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The Future of Energy: Why Power Density Matters

The Energy Transition

This is the first column in The Energy Transition series by Robert Wilson. This series, exclusive to theenergycollective.com, will take a critical look at the prospects of a transition away from fossil fuels, and promises to abide by the advice of Richard Feynman that reality must take precedence over public relations.

Hong Kong Wind Farm Wakes

The twenty first century will almost certainly witness a transition to an overwhelming urban human population, and hopefully a transition to a low carbon energy system. The former however will have a significant impact on the latter, because a fundamentally urban species cannot be powered locally.

The  continued, and essentially unabated, accumulation of carbon dioxide in the atmosphere may at times make considerations of the requirements of a de-carbonised energy system appear somewhat self indulgent, but I must ask the reader to indulge me, and at a little length.

What would a low carbon energy system look like? (And let’s avoid such fanciful ideas as “zero carbon,” because that would be truly self indulgent.) In essence we would get as much electricity as possible from some combination of renewable and nuclear energy, and electrify as many aspects of our energy systems as is feasible. Predicting the relative composition of such a system is a largely fruitless exercise. However, we can say something about the extent to which it a low carbon energy system will be distributed and “local”. This confidence comes from the difference between the high physical concentrate of energy use in cities, and the relatively low physical concentration of renewable energy resources.

Power density

There are fundamental physical limits to how much energy we can extract from renewable resources for a given area of land. If we want to rigorously quantify this we calculate an energy source’s power density in watts per square metre (W/m2 ).

To get an understanding of this concept consider the recently opened London Array wind farm to the south of England.This is the world’s largest offshore wind farm and according to its owners will generate “enough energy to power nearly half a million homes.” Its total capacity is 630 MW covering a total of 100 km2, and is expected to have a capacity factor of 39%. In other words the power density of the London Array will be 2.5 W/m2. This number is also very similar to the average calculated by David MacKay for existing UK wind farms. The United Kingdom is windier than a lot of the world, and some research suggests that large extraction wind farms will reduce average power density closer to 1 W/m2, so 2-3 W/m2 can be viewed as an upper limit on the power density of large scale wind power. This power density reflects average output, however peak power density of wind farms will be perhaps three times higher, and minimum power density will be close to zero. And it should be noted that it excludes the requirements for manufacturing steel required for turbine towers and the extraction of fossil fuels for conversion to plastics for wind turbine blades. However inclusion of these factors is not likely to result in a significant reduction to power density estimates.

Globally solar radiation available for conversion to electricity averages 170 W/m2, and in sunnier locations it can reach above 200 W/m2. This solar energy however is currently not converted at anywhere close to 100% efficiency. Commercial solar photovoltaic panels typically average between 10 and 15% efficiency. Power density of solar installations must also account for space between panels, either for servicing in solar farms or for spacing between houses in rooftop solar installation. As a result the highest power density achieved is around 20 W/m2 in desert solar PV farms, whereas solar farms in Germany generally achieve 5 W/m2. Future improvements in panel production will hopefully see significant improvements in panel efficiency. However there will remain a firm physical upper limit of 200 W/m2, which will be significantly lower when only considering large scale deployment of residential rooftop solar, due to obvious physical restrictions on panel placement.

At their best biofuels might be able to produce close to 2 W/m2. However power densities of 0.5 W/m2 and below are more typical, with prominent examples of this being corn ethanol for transport and the burning wood for electricity. We will see later that this is a very important consideration for the scalability and sustainability of biofuels.

In contrast typical generation of fossil fuel and nuclear electricity has a power density of at least an order of magnitude greater than that of renewable energy. Power densities are comfortably above 100 W/m2 after accounting for mining etc. And conventional power plants often have power densites in excess of 1000 W/m2. A simple example of this higher power density is this small propane powered generator, providing in excess of 1000 W/m2. This is far in excess of the power density of any conceivable new method of generating renewable energy.  

propane

Why power density matters

A simple thought experiment can demonstrate why power density needs to be a fundamental consideration when evaluating renewable energy. Here it is: Imagine a world where all energy comes from bio-energy. What would be the requirements?

Currently the planet consumes energy at a rate of over 16 TW (16 trillion watts). If we include non-commercial biomass energy used in Africa and Asia, an uncertain figure, this number would increase. However for simplicity I will ignore non-commercial sources and will round our figure down to 15 TW. If we got all energy from corn ethanol we would need to convert a total of 75 million km2 to corn ethanol plantations. This is roughly half of the land surface of the entire planet, land which is somehat scarce. So this simple thought experiment shows there very real limits on how much energy we can, and should, get from biofuels. If we want large scale biofuels to become truly sustainable, a questionable prospect, we will need to see significant improvements to their power density, perhaps improvements of at least an order of magnitude.

Physical concentration of energy consumption

How much energy do we consume per unit of land? For ease of comparison this figure again can be calculated in W/m2. On a global level this is 0.1 W/m2, if we only consider land surface area. Global averages however are not very instructive, power density averaged at the scale of countries and cities is much more important. David MacKay has visualised this much better than I can in his “Map of the World.” Here is the average rate at which countries consume energy, in W/m2, compared with the power density of different renewables: Ideally a country wants to have lots of available land for renewable energy, i.e. they want to be in the bottom left of this graph. Being in the top right however may lead to some problems.

Consider first the United Kingdom and Germany. Both use energy at a rate of just over 1 W/m2. So a back of the envelope calculation will tell you that getting all of their energy needs from onshore wind will require covering half of the UK or Germany in wind turbines. If you have ever been confused by why these countries are building wind farms in the North Sea, instead of on land where it is much cheaper, now you know why. Wind energy’s low power density means you need to put it in a lot of back yards. And there are not as many of them in the North Sea.

Things are even worse in Japan and South Korea. If you covered all of South Korea in wind turbines they would generate less energy than is consumed there. Japan has a similar problem. And this ignores another difficulty: trees. Both Japan (68%) and South Korea (63%) have very high forest cover. If we ignore forested land (which should be out of bounds for large scale renewable energy generation, unless large scale biomass plantations are deemed acceptable) energy is used with a power density of almost 6 W/m2 in Japan and 7.5 W/m2 in South Korea. This calculation makes it clear that these countries can only be predominantly powered by renewable energy through the large scale utilisation of the more power dense solar energy. And social and political constraints may mean this can only happen if the efficiency of typical solar panels increases significantly from their current 10-15%.

