyone can make any argument valid with enough exclusions and narrowing of the subject. Without considering the value of point of generation storage, which will become by far the largest player, there is little point in responding. That argument is like a 1910 discussion asking how could we possibly ever use coal and discounting rail as a means of transportation.

Joseph, You really must get with the times. Smart metering with real time prices is coming and end user load shifting, storage and on-demand generation will follow. Add to that the non-grid-electric means of air conditioning that will further reduce the afternoon peaks and you've got some serious peak shaving. The quantity available in aggregate from those sources will make the grid peaks almost a thing of the past. How will you justify the 'must run' prices for centralized equipment when the end users have better AGGREGATE reliability AND no transmission losses? My guess is that as soon as those "pet technologies and projects" attain a sufficient penetration and the overall response time shrinks proportionally, even highly variable sources such as wind will be absorbed into the mix without concern.

You don't think they'll ever reach that level? Consider this. Public comparisons between grid power and renewables for the largest group of members of the chain, the residential customers, have always discussed apples and oranges and people won't miss that much longer. (i.e. A quoted utility rate doesn't include taxes and other expenses.) This means the comparison will become utility rate plus inflation plus taxes plus hidden charges for 20 years vs. a home equity based capital purchase with flat payments and a 10 year payoff and another 10 years of routine maintenance only. My guess is that utilities will be begging for customers before too long.

Perhaps the problem is that you always refer to examples of 5-20 years ago (Luz, TOD meter, CA thermostat experiment). We're discussing systems that will be utilized 5 years from now so why not refer to technology relevant to that time frame.

August, 22 2008

Joseph Somsel says

Todd,

As I've said, my mind is relatively open on time-of-day rates. There are some theoritical economics arguments in their favor. My experience and observation of consumer behavior in other markets (like cell phones and conservation investments) suggests skepticism is still warranted.

The CA thermostat fluff-up was January, 2008 - my how time flys! If we're talking technology 5 to 10 years in the future, it is obviously not proven in the market place and might be a path best not taken. I clearly (I hope) excluded point-of-generation storage from discussion because it ain't invented yet! Guess I'm not on board with hopey changitude nor do I fall for big promises. Plus many of these new ideas are premised on the promoters changing the behavior of the multitude through government action. That's like drawing to an inside straight.

Len,

Please don't ask me to publicly criticize my wife's homemaking skills in public!!!!! I've done enough already - you want to get me in trouble or what?

August, 22 2008

Todd McKissick says

Joseph, I was placing TOD rates in the old news category. The decendent of which is real time pricing where the price varies by the second or faster. This allows customers to make their own decisions on power use AND power generation and obviously onsite storage. This is the only way that giving the customer incentive to make money actually coincides with the actions needed to balance the grid. It's also in complete opposition to:

"Everyone in the utility business wants to integrate the customers into our control and management networks so that the customers change their lives to match our system needs and capabilities. Funny, but few customers see it that way. Our customers expect the electric grid to serve THEIR needs, not the other way around. Plus, many of these alternate schemes push the capital investment from the grid to the consumers. That will go over big."

Take note of the emphasis in your statement of the utility's control over the customer and contrast that with monetary incentives given to them to make the decision on their own.

Now consider that pushing those capital investments to the customers might actually give them a healthy return on that investment. The masses haven't caught on to this yet, but they will, especially since many of today's offerings have instant ROE (reaching 120% in many markets). Keep in mind that these are the first real offerings and those number only get better with time and inflation.

This is not futuristic miracle magic. It's done in other industries all the time. Checked the stock market lately? Global transactions take place based on tiny fractions of a penny change in value at breakneck speeds and that process happens for thousands of stocks each of those seconds. The future part of this is because of the utility company's fight against it, not because it's technically futuristic.

I also love your statement suggesting that anything not proven in the market place .. might be a path best not taken. Are you a relative of the patent officer that, in 1899, said everything worth inventing had been so already? Maybe we should only look to a nuclear track record that's been proven out already? As you should notice in an equal comparison, both nuclear and renewables have advances that are technically proven and economically likely, but they don't both get the same approval.

August, 22 2008

Len Gould says

Ha Ha. Agreed Joseph. If any further needed, lets use a theoretical example, Blondie Bumstead (oh, so out of date!). How about Family Guy's wife, Marge Simpson, or Cartman's mom?

August, 22 2008

Joseph Somsel says

Todd,

I guess some of us should be still plumping for the nuclear-powered airplane.

August, 22 2008

Roger Arnold says

Joseph,

Good article. However ...

I'll start with a few quibbles in this note (apetizers). It may take a bit more time to formulate the main course, so I'll reserve that for a second post.

First, you've inverted T and M in your formula for the fixed cost per kWh. Twice, even! That doesn't really affect anything, since in your discussion you're clearly using M/T ("Mortgage / Thruput") rather than T/M. Just interesting that none of the earlier commentors noticed it. Tch, tch.

Second, you wrote:

So far, actual commercial installations of electric storage for the grid have used pumped storage exclusively, insofar as I’m aware.
Kinda sorta correct. There are certainly many grid-connected battery installations, but they're used more for short term quality of service purposes, not the extended arbitrage that you're writing about. At least in this part of the world. (Japan has some large sodium-sulfer battery installations that are used for load leveling.) Oh, there's that large VRB installation in Utah that was put in to enable a growing but isolated community to be served by existing feeder lines. But that could be classed as experimental, so you're OK there. However, I don't think you could classify the McIntosh CAES facility in Alabama as anything other than commercial. So there! Take that! ;-)

Of course that doesn't change anything substantive either, since your thesis is based on considerations of capital cost and round-trip storage efficiency, not specific technology.

I'll stop there for now. But be prepared for a devestating follow-up.

August, 22 2008

Joseph Somsel says

Duh. You're correct about the T/M typo. I must have been standing on my head when I typed that.

The CAES installation only stores some energy as compressed air - a good percentage if not majority of the output power comes from burning natural gas or oil. I think we can agree that batteries are not going to scale up and steal major grid storage market share from pumped storage any time soon.

Looking forward to more of your comments. Really!

August, 22 2008

Roger Arnold says

I think we can agree that batteries are not going to scale up and steal major grid storage market share from pumped storage any time soon.
The way you've cleverly phrased it, yes, I'm forced to agree. It's those words"major grid storage market share" and "any time soon". But don't discount the potential of batteries (heh, heh) too much. Costs per kWh of throughput are coming down, and there's the huge issue of upcoming PHEVs and "vehicle to grid" capacity. Or the less discussed but equally significant market (IMO) of backup power to individual homes and offices. Likely in conjunction with distributed solar and the DC-wired home and office, but that's another topic.

Back to my major beef with your article: it comes down to the last line of your table on output costs -- the row labeled "at source's capacity factor". There it stands, bold as brass, just as if it meant something.

It doesn't. The capacity factor of any particular source has almost nothing to do with the capacity factor of a pumped hydroelectric facility. And to the limited extent that there is a correlation, it's in the other direction. I.e., the larger the share of highly intermittent sources, the higher the throughput (or capacity factor) of a pumped hydro facility will tend to be. Instead of having one extended period of pumping and one shorter period of generation each day, it may switch between pumping and generation several times. And its throuhput, in kWh, may be substantially larger than it would be if it were only augmenting a baseload source.

The reason the correlation is weak is that any pumped storage facility that exists will tend to be fully utilized anyway, regardless of sources. System operators love hydroelectric and pumped hydro facilities, because they can vary their output continuously under real time control. The reality of system operation (in most regions) is that 95% of variability in the daily power curve is met by scheduled start-ups and shut-downs of individual generators. Having hydro capacity under regulation by SCADA computers simplifies scheduling. Start-ups and shut-down tend to be hard on equipment, and with pumped hydro to fill in gaps and smooth the flow, fewer transitions are needed. "Contingencies" can be accommodated with less dependence on spinning reserves.

The bottom line is that, contrary to your conclusion, reliability of sources has little to do with the economics of pumped hydroelectric energy storage. Other things being equal, of course, a reliable source is always more valuable than one that is intermittent. Nobody is disputing that, I would hope. But if one happens to be the operator of a grid with high penetration of intermittent sources, then the utility of regulated storage capacity -- pumped hydro or otherwise -- goes from its normal level of "high" to "can't do without it".

August, 24 2008

Joseph Somsel says

My analysis is based on the OBSERVATION of facts, not on supposition, projection, or "hope."

"The capacity factor of any particular source has almost nothing to do with the capacity factor of a pumped hydroelectric facility."

Sorry, this is completely wrong in the real world. No one has invested in grid storage without a reliable, economic, predictable source of electricity with which to charge it. There are no storage investments built "on spec" that I'm aware of. The first order economics of storage compells a high reliability of source generation. One need only LOOK at the world's inventory of major electric storage facilities to test this assumption and arrive at the same conclusion as the storage investors' arrived at. Of course, picking up small amounts of power on an opportunistic basis might well happen.

Assertions to the contrary posit conditions that do not now exist and are so unverifiable. You're asking us to take you on faith.

Large pumped storage facilities do have an advantage over thermal units in cycling on/off or charge/discharge but I wouldn't over-state that. I don't have any specific performance information on large pumped storage units but stopping and reversing the flow of the massive amounts of water in a penstock can't be instanteous. I'd be surprised if one could do a gigawatt scale reverse in less than 15 minutes. I do know a 25 MW gas turbine should cold-start and load in 10 minutes but that's emergency duty.

Even if batteries improve to the point where they compare to today's sizes the same issues of losses from internal inefficiencies and amortization of capital costs will hold. I can certainly see ancillary and distribution services as a possible market though.

My conclusion still holds - adding electrical storage to the grid requires cheap and reliable sources of off-peak generation. Storage economics favors coal and nuclear and vice versa.

Grid storage is no panacea for wind and solar. As you state, if a utility is burdened with "a high penetration of intermittent sources" then one should ask, how did that happen? The answer will be political imposition. If a grid storage investment must be made to manage the grid, then ADD the capital and operational costs of the grid storage to the premiums paid for solar and wind resources. that just makes the economics of wind and solar even worst in comparison.

Once again, government creates a problem then government makes you pay to fix their mistake.

August, 24 2008

Jim Beyer says

I am a little wary in wading into this because I will likely get both Joseph and Roger annoyed with me. But I also feel that this is a good, meaty debate that deserves to be carried forward, no matter where it leads. I think I will end up taking pot shots at both parties.

First, the comment by Roger about vehicle-to-grid having even a possibility of significant storage is a pipe-dream. I can think of about 4 reasons why it will not be (sensibly) deployed anytime soon. First, the marginal cost of charging/discharging of a battery is huge with today's technology. This is the cost of the slight aging of the battery that occurs, which is probably about 30 cents per kw-hr or more. This is acceptable for automotive applications (which is competing against 40 cents plus per kw-hr gasoline, but not for the grid. A utility would have to be really reaching to justify that expense; or be screwing over the vehicle owner to get the juice. Second, the cost of metering from vehicle-to-grid would also be very high, and hard to justify given the limited opportunities of use. (Notice that unlike grid-to-vehicle which could record with some ease even time-of-day charging, vehicle-to-grid would have to note how to credit a particular vehicle connected to a particular charger. I'm not saying it can't be done, but even updated AMI technology for homes have the utilities cringing. There is simply no margin here.) Third, you are talking about relatively tiny amounts of power available in disparate parts of a city. Each vehicle might be about to source 10-20 kwatts (any more than that and you'd be hammering on the battery even harder.) so 100 amenable vehicles would be needed just to get a megawatt. It would seem alternative methods of demand response (HVAC) would be a much less expensive method of obtaining the same result. So they are likely to me mined first before vehicle-to-grid is ever effected. Fourth, in addition to metering, there is the cost of power inversion. Again this is very high, unless multiple vehicles could be ganged from a single site, which is unlikely. A charger could perhaps be designed for two way operation, but this would increase costs and require additional hardware that would be infrequently used.

