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How Big Is The World's Biggest Solar Farm?

Solar Energy Space Needs

In the last few months we have seen both the world’s largest solar bridge and the world’s largest solar farm open. The bridge was opened in London, a city so famous for its fog that they named a fashion label after it. The farm was built in the middle of the Californian desert.

Now, I sit and type this during the supposed beginning of a British Spring so I find it difficult to drum up any enthusiasm for the opening of a solar farm on top of a railway station in our capital city. In these cases political correctness should be abandoned and it should be stated clearly that such things are nothing but public relations ventures.

But a solar farm in the middle of the California desert, this I can be enthusiastic about. At least we have moved on from the strange situation where the world’s largest solar farm was in Bavaria. Progress of a kind.

This power plant however seems to have not been universally popular. And in this case it wasn’t only from subsidy opposing conservatives. Some environmentalists weren’t happy about its potential impact on desert wildlife. Now, I am not going to adjudicate on the environmental merits of the project. However, the people who say no to such things must ask what they are saying yes to.

Is there any evidence that the power plant that would have been built in place of Ivanpah would have been better for the environment? Are tortoises fond of fracking? We often imagine that things are bad, so we oppose them, but often we should be asking instead if something is better or worse than the alternatives. Such attitudes are rare.

Ivanpah then has been built, generating electricity, and people are now free to debate the merits of its carbon emissions reductions and the current state of Californian tortoises. But how big is the thing?

Power density of Ivanpah solar farm

Covering 14.2 square kilomtres the press release tells us that it will have a capacity of 377 megawatts, reduce carbon dioxide emissions by 13.5 million tonnes over 30 years, and power the equivalent of 140,000 homes.

However total capacity only tells us what the output is when the sun is shining at full tilt. The sun goes down in California, so what we really want to know is the average output. This is expected to be 123 MW, that is it will have a capacity factor of 33%. Power density of the power plant is therefore 8.7 watts per square metre.

California consumed 234.8 trillion watt hours (TWh) of electricity in 2012, an average output 26.8 GW. In other words Ivanpah will generate 0.46% of California’s electricity consumption.

So given California’s average electricity demand of 26.8 GW how much land would we need to provide all of California’s electricity with solar thermal if Ivanpah is a reasonable indication of future land requirements?

Total area required is approximately 3,200 square kilometres.

This is a rather approximate estimate. First, until a cheap way to store electricity is found, 100% solar remains off the cards. Second, a very high level of solar energy will require significant losses in electricity production in both storage and as a result of curtailment of excess electricity. This, and our inability to accurately predict future efficiency gains in solar conversions, means that this estimate is somewhat uncertain.


These numbers can be put into context. 3,200 square kilometres is smaller than the Los Angeles metropolitan area, and the equivalent of around 1% of California’s land.

The size of renewable energy power plants will soon start, and already are in some cases, causing problems. However is it possible that a state so famous for its tolerance of suburban sprawl would object to around 1% of its land being used for solar power plants?

Robert Wilson's picture

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Robert Wilson's picture
Robert Wilson on Apr 8, 2014 11:42 pm GMT

Please do not attack people for misusing terms such as capacity, and then refer to MWh as a unit of power output. It makes you look like an uninformed big mouth.

Paul O's picture
Paul O on Apr 9, 2014 12:12 am GMT

Petajoules and MWh are the same quatity..Energy.

Even if he meant to say energy and instead he’d typed power, there is still a whole world of difference between misstyping, while being correct in comparison of units on the one hand, and intentionally using large capacity numbers to fool the public into thinking that something is producing more than it actually does.

The 2.2 billion dollar 123 solar MW plant is flat out ridiculous.


Joe Deely's picture
Joe Deely on Apr 9, 2014 2:38 am GMT


Good job on both research and presentation.

Roger Arnold's picture
Roger Arnold on Apr 9, 2014 3:11 am GMT

The problem with Ivanpah is that it’s such an incredibly awful representative for solar power. 

Even ignoring the far-from-minor issue of non-availability when needed, $2.1 billion for an average 123 MW is roughly 30 times the capital cost per MW of a natural gas peaker plant, 20 times that of a modern high efficiency NGCC plant, 10 times higher than a coal-fired power plant, and 5 times higher than the outrageous price of new nuclear capacity in the US.  Ivanpah completely dominates the patch of desert it sits upon, and leaves the land unavailable for any 2nd use.  It’s not even good as wildlife habitat for anything trying to return after the road grading and scraping of the land.  Any land that isn’t permanently shadowed by the heliostats is roadway for the maintenance vehicles.

It’s possible to do much better.  I’ve personally proposed sparse arrays of solar PV panels held in a “tensegrity” space frame 30 feet above orchards and agricultural fields in the California’s Central Valley.  Coverage would be maybe 25%, so the moving shadows from the panels above would resemble the effect of clouds on a partly cloudy day.  Most crops wouldn’t notice the reduction in direct sunlight; some would benefit.  The space frames could also carry water lines for crop irrigation and sprayers and/or reflectors to protect crops that are sensitive to frost damage.