Local Energy Is Not A Solution

Some environmentalists and renewable energy advocates have an ideological preference for small and community scale renewable energy. However what if your community looks like this: missingTokyo skyline

Some people may like the idea of running Tokyo on local renewable energy. They will have some difficulty actually doing it, and that’s putting it mildly.

Since 2008 the majority of humanity live in cities. And by 2050 it is probable that we will see seventy or eight percent of humanity living in cities. The key energy challenge this century will be providing energy for these cities, and quite clearly local distributed energy is not a solution. To see why this is the case requires untangling some issues.

Here are some considerations. An average North American has an annual energy consumption of just over 7 tonnes of oil equivalent (toe)., which is the equivalent of a rate of 9,000 watts. However, this is almost double what it is in countries such as Germany, France and Japan. A comparison of these countries in terms of key well being measures makes one thing clear: there is no evidence that North Americans have greater well being as a result of their excessive energy use. Americans don’t live longer, aren’t healthier, or better educated than countries that consume half as much energy per capita. That this high per capita energy consumption comes with a very significant environmental cost – global carbon dioxide emissions would drop by almost 10% if North Americans consumed like Europeans – but little gain in terms of human well being, suggests that is is not desirable for other countries to emulate North American consumption patterns.

Further evidence for the desirability to limit, and probably reduce, per capita energy consumption in modernised countries is given by its evolution in recent decades. Instead of increasing in the long term, per capita energy consumption now appears to have peaked in almost all modernised countries. Here are some examples:

Per capita consumption has declined steadily in the United Kingdom for the last decade and is now at its lowest point for over four decades:

United Kingdom

The United States saw peak per capita consumption in the 1970s, with consumption now seeing an apparent decline. And the fact that per capita consumption did not rise in the age of the Hummer suggests significant room for movement.

US

Germany is also now seeing declines in per capita consumption.

Germany

In Japan per capita consumption appears to have peaked in the late nineties and is now in decline:

Japan

So, many modernised countries are now seeing reductions in per capita energy consumption, and this is not being accompanied by a reduction in quality of living. Any sensible long term energy and climate policy should include a strong desire to continue this trend. The belief that the world can transition to both American levels of energy consumption and to a low carbon energy system by the middle of this century ignores the vital lessons of previous energy transitions, and given the current position of renewable and nuclear energy it appears delusional. The world therefore must be much more like Japan than America.

And cities must play a key role in reducing energy consumption. The most important and effective way to do this is simple: make them dense. For a full elucidation of why, I recommend books by Edward Glaeser and David Owen. But the key reasons are easy to understand: a dense city lets you walk or take public transport instead of drive and it lets you live in a more energy efficient apartment building instead of a large inefficient house. Packing people more tightly together in cities may not be to the taste of everyone, but it appears to be one of the most achievable and practical ways to reduce how much energy people consume.

Let us now move forward to 2050, and the world is as I hope it will be. Global population will have peaked below 9 billion as a result of the spread of the demographic transition to modernising countries, and the success in reducing infant mortality and widespread availability of contraception. Perhaps 7 billion of us will live in cities, and they will consume much more like modern day Japanese than Americans.

How will we provide energy for these cities? The answer appears to be large, centralised power plants, whether they are wind, solar or nuclear. Here I assume, wishfully, that we have managed to get rid of fossil fuels, an unlikely prospect. The answer however is almost certainly not local distributed energy, and for simple reasons.

Consider Manhattan, not what many would typically look at as the green ideal. Yet here you will find significantly lower per capita energy consumption than in almost every American city. You will also find energy consumption far greater than can conceivably be provided by local renewables. A recent study managed to map energy consumption in the city that never sleeps right down to the individual city block. This is what it looks like:

A typical block in Manhattan consumes energy at a rate of over 1,000 kWh per square metre each year, a power density of over 100 W/m2. This is almost two orders of magnitude greater than the power density of wind power, and obviously you could not plaster Manhattan in wind turbines. Solar power is not much better. Imagine that we could cover 20% of Manhattan in solar panels. This would give us no better than 5 W/m2. Clearly Manhattan is not getting its energy locally. And as you can see from the above map the other boroughs of New York are not going to fare much better.

How about the rest of North America? If we reduced per capita energy consumption to Japanese levels, a sensible but unpopular idea, could many American cities run largely on local renewables? The graph below shows population density versus energy use density in this lower consumption America: usDensity

Low density Phoenix perhaps has a shot at getting most of its energy from solar power. Covering 25% of Phoenix in solar panels would produce as much energy as is consumed in Phoenix. The practicality of this is of course rather questionable, and getting more than 50% of Phoenix’s energy from local solar will require something that currently does not exist: a cheap way to store energy on a large scale. A system involving more than 50% of energy coming from solar will thus inevitably require the accounting of land requirements for large scale storage, an uncertain prospect, and significant losses of solar panel output due to efficiency losses during storage and curtailment of excess.

The prospects of American cities running largely on local renewables thus seems unlikely, and 83% of Americans live in cities.

A global appraisal

The world’s two hundred largest urban areas are home to over 1.2 billion people, and a quarter of these areas are more densely populated than New York (10,000 people per square kilometre). This is shown below: PopDensity

Before asking if these cities can run on local renewables I must first mention the too real disparities in global energy consumption. Below is a comparison of the population of countries with their per capita energy consumption, with population plotted on a logarithmic scale due to China and India being much larger than other countries. And I include lines showing typical European and North American per capita energy consumption. GlobalEnergyComp

While there are about 350 million North Americans who can, and should, reduce their energy consumption to European levels, there are even more at the bottom who must increase their energy consumption significantly to improve their quality of life. Quantitative comparisons are sobering. Over 35 countries have per capita consumption at less than 10% of North American levels, with populations totalling over 2 billion. Despite the apparent desires of some environmental NGOs (for an example see page 11 of this WWF report) it is therefore undesirable to propose reductions in global energy consumption. The modernised world may consume excessive energy, but energy consumption is much too low in modernising countries to let us decrease global energy consumption without negative humanitarian impacts.

We therefore should have a desire to both reduce excessive consumption in modernised countries and increase energy consumption in modernising countries. I am not going to suggest a prescriptive end point. Instead I will assume that consumption levels in modern day Japan can provide a very good quality of life, and exceeding these levels is unnecessary.