In theory, a case might be made for vehicles supplying short-term power bursts from on-board ultracaps. This has several benefits: no appreciable aging to the vehicle (ucaps last for many cycles), power peak shaving has benefits to utilities (even short ones), very high power possible from even one vehicle (megawatts or more). However interconnect and re-compensation issues remain.

The main benefit the PHEVs could provide is as a sheddable load for intermittent renewables such as wind. That is, conditional grid-to-vehicle. No vehicle-to-grid is needed. This deals with one half of the intermittent renewables problem (supply surge) if PHEV populations can be built up commensurate with the intermittent sources. In the case of no wind blowing (demand surge, in effect) then that is best served by demand response (DR) via smart grid technology. Again, not in place yet, but very doable technology which has other motivations (conservation, efficiency, peak shaving) pushing it forward.

DR, perhaps combined with sheddable PHEV loading, will go very far in servicing even high penetrations of intermittent sources to the grid. Grid storage and vehicle-to-grid strategies are not likely to be needed for quite some time, if ever.

August, 24 2008

Joseph Somsel says

Oh great! Now we want to link renewable, intermitent electrical generation with transportation and make that intermittent too. So we here in California would have another heat wave with no wind AND not be able to drive our cars to the beach (or work.)

Seriously, a plug-in hybrid would still be able to run off the gasoline engine so maybe we still could go to the beach.

At root I'm continually amazed at the degree of lifestyle imposition and the extent of inflated costs that advocates of wind and solar will propose to implement their prefered technology. These efforts are ultimately pointless since there are already solutions to electrical generation needs that satisfy our requirements for low cost, reliability/dependablity, cleanliness, safety, and adequacy. That technology is, of course, nuclear power.

As to scheduling dishwashing in my home - the machine gets run whenever we run out of clean forks. We notice that there are no clean forks when we realize we need them so the machine is in a must-run-now mode.

I'm more successful with turning off unnecessary lights.

Agreed that this is useful exchange. No annoyance here and I hope no gouging, no biting, no hitting below the belt.

Thanks to all for the comments!

August, 24 2008

Jim Beyer says

Joseph,

I agree that nuclear power is safe and clean, but the much-vaunted free market does not think so. Otherwise, we'd not need federally-backed insurance to underwrite the plants. And with the Feds involved, as you well know, everything goes downhill from there.

And if you are annoyed with inflated costs that impose on your lifestyle, I'd argue that such is what happens when 50 million or so people decide to live in a desert (i.e., California).

A larger case can be made of the wisdom of populating the planet with 6.5 Billion souls, most all of them yearning for a lifestyle like Joseph's, that is, being able to wash their forks whenever they damn well please.

August, 25 2008

Roger Arnold says

... No one has invested in grid storage without a reliable, economic, predictable source of electricity with which to charge it.
Hmm, I'll go you one better: No one has ever invested in grid storage with only a single source of electricity from which to charge it. Or even a handful of sources. Regardless of reliability.

The source of electricity for any pumped hydro facility is invariably the grid itself. That's one of the problems that I had with your article that I didn't choose to go into above. Your model of a pumped hydro facility seems to be that of an independent investor-owned facility in a deregulated electricity market. It would presumably contract to purchase off-peak power for pumping on the day-ahead market, and then contract to sell blocks of peak power on the same day-ahead market. Under that model, lack of reliability from the contracted source would certainly be an issue.

But that's not how it works. (He said, confidently.) OK, I'm no expert on this, and perhaps somewhere there's a facility that tries to operate on that model. If so, good luck to them. Pure arbitrage in the power market is a hard way to make a business case. Capital costs are too high, round-trip efficiencies too low, and rate differentials are not all that large.

AFAIK, pumped storage facilities are never independent; they're effectively part of the transmission system, usually operated under control of the TSO. The major part of their "value proposition" is not simple arbitrage, but rather regulation and other ancilliary services for which they are inherently suited.

The TSO's job is to maintain the balance between electricity supply and demand, as economically as possible. It doesn't matter whether an incipient imbalance is due to variation on the supply or demand side. The TSO has a limited "bag of tools" with which to respond. One of those tools may be a pumped hydro facility. If so, and the state of the storage system permitting, its characteristics will typically make it the tool of first resort -- if only to buy time for slower, gentler start-ups or shut-downs from other sources.

In any case, the economic case for a pumped hydro facility is a complex matter involving geography, the shape of the demand curves in that region, details of the generation asset pool for the region, and the availability of other options for dealing with variations (e.g., discretionary loads). One thing that it does not depend on, however, is the source of variability between supply and demand. It's a solution (or partial solution) to the problem of variability, and what matters is how it compares to other solutions.

I know, Joseph, that you advocate nuclear power over renewables. There are a lot of things that can be said about that. If you want to say that renewables carry an implicit requirement for higher levels of capacity for responding to variability, and that legislated mandates for renewable energy portfolios force utilities to purchase renewable energy at prices that don't reflect the true cost of its variability, then I will agree 100%. I just don't think it's legitimate to bring in the nature of available sources as a factor in the economics of pumped storage itself.

August, 25 2008

Roger Arnold says

Jim,

You'd have to work at it to get me annoyed with you; your views are usually reasonable and well-informed. But don't put words in my mouth. I agreed with Joseph that "batteries are not going to scale up and steal major grid storage market share from pumped storage any time soon." Emphasis on the major and soon. The option of vehicle-to-grid is an "issue" for the longer term that I mentioned as something that should not be discounted. And I do think that's true, regardless of the points you raise.

If competition for remaining oil supplies is destined to drive oil prices ever upward (and I believe that's true), then the future of personal transportation has got to be electric: BEVs and PHEVs. The associated battery storage capacity is HUGE. If as much as 10% of the current auto market were switched, the storage capacity would dwarf current grid storage, in agregate, by about two orders of magnitude. Asserting that none of that capacity will ever be used for grid storage seems, .. well, a bit rash.

Some points to consider:

1) You're right about the marginal cost of charging and discharging batteries of current technology. However, some of the newer lithium-ion technologies are already negligibly degraded by cycling -- as long as it stays within the 10 - 90% range. Capacity degrades more as a function of calendar life than cycle counts. With this type of battery, there's no significant cost penalty to cycling within the "safe" bounds.

2) If you read the literature on VTG, you'll find that the payoff is not for kWh arbitraged; it's for ancillary services. A utility is legally required to maintain a certain level of capacity for response to power excursions and "contingencies", whether or not that capacity is utilized. A contract for ancillary services is a contract for capacity, independent of whether or not the capacity is used. When it is used, it entails additional payment for the kWhs delivered. But most of the revenue to a VTG provider is for the promised capability to respond, not for actual kWh delivered.

3) Indeed, one of the strongest criticisms of VTG proposals is that, if implemented on a large scale, VTG would quickly saturate and deflate the market for ancillary services. That undercuts its business case, and leaves it dependent on good old arbitrage -- a difficult sell. To be successful, it must not be too successful.

4) Ancillary services notwithstanding, there is no added cost for inverters. An electric vehicle already has inverter capacity far in excess of anything it would be called upon to deliver to the grid. An inverter capable of delivering 100 kW of continuously variable AC to its traction motors can certainly deliver 10 kW of 60 cycle AC to the grid.

5) If battery cycling degradation is a non-issue (either because actual cycling is rarely called upon, or because the battery technology is such that it doesn't matter), then provision of VTG services seems a good way to offset the cost of an expensive asset that the owner acquired for other reasons. The batteries might be much too expensive for a utility to purchase for its own needs, but if they're available for other reasons, why not use them?

6) The cost of metering for VTG can be debated, but it's pretty much a non-issue, IMO. The VTG proposals I've read envisage an "aggregator" who provides the SCADA interface to the utility and is the service guarantor. The aggregator maintains a stable of 100's to 1000's of vehicle owners who have enrolled to make their vehicles available, for some number of hours per week, to provide VTG services. The link between the aggregator and its subproviders would presumably be a secure, always-on internet connection. The cost of providing that, these days, is a few dollars. The bandwidth needed is absolutely trivial.

I'm not about to challenge your statement that an HVAC with thermal storage and "as-available" electricity usage are an easier way to accommodate variability. I agree. It avoids a lot of the infrastructure hurdles that confront VTG. But there's still major capital cost associated with upgraded HVAC systems, and I'm not sure its market will grow fast enough to accommodate the growth of renewables. Guess we'll just have to see.

August, 26 2008

Len Gould says

Roger's clearly correct in his assesment of vehicle battery potential effects, though proposing aggregators for the purpose means he believes utilities are simply too dumb to compete in the retail market with Shai Agassi. (See this article on Wired) Given he could raise $200 million to just describe the future plan for one small fragment of the development of a genuine retail electrical market, it seems to me utilities are clearly missing the boat.

I know, i know. "But... but ... utilities aren't configured to be competitive..."

August, 26 2008

Jim Beyer says

Roger,

I appreciate your comments. In particular, I can see how the assets of millions of PHEVs tied to the grid, representing 1000's of Megawatt-hour storage is something that can't be dismissed so easily. Note also that, in theory, each of the vehicles also has engines which if running, could provide further power as well. Tens of millions of electric generators as well.

It would seem wise that any PHEV manufacturer might also allow for such capability; your car as emergency generator. I don't know if anyone is planning on doing this, but it seems like a way to more directly leverage such an asset. (Imagine how the problems from Katrina would have been mitigated had the city contained a few thousand PHEVs.) This might be an argument for V2G to be implemented as a more local DG. If a given site has this capability, then the utility can shut off power going to the site, knowing they can make use of their vehicle power. Maybe this is what you were referring to.

August, 26 2008

Jim Beyer says

I wish I knew the recipe for the Kool Aid that Shai Agassi sells. His plan doesn't make much sense except perhaps for some limited island-like markets.

August, 26 2008

Joseph Somsel says

Roger,

Looks like a major disagreement we have is that you think that the storage should be looked at independently of the nature of the generation resources available to be stored. I think what you want to do is postulate lots of intermittent generation and THEN consider building grid storage for it.

I'd be willing to do so in the future if there were a market structure that would effectively support independent investment in grid storage. I think we agree that the current "free market" experiments that supposedly deregulated our electric systems are not yet capable of third party investment in grid storage.

The storage we have today was indeed built under a regulated utility regime where the technocratic control of the grid was centralized in its owner. Except for its vulnerability to political interference, that system seemed to work pretty well and I've been critical of deregulation in articles here on EnergyPulse and in comments to articles by others.

Maybe I'm getting tried of that argument but I too have learned to love Big Brother and now try to look at the grid in a free market perspective. Sometimes I even embrace change! Unfortunately the current industry is neither fish nor fowl so we will continue to get crosswise in our common assumptions.

That's why I won't divorce an investment decision for storage from the performance of specific off-peak power to charge that storage. The performance of that storage depends on the performance of the generation assets one expected to charge it. It works the other way too - the economics of a generation asset changes if there is grid storage.

Load, generation and storage are coupled. That's the way any rational investor HAS to view it. Smart money will NOT play, "if we build it, they will come."

August, 26 2008

Joseph Somsel says

Len,

Are utilities just missing the boat or are the VCs throwing money down ratholes again?

August, 26 2008

Jeffrey Anthony says

Very interesting that nuclear proponents somehow feel threatened by renewable energy, refuse to understand how it works and that it does NOT require enery storage today -- and they continually point to the variable output nature of renewable energy, wind and solar in particular, as somehow indicating that energy storage must be needed to "firm up" renewable energy so that they can make those technologies fit their own views of what resources should be on the grid.

Nuclear power may indeed see a resurgence in the U.S. and Canada someday, or it may sink under its own (cost) weight as prices head upwards of $7700/kW installed cost (see: Progress Energy).

Meanwhile, wind power will continue to thrive and SAVE consumers money in the long run as fossil fuel prices continue to rise, by providing an energy resource (but not a baseload technology, capacity resource) that lowers the cost of energy to consumers. Len and Jim and their kind are flat wrong when they say wind power needs energy storage, just as they are wrong to say consumers are paying more for wind power than they should. They do not understand how wind power is being integrated into the grid today (it was the second largest form of new generation added to the electric grid in 2007 after natural gas).