There may be other better ways to go, but Ivanpah is a boondogle by any standard.

Nathan Wilson's picture
Nathan Wilson on Apr 9, 2014 6:27 am GMT

A few further notes:

This plant uses dry cooling (which makes its water use similar to PV – mainly for cleaning).  It also proves the viability of the technology for advanced nuclear plants.

Unlike some other CSP plants (such as Solana Solar, Crescent Dunes, Andusol 1-3, and Gemasolar), Ivanpah does not use thermal energy storage.  This will make it very hard to justify this technology over cheaper PV.  But there is still no energy storage system for PV that is affordable and environmentally friendly.

The NREL page for Ivanpah claims that the plant includes natural gas backup, but Ivanpah and Brightsource webpages are mum on the issue.  According to old Luz/Brightsource material, their 550C steam technology should have 40% heat-to-electricity efficiency (not counting light collection losses), so the natural gas performance would be much worse than a modern combined cycle plant (up to 60% efficient), but better than a trough CSP plant could achieve (with 400C heat transfer fluid).

Still, with the huge amount of PV coming on the California grid, expect to see that natural gas backup used not just for passing clouds, but for a couple of hours each evening to help reduce ramping of the other fossil generators.

Nathan Wilson's picture
Nathan Wilson on Apr 9, 2014 6:48 am GMT

I don’t buy the wasted land argument.  We plowed over the entire US central plains for cropland.  Why complain about a little more (per person served, I’m pretty sure CSP uses less land than agriculture: food production takes about 30% of the US, all-CSP electricity would be around 1%).  And CSP is a much better use of deserts than farming (yes, California does farm the deserts of their central valley – they use imported water).

If the heliostat pylons are made just a bit taller than the minimum for ground clearance and spaced a bit further apart, there need not be any land that is permanently shadowed.  Desert life is water-limited, not sun-limited.  Wait a couple of years, and we’ll see how much wildlife lives at Ivanpah among the mirrors.

I agree that this (first of a kind for large US power tower technology) cost is ridiculous, but this one data point does not prove that CSP with thermal storage will always be more expensive than PV with storage (storage can be added to CSP for roughly zero extra cost, as the cost of the storage system is offset by a smaller and less expensive power turbine/generator/transmission-line; the longer the required transmission, the more savings).

Roger Arnold's picture
Roger Arnold on Apr 9, 2014 7:36 am GMT

Had Ivenpah truly been a “first of a kind”, had it included thermal storage, or done anything particularly innovative to advance the “state of the art” in solar thermal power generation, I’d be less down on it.  But as far as I can tell, it didn’t.  It was a deliberately conservative design using previously developed technology, intended to demonstrate a grid-scale solar thermal power plant.  What it seems to have demonstrated instead is the utter impracticality of that approach.

If somebody can produce a credible roadmap, drawing on experience with Ivanpah, showing how a 10-fold reduction in cost can quickly be achieved, then I’ll take back my words.  But for now, a subsidy-reaping boondoggle is still a boondoggle.  A ripoff of federal and state taxpayers and state ratepayers and a black mark against renewable energy.

Robert Wilson's picture
Robert Wilson on Apr 9, 2014 8:43 am GMT

You clearly do not care about this conversation, otherwise you might have made some effort to actually address the subject of the piece. It was about the size of solar farms in California. You however just see the word solar in the title and decide to have a general rant against “junk” solar. This is really tiresome behaviour and helps to make it impossible to discussion the actual subject of the pieces here at Energy Collective.

Is it really necessary to respond to everything you see about renewables by responding “Renewables are useless!”?

Robert Wilson's picture
Robert Wilson on Apr 9, 2014 1:08 pm GMT

I complain about you ranting against solar energy instead of addressing the contents of the piece and you respond by ranting against solar energy. Rather tiresome, wouldn’t you agree?

Paul O's picture
Paul O on Apr 9, 2014 1:51 pm GMT

Sorry to intrude NNdair, but if I may,

Robert, any  reader would have read your comment as i’ll tempered  sniping or snapping.

You were transparently inferring that he, being ill informed on distictions between Energy and Power is not entitled to momment other who you Capacity to misleed.

To me you just seemed like an ill tempered person who enjoys lashing out with snide comments. The term “big mouth” was entirely condescending and unneccessary, and unbecomming of a contributor.

Robert Wilson's picture
Robert Wilson on Apr 9, 2014 2:56 pm GMT

Yes. NNadir says that the renewables industry are frauds, and it is me who is acting in a manner “unbecoming of a contributor” when I criticise his tone. Play me the world’s smallest violin.


Paul O's picture
Paul O on Apr 9, 2014 3:36 pm GMT

At least he is stating why he thinks they are frauds, and not dishing out one liners.

Clayton Handleman's picture
Clayton Handleman on Apr 9, 2014 3:56 pm GMT


My take-away from your post is that it was about land use and the fact that in comparison to the scale of other land use, the environmental impact of solar may not be so bad as some are making it out to be.  I liked this quote:

“We often imagine that things are bad, so we oppose them, but often we should be asking instead if something is better or worse than the alternatives.”