If the populations of the world’s 200 largest cities consumed energy like modern day Japanese energy use density would look like this:

PowerDensityofCities

In total 10 cities would have power density greater than 100 W/m2, 56 would have power density greater than 50 W/m2, while 181 would have power density of over 10 W/m2. That is 90% of the planet’s 200 largest cities almost certainly cannot be powered predominantly by local renewable energy. The population densities of these cities are not significantly different than the rest of the world’s cities, so we can conclude that the the vast majority of cities cannot be powered by local renewables. And this suggests very serious limits to the role of local distributed energy in a world where more than 70% of us will probably live in cities.

The prospects are even worse in individual countries. Of the world’s 200 largest urban areas, 17 are in India. Below I have isolated these cities.

India power density

120 million people live in these cities. Covering any of them entirely in 10% efficient solar panels will generate less than half of their energy needs. And look at that dot in the top right, that is Bombay. For Bombay to get all of its energy needs from solar in my hypothetical future it would need to harness almost 100% of the solar radiation that strikes it, a remote prospect. This extremely high population density is routinely ignored by western environmentalists calling for distributed energy to be the solution to India’s energy problems. It quite clearly is not.

In this century the bulk of humanity will live in large densely populated cities. If the citizens of of these cities are to attain a high quality of life they will require large centralised energy generation. This is not a matter of ideological preference, but of engineering reality.

Robert Wilson's picture

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Robert Wilson's picture
Robert Wilson on August 10, 2013

Zackary

Morocco is almost 60% urban, and this figure is rising about 0.3% every year. So I am not really sure if your personal anecdote makes much difference to the overall trend of a rapidly urbanising world, and has very little relevance overall.

Per capita energy consumption is higher in Norway, Sweden and Finland than it is in Japan. If they were to consume like Japan they would have to reduce per capita consumption significantly.

Robert Bernal's picture
Robert Bernal on August 10, 2013

Can I link to this? Actually, I already did from another article here called 

“Climate Change: Extreme Weather is Here to Stay”
Robert Wilson's picture
Robert Wilson on August 10, 2013

Robert

If you are only interested in promoting LFTR, and not commenting on this post, then please do not comment.

Robert Bernal's picture
Robert Bernal on August 10, 2013

Thought is was all about power density. Why are you all of a sudden against my comment? And i am not only for LFTR, etc, also for CSP and any tech that can minimize excess CO2.

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 11, 2013

Nathan:  My belief is that it’s going to take an “all of the above” sort of strategy to make up for the lower energy density and roof top solar is going to play a part in that solution. 

For one, it takes advantage of an under utilized asset (roof tops with good solar isolation).  Also, the power curve of solar in general matches up very well with the demand curve for power and this lessens the need for additional centralized capacity to be built. And, every little bit helps!

As far as net metering goes, I don’t see what is unfair about being able to sell your surplus power back into the grid?  Especially, when you consider the fact that roof top solar helps save utilities money in that they don’t have to build additional peak capacity or buy that power at a premium price on the open market since roof top solar systems are most likely to be pumping their power back into the grid right when the grid happens to need it most.

Distributed solar also cuts down on transmission losses since the majority of it’s output is usually consumed at the point of production.  At somewhere between 4 and 8% on average, this loss can be significant.

 

Bob “The Clean Energy Guy” Mitchell

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 11, 2013

Forrest:  In a truly free market, the “invisible hand” would guide the resources towards their highest and best use.  But, there are very few truly free markets out there and energy is definately not one of them!

That said, the point of my earlier comment was that by removing the “crony capitalism” and other market inefficienctcies from the energy markets (in this case by putting a tax on carbon that would cause fossil fuels to be priced at their true total costs), that the market forces would indeed push us towards the most efficient over-all solution.

Now, THAT SAID, if we have the political will to address these market inefficiencies is the $24,000 question!  My gut tells me that the entrenched interests still have a lot of power and that it’s going to have to get a lot worse (and more painful) than it now is for our society to muster this will.

 

Bob “The Clean Energy Guy” Mitchell

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 11, 2013

Clayton: Additional transmission lines are always going to get the NMBY folks up in arms and a lot of times, I don’t blame them because there is a down side to building them.

That said, the downside of beefing up the grid is far less to society as a whole, as well as to the environment as a whole, than in NOT BEEFING the grid up.

As pointed out in this article, as well as in upteen other articles out there, renewable energy is unarguably less dense than fossil fuels or nuclear.  It also suffers from problems with intermittency that can not be denied.  BUT, as I’ve pointed out, these problems can be engineered around.

One of the ways to engineer around this problem is to build out a smarter, more robust electrical grid that can then help mitigate these issues by making it possible to move power from where it’s being produced to where it’s needed.

It is ashame when people get so wrapped up in believing in a particular technology or generation scheme that they lose sight of the big picture or fail to take into account the legitimate points made by people with whom they disagree.

 

Bob “The Clean Energy Guy” Mitchell

 

Rod Adams's picture
Rod Adams on August 11, 2013

Deleted by author. Post did not appear in correct location in thread, so it made no sense.

Rod Adams's picture
Rod Adams on August 11, 2013

You used a lot of words to come to an incorrect conclusion based on more than one false assumption.

For example, I once ran an engineering department on a nuclear submarine. I was 27 years old with a BS in English and an MS in Systems Technology. Five or six members of my department has BS degrees. The rest of the 35 were skilled tradesmen with technical training.

The average age was about 24.

Running a nuclear plant requires trained people with high integrity and a good work ethic, but they do not need to be PhD level intellects. The necessary skills are widely available and can be developed.

System costs can be brought down by applying well understood concepts of series production and interchangeable parts.

Rod Adams, Publisher, Atomic Insights

Rod Adams's picture
Rod Adams on August 11, 2013

Robert

Excellent post on an important topic. I apologize for being a little late to the party.

When it comes to energy density as measured by watts per square meter of land use, you did a good job of pointing out both current figures and the asymptotes for many renewable sources. Have you thought much about the theoretical limits associated with nuclear fission technology?

Here is some food for thought for you and others in this discussion. The B&W mPower(TM) reactor is designed to produce 360 MWe and to be sited on a 40 acre site. That works out to roughly 2,200 watts/square meter.

That kind of power plant may someday be located within densely populated cities, reducing the need for land to be devoted to transmission lines. As a submariner who has coexisted inside a sealed ship with a reactor all ways less than 200 feet away, I am comfortable with having mPower type reactors as next door neighbors.

There are many other fission power systems that can achieve this kind of power density. They are safe and emission free. I used mPower numbers because I happen to have them at my fingertips.