The recently-completed U.S. DOE study on "20% Wind Energy by 2030" painted a very clear scenario where fast-response natural gas plants are added to provide additional capacity in the 20% wind scenario while 305 GWs of wind projects provide 20% of the energy needs of the U.S. While more fast-response natural gas plants are added in this scenario, the plants themselves are run 50% LESS and thus save 50% of the emissions from these plants at the same time. Electricity from coal-burning plants is reduced 18% and the resulting new enery mix results in significant reductions in CO2 emissions from the electricity sector with overall net positive SAVINGS to U.S. consumers. See the report at: www.20percentwind.org

Learn how wind power can be and is already being integrated into the grid in large quantities WITHOUT the need for expensive energy storage technologies. Don't buy into the myths perpetuated by Len and Jim -- who should stick to trying to figure out how to get new nuclear power prices off the ceiling -- if we can get new nuclear plant costs below the stratospheric range of $6000-$8000/kw installed costs, then maybe nuclear power can also contribute to a clean energy, emissions-free portfolio of new generation in the future as well.

For now, wind power is here, is working, is saving consumers money, and is reducing emissions as we speak.

Jeffrey E. Anthony American Wind Energy Association

August, 26 2008

Joseph Somsel says

Mr. Anthony's misdirection sidesteps the issues and analysis presented in the article. Advocates of wind and solar have been very vocal in positing the benefit of energy storage to remedy the intermittency defects of their products. In my article, I attempted to bound the problems in the real world and to provide a realistic analysis of the financial behavior and interactions.

Maybe wind has a place for natural gas substitution but that alone would not be adequate recompense to build the windmills in the first place. I think Mr. Anthony is advocating building standby natural gas-fired generation to backup the windmills his organization promotes. I would suggest he explain that proposal in more detail in a future EnergyPulse article of his own. I for one would be interested in reading it.

As to the Progress Energy cost estimates, remember that their projection is for many years in the future, in dollars at that future startup date, and is very sensitive to escalation rates for labor, materials, and land. It is also only one company's estimate. The cost of capital during the construction period is another very sensitive parameter and one that killed many nuclear projects in the Carter years when short term interest rates exceeded 20%.

According to the EIA (http://www.theoildrum.com/node/4381#more) the US got 20% more electricity from WOOD than from WIND in 2007. That makes it easier for wind to be the fastest growing source.

I'm still a bit fuzzy on this 20% mandate. Is it to make 20% of MW-hrs from wind/solar or to have 20% of our connected capacity as wind/solar or, as Mr. Anthony claims, to meet "20% of the energy needs of the U.S"? The latter is certainly even more ambitious than I thought.

As to Mr. Anthony's closing sentence:

"For now, wind power is here, is working, is saving consumers money, and is reducing emissions as we speak."

I can only add "Because the government made it so." Although I'm not so sure about the saving money part, if we take out taxpayer contributions. If we removed the government requirements and taxpayers subsidies, would we still be building windmills?

August, 26 2008

Ian McQueen says

This discussion has been exlusively about pumped water systems. I have read elsewhere about the use of sodium-sulfur batteries to store the output of wind and solar arrays. Here are two websites with information on existing systems. http://thefraserdomain.typepad.com/energy/2006/01/sodiumsulfur_na.html http://thefraserdomain.typepad.com/energy/2008/03/sodium-sulfite.html

August, 26 2008

Ian McQueen says

My posting got interrupted. Would you care to comment on the practicability of such sodium-sulfur systems?

Ian M

August, 26 2008

Al Cioffi says

I have to say that I am a bit taken aback by the "absolute" nature of Mr Somsels assertions. As a student of technology and history I agree with the poster who referenced the head of the PTO in 1899. To posit that no solution to a problem exists and then to dismiss ideas to the contrary as "unproven" and therefore unattainable is just plain wrong and goes against everything that is noble about the scientific and engineering professions.

History has repeatedly proven that when enough money and brains are applied to a problem it will be solved - Manhattan project, Lunar landing, Human Genome, the list goes on and on - and oh yes, usually with large amounts of Fed money and political support. I don't know what the final answer will be but I am gratefull there are many open minded and ambitious people on the receiving end of those funds.

August, 26 2008

Don Hirschberg says

Al Cioffi, You seem to be saying that if we only try hard enough and spend enough money we would find a solution to every problem.

I disagree. Science can tell us in advance when not to keep trying and spending. A good example are the Laws of Thermodynamics. These laws tell us that nearly all the problems politicans rant about solving with apropriations are unsolvable. Good science is knowing what can and what cannot be done.

I kinda like this version of the Laws of Thermodynamics: 1) You can't win: 2) You can't break even; 3) You can't get out of the game. I say the reason we have never found unicorns is not because we have not looked dilegently enough nor spent enough money on the search..

August, 27 2008

Len Gould says

Jeff Anthony asserts: "Len and Jim and their kind are flat wrong when they say wind power needs energy storage, just as they are wrong to say consumers are paying more for wind power than they should. They do not understand how wind power is being integrated into the grid today "

Jeff, I'll agree you're correct ONLY because I failed to add "OR a very fast acting backup generation system, such as gas turbine OR a fast-acting realtime load management system capable of compensating for the entire connected wind capacity". When all the wind generation installed in Ontario, presently 475 MW in at least 5 widely dispersed areas, can go an entire summer day's peak period generating only 1% of nameplate capacity, THEN it is impossible to argue against my re-worded assertion.

August, 27 2008

Len Gould says

It is also obvious that ALL wind generation connected to the grid should be being charged the cost of these backup mechanisms as part of their connection costs. Solar not so much because it's output co-ordinates nicelt with peak load periods and is reasonably predictable in advance, and solar thermal with thermal storage not at all.

It is GLARINGLY obvious that solar-thermal should be supported FAR more strongly than wind generation, EVERYWHERE.

August, 27 2008

Jim Beyer says

Jeff,

Hey! I thought I was one of the good guys! I'm trying to rationalize the use of wind power. I think there is one, probably. Assuming wind is randomly available, then it is not very likely to contribute at times of peak use. Therefore, it's most likely replacement resource is probably coal. That's because there isn't much nuclear around, and of the two, coal is more easily regulated to accommodate the influx. As the wind people now say (all of the time now) its an energy resource, not a capacity resource. Like Joseph, I don't even know what 20% capacity means. Is that nameplate capacity? 20% of all energy used? If I don't know, then I'm sure the legislators (that vote on this stuff) don't know either. If it's the latter, then that would imply a huge amount of wind turbines which would be difficult to use effectively. If wind displaces coal, then it's basically a carbon play, not a cost play. Coal doesn't cost very much.

Some of the wind could be displacing NG, which IS a cost play. But if it is displacing NG, then that means a lot of NG needs to be burned when the wind isn't blowing, which leads to higher overall costs. You can't have it both ways.

DTE's new nuclear plant is projected to cost 8.5 Billion, and produce 1520 MW. So that's $5500/kw.

PHEVs are a rational choice to marry with wind for two reasons. First the thing you are displacing is gasoline, which is far more expensive than coal or natural gas or nuclear power. Second, since a PHEV could be plugged in 20+ hours per day, then you have a perfect, amenable consumer for wind energy if and when it is available. I don't see why this is problematic, and makes wind people feel defensive. Note that a single vehicle might consume 20 kwatt-hours daily, whereas a 1 MW (nameplate) wind turbine at 20% utility produces 4800 kwatt-hours daily, enough for about 240 cars; displacing 250-500 gallons of gasoline daily. $1500 worth of gasoline compared with $200-250 worth of electricity. I see a lot of value arbitrage here. Wind people (and utility people) should be pushing PHEV technology further!

August, 27 2008

Jim McDowall says

Joseph, I want to pick up on Roger Arnold's comments about the use of storage for ancillary services. Using fossil-fueled generation for regulation or spinning reserves results in large amounts of fuel burned for zero net energy output - so your arguments about the relative efficiency of storage become moot when the storage is used in these applications.

The 1060 MW Goldisthal pumped storage facility in Germany was completed around 2004 and indications at that time were that the potential returns for arbitrage were small but that the plant would achieve a 3-4 year payback when used for ancillary services. In 1997 the projections for capital costs of the plant were $700/kW - hardly an exorbitant amount.

"I'd be surprised if [a pumped storage facility] could do a gigawatt scale reverse in less than 15 minutes." The fact is that conventional single-speed turbines can ramp at 4% to 6% per SECOND and adjustable-speed turbines can ramp at 0.4% to 12% per second.

You're very quick to reject the notion of CAES - "The CAES installation only stores some energy as compressed air - a good percentage if not majority of the output power comes from burning natural gas or oil." A typical heat rate for a CAES plant (BTU/kWh) is 4,100 versus 11,000 for an open-cycle gas turbine. This means that CAES will be increasingly favored over combustion turbines for ancillary services as fuel costs rise. Going further, EPRI is funding work on adiabatic CAES, which will burn no fuel and have an overall efficiency of 65%. You might scoff at this number but it looks pretty good compared with 35% efficiency for a combustion turbine.

Also as mentioned by Roger, battery storage may not be a significant factor "soon" but don't count it out. The value streams for storage multiply as it is placed nearer to the consumer, enabling uses such as voltage support, power quality and power reliability. Battery storage is also likely to be the "glue" that holds microgrids together, providing ramping support and peak mitigation for distributed generation.

The bottom line is that there is a place for everyone in the future grid, including nuclear, renewables, fossil generation, storage and load management. Let's not concoct arguments using limited scenarios to try to eliminate any of these elements from the mix.

August, 27 2008

Alok Misra says

All power systems when being evaluated are treated golbal by the methodologies of cybernatics which will consider cost of loss of network block.Cybernatics in turn is based on the type and variety of information. At this point of time there is lot of reliable info available on usage and technology of renewables and USD 1/ kw target for PV is not far off. Cybernatics also deals with the political/ economic and technological aspects of the system Who can say that in the current scenario on oil and Carbon di oxide reduction, technology systems on the fuekls will last? True they could last because the world will work for it to last. But then if a systematic cybernatically base study is done on renwables I am confident that storage systems for these energies are not only disreable but needed urgently. I have experience on such studies and my preliminary work confirms what I have stated. Detailed studies will be very surprising and reverse of the conclusions of these articeles

August, 27 2008

Al Cioffi says

Don H. What I failed to state explicitly is when humankind has been in a position of needing to solve a problem, solutions have been developed and put into practice. Clearly we all agree that our dependence on non-renewable/fossilized energy sources is a problem that must be solved, and I have great confidence that the mobilization of intellectual capital currently underway will achieve results. Chasing unicorns as you put it serves no purpose, but figuring out how to use ALL available renewable energy sources serves a great purpose. I would not out of hand discount anything. That doesn't mean that viable solutions exist in their current forms. It also doesn't mean that we stop working because there are detractors. That would be truly tragic.

August, 27 2008

Jim Beyer says

Alok,

I don't know much about Cybernetics except that Norbert Weiner felt they he'd already discovered everything that Claude Shannon had to say, but never bothered to write it down. True, $1 per Watt (I'm assuming that's what you meant) PV would change the game, but maybe not at much as you'd think if batteries stay freaking expensive. If PV made electricity "free" during daylight hours, we'd might just synthesize fuel instead of setting up battery banks. I'm not holding my breath though.

Al,

I don't think everyone agrees that our dependence on fossil fuel energy sources must be solved. Especially w.r.t. coal. Or non-renewable nuclear fuel for that matter.

Joseph,

Speaking of coal, I think one could make the case that "clean coal" so-called, is probably at least as problematic as wind turbines, yet is being pushed forcefully by it own lobby. Though they imply this means CO2 sequestration, they are vague enough so it means whatever you want it to mean.

August, 27 2008

Joseph Somsel says

Good, healthy discussion! Thanks for taking the time to read the article and the comments and providing your views.