Rod Adams, Publisher, Atomic Insights

Disclosure: My comments on the web are strictly my own views and do not necessarily reflect those of my employer. However, I am employed by B&W on the mPower reactor development team, so I suppose I have an inherent bias. I am proud of the technology we are refining.

Robert Wilson's picture
Robert Wilson on August 11, 2013

Rod

Is your suggestion that we can locate large numbers of nuclear power plants in densely cities a serious one? 

Which neighbourhoods do you imagine will be the takers for these plants?

Promoters of nuclear power really need to strengthen their grip on reality. 

George Stevens's picture
George Stevens on August 11, 2013

maybe not within cities but 2000+ w/m2 of dispatclable power plants  around the perimeter of such a metropolitan area could probably do the job and minimize transmission and land costs compared to other alternatives.

plants currently powering US cities have decent footprints of land as it is, I don’t think the idea of the mpower reactor being deployed within a city is completely unreasonable. I’m guessing there exist several 40 acre industrial parcels within cities.

George Stevens's picture
George Stevens on August 11, 2013

Sure, the Shockley Quissler theoretical efficiency limit for single junction Crystalline Silicon PV tells us that we cannot hope for current commercial solar cells to make the efficiency gains necessary to cost remotely cost competitive with fossil fuels. Due to huge investment by the Chinese government (more than 30 billion usd over a two year period) the manufacture of crystalline silicon PV panels as we know them is now a fully matured industry and most PV advocates expect the price of current technology to level off around 2017.

There is always the potential for new semiconductor technologies to provide a price breakthrough. This could come about by high efficiency multi junction cells, currently used in satellites and concentrated PV, somehow becoming commercially viable which is highly unlikely given what we know today. Another more likely possibility is the advent of less efficient but cheapest and more flexible PV substrates (thin film, dye-sensitized, organic). Such substrates, while less efficient, are lighter (which is very important for rooftop systems) and do not require aluminum racking, frames, or substantial amounts of glass for installation. The vapor-deposition or similar process used in making such PV is also much more efficient then the wafering of Silicon cells. In this case energy density would fall and I see it as the most likely scenario if PV is to become at all economically competitive within the first half of this century.

Contrary to popular belief not all industrial and commercial rooftops can be permitted for the additional deadweight and wind load that a PV system adds. Lost in the Solyndra hoopla was the fact that the Solyndra product was comparably very low-weight and could be deployed on many weight constrained rooftops. You would be surprised how many urban rooftop spaces are too weight constrained to handle conventional PV, which is a relevant point of consideration for the discussion in the article above.

Randy Voges's picture
Randy Voges on August 11, 2013

Was wondering where you were.  Make sure you read Schalk’s latest, too.

Atomik Rabbit's picture
Atomik Rabbit on August 11, 2013

deleted

Roger Faulkner's picture
Roger Faulkner on August 11, 2013

Small hydro is coming on strong in China. I do not know if these units are strictly “run or river” or if they can be dispatched to some extent. In the US, DOE estimated there is a potential for small hydro power ~ 200 GW. A lot of that is at small existing dams with no generators. Not my specialty, but I’m glad some companies are working on it…it seems like “low-hanging fruit,” though in the US the licensing can be quite expensive, which is why so many small hydro generators went out of business since WWII.

Roger Faulkner's picture
Roger Faulkner on August 11, 2013

There is one particular renewable energy source that is highly concentrated, reliable, and steady: hydrothermal vents. See for example this site:

http://www.marshallhydrothermal.com/

This looks highly feasible to me, but is clearly a late entryin the rush for renewable energy solutions. It is a type of geothermal energy without the need to drill wells.

Robert Bernal's picture
Robert Bernal on August 11, 2013

I’ve done the math on solar (albeit, rather simple) and it points in the direction of 8 times less as expensive for an all out theoritical installed solar global power system.

However, I calculated for the more costly CSP, because, in the long run, solar must be stored. PV could in theory be stored in batteries, but we all know that just isn’t happening anytime soon on a global scale. The molten salt storage scheme has already been developed and proven, but not yet on a cost efficient scale of economy because itis not cheaper than fossil fuels.

Now, just how much would it cost to plaster the world’s deserts with a bunch of mirrors, a generator (hopefully, the Brayton cycle turbine) and heat storage? Keep in mind that the cost for molten salt (there are now ideas about molten glass for heat storage) is way less than batteries and requires far less space than pumped hydro per unit of energy stored. In fact, the storage for a power tower is less than that of the (more common) trough because it is of a higher temperature and therefore requires less of it.

According to IEA, total world energy supply was about 144,000 TWh (from wikipedia). Capacity factors for a good CSP tower is up to 70% (estimated). I will assume 50%.

144,000 / 8760 (hours in a year) = 16.5 x 2 (for 50% CF) = 33TW CSP towers needed to be installed = 33 billion KW (or 33,000 one gigawatt plants). At (a whopping) $10 per watt of installed capacity, that’s $330 trillion!

But (and this is a big “however”) the power does not have to be reduced by a factor of 2/3rds to account for the thremodynamic losses as in the real world’s combustion processes, thus this would be a WAY overbuild.

Another way to look at it is to divide the aprox 500 quads of total primary world energy consumption by 3414 (which is btu/kWh) to get 146 TWh. This number accounts for ALL energy input. Again, 2/3rds of that is wasted as heat even before going throught the power lines because of the inefficiency of converting heat to useful power.

With further efficiency improvements (like electric cars, led lighting, passive solar site planning for houses, more insulation for houses, etc) the total price tag shoul be less than $100T. But wait, IRENA puts estimates of costs to about $5.70 (not $10 as I had) after economies of scale are figured in (assuming 2020), which lowers the bill to about 60 trillion.

http://www.irena.org/DocumentDownloads/Publications/RE_Technologies_Cost_Analysis-CSP.pdf

Rod Adams's picture
Rod Adams on August 11, 2013

@Robert Wilson

It’s quite arrogant and insulting for you to imply that I do not have a grip on reality. Small, modular reactors with passive safety features can fit quite nicely on sites that currently house old coal plants or retired oil fired plants. Those locations have existing rights of way. They often include existing water and grid infrastructure that can reused. Any site that was safe and acceptable for a reasonably good sized fossil plant should be safe and acceptable for an appropriately sized and designed ultra low emission nuclear plant.

I have operated nuclear plants in downtown harbors in densely populated cities without any resistance from the local population. Why do you ASSUME that similar plants cannot be built and operated?

Putting plants close to customers comes with a lot of natural economies. It also provides the opportunity to beneficially use the “waste” heat for a cogeneration or water purification system.

Rod Adams, Publisher, Atomic Insights

Bob Meinetz's picture
Bob Meinetz on August 11, 2013

Rod / Robert,

You seem to be discussing two different aspects of the same topic, and you both make good points.

Rod, I assume you’re referring to bringing in a nuclear sub or carrier to harbor in a major city. The public perceives little or no danger from that – but propose a nuclear power station, with fuel at 1/10 the level of enrichment, and panic multiplies exponentially. Would the public find nuclear subs in permanent drydock, connected to the grid, acceptable? An absurd scenario, but I would guess most people don’t even realize there’s a functional nuclear reactor inside these vessels. Ignorance = bliss.

Robert, all we need to do is imagine a Fukushima happening in Tokyo and a serious problem takes on nightmarish proportions. I don’t believe Rod nor anyone entertains building a Gen 1 PWR in a metropolitan area, but the public is largely oblivious to these distinctions and opposition would be the biggest hurdle. It might take a decade or more of Gen IV units operating safely in more benign locations to make “local nuclear” a reality.

Robert Wilson's picture
Robert Wilson on August 11, 2013

Rod

I don’t see what is arrogant about. Anyone who thinks we can build nuclear power plants in cities is borderline delusion. Do you actually believe this can happen?

Do you think a utility would even think about building a nuclear power plant in a city? The US nuclear industry is in a bad enough state without nuclear advocates pushing delusional ideas like this. Time to get a little more realistic.

Jesse Jenkins's picture
Jesse Jenkins on August 12, 2013

I’m not 100% sure, but I believe this post sets the record!

Jesse Jenkins
Digital Community Strategist,
TheEnergyCollective.com

Jesse Jenkins's picture
Jesse Jenkins on August 12, 2013

I’m not 100% sure, but I believe this post sets the record!

Jesse Jenkins
Digital Community Strategist,
TheEnergyCollective.com

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 12, 2013

Cliff:  I would agree with you if all we were doing was throwing things against the wall in order to see what stuck.  But, that’s not what I meant by my use of the phrase, “All of the Above”.

Renewable energy is very situational in it’s applications.  For example, you wouldn’t want to install a utility scale wind turbine in a place where the wind doesn’t blow consistantly or solar PV on a building that is shaded a good portion of the day.  Another example would be trying to install a geo thermal heat pump on a property that is built on bed rock.

Now, when installing a suitable renewable energy technologies in suitable locations, renewable energy can be very functional and not only reduce the carbon footprint of a building, a community or a nation, but can also pay for themselves in relatively short periods of time.

I also have to disagree with your accessment that, “putting renewables on the grid without storage is forcing a square peg into a round hole.” 

While adopting our antiquated, maintainance defered, developed for a different energy paridaigm grid to renewable energy hasn’t been without it’s difficulties, there is no reason to suspect that it can’t be done.  In actuallity, there is all kinds of emperical data that shows that we’ve actually done a pretty good job of it.  Germany, Denmark, Spain and some other countries currently produce over 20% of their electrical generation needs from solar and wind.  If you count hydroelectrical power generation, there are several countries that generate in excess of 100% of their electrical needs via renewable energy.

The issues of intermittency and energy density can be engineered around through expansion of grid networks, increased energy efficeiencty standards, and the adoption of smart grid technologies.  And in the mean time, while we are waiting for these improvements to be made, so what if we use fossil fueled power plants to firm up the power generated by renewables as long as the net carbon emmissions are less than they would have been if you hadn’t incorporated renewable energy into the scheme.

True, the price of the “backup” or firming plant should be factored into the total costs, but when you consider what the true total costs of simply burning fossil fuels (or even throwing nuclear into the mix), renewable energy still comes out cheaper in the long run.

Regarding subsidies, I personally don’t see a problem with the government incentivizing the adoption of renewable energy because it will eventually pay for itself and even provide a decent return on societies investment.  The same can’t be said for the billions of dollars each year that the fossil fuel industries recieve in subsidies world wide.

 

Bob “The Clean Energy Guy” Mitchell

Joris van Dorp's picture
Joris van Dorp on August 13, 2013

I used to live in Delft, The Netherlands, in a student flat that was a few stonethrows away from an almost 50 year old working nuclear reactor. It was only 2 MW thermal, (pool-type, TRIGA), but it was a nuclear reactor nonetheless. While during its decades-long history that reactor has been the target of several bouts of protests, and there have been many attempts by (so-called) environmentalists to impress upon the Delft citizens the ‘danger’ of being so close to a nuclear reactor, there has never been a problem and there is no credible danger. I visited the reactor myself on two occasions to watch the impressive Cherenkov radiation from the core with my own eyes. I am completely satisfied with it.

I’m not a nuclear expert, but I have learned enough about nuclear energy to agree with Rod Adams that living next to a nuclear plant should be no problem. I would have no problem with it. Far from it. I worry about the climate change problem and the listless economic times, with increasing numbers of friends and acquantainces suffering from losing jobs or not finding any. And I see the government pumping billions of dollars into prestige ‘green’ projects that clearly don’t amount to a lot of climate change mitigation, and only add to the already increasing cost of energy. I see the new-builds of coal and gas plants, happening in my country and other EU nations. It is shocking!

A new nuclear reactor, built close to my home, would make me very happy. If anything, it would give me at least some hope that we WILL actually solve the climate change crisis in time. Only nuclear power can give me that kind of hope. I don’t say that because I don’t understand the potential of alternative low-co2 energy options lie wind and solar, but because I do!

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 13, 2013

Mr. Perelman: 

I, for one, have not ignored the issues of power density that come with renewable energy.  There is no getting around the fact that fossil fuels (and nuclear) all have much greater power densities than wind, solar or other renewable sources of energy.  My position is that while this issue and renewable energy’s intermittent nature are real, that they’re not issues that can’t be engineered around through:

1) The beefing up and expansion of the nation’s electrical grid.

2) By adopting distributed renewable energy where it is practical to install and by making better use of the energy (no matter what the source) that we use through common sense, low impact means.

3) By implementing smart grid technologies.

Regarding your point about renewable energy not being cost effective, I still argue that the only reason that they are not cost effective at the moment is because we currently don’t include the fossil fuel’s external (and real) costs in their price.  This could be fixed with the stroke of a pen and then renewable energy would be able to compete on a level playing field.