Let me point out to Al Coffi that the two terms of the equation (as corrected!) represent a law of thermodynamics and a law of either economics or accounting, I forget which. Yep,I'm an absolutist as charged. If you find an exception for either, let me know and we'll go talk to some Silicon Valley venture capitalists ASAP.

For Jim, I don't doubt the ramp rates you mentioned - hydro does that stuff very well. However, I specified a REVERSAL. I doubt that your ramp rates are good for a change of sign, The water in the penstocks has substantial inertia and there will some electrical switching involved. Maybe you could design immediate reversal in, by using one hydrogenerator unit producing while you're simultaneously pumping while on a separate penstock, but that's probably an unnecessary expense.

As to the German example of a pumped storage unit paying for itself from ancillary services, I'd suspect out that ancillary services are in high demand in Germany because THEY BOUGHT TOO MUCH WIND! That storage is the price they pay for making the mistake I'm warning against.

Also, for what its worth, I got my latest info on CAES from the Oil Drum in July:

http://canada.theoildrum.com/node/3473

For Ian, batteries are good and better batteries are better. My battery interests are for standby service in nukes (old style lead-acid) and for electric vehicles. Both are narrow purpose and have differring requirements. But no battery will ever be perfect. It will have electrical losses and it will cost money so the basic equation will apply. Ultimately, a battery designer is limited by the electrochemistry of the periodic table.

Clean coal - whoopee. Lowering emissions of pollutants is always better but never free. Carbon sequestation appears to me to thermodynamically expensive - that lowers the electrical output, increases the coal consumption, and increases operating and capital costs. Further work will just make nuclear that much more attractive.

Let's talk costs again. $1/W PV sounds good but only covers the cells but not installation labor, supports, power conversion, land rents, etc. I'm underwhelmed and suspect little ultimate market penetration without government coercion. Again, I'll bet these high nuclear price tags are in future dollars at plant startup, in what?, 2018 or 2020?

Go to this site and play some games with inflation rates:

http://www.westegg.com/inflation/

I tried a current $5500 cost in 2007 and worked back 12 years to 1995. That would have been $4000 in 1995 dollars.

For a real eye-opener, try a plant announced in 1970 and completed in 1982 at $5500. The 1970 dollar projection would have been $2200.

Maybe what these high cost estimates are trying to tell us is that the estimators want to cover their bets by using inflation rates seen in the recent past, like during the Nixon and Carter Administrations.

Len - solar thermal storage does sound like it has some prospects and would be somewhat more reliable on a day-to-day scale. But I just saw where a new plant cost out at 17 cents per kW-hr in Nevada These things have to be material-intensive so the avenues for cost reduction are few.

My purpose in writing this piece is to clarify public thinking on electricity storage economics. I love Jim B's exclamation - " I thought I was one of the good guys! I'm trying to rationalize the use of wind power." I hate to sound cynical, but "Been there, done that." I've been looking hard at these alternate energy proposals for almost 40 years now. If I could find one worthwhile I'd jump on it and abandon nuclear and make some real money! However, nuclear remains the best fossil fuel replacement out there.

August, 27 2008

Kent Wright says

Len, If I may ask, where do you get your information supporting your assertion that solar output fits “nicely with peak load periods”? My source of solar data, TVA, indicates solar production peaks at solar noon ± about one hour.

[http://www.tva.gov/greenpowerswitch/solar.htm, click on “how much power are we generating?” And then click on any of 16 sites from which to view historical and up-to-date real data, not projections.]

From early sunrise to around 9 to 10 am and late daylight say after around 3 pm, the output is anywhere from next to nothing to half power and back to next to nothing --- and that’s on days of no cloud cover. Cloud cover, even sporadic broken cloud cover, can blow the whole day’s output to fractions of potential. As for load peaks, they occur twice a day in the TVA service region, one in the morning from around 6 to 8 am and one in the afternoon from around 4 to 6 pm. Winter and summer peaks are about matched in load and time of day, but of course winters are more prone to cloud cover.

I can see a reasonably good case for solar thermal, but even that is solar + storage where the storage could presumably cover the afternoon peak load after 2 to 3 good hours of charging, but not both am and pm. A couple of days or more in a row of cloud cover would make for essentially a dead battery or cold heat sink for which there is no predictable time of recovery on solar alone. I suspect that in the long run, recharging, i.e. reheating of solar thermal storage or filling any other large scale storage device will be no different than the current large scale pumped storage facility at Raccoon Mountain, and that is by baseload coal and nuclear done mostly at night. Not trying to discredit solar’s potential, just trying to look at it realistically. I welcome any realistic view which could explain how solar would fit into the mix intelligently and economically.

August, 27 2008

Al Cioffi says

Joseph, I absolutely agree that nuclear must be embraced as the number one best option. I do not however believe that there is no room for other renewable, intermittent options. I guess I don't believe in silver bullets and believe it is better to explore all options. To what percentage these options contribute to overall grid supply is anyone's guess, but I know quite a few VC's that have placed big bets, all without seeking your input. Most of them have no clue, but some are very savvy and shrewd and I suspect will make an impact

I guess I also have the perspective that alternatives and storage are not necessarily best used as a centralized power source, but may have better application as distributed sources. This is where PV is making it's inroads. If PHEV's catch on and PV conitues it's local penetration it is easy to envision a large percentage of homes and businesses with readily available local energy storage, making the locally generated PV power dispatchable. I can also see that yet to be developed improvements to large scale storage eventually makes wind farms that much more viable.

There are ideas that deserve to have R&D funding because the cause is worthy. Not all will work out, but I think it was Einstein who said If we knew what we were doing it wouldn't be called research. Some will eventually become viable and become PART of the electric grid. I don't see this as an either/or situation.

August, 27 2008

Al Cioffi says

Joseph, One more comment on batteries. I am close to several battery manufacturers that have advanced programs well underway and your comment about being limited to the electrochemistry of the periodic elements is true. But the nanoscale tehcnologies that have been demonstrated in the laboratory are producing results that no one would have thought possible even three years ago. Most of the money is going into perfecting the manufacture of these materials and how to best package them as part of an effective battery system. Most of this is driven by the electric vehicle. I suspect that within 3 years we will begin to see eyebrow raising battery performance and within ten years we'll see breakthrough performance as these materials get better and better. Think Moore's law but on a slower pace.

August, 28 2008

Don Hirschberg says

Those who know me will wonder why I have not brought this up before: Too many people. I say that unless we drastically reduce world population all our other attempts to "save the planet" are futile. Life on this planet has been based on oxidizing carbon-hydrogen molecules. Whether it's worms or elephants or coal fueled power plants. (For rigor I suppose I should exempt some tube worms in the plunging plates off western South America that perhaps use a sulphur cycle.)

Outside of the oxidation of organics (burning carbon-hydrogen moecules) what has science and technology given us outside of wind and flowing water which we always had? As I see it: exactly two, that is fission and photovoltaic. As photovoltaic supplies an infintisimal percentage of our power that leaves fission as our sole claim for success.

Don't tell me how to supply 1% of our by some new clever scheme. Tell me how to reduce world population.

August, 28 2008

Len Gould says

Ken Wright "If I may ask, where do you get your information supporting your assertion that solar output fits “nicely with peak load periods”? " -- Ok, perhaps you'd prefer "A lot better than wind"? 1) Whatever you might like to assert regarding what you think about solar's output curves, it's still obvious that whatever power it does produce is produced at exactly the same times as peak air conditioning loads are happening, or perhaps slightly before. 2) When I say solar power, I ALWAYS mean concentrating solar thermal, and expect that to remain the case until the Optical Rectenna arrives.

August, 28 2008

Jim Beyer says

I agree with the technical assertion that nuclear makes more sense than alternative energies. So why even pursue them, as Joseph asks? Well, there are practical and political problems with nuclear power. Note the lack of a long term storage facility. Note the huge economies of scale needed to make nuclear viable, and even then, it takes 40 years for the plant to be paid off.

I think the biggest problem with nuclear power is the poor track record humans have in general with managing monolithic entities. They recently convicted one guy for the Davis-Besse safety problem. A single guy! Yet distributing responsibility for decisions results in bureaucratic slowness. We as people simply haven't figured out how to do this as well as needed despite our best efforts. (I don't think Bear Stearns WANTED to vanish from Wall St. but that's what happened.)

There is a subtle vulnerability that creeps in when adopting such monolithic strategies. The benefit, of course, are the huge efficiency gains. Nuclear power, as used, sits closer to this edge than I am comfortable with. To be fair, I think it can be managed well. Look at the French (who da thunk it?). In the US, huge nuclear fears need to be overcome. Our problems at Three Mile Island didn't help, but Chernobyl probably would have created the same sentiment even without TMI.

I think in general nuclear proponents don't acknowledge the huge non-technical barriers to forwarding the technology, logical or otherwise. Maybe a more distributed system is more palatable to the human psyche. We tend to have an innate fear of Big Brother, probably with good reason. Is this worth a few cents per kw-hr?

Anyway, so that's why we waste our efforts on energy storage. PHEVs (needed because of oil depletion - a separate matter) fill the bill well enough for the near future.

August, 28 2008

Roger Arnold says

In the spirit of Jim's comments above, I believe that nuclear power would be the most economical and environmentally benign option for utility-scale central power generation. But that's assuming two things: 1) sufficient public acceptance to enable production of standard designs in large numbers, with minimal licensing hassles; and 2) that society will hold up well enough in the face of assorted crises that reliance on the central power model continues to make sense.

I realize that the latter point is usually taken for granted in "serious" economic and business discussions. But I, for one, am no longer quite as willing to take it for granted as I once might have been. The world is starting to bump up against some very real limits to growth, and competetition for water, good farmland, and remaining high grade mineral resources has already turned nasty in places. I'm not all that sure that violent competition will remain confined to a few "hot spots" in Africa, the Mideast, and central Asia, or that social disintegration is nothing we in the privileged West need worry about.

Given what appears to me an increasingly uncertain future, the idea of small, cohesive communities equipped with their own renewable energy resources looks pretty appealing. Renewables allow us to distribute our eggs in widely dispersed baskets. In times of uncertainty, that's simple prudence.

August, 28 2008

Roger Arnold says

To amplify on Len's response to Kent Wright's question regarding the timing of peak usage, what matters to utility companies is not so much the daily peaks that Kent talks about; it's the highest peaks over the course of a year. That's what determines the total amount of generating capacity that the utility must be able to draw upon.

For much of the US, the highest demand peaks occur in the early afternoon on hot summer days, when air conditioners are operating at full. At those times, solar power output is pretty much guaranteed to be at its peak as well. (If the day were cloudy, it would be cooler and wouldn't be a peak AC day.) Hence the utility is able to count almost the full nameplate rating of the solar installation against its required generating capacity.

August, 28 2008

Joseph Somsel says

Solar insolation and hence peak PV output occurs from about 10 am to 2 pm with steep shoulders before and after. Steering the panels can help but adds greatly to the costs and maintenance.

Here's a typical California summer day load curve (link may be real-time)

http://www.caiso.com/outlook/SystemStatus.html

As of this writing for late August, the system peak is out towards 4 pm, after the PV output declines. The peak is even later in the afternoon, if memory serves, earlier in the summer. Of course, insolation is higher near solstice too.

As to the population issue, I'll leave that to others to debate and to make their own personal decisions. There does seem to be a strong corrolation between affluence and low birth rates with energy abondence as the prime cause of affluence.

August, 29 2008

Ferdinand E. Banks says

Not convinced Roger that "small cohesive communities" equipped with renewable energy resources are better than small cohesive communities like those in Sweden getting at least half of their energy from nuclear. Of course the ignorant Swedish prime minister pronounced nuclear "obsolete", and many in the TV audience agreed, but I think that intelligent people can ignore that kind of thinking.

Actually, the nuclear story is just beginning. Once they start building these items in large numbers in Europe and maybe North America, they will have the technicians and engineers required for minimum cost construction. As for the security problem, I don't think that I'll bother with that at all. There was a time when I was a diligent reader of mainstream French newspapers, and I cant recall one occasion when security issues cropped up, although France is the largest producer (percentagewise) of nuclear energy.

The best arrangement as far as naive me is concerned is for nuclear opponents and nuclear boosters to cooperate: increase the amount of nuclear and use the 'profits' to promote the kind of high quality communities that nuclear opponents ostensibly desire. And, yes, there will be profits, as the Swedish company Vattenfall would assure you if they could be relied upon to be truthful in matters of this sort.

Fred

August, 29 2008

Kent Wright says

Well Len, having asserted nothing in my posting, your sarcastic non-answer to my question leaves me a bit puzzled. It seems so out of character from your usual high quality remarks. So I ask again, what exactly is the evidence to support your assertion that solar output fits “nicely with peak load periods”?

I merely presented evidence that solar peaks and demand peaks are not well matched in the TVA service region and they are not. That’s not an assertion, that’s factual data. (The TVA service region is the sunny mid-Southland, mostly TN and parts of each surrounding state). The TVA website I posted has a wealth of historical data, in the form of historical charts on virtually every day in the ongoing lifetime existence of 16 operative PV solar sites.

In researching the data, one rarely finds totally smooth curves for multiple days in a row and even rarer, in fact virtually non-existent, is a day’s output peak that even comes close to the nameplate capacity rating. Around 85 to 90% was about the best I could find on completely sunny days, i.e., no broken up curves due to random clouds and summer pop-up thunderstorms which characterize the region. Much like Canada, the winters around here are characterized by cloudiness for days on end.

About once a year TVA publishes the annual integrated kw-hours of each solar unit. I have crunched the numbers and found that all 16 installations taken together have a rather dismal integrated capacity factor of around 13%. Again, no assertions -- the data are there for all to see and to comment upon so please don’t accuse me making up unsupportable assertions.

As for solar thermal, I think I was clear that I agree that it has promise. Upon careful consideration however, I think even you might agree that whether it is a PV solar or a concentrated solar-thermal system, a mid-day thunder boomer is disruptive to the solar output, be it heat or electricity, and that would be true regardless of whether the output is sold immediately (PV) or stored for later use (thermal heat sink, battery, pumped storage, you name it). I further note that solar resources in TN are about the same for the entire tier of our northern states that touch Canada so I will also ask of you to state why, if so, Canada would be any different. Data, not opinion, will be much appreciated.

August, 29 2008

Kent Wright says

(Part 2) Moving along here without speculating, I can safely say that the charging of a storage component for say 3 good hours of a day (compromising with Joseph’s 10 a.m. to 2 p.m. in California) can only yield < 3 hours of steady drain on the stored energy at the same rate later in the day. In other words, with storage you can service only ONE load peak per day, not two as they presently exist in the mid-South. A day or two without sunshine around here (and Canada too, I suspect) would throw the dependency over to the more traditional and reliable back-ups until solar-thermal could catch up.

Perhaps Canada has a similar ONE massive load peak per day like California (thanks Joseph for the marvelous website giving California load data), which would seem to fit nicely with solar thermal, but I’ll remain skeptical about other climates until I see some real data.

And Roger, just because my referenced data points were accumulated one day at a time, that does not mean that I was overlooking the obligation of existing utilities to meet the maximum demand whether on a daily basis or a given year’s highest peaks. Typically in the TVA area there are two annual highest peaks, typically for a few days in July and a few days in January, and they are rather evenly matched albeit lately with summer loads edging upward to slightly higher than winter.

But your comment touches upon another reality, not speculation, and that is this: only the utilities have the very large and expensive obligation to meet public demand WHEN DEMANDED and they do it with reliable generators and a reasonable good, but aging, T&D system. In my humble opinion (yes, I will go out on a limb here) any significant changes for the better in that situation are still largely imaginary.

BTW, I would further argue that all this talk about new generation of ANY kind, traditional or renewable, detracts from the far greater problem of a nearly obsolete transmission and distribution system. We absolutely DO NOT have the infrastructure to support the vast amount of electricity that will be needed to meet future growth, much less the needs of the transportation sector if there is a massive shift to plug-in hybrid electric vehicles (PHEV). Unless T&D are vastly improved upon to accommodate far greater supply and demand, charging forth with large-scale new generation is pointless.

And finally, just for the record Len, I don’t like to make points in the form of questions. I asked my question for one simple reason…. I want to know. If my line of questioning makes you uncomfortable, I suggest you simply ignore the question and refrain from sarcasm. I hope I am correct in assuming that you were only being humorous in mentioning the “Optical Rectenna” you have ordered. So in the same vein of humor, not disrespect, I will just say I hope it comes with batteries. I shudder to think of where you might have to plug it in. ?

September, 01 2008

Rod Adams says

Joseph, as is often the case, has stimulated an interesting discussion through the use of simple, straightforward math that disagrees with some people's favored technologies.

Many people who remain in the anti-nuclear or nuclear skeptic camps are focused on the cost projections being offered by the vendors and utility customers for large, central station nuclear plants.

There is an option that is increasingly gaining some attention in the market and interest from financial backers - smaller, simpler nuclear plants in sizes ranging from a few tens of megawatts to about 200 MWe. These devices avoid some of the complexities associated with traditional plants, they side step some of the supply chain constraints on large parts, they make operator training less of an issue, they take advantage of the economy of series production, they avoid some of the transmission system requirements for the large plants and they retain all of the fuel cost advantages of the large nukes.

Their major disadvantage is that they are different enough to cause some degree of uncertainty about whether they will fulfill their promise, but at least the financial risk per unit is significantly lower.

If you want to hear some of the entrepreneurs involved in projects like NuScale and Hyperion Power Generation, you can find recent interviews with the CEOs at The Atomic Show Podcast (http://atomic.thepodcastnetwork.com). You might also want to look through some of the posts on Atomic Insights - search for "small nuclear power".

Disclosure: I have been a fan of small nuclear power plants for more than 26 years. I founded Adams Atomic Engines, Inc. in 1993 to do what Hyperion and NuScale have done more successfully - so far - with regard to establishing a real capability to produce the units to meet customer needs.

September, 01 2008

Mathew Hoole says

Geez these discussions annoy me!!!

The first essential requirement for baseload energy after the source is reliability. If it is not reliable or for argument sake cannot strategically and reliably deal with peak periods it should not be considered. - Get this into your skulls some of you!!!

You don't need to be a scientist or use fancy math (no offense Joseph) to understand common sense.

Wind and solar are fantastic that they don't use fuel. However solar panels and windmills they are not made out of thin air and require resource exploitation to manufacture. They also require a lot of land to implement, competing with housing, agriculture or (re)forestation ie regarding high density housing, commercial centres etc. This of course makes wind and solar very "unfantastic".

How good is solar in a place like Finland that has a very low sun and short days in winter. How effective would a gridded solar and wind solution be in winter with cloud covering your nation and no wind? Utterly useless I tell you!!! Even countries like the US can have cloud covering most of the landmass AND have little wind.

Then we have hybrids. Granted Thermal Solar plants can offer reliable energy in a suitable landscape. However most people don't live in a desert; and why pay for 2 power stations (ie gas and solar) when you only need one?

The longer politicians behave in a spineless manner appealing to the activist vote, and the longer the privileged intellectuals distort fact with self interested or political fantasy, when they should be ethically educating the public, the harder it will be to do the right thing.

Reliable and affordable energy is critical to a developed/developing society. There is a proven link between propserity levels and birth rates. If you want to stabilise world population you can either do it passively ie increase living standards, or by breaching civil liberties (or worse) e.g. forced birth control. Breaching civil liberites will of course create more resistance.

The conservative side of politics is not faultless here (e.g. GBj), but most of the rot comes from the left. Get your act together guys. Display a bit of honesty and integrity, especially the intellectuals granted such promincence and influence in society.

Getting back to baseload energy. If it is not reliable it should not be considered!!! PERIOD!!!

Cheers

September, 02 2008

Roger Arnold says

Rod,

If anything, I think you understate a key advantage of very small nuclear reactors like Hyperion's. "They retain all of the fuel cost advantages of the large nukes." As I understand it, they actually do considerably better. The fuel cycles they use achieve very high burn-up; at least 10x that of current generation reactors. They have to achieve high burn-up in order to maintain output for ten years or more without refueling. Hence much less fuel needs to be mined, and it becomes feasible to exploit much lower grade ores.

Of course, large reactors could and presumably will be developed to achieve similar fuel burn-up, but they appear to be on a slow path. Nobody wants to push them while fuel for current reactors is so cheap. The financial risk and the technology hurdles are too large. The small reactors and "nuclear batteries" have a big advantage there because, as you noted, the investment per reactor is so much smaller.

Small reactors offer pretty much all of the advantages claimed for distributed generation, and then some. They're close to their loads and don't require long-distance transmission. They enable CHP. And most of them, AFAIK, are designed for variable output. So they're not limited to baseload, and don't require auxiliary generators for peaking.

That's the promise, anyway. Now we just need to see if they can deliver.

September, 02 2008

Len Gould says

Ken Wright: I respectgully propose that we can agree to disagree on practically all your points.

September, 02 2008

Len Gould says

Ken: Just to help. eg. in Tennesee in August, a house roof properly built and carrying 150 sq m of modern "static tracking trough" collector system as its roof (call Duke Energy) will recieve at minimum 600 kwh / day of solar energy, free after amortization. Up to you to figure out the correct mix of absorption refrigeration, stirling or renkine electrical, thermal storage. You should be able to satisfy electrical requirement aside from A/C and PHEV with even a 4% net collector to engine/generator efficient unit, though 10 to 15% electrical, waste heat to home hot water and absorption refrigeration should be easily do-able with present technology. Therefore I cannot see where you get your "insufficient available solar energy" claim. The problem is "excess sufficiency of naysayers like yourself killing venture investing".

US Monthly Average Daily Insolation - NREL

September, 02 2008

Len Gould says

(That's "rankine" of course, not "renkine").

And btw, that 600 kwhr/day mostly arrives "during" your peak, if not precisely at your maximum. A bit of short-term thermal or grid-wise PHEV storage would resolve that. Agreed, it's a bit different than how "the market" would like to do things, esp. incumbent utilities.

September, 02 2008

Jim Beyer says

Mathew,

I appreciate your sentiment. The reality is (right or wrong) that coal is becoming less favored as an energy source for electricity generation in the U.S. This is likely due to the threat of pending regulation in the future. Nuclear has been stagnant, with no new plants to come on line since when? '92? That is slowly been revised, but chiefly due to concerns about climate change. Since large nuclear plants can't vary output quickly, there is a practical limit to how much baseload we can accommodate with nuclear in this country. I'm not sure what that might be. France is close to 90% nuclear, but they can export much of this electricity (presumably to the green-loving, wind-loving, solar panel-buying Germans). I'd say if we got above 50-70% we'd start to have problems.

In lieu of (or in addition to) all of these nukes, a reasonable tactic is some kind of solar technology that can fit on our roofs and provide at least some capability for electrical generation (or cooling) to deal with peak energy times in our cities. Such technology would be competing against 30-35 cent per kw-hr electricity, and would tend to work fairly well at approximately the times of concern (Ken's comments notwithstanding). From that standpoint, one could see some utility in such a concept, even in the cold eye of economic reality. The DG aspect of local solar would also mitigate transmission concerns of a society that continues to demand more electricity.

September, 02 2008

Joseph Somsel says

One would think that smaller nuclear reactors would be better but the critical metric for buyers is $/kW. In this the economies of scale are powerful. For example, a 10% power uprate I ballparking came in at $600/kW.

Economies of operating scale are almost as important. Consider all the staff required just for the NRC informational reports. A 100 MW plant has the same regulatory burdens as a 1600 MW plant but smaller sales to spread those costs over per year.

The pebble bed concept will have to address the capital cost issue to be economic in the market. The operational costs are addressed by building and operating the reactors in 10-packs.

Still, I'm liking the pebble bed more and more since its first costs do seem surprisingly modest.