And I too think that Robert has been a bit “cheeky” and dismissive.  Hopefully, that doesn’t come off as being cheeky in and of itself!

 

Bob “The Clean Energy Guy” Mitchell

 

Steven Scannell's picture
Steven Scannell on August 13, 2013

If nuclear power were safe then it could and would  be properly insured.  The high end astranomical risks are the worry.  I think we should study the feasibility of US Navy owned and opperated nuclear plants. Security is my main worry especially with a private companies ability to defend a plant.  

There was also an earlier comment about the “either or” situation with wind v nuclear.  Nuclear OR offshore wind?  Let’s check ourselves here.   This is not the case.  Nuclear and wind are congruent IF wind to CAES and hydrogen is a concentration, as I believe it should be.   Wind then CAN boost steam production of any steam plant.  Using compressed air also lessens the need for electrical because refrigeration and air conditioning can be run with compressed air.   www.environmentalfisherman.com

Offshore wind and wave does make sense from a fisheries angle, which is almost never discussed.  The hybrid wind and wave “Georges Banks Mega Mill”  of my design uses a unique intergrated energy and fishery management approach.   I say we need to grab any cash flows we can on the way to saving the world.  

Clayton Handleman's picture
Clayton Handleman on August 13, 2013

 

Could you clarify how you are monetizing impacts such as are depicted here or what studies you have found that monetize them.

http://ilovemountains.org/reclamation-fail/details.php#extent_study_2012

And since the processes for tar sands extraction of petroleum and mountain top removal in the Appalachians permanently destroy irreplacable land, how are you accounting for that? 

It appears to me that most of the folks who argue for market solutions are not so clear on how to have markets account for these things and have the attitude that since it is not covered in the market calculus then just pretend like its not happening.  The issues you are commenting on above (firewood, grid instability, cost of electricity) are solvable on a timescale of less than a generation, in fact less than a decade.  The problems they avoid are addressed on geologic timescales.

Our property laws have their roots in a time when people did not have the ability to break land, watersheds and ecosystems permanently over any appreciable time scale. 

Since we are now breaking our natural, finite resources with repair times on time scales that exceed lifetimes of individuals, civilizations and even the species, perhaps new laws are in order that recognize that value.  And I will commit blasphemy here but I would argue that markets are ill suited to addressing the problem of permanent destruction or degredation of irreplaceable assets.

 

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 13, 2013

Mr. Voges:  I am actually one of those environmentalists who has come to accept the necessity of nuclear fisson.  At least in the short run.

My original objections are still there; uranium mining is dirty and water intensive and that, no matter how hard we seem to try, that we still have safety issues with the plants.  In addition, there is the transporation and storage of the waste.  I also think that it’s pretty expensive and will become more expenisve as our global suppy of uranium starts to dwindle (it turns out that at current consumption levels that we only have about 80 years of econonmically recoverable supplies left.).

That said, it is energy dense and doesn’t emit greenhouse gases directly and we already have a lot of operating plants.  So, I’ve mellowed and am ok with not shutting these plants down until we build out the truly renewable energy sources. 

In the mean time, we need to go full steam ahead towards building out the renewable energy infrastructure so that we can ween ourselves as quickly as possible from fossil fuels first, then nuclear second.

 

Bob “The Clean Energy Guy” Mitchell

 

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 13, 2013

Mr. Stevens:  As I’ve mentioned in my earlier comments, renewable energy IS cost competitive RIGHT NOW….if you count the external costs of fossil fuels and that’s at today’s current efficiencies. 

Regarding your point about the weight of a solar array, I’ve never heard of them weighing too much, at least not for most buildings built since 1970.  The typical solar array only ends up adding about 4 pounds per square foot overall.  If you factor in that most installers avoid roof pentrations as much as possible, so that some of this weight ends up being concentrated where the racks are attached to the roof, it only adds about 12.5%….so, let’s round up to say 5 psf. 

Now, I’m no expert on roofing codes, but my gut tells me that this shouldn’t be a problem unless there is something wrong with the building or it wasn’t constructed properly??  And even then, I would think that if you were close, that you could work around the issue by adding supports or fixing the structural inadequacies..

 

Bob “The Clean Energy Guy” Mitchell

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 13, 2013

Mr. Stevens:  As I’ve mentioned in my earlier comments, renewable energy IS cost competitive RIGHT NOW….if you count the external costs of fossil fuels and that’s at today’s current efficiencies. 

Regarding your point about the weight of a solar array, I’ve never heard of them weighing too much, at least not for most buildings built since 1970.  The typical solar array only ends up adding about 4 pounds per square foot overall.  If you factor in that most installers avoid roof pentrations as much as possible, so that some of this weight ends up being concentrated where the racks are attached to the roof, it only adds about 12.5%….so, let’s round up to say 5 psf. 

Now, I’m no expert on roofing codes, but my gut tells me that this shouldn’t be a problem unless there is something wrong with the building or it wasn’t constructed properly??  And even then, I would think that if you were close, that you could work around the issue by adding supports or fixing the structural inadequacies..

 

Bob “The Clean Energy Guy” Mitchell

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 13, 2013

Whoops, didn’t see this comment earlier…sorry.  Anyway, I have read up on the trouble that grid operators sometimes have with incorporating renewable energy onto their grids.  As a matter of fact, I’ve talked with the folks who operate the Pacific DC intertie which has to coordinate power from the dams along the Columbia River, as well as the numerous wind farms in the area and they aren’t shy about saying that it’s a pain the the butt.

BUT, that doesn’t mean that it can’t be and isn’t being done!

The problem isn’t so much the way that the power is produced, as much as it is the way that the grid has been designed (hodge podge) and built (with large centralized – usually fossil fueled – power stations) in mind.

Let me ask the engineers out there a question…If given enough time and paid enough money, could you put pencil to paper and come up with a grid solution that is capable of handing the intermittent nature of renewables?

My gut tells me that the answer is and will be, “Yes”.  In the long run I hope that it is because, while it might not be tomorrow, someday, barring some radical new power source being developed, we’re going to have to adopt renewables as our main source of power.

 

Bob “The Clean Energy Guy” Mitchell

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 13, 2013

Whoops, didn’t see this comment earlier…sorry.  Anyway, I have read up on the trouble that grid operators sometimes have with incorporating renewable energy onto their grids.  As a matter of fact, I’ve talked with the folks who operate the Pacific DC intertie which has to coordinate power from the dams along the Columbia River, as well as the numerous wind farms in the area and they aren’t shy about saying that it’s a pain the the butt.

BUT, that doesn’t mean that it can’t be and isn’t being done!

The problem isn’t so much the way that the power is produced, as much as it is the way that the grid has been designed (hodge podge) and built (with large centralized – usually fossil fueled – power stations) in mind.

Let me ask the engineers out there a question…If given enough time and paid enough money, could you put pencil to paper and come up with a grid solution that is capable of handing the intermittent nature of renewables?

My gut tells me that the answer is and will be, “Yes”.  In the long run I hope that it is because, while it might not be tomorrow, someday, barring some radical new power source being developed, we’re going to have to adopt renewables as our main source of power.

 

Bob “The Clean Energy Guy” Mitchell

George Stevens's picture
George Stevens on August 13, 2013

Hi Robert,

Weight constraints certainly do play a role in the adoption of rooftop PV currently. You are correct that most installers avoid penetrations and the costs that they add, and they instead turn to ballasted systems which of course add weight. The ballast requirements are set according to estimated wind load and guided by structural code, including of course a generous safety factor. Most large industrial buildings are designed to withstand worst-case live-loads (rain, snow, wind) including some safety factor mandated by structural code. These buildings are designed with little additional margin over the live-load (and safety factor) requirement, which makes permitting the seemingly inconsequential weight of a PV system more difficult than you might think. It is obvious that a building can handle a PV system, but can it handle a PV system and a worst-case snow load with the required safety factor?

This is how weight constraint is a real issue in deploying conventional flat-plate PV systems. Lighter rooftop racking products will list psf prominently as a selling point because of this issue. With the modest rate of deployment of rooftop systems today it isn’t such a well known issue, but in the scenario of cities powered by ‘local energy’ discussed above it would be a considerable constraint. I believe PV will need to rid itself of  the associated weight and cost of frames, glass, and racking if it is to ever play large enough role in the energy mix to even require accompanying storage systems in the first place. 

George Stevens's picture
George Stevens on August 13, 2013

Hello again,

Yes external costs of fossil fuels obviously do exist, but quantifying the cost associated with the carbon released from natural gas is far from straight forward. Climate models from the authority on the topic of global warming, the IPCC, can hardly provide an estimate on the correlation between CO2 emission and temperature increase without a substantial margin of error. And even if more certainty existed in this area there is another large layer of uncertainty in the topic of the economic impact of temperature increase. This isn’t to say we should do nothing, but arriving at a fair price on carbon emission is not at all simple.

So perhaps you might suggest that we err on the conservative side and place a hefty tax on carbon emissions to limit warming. The consequence of such a tax would inevitably be a rise in the cost of energy (and the goods and services that depend on it) followed by a sharp decrease in economic activity and the standard of living for the average population. This is precisely why the world at large has avoided any real meaningful carbon tax thus far.

So the question is what benefit does cheap fossil energy afford society and how does it compare with the external costs of carbon emission? Not such an easy question to answer. We should instead aim our focus on championing clean energy technologies that can approach the cost of fossil fuels. Nuclear energy has accomplished this on national scales in the past, and it is undoubtedly has the most potential of all options to create affordable and clean energy in the future.

Clayton Handleman's picture
Clayton Handleman on August 14, 2013

 

In areas where there is no snow it can be a problem.  For example I understand they run into difficulties in LA.  However in the Northeast it is pretty much a non-issue.  The safety factors are sufficient.  Fly into Newark airport some time and you will see rooftop after rooftop covered.  And in MA we are seeing a lot of this as well.  It was generally doable with the old cinder block and tray style.  However with the price of modules down and efficiencies up, the economics are such that people have moved to low profile systems that are very light making it quite rare to run into structural concerns. 

In MA we pretty much weeded out all of the inelligible buildings.  A year before the SREC program really got rolling we had an unusually heavy snow followed by rain.  A good number of the roofs that would have presented problems collapsed before anyone even bothered asking if the question of whether to put PV on them   : 0 

Clayton Handleman's picture
Clayton Handleman on August 14, 2013

I am confused, your reply as nothing to do with the question I posed. 

How do you suggest we deal with the externalities that are not being fed into the markets as they currently exist? 

 

 

 

 

 

 

 

Rod Adams's picture
Rod Adams on August 15, 2013

@Robert

I have just a little bit of education and experience in both engineering and the humanities. I’ve liven in about a dozen different cities and explored numerous components of their infrastructure. I would not necessarily recommend building most types of reactors in the downtown section of a densely populated city, but certain types of reactors would be well suited for locating in the types of areas that house necessary facilities like sewage treatment, ports, power generation, landfills, recycling centers, and cement factories.

Public resistance will be met, but it can be overcome with transparent information sharing and a well founded effort to explain the benefit to risk balance.

The arrogant part of your response was your presumed assumption of superior knowledge from your experience base of being a grad student who is steeped in academia and is dismissive of people who might have a little more experience than you do.

Rod Adams,

Publisher, Atomic Insights

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 15, 2013

Mr. Stevens:  In response to your comment, I did a google search on issues related to weight and the installation of solar panels and found almost no references to people having problems with the weight.

Now, I’ve only been involved with renewable energy for going on 4 years and the only time that I was concerned with weight was when I was involved with an install on an old house in San Diego.  The weight of the solar system wasn’t the issue, but rather that somebody decided that we should all pose for a picture on the roof next to the panels!

Anyway, if you don’t mind, could you post some links to any articles that you might have on the topic?

 

Thanks,

 

Bob “The Clean Energy Guy” Mitchell

Robert "Bob" Mitchell's picture
Robert "Bob" Mitchell on August 15, 2013

Hello again yourself Mr. Stevens!

The most reliable figure on the external costs of fossil fuels was issued by the National Academy of Sciences (http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=12794) which puts the figure at $120,000,000,000 per year!  And that’s not really the true costs because it doesn’t take into account the costs of global climate change or even the costs of all of the polluntants such as mercury.

Now, how much are the external costs of fossil fuels as they relate to climate change?  I honestly don’t know and I can see where it might be difficult to put a finger on the exact costs since some costs, such as the costs of damage from hurricanes is difficult to peg directly on the burning of fossil fuels, but nonetheless, we have a pretty good idea that it’s contributing!

That said, even if you take a very conservative approach to coming up with that number, I can see where it might be in the trillions of dollars due to sea level rise and droughts.  Regardless of what number you come up with, I hope that we can all agree that there is indeed a cost and that no matter how you figure it, it’s a substantial one!  Is that fair?