Rod - thanks for the compliment. I do try to oick topics that need some public debunking. There's little need for the same-o-same-o. Fortunately, most of this crowd are willing to test their beliefs against logic and facts and to think issues through.

BTW, I've been posting on AmericanThinker.com of late on more political and less technical topics but still with an energy hook.

September, 02 2008

**** **** says

Joseph has the last word at this point. However I want to inform those interested, that CAES for Bulk Energy Storage using Wind energy or any energy source at the right price is a very competeitve technology. Such systems from 100MW to 400 MW generating capability or multiple units operating from a large storage cavern, can be built for lower $/kW than a Combined Cycle plant today. Including the storage resevoir the investment cost would be about $850/kW with a capability of 8/10 hours generation 5 days a week. The many GT's used to support wind can be re-utilized at storage facilities. The fuel consumed by the 85 MW GT will deliver in excess of 220 MW using the stored air.The equivalent heat rate for the fuel used is equal to 3850 Btu/kW/hr.Stored wind energy is delivered with no combustion products.

"A LEADING power company has claimed wind energy is so unreliable that even if 13,000 turbines are built to meet EU renewable energy targets, they could be relied on to provide only 7 per cent of the country's peak winter electricity demand. E.On has argued that, during the coldest days of winter, so little wind blows that 92 per cent of installed wind capacity would have to be backed up by traditional power stations". This scenario will also happen here in the USA--the rate payer will bear the brunt of increasing power costs. Septimus van der Linden.

September, 02 2008

Jeff Presley says

Len, could you please clarify your comment about the 600Kwh/day power? You're not saying that the energy PRODUCED is 600kwh, but rather that 600kwh worth of raw solar arrives on the roof? Unfortunately the link you provided referred to this link to back itself up, which produces a 404 error: http://www.nrel.gov/gis/il_csp.html

Nrel has a decided skew towards the southwest for solar, and seems to talk more about parabolic troughs than static, but you might be looking elsewhere than I.

September, 03 2008

Len Gould says

Yes, the 600 kwh is raw daily insolation in August for 150 sq m of 2 axis tracker, which is how a well-oriented collector with moveable trough would work. Electrical energy produced per day would be that times overall system electrical efficiency, which should easily achieve at least 4% required to provide the 36 kwhr/day needed to supply the typical 1.5 kw average load of a north american home. The big advantages of solar thermal such as this over PV or wind etc. are a) can use stored heat as a battery, reducing the cost of the engine-generator, if grid exchange is available. Increase engine size if not. b) can use waste heat from the system to provide both home hot water, space heating, and driving of an absorption refrigeration system. Some engineering required of course.

Not sure why the link fails for you, Jeff, it works to get to the August data from the following list. US Monthly Average Daily Insolation - NREL

September, 03 2008

Len Gould says

Re NREL being "oriented to the south-west", I suspect they're simply going for the low-hanging fruit first. Why try to pitch installations in Tennessee when there's still opportunities unexploited in Phoenix?

September, 03 2008

Len Gould says

(sorry, that should be "6% needed". Was calculating a 1 kw load originally)

September, 03 2008

Kent Wright says

OK Len, as I repeat what I have stated earlier that solar-thermal has some promise, I remain doubtful that it has great viability anywhere but in the North American Southwest. And since you brought up the subject, let's talk it out with a little respect.

The costly additive of storage is the only way put PV solar on the grid just to cover a similar, but less than equal number of kwh’s of generation over a short period of the day. Therefore, I do assert based on evidence that it is unwise to wedge solar into grid service at-large. Instead, find off-grid uses that are not time-of-day sensitive and that can tolerate intermittency, say, desalination or hydrogen production at discrete locations.

Be that as it may, your 600 kwh per day data for Tennessee is a very nice and believable AVERAGE for a 150 m² solar unit with 2-axis tracking capability (2-axis tracking is another costly additive). The trouble with solar averages, however, is that they disguise the numerous days, even in August, when solar output is just a small fraction of the daily average, at which times a reliable back-up is needed. In other words, on any given day in TN you can’t depend on a solar unit to produce the average amount.

If you are counting on thermal storage of solar energy to be the reliable back-up, would you at least agree to agree that the number of kwh’s in storage is limited to < the converted solar energy generated due to natural losses and inefficiencies? So let’s say that on a good day of sunshine you do store your 36 kwh’s. How many days are you counting on for the one day of stored energy to provide? TWO days without sunshine would surely deplete the stored energy (assuming a lower consumption rate) and prolonged days of low sunshine upset the apple cart big time.

Obviously, we can’t tout any one source as a panacea or even an alternative to the exclusion of others. The answer lies in an intelligent and diverse mix of sources in conjunction with an improved grid. Improving the grid alone and gaining efficiencies in distribution could obviate the need for some number of new generators and make better use of the ones we already have. This is also a good time to implement high voltage DC (HVDC) on a larger scale than presently exists.

So you see Len, labeling me as a naysayer is meaningless because you don’t know me and besides, name-calling is beneath the dignity of this forum. As a gentle reminder to gentlemen, this is an open discussion which could influence a rational energy plan, not a contest between pro-nuclear and pro-solar advocates. I even share your enthusiasm for solar-thermal, but I also see that overcoming the limitations will be incredibly costly.

The “Grand Solar Plan” recently portrayed by an article in Scientific American (December, 2007) as the potential displacer of virtually all other sources is optimistically estimated at costing around $460 Billion USD, which is admitted by the authors to be impossible without unprecedented government subsidies and large-scale storage. Completion date is guessed at around 2050 at best. It is without a doubt a noble venture, but that's a lot of eggs to put in one basket.

Implementation of the GSP would require covering around 46,000 square miles of the SW and also installing a massive grid which is presently non-existent in order to connect the proposed vast array of solar collectors (a mix of PV and S-T) and then reach out over many hundreds of miles to serve those areas with large populations in the more livable regions. Where population centers do exist in the desert and near-desert regions, roof-top solar would add a small fraction of the total. Nevertheless, we are talking about a source with PV capacity factors (assuming 2-axis automatic tracking) of around 30 to 35% in the proposed source region --- still not likely to meet all needs without reliable back-ups

If you have some good historical numbers for S-T capacity factors, please post them. I will be pleasantly surprised if S-T capacity factors are greater than PV simply because you can’t store any more energy than is produced. The benefit of S-T is simply the extending of availability of solar for a few hours and perhaps smoothing out grid power during the afternoon peaks. This would indeed make S-T a useful supplement, if we can afford it.

Here is where I found my data to support solar CF calculations: http://rredc.nrel.gov/solar/codes_algs/PVWATTS/version1/US/US_text_only.html.

September, 04 2008

Roger Arnold says

Kent, I'll jump in here with my own replies to your comments above -- even though they're addressed to Len. (Len, of course, can answer for himself, if he hasn't run out of patience.)
The costly additive of storage is the only way put PV solar on the grid just to cover a similar, but less than equal number of kwh’s of generation over a short period of the day.
"Similar, but less than"? What's your rationale for that? And why "a short period of the day"? There is nothing whatsoever that I can see that would preclude putting 100% of the solar input into heat storage, for generation as needed over the course of the following day (or week, if the thermal store were large enough and sufficiently insulated).

This seems to be a central point of misunderstanding, as you've referred to it several times. We ought to get it cleared up.

The trouble with solar averages, however, is that they disguise the numerous days, even in August, when solar output is just a small fraction of the daily average, at which times a reliable back-up is needed. In other words, on any given day in TN you can’t depend on a solar unit to produce the average amount.
So? What's your point? Of course you need backup. In the solar thermal plants that are the most cost-effective solar plants currently operating, the backup is an alternate gas-fired heating loop for the thermal oil. That's all. The added capital cost is almost nothing. It feeds into the same system as the solar heating loop; thermal store, steam boilers, steam turbines, and generators are all common.
If you are counting on thermal storage of solar energy to be the reliable back-up, would you at least agree to agree that the number of kwh’s in storage is limited to < the converted solar energy generated due to natural losses and inefficiencies?
I can't answer for Len, but I certainly would not agree with that. We're back to that central misunderstanding. Let's be clear: in a solar thermal system, 100% of the solar input is used to heat a specially formulated thermal oil. The heated oil goes an insulated tank. Some or all of the incoming oil may be routed more or less directly to the steam boilers to generate power, but it doesn't have to be. Input and output are completely decoupled. The only limitation is the size of the storage tank. For economic reasons, I believe it's usually limited to storage for a few hours of generation, but that's a plant optimization issue that depends in part on the price of fuel and the availability of other sources within the regional balancing area.
Obviously, we can’t tout any one source as a panacea or even an alternative to the exclusion of others. The answer lies in an intelligent and diverse mix of sources in conjunction with an improved grid. Improving the grid alone and gaining efficiencies in distribution could obviate the need for some number of new generators and make better use of the ones we already have. This is also a good time to implement high voltage DC (HVDC) on a larger scale than presently exists.
That I agree with. Except that a mix of sources and an improved grid are only half of the solution. The other half is more extensive development of discretionary loads and energy storage systems. (An energy storage system representing a combined discretionary load and dispatchable generation.)

September, 04 2008

Jim Beyer says

Perhaps slightly off topic (but not really), but it occurs to me that another viable use of solar/wind power would be for carbon capture & storage by pulling carbon dioxide from the ambient air (google Klaus Lackner). I'm a bit tepid about CC&S, but given the likely adoption of cap and trade or some kind of carbon tax, I can see a play here. The advantages (over capturing CO2 directly from a coal plant) are:

1. Overall carbon emission is lower, because no extra coal is burned to fuel the parasitic capture technology.

2. Precious, on-demand power technology is 100% devoted to power generation, not CC&S.

3. Intermittent nature of wind power does not impact on CC&S.

4. Wind-driven CC&S is more mobile than billions of dollars of capture technology built into a single plant. Wind farms can (to some extent) move to places advantageous for storage. Do not need to be near places of power demand.

The obvious disadvantage is the lack of a concentrated CO2 source. But this is more of a membrane/area issue, and not really an energy issue. The main problem is the energy needed to separate, move, and store the CO2.

But what this is really saying (along with many other posts) is that this whole topic is a bit of a canard. There is no real issue with energy storage with respect to intermittent sources in any macro sense. If and when renewables penetrated the grid to the extent that intermittency became a problem, there are myriad ways to the system to adapt and make use of the power available. Smart Grid technology, PHEVs, and perhaps CC&S all point to viable alternatives to implementing energy storage per se.

September, 04 2008

Joseph Somsel says

Jim,

You continue to put the cart before the horse. You WANT wind and you're willing to force consuming or storage investments to use the power produced. That's "push marketing" rather than the normal "pull marketing."

My issue remains - wind doesn't serve the customer. Likewise the "smart grids" intiative doesn't serve the customer. You continue to insist that shortcomings in your proposals (cost and intermittancy) can be accomodated by even more investment.

In the end, advocates of wind and solar are trying to force their proposals upon the public in ways that are, ultimately, deceptive and self-interested. I wrote this piece to expose one of the bogus claims.

September, 04 2008

Jim Beyer says

Joseph,

I do not want wind. If anything, I am somewhat negative about wind. I find its overall value somewhat suspect. But even if wind (or solar thermal) is around, you don't need much push marketing to sell it. There is considerable "pull" from the prospect of PHEVs. PHEVs are motivated by oil depletion, not climate change, and not even the prospect of more renewables. Likewise, the smart grid is motivated by higher overall costs pushing for greater efficiency in the grid, including peak shaving. Both of these investments will occur with or without wind or solar.

Your issue was energy storage. That was the title anyway. There are many valid concerns about wind and solar energy. But energy storage, at least for the foreseeable future, does not seem to be one of them.

September, 04 2008

Len Gould says

Just to add a bit to Roger's excellent post.