Personally, I would suggest that we phase the carbon tax in over a period of years….not so long as to be meaningless or futile, but no so short as to cause major economic disruption.  I would also vote to make it short enough to send a strong signal to the markets that the age of fossil fuels is coming to an end!  If I had to pick a number, I’d say take 10 years to phase in a carbon tax that would at least equal the $120,000,000,000 in external costs that we are currently paying.

That figure shouldn’t cause that much of a disruption because it’s a cost that we are already paying and that will be reduced throught the adoption of renewable energy.  So, a net wash.

Lastly, you’re right that there are benefits to “cheap fossil fuels” and these too can be difficult to ferret out, BUT the days of cheap fossil fuels are coming to an end anyway, so I don’t really see that as much of a loss.  One way or the other, you would still have to factor in the economic benefits of investing in a renewable energy future.  Which are substantial in that renewable energy doesn’t have fuel costs after the initial payback period, the energy is largely free.

Actually, one more thing…;-)  to your point about nuclear be able to save the day…in an earlier comment I noted the estimate from the World Nuclear Association that at current consumption that we have about 80 years of economically recoverable uranium left.  If we (and the world) go your way and build out our nuclear infrastructure in a magnitude sufficent to address our world energy needs, how long will the supply last? http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Uranium-Resources/S...

Bob “The Clean Energy Guy” Mitchell

 

George Stevens's picture
George Stevens on August 15, 2013

There are a lot of engineering issues in general which you are not likely to easily find pertenint articles by google search. Im not going to look for articles to substaintiate a viewpoint that I experienced as an engineer in the southwest US on many occassions. If you want to believe I just fabricated this whole issue in detail then that is your prerogative.

Ask any product engineer that was formerly employed by solyndra, or currently sells or designs rooftop systems in the Southwest and they will echo what I have said.

 

George Stevens's picture
George Stevens on August 15, 2013

No that figure of $120,000,000,000 per year isn’t “reliabile”, it is arbitrary because it isn’t applicable to natural gas, which doesn’t cause the respiratory conditions and ailments that coal does. Sure, extraction of natural gas disrupts land, but alternatives such as wind, solar, and hydro have arguably more negative land impacts per unit of energy. I would support a carbon tax but I think most carbon tax advocates underestimate how important cheap energy is to a national economy.

In regards to uranium supply:

1. Enriched uranium for a nuclear reactor comprises 14% of overall costs. Therefore mining the ore from less concentrated reserves or even extracting uranium from seawater would not necessarily be detrimental to overall cost of electricity from modular reactors. Also as has been shown with virtually every other high demand global resource, as demand starts to approach known-supply intense exploration efforts are funded which inevitably leads to discovery of more reserves. Uranium is abundant in the Earth’s crust, I have little doubt that there are vast undiscovered reserves.

2. Fast neutron reactors exist and can run on a majority of spent fuel, essentially closing the nuclear fuel cycle and potentially providing global power for centuries.

I don’t envision nuclear as a sole energy technology in the future, I think renewables will undoubtedly play a part. But I don’t see the mankind avoiding major temperature rise without utilizing nuclear energy.

 

 

Clayton Handleman's picture
Clayton Handleman on August 15, 2013

If you object to Robert’s number then offer a credible alternative.

Regarding RE impact on the land, it really is not comparable.  RE, at least wind and solar, allow the land to revert to its natural state almost immediately after removal.  Many forms of fuel extraction leave permanent damage to the land and aquifers.  It is not apples to apples.  Furthermore, the aquifer damage can extend beyond the site.

George Stevens's picture
George Stevens on August 15, 2013

US nuclear generating facilities are properly insured. The NRC requires just shy of 13bn in coverage be available per facility, and the Price-Anderson act exists to cover the unlikely occurance of claims exceeding the insured amount.

It is difficult to think of a scenario where a modern reactor with passive safety systems would have such an incident that would require the full 13bn of mandated coverage.

Clayton Handleman's picture
Clayton Handleman on August 15, 2013

Robert,

Good point.  And some argue that your number is too high.  The carbon tax could be relatively innocuous and still have a large impact.  One could take 1/4 of your annual number and apply it to a renewable energy transition fund that would fuel, T&D upgrades, R&D, Demand Pull programs and loan gurantee funds like those that were used by Tesla, FIRST and SunPower.

Phase it in over 5 years and it would not be particularly burdonsom. 

Clayton Handleman's picture
Clayton Handleman on August 15, 2013

Nobody anticipated TMI and nobody anticipated Fukushima.

If it is exceedingly unlikely then let them privately insure to $100B.  Should be some companies eager to take on the risk if there are no scenarios where it could happen.

Tim Havel's picture
Tim Havel on August 15, 2013

Good article. But I would guess (or at least hope) that the ca. 2 billion that do not live in cities as of 2050 will be happily supplementing their incomes with lots of distributed renewables. As for nuclear: Stand and deliver something that won’t result in another Fukushima, let alone a diversion of nuclear materials to terrorists, or else shut up. I happen to think that could be done, but Rod Adams types just want to proliferate the grossly inadequate technologies with which we’ve covered the landscape today. By so doing, they are murdering their own cause. And certainly not helping stop climate change either.

Warren Weisman's picture
Warren Weisman on August 16, 2013

While you included liquid biofuels, you left out biogas, which offers not only makes 3-5 times more energy per acre than liquid biofuels and doesn’t compete with food crops, since waste can be used and it doesn’t require dedicate carboyhudrate or oil crops, but it also has symbiotic benefits of reducing waste and pathogens, and recycline nutrients for agriculture.

In fact, I’ll go out on a limb and guess there’s nobody on this site who understands the first thing about biogas, which is why you keep lumping it in with liquid biofuels.

Robert Wilson's picture
Robert Wilson on August 16, 2013

Warren

Let’s accept that biogas is 3-5 times more power dense than liquid biofuels. This is still pretty awful. We would need these things to offer a power density much greater than an order of magnitude higher than corn ethanol.

But I can be persuaded. Can you tell me the land requirements for, let’s say, the United Kingdom to replace 100% of its current gas consumption with biogas? Current UK gas consumption is 78.3 billion cubic metres per year, so a back of the envelope calculation for land requirements should be easy

Robert

Warren Weisman's picture
Warren Weisman on August 16, 2013

You tell me what your home energy need is and I will tell you how much waste you will need to meet that need to the joule – which we do in the real world, not on paper, every day. I’m not playing stupid open-ended questions about entire countries.

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