Kent: "but I also see that overcoming the limitations will be incredibly costly." -- I refer you to the excellent Assessment of Parabolic Trough and Power Tower Solar Technology - Cost and Performance Forecasts -- Sargent & Lundy LLC Consulting Group Chicago, Illinois. Just to quote a final conclusion "

• Assuming the technology improvements are limited to current demonstrated or tested improvements and a deployment of 2.6 GWe of installed capacity by the year 2020, tower costs should be able to drop to approximately 5.5¢/kWh

• Assuming the projected technical improvements are achieved by an active R&D program combined with incentives and deployment of 8.7 GWe, the tower costs projected by Sunlab of about 3.5¢/kWh could be achieved. "

Analysis of trough technology comes up similar, costs in both technologies depending somewhat on amount of stoage included in the projects. With these conclusions in hand from very knowledgeable and reputable independent engineering firms, I simply fail to see where you come from regarding solar.

With all due respect, of course.

September, 04 2008

Len Gould says

I note as well that the thermal storage systems presently in use in a couple of the large solar generation technology demonstrations only loose about 0.01% of storeg energy / day, meaning there is no real limit to the the amount of time energy can be stored. They're also using "sand and gravel" as the thermal storage medium, and "Overall, storage losses are slightly larger at the trough plant; however, the storage thermal efficiency is still greater than 99%."

September, 04 2008

Len Gould says

(I meant that to read "loose less than 1%")

September, 04 2008

Jim Beyer says

Is heating the oil with NG really a good idea? Assuming 100% heating efficiency, 90% transfer efficiency (oil to steam) and 30% steam efficiency (to electric), that leaves about 27%. Not too bad, and the capital costs are favorable. But this is much less than a combined-cycle NG plant running over 50%. You'd have to examine that pretty carefully to assess whether you'd still be better off with a separate NG plant.

On the other hand, if you heat the oil with something less utile, like biomass, then you might be able to make a better case. The fuel is less expensive (though more problematic to obtain) and the comparative efficiency for other uses is not unfavorable.

September, 04 2008

Len Gould says

Jim: I'd expect a "good" system would use a combination of an aeroderivitive turbine generator with the exhaust heat from the turbine used either to generate steam directly for the solar station's steam turbine or perhaps to heat the station's thermal fluid.

September, 05 2008

Joseph Somsel says

Jim,

Your analysis of solar thermal is a huge contribution - thanks!

September, 07 2008

David Laurence says

Reliable energy sources are definitely a most important factor to consider in this discussion together with clean and carbon-free energy produced wholly within our own country. Without a doubt, the Sun is the most reliable and safe energy source on the face of the globe. We just have a lot more to learn about using it.

Nuclear power will never be completely safe or reliable. France, with many nuclear generating plants, has been plagued with leaky containment vessels lately because they or getting old and the radiation is raising havoc with the vessel properties. Down time is not reliability. France is also struggling with the very expensive disposal problem. Has anyone ever factored in all of the realistic costs associated with running a nuclear plant including decommissioning?

Nuclear is hot on the table right now because big oil and coal are trying to buy time to avoid market share shortfall. Nuclear plants in sufficient quantity to break our dependence on foreign oil will take 10 to 20 years to go on line. That is about the right amount of time big oil needs to find additional domestic supplies of oil and gas and for big coal to find solutions to their CO2 problems.

Instead, if we spent that kind of money on clean renewable energy solutions, big oil and coal would start to lose market share immediately and in 10 to 20 years would no longer be big players in the energy market. Not good for big oil and coal.

Currently, we depend largely on burning coal for electrical generation-- extremely dirty, highly toxic, and inefficient. Strip-mines are not kind to land and watershed. The more solar panels we get online in the sunbelt where NG is widely used, the more NG is be available to replace coal in the northern states.

For periods when solar is insufficient in the Sunbelt, we can continue to use diesel or natural gas generators instead. Most locations in the US have diesel and NG generators now. We can use diesel with biofuels with no pollution or greenhouse gas and no equipment modification or replacement needed. Leave the coal in the ground at least until the engineers find ways of dealing with the carbon.

We should continue to use natural gas for generation of electricity. It is relatively clean, easy to transport by pipeline, efficient and is in place almost nationwide. We can mix methane with NG in any proportion. As new sources of methane become available, we can meet new demands with no required changes in equipment. We leave coal in the ground and start to replace NG with renewable fuel as capacity increases. When we treat sewage, we can generate electricity with its natural byproduct.

We don't even need to do too much to break our dependence on coal. You simply take out the coal grates in the boiler furnaces and put in NG burners. The buildings, boiler, turbines and generators all stay the same. Any form of wasted heat can generate electricity. According to T. Boone Pickens there is plenty of NG in North America to buy us lots of time.

Part of the reliability solution must be to have as many back-up sources of energy as practical -- sun, wind, bio fuels, and new hydro all can play a significant role in accomplishing this. Although we lose our sun at night, the wind often blows at night. Wave energy and tidal energy are other forms of hydro electric energy that give us very good day to day reliability even if not hour to hour. Has anyone calculated the amount of available energy from the ebb and flow of water entering the San Francisco Bay? New geo-thermal technologies haven’t been discussed here and should. Concentrated Solar Power (CSP) using molten salts as heat transfer fluids are not only efficient, but have the capability to store energy as well. Many of these clean options when working together can provide energy when needed, smoothly and reliably.

Unless you want to dangerously stall for time, nuclear energy is not the answer. The nuclear energy we have will help with the total energy mix. We must consider our current economic problems and spending money for alternatives will create vast-new industries and open new opportunities for discovery.

Thanks for the opportunity to discuss this important subject with you esteemed men.

September, 08 2008

Ferdinand E. Banks says

You should brush up your French, David. Nobody in France with anything upstairs wants to see their nuclear sector scaled down. I dont think much of Mr Sarkosy and his gallivanting-around-the-world-style, but unlike the ignoramus who was the former Swedish prime minister, he understands that the voters are not enthusiastic about ditching nuclear in favor of inferior technologies. As for your opinion about gas, Ms Palin is a friend of a Canada-Alaska pipeline to the US Midwest. They were discussing that when I was writing my gas book, and it was considered too expensive then. In the present situation, it's almost certainly out of the question.

Fred

September, 08 2008

Joseph Somsel says

The metric of success for any energy source is not how MANY jobs are created, but how FEW!

That is a useful stand-in for Energy Returned on Energy Invested (EROEI). People require energy to support and feed. The fewer people employed in an energy source per unit output, the more energy left over for the economy to do other things, like hire nurses and doctors, entertainment, better homes, faster transportation, etc etc.

Mr. Laurence really doesn't understand the points in the article and offers little in the way of cogent rebuttal.

September, 08 2008

David Laurence says

Fred and Joseph, i agree with you Joseph that I added nothing of value to your excellent work, nor did I entend to. I was really trying to address the proponents of Nuclear Energy expressed by Joseph Somsel and others. I feel that there is too much politics and big money dictating the direction we should take that in the end will circumvent good choices. Nothing I say will change that, so perhaps I am totally out of my element. However, I will continue to read EnergyPlus for its excellent work. And Fred, maybe the French have limited choices, but we don't.

September, 08 2008

Kent Wright says

Len: All I ever “came from” regarding solar is that it has some serious limitations regarding both availability – the number of hours of daylight in a day/week/season/year; and reliability – referring to the unpredictable number of times that cloud cover can ruin a good day of solar input. I even provided the links to the historical data to back up my statements. Of course you and Roger come back with a hypothetical pat answer… just imagine unlimited solar collectors and storage units. OK, I imagined them. Now what? Or rather, what exactly is YOUR point? That we should also imagine unlimited national budgets to pay for them? As always, the devil is in the details. The capture of solar energy into a thermal storage unit certainly is close to 100%, but conversion to electricity is not. Roger, as Len himself has stated in a previous post only 6% of the heat from captured solar energy actually converts into AC electricity for the grid and the capturing of solar energy has limits to its availability as well as its reliability. Len, I did some reading of my own and find your data closely matches PV installations. Was that your intent? …or did you mean, as you stated earlier, that you ALWAYS speak of S-T when referring to solar power generation?

Regardless of how they perform on the output side, on the collection side solar-thermal and PV are in the same boat. They can’t collect at night and on cloudy days they may collect only a small fraction of rated capacity. In other words it is incorrect to claim that a few good hours of collection (4 to 6 on a good day) will yield enough kwh’s of electricity to meet needs for a 24-hour period from any reasonably affordable array of collectors/storage units. And Len, surely you don’t believe an average home’s electric loads are a relatively constant average of 1.5 kw over a 24-hour period.

September, 08 2008

Kent Wright says

[Part 2] Just for the record, many commonly expressed averages in the debate over electricity mean very little because the variance around the average is so great. It may well be that 1.5 kw of capacity could meet an “average” austere household’s needs, but who stays on the average all day every day? One simple appliance like a hair dryer or a microwave oven can easily double the consumption rate to over 3 kw. Household needs, in fact routinely exceed 6 kw at peak on a washday or high air-conditioning day. Everybody, count the wattage on your own appliances and see where you stand.

I agree with you Len that smart metering and automatic on-off timing could provide the incentive for individuals to spread the load out over the non-traditional peak times, but that would not necessarily reduce the average consumption of kilowatt-hours of electricity in a day.

I agree with you Roger that the primary advantage of S-T is its deliverability on demand without a direct link to input and output. But your conclusions hang on the premise that the capability to collect and store solar heat will always be much larger than the heat which is converted to electricity (or other usage) on a daily basis. Otherwise, a few days of minimal collection would overburden the back-ups. For the foreseeable future, it is apparent that an over abundance of collectors and storage tanks are likely. It further appears that just keeping up with the peaks and ensuring the availability of back-ups is and will continue to be a serious challenge for solar energy much less take on a much larger share of the mix. And that's not even counting when PHEVs hit the system in large numbers.

All-in-all, solar-thermal is probably a good idea, but only if the collectors, storage units and generating systems are cheaper than the alternatives AND if they can do baseload service. All I ask from you guys is a little more evidence and a little less hype. What is the capacity factor of solar-thermal? Does it really beat a PV-battery system in output and cost? … or is that just supposition? Just a few working details would suffice. Have a nice day.

September, 08 2008

Kent Wright says

Correction for: "For the foreseeable future, it is apparent that an over abundance of collectors and storage tanks are likely."

Meant to say NOT likely.

September, 09 2008

Len Gould says

Ken: 1) The Sargent and Lundy's independent engineering consultant's report to NREL I referenced above places solar-to-AC efficiency at 15% current, 17.5% near future likely. Where'd you get 6%?

2) Of course I didn't say a home uses "1.5 kw continuous". That's why I and others have been working on IMEUC realtime market, to incent and reward customers for exploiting electricity as available when available. And from there, a large tank of sand and gravel for thermal storage (see above report) takes care of the balance of requirement. Current plants which do implement thermal storage typically operate continuous for 12 hr / day, which is more than adequate for peakers. If greater reliability required, simply implement a standby simple-cycle gas turbine and use the exhaust to supply heat or steam to the solar plant's turbine.

3) Regarding "cheaper than alternatives", S & L above believe by 2020, if construction rates can reach a cumulative 2.2 GW, the cost / kwh comes down conservatively to 5.5 cents / kwh, while the developing company, more optomistic, believes if 8.5 GW the cost comes down to 3.5 cents / kwh. That beats coal generation even if society ignores its horrendous externalities.

"a little more evidence and a little less hype." -- that's insulting. In what way is Sargent & Lundys consulting, hype? You want "evidence" before installation? What the heck sort of evidence did you have in mind?

September, 10 2008

Ferdinand E. Banks says

David, the issue isn't "politics and big money" but rationality. People have stopped thinking. The problem, as I see it, is that they have too many other things to do. Why think when you can watch a daytime soap on the box. Speaking of big money, I have heard - on the grapevine - that young people in the financial district of New York have turned against nuclear. Hmm. Time to put some pensioners in front of those screens, or maybe trained kangaroos.

Fred

September, 10 2008

Joseph Somsel says

"[T}hey have too many other things to do."

Anyone considered how cost conscious the average homeowner is? What choices does the average homeowner have in where to spend their home improvement budget?

Should they landscape, put on a new roof, replace the kitchen countertop, re-tile the shower, add more insulation, new carpets, replace the garage door, etc, etc? Even if they have to replace the HVAC, do you really think they'll spend $10,000 rather than $2,000 if given the choice?

The point is that most households apply a 100% discount rate for energy-saving investments which means a one year payback. Don't argue that this is irrational - these are free actors deciding on their own best interest.

Then what about renters? You mandate my landlord to install a heat storage unit and he'll raise my rent.

Sorry, but years of field experience shows that people make other choices. "Conservation" is nice but it really means government compulsion.

September, 10 2008

Jim Beyer says

Fred,

I think an anti-nuclear mindset was formed post-Chernobyl and simply allowed to gel. I don't even think nuclear proponents were excited about their own technology; it had been written off. Then along comes global warming, and coal is the bad guy. Look a little closer, and you see coal has been the bad guy for a long time (mercury emissions, mining deaths, etc.). It is hard to change non-technical minds that nonetheless hold a technical belief.

Joe,

Joe Romm will tell you that the conservation/efficiency office of the DOE actually made money. They promoted energy savings strategies for businesses with rapid pay-backs (1 yr or so). GWB closed down the office in 2001.

But I agree with your sentiment. I think you could perhaps stretch that to 2 years, but that's about it. A really forward looking utility might be able to help with financing and even make money off of it, but I'm not holding my breath on that one.

PHEVs are not cost effective in that time-frame but gasoline price fears and hatred of oil companies are sufficient to drive forward interest in the technology beyond purely economic reasons. In the end, however, PHEVs will have to make sense economically.

September, 10 2008

Kent Wright says

Len, I agree that the sarcasm is getting a little old, so if you apologize for yours, I’ll apologize for mine (which was not intended). I was just hoping you would be open to some critical thinking which may not match your views. After all this is a debate.

So let’s get to business. Lens asks, Where did I get 6% solar to electric? Well Len, I was quoting from, ahem…, you. In your post dated 9-03-08, you stated the following: “Yes, the 600 kwh is raw daily insolation in August for 150 sq m of 2 axis tracker, which is how a well-oriented collector with moveable trough would work. Electrical energy produced per day would be that times overall system electrical efficiency, which should easily achieve at least 4% required to provide the 36 kwhr/day needed to supply the typical 1.5 kw average load of a north american home.”

Actually, you understated your own data inferring that 4% of the 600 kwh/day of insolation would supply 36 kwh/day of electricity. I gave you the benefit of 2% extra because 36/600 = .06. Didn’t think you’d mind. So you see, you ARE the source of the 6%. I also took it that the 36 kwh/day, being your number for the average daily home consumption, was tied to your other number… the 1.5 kw “average load of a north american home.”

The numbers you provide are highly disputable because: a) the average daily consumption per customer, not distinguishing between house or apartment, is 54 kwh/day according to our local utility, which I sort of doubt is much different than the rest of the nation; and b) an average of 1.5 kw per customer is meaningless even for your assumed 36 kwh/day. Why? Because it does not reflect the maximum consumption RATE of energy use per customer in kw. In other words, we typically must have a much larger kw supply than average in order to meet maximum NEEDS. The maximum is the important feature here because that is what makes peaks – hourly/daily/monthly/seasonal/yearly – however you wish to see it, and it is the peaks + the average that must be met by the suppliers.

Now someday if the power peaks are ever successfully flattened out by smart metering and programmable automatic start/stop appliances, you may have a good basis for making valid statements about “average” wattage. For example, if 54 kwh ever becomes an average with only minor variations, then the power needed will fall around a more reasonable average of 2.25 kw. Of course if this is ever mandated, a lot of homeowners will be P.O.’d if they can’t run a power tool when they need to, or say kick on an extra space heater in January.

I like your enthusiasm and the normally high quality of your comments, but lately in regard solar you seem to select only those numbers that favor your opinion. Personally, I try to avoid that by seeking only historic data from which to draw conclusions, not the projections of promoters which are nearly always motivated by their own self-interest, not mine.

Very respectfully, Kent

September, 11 2008

Charles Toca says

"I think we can agree that batteries are not going to scale up and steal major grid storage market share from pumped storage any time soon."

Why would they ever steal market share from existing hydro? The issue to me is new storage. Conversely, I think we can agree that developing new pumped storage in the future is highly limited, whereas distributed storage opportunities are unlimited.

Regarding VTG, I think it's hazardous to commit to future plans based on forecast technology acceptance by consumers. I remember the Monsanto House of Tomorrow, the People Mover, Monorails and the auto-gyro for future commuting - not to mention the city inside a bubble. I suggest we are better off using what we have to plan for future needs - and I like distributed advanced energy storage, including the VRB installation in Moab.

September, 11 2008

Joseph Somsel says

Mr. Toca,

"Stealing market share" doesn't imply that existing pumped storage will disappear or be replaced with batteries. It presumes that any increase in storage capacity will be largely pumped storage.

Say that pumped storage is 100% of the market at 10 GW today. Future growth is to, say 12 GW. If all that new 2 GW was batteries (unlikely) than batteries would hold a 16% market share and pumped storage market share would fall to 84%.

That would be stealing market share but I doubt it will happen within the next 10 years. I'd guess that batteries might get 2% market share of grid-based electrical storage by 2018. Remember that battery technology is pushing 200 years old now. Big breakthroughs in mature technology are unlikely.

September, 11 2008

Charles Toca says

Joe, thanks for the comment. I appreciate your view and the copious data and calculations. My view on pumped storage may be biased a bit by my preference for distributed solutions v. centralized solutions. I know that many power folks like to build big centralized power plants, dams, transmission lines, etc.. I tend toward small and localized solutions close to the load. Sort of a "Power to the People" mindset. We probably need to view solutions from both perspectives.

I just think that we are going to need lot's of storage, as you point out, but that getting large hydro projects done will be unlikely. The People's Republic of China was able to convince one million of it's comrades to vacate their ancestral homes in order to dam the Yangtze, but I just don't see their particular style of persuasion working in the USA - especially in light of the 2nd Amendment.

So, if we can build pumped hydro - great! But I think we'll be pressured for other solutions. I agree that breakthroughs in mature technology are unlikely. That leaves the opportunity for VRB flow batteries and NAS - sodium sulfur. I will concede that the technology is not widespread, but there was a time when PC's and wireless phones were rare. If we need 2 GW of storage in the next ten years, I doubt (my personal opinion) that we will get it from hydro - too darn hard to get them built. Necessity being the mother of invention, I believe we'll be forced to look to alternative, distributed alternatives.

September, 11 2008

Roger Arnold says

For the record, I think there's plenty of potential for additional pumped storage in those parts of the country already served by hydroelectric power. It would mostly be implemented through enhancements to existing hydroelectric facilities, rather than new "from scratch" projects. The enhancements would need to include: (1) upgraded transmission facilities, enabling higher power flows to and from the facility; (2) construction or enlargement of small holding reservoirs below the primary dam to buffer stream flow; and (3) replacement or augmentation of turbines and generators to accommodate heavy peak generation and off-peak pumping operations.

I wrote a 3-part series of articles in this forum about two years ago that addressed many of the issues that have been discussed here. The title of the series was "Coping withVariability". Here are the URLs: http://www.energypulse.net/centers/article/article_display.cfm?a_id=1391 http://www.energypulse.net/centers/article/article_display.cfm?a_id=1396 http://www.energypulse.net/centers/article/article_display.cfm?a_id=1404

And if I can get the HTML right, here are clickable links: Part 1
Part 2
Part 3

September, 15 2008

Scott Brooks says

I have tried to make sense of Joseph Somsel article but I usually go by what results and facts I can acquire. As far as renewable energy goes the only technology that's near viable would be bio and concentrated solar. As joseph has observed the biggest drawback of solar is it best applied in those areas that have high WHp insolation levels. I have seen HVDC plots and their efficiency depends on the distance transmitted. If it's under 300km it less efficient then HVAC but when it over 1000KM it's 20% and increases proportionally. so costs will have to be based on that.

Interesting enough the Hyperion Power Module could be used to extract oil from oil shale reserves. That's power!

Wind, on the other hand provides no real power prospects when used as supplying grid power. It's main drawback is no dependable capacity that has to be backed up by some form of other capacity generation like coal, nuclear or gas turbine generation as spinning reserved. I've read where it requires 5 x the construction materials when compared to nuclear generation and has very detrimental noise and foot print environmental problems.

In Denmark, the Danes are paying the highest electrical rates in Europe. The wind power is produced when they can use it so they dump it on the European mainland at a loss. The government dropped the subsidies on wind power when they found their system couldn't handle over 20%, they found it couldn't handle much handle over 10%. The wind industry over their collapsed when the subsidies evaporated. And so would Pickens plan if the government doesn't extend wind tax credits.

Despite these negatives there are some applications where wind could be well employed like Uranium extraction from the ocean.

David J C MacKay of the Cambridge University Department of Physics who holds a PhD in computation from Cal Tech has an interesting study on energy sustainability that can be found on www.withouthotair.com. It's a good resource. You can read about him at:

http://www.theregister.co.uk/2008/06/20/mackay_on_carbon_free_uk/

Heavyweight Physics Prof Weighs into Climate-Energy Scrap

Very good article.

And I very much doubt that CO2 is a significant factor behind global warming, something that has progressively been happening since the last ice age. It at first accelerated tremendously and then flattened out for the last 10,000 years. The surface temperatures have been very skewed and polluted by ground effects.

September, 26 2008

Jeffrey Anthony says

Very interesting that nuclear proponents somehow feel threatened by renewable energy, and refuse to understand how it works and that it does NOT require enery storage today -- and they continually point to the variable output nature of renewable energy, wind and solar in particular, as somehow indicating that energy storage must be needed to "firm up" renewable energy so that they can make those technologies fit their own views of what resources should be on the grid.

Meanwhile, wind power will continue to thrive and SAVE consumers money in the long run as fossil fuel prices continue to rise, by providing an energy resource (but not a baseload technology, capacity resource) that lowers the cost of energy to consumers. Len and Jim and their kind are flat wrong when they say wind power needs energy storage, just as they are wrong to say consumers are paying more for wind power than they should. They do not understand how wind power is being integrated into the grid today (it was the second largest form of new generation added to the electric grid in 2007 after natural gas).

The recently-completed U.S. DOE study on "20% Wind Energy by 2030" painted a very clear scenario where fast-response natural gas plants are added to provide additional capacity in the 20% wind scenario while 305 GWs of wind projects provide 20% of the energy needs of the U.S. While more fast-response natural gas plants are added in this scenario, the plants themselves are run 50% LESS and thus save 50% of the emissions from these plants at the same time. Electricity from coal-burning plants is reduced 18% and the resulting new enery mix results in significant reductions in CO2 emissions from the electricity sector with overall net positive SAVINGS to U.S. consumers. See the report at: www.20percentwind.org

Learn how wind power can be and is already being integrated into the grid in large quantities WITHOUT the need for expensive energy storage technologies.

For now, wind power is here, is working, is saving consumers money, and is reducing emissions as we speak.

Jeffrey E. Anthony American Wind Energy Association www.20percentwind.org

November, 17 2008

Joseph Somsel says

Unfortunately, Mr. Anthony is not hearing the same special pleading that is common from other advocates of wind and solar. "Just give us better storage!" they claim. Here's an example from the Wall Street Journal:

http://online.wsj.com/article/SB122661019700825653.html#articleTabs%3Darticle:

Mr. Anthony is free to try and make the case for wind but his comment above fails in that. Wind will require either invasive demand response (ie electrical rationing) or backup conventional generation. It's proper value to an electric grid is only in the avoided cost of fuel and O&M for those gas turbines or spinning reserve that still requires large capital investments above and beyond the price of the wind generation.

In today's regulatory schemes the current payments to wind farm developers and operators are far above the value to the customer of the power they generate. In other words, a rip off.

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