It is unfortunate that the comment thread got hijacked.  There is plenty of time to debate the relative merits of nuclear vs solar and their economics.  In fact those subjects get a lot of airplay in TEC.  However, the question you have raised has not gotten a lot of discussion in the TEC and I think it is important to look at.  It would be great to see the conversation expand on how a temporary (30 – 60) year lifespan structure compares environmentally to energy sources that are destructive on time scales large in comparison to human history.  Mountain Top removal, Fracking (while theoretically it can be done clean if done right, the fossil fuel industry has a shabby record doing things “right” ). 

It would be interesting if we could develop an environmental damage scale.  What is the relative damage of a mirror array or solar array compared to mountain top removal or open pit mines with toxic waste pools.  When the mirror array is removed, the land can revert relatively quickly to its natural state.  When a mountain is ripped apart or a 1000 ft deep pit is dug, the land is gone.  Shouldn’t these be scored differently?

Photo by Vonvon

I found one commenter’s statement a fascinating study in denial.  They said that the renewable industry is “fraudulent” in their use of capacity when talking about power plants.  However that commenter then went on to describe the footprint of a nuclear power plant as trivial in comparison to that of a solar array.  Oddly, they neglected to associate the footprint of mining, processing and disposal of nuclear waste in the discussion of footprint.  Are they “fraudulently” missleading us or is it simply enthusiasm about their point of view that led them to paint such a distorted picture of reality.  Hopefully they can have a laugh at their own expense and then get back on topic. 



Robert Wilson's picture
Robert Wilson on Apr 9, 2014 5:02 pm GMT

Clayton, there are very simple rules of thumb for online energy debates. A significant number of energy sectarians only want to discuss debates in terms of anti this, pro that, this versus that.

If you write about solar from a perspective that they cannot quickly corrall as an anti-solar talking point they will quickly change the topic to something else: solar is too expensive, solar is intermittent. It’s a toxic mindset that dominates these debates. Pure tribalism.

Comparisons of the environmental footprint of different energy sources have rarely been made. Certainly if we isolate particular aspects then we can say certain things. Natural gas is far preferable to coal in terms of air pollution. Nuclear is preferable to wind in terms of visual impact. Wind is preferable to wind in terms of the ability of power plants to convert land into un-inhabitable regions. However systematic comparisons are far from easy.

We know enough to say that coal is worse than almost anything for electricity generation. And gas is probably worse than nukes/wind/solar due to climate change impacts. But beyond this we have subjective sudgements. I have come across a large number of armchair ecologists/nuclear advocates tell me the ecological impact of nuclear is a lot less than that of wind. Actually ask these people to point to peer reviewed research to back this up and you won’t get very far. I once spoke to someone who met with the UK government about coming up with an accurate way to compare the environmental impacts of various forms of low-carbon electricity generation and he advised them that there simply wasn’t enough research to answer the question with any real objectivity.

Land use impacts appear to me to be more of a social problem than an environmental one. Wind farms cover huge areas, and not many people want to live near them. This makes expansion more difficult in dense countries. In places like California this is less of an issue. Low power density of renewables may place some limits on them, but saying this means they are useless is just silly. It’s rather like arguing that because you cannot live on a water only diet that you should stop drinking water.

Paul O's picture
Paul O on Apr 9, 2014 9:27 pm GMT


Thank goodness for TEC where Energy partisans of every stripe have their opportunity to debate and disagree without being called names like big mouth.

I would wonder why you would not point out to the commenter you mentioned, the discrepancy in his views, and have him defend them like a gentleman. Who knows he might ebven have agreed with you.

Let’s me also point out  that there mines in China ripping the earth to produce the Neodenium, rare earths,  Lead,  Cadmium, gallium, and whatever other toxic stuff, that are essential to Solar PV , Windmills, and Storage. 

The reason I camre to TEC and Stayed is because there has always been more civility here than on other forums. I definitely fell for Geoffery Styles, and the cordial and gentlemanly manner that he always addresed readers, no matter how rude they were.

If TEC suddenly became a place where a contributor becomes dismissive or abusive, I’d be happy to vote with my feet and leave, and I wouldn’t care less who wished me good riddance or not.

Robert Wilson's picture
Robert Wilson on Apr 9, 2014 9:48 pm GMT

Calling for civility while defending calling the “so called renewables industry” frauds. Either you lack self awareness or you are a man of deep irony.

Bill Hannahan's picture
Bill Hannahan on Apr 9, 2014 11:00 pm GMT

Robert, what is your definition of “ranting”. I see mostly facts and logic in Nadir’s comments.

Nathan Wilson's picture
Nathan Wilson on Apr 10, 2014 5:06 am GMT

Of course there have been plenty of studies predicting a drop in cost for CSP.  NREL’s 2003 study from Sargent and Lundy predicts a factor of 2 or 3 reduction by 2020.  The 2006 report from the Western Governors Association solar task force also predicted a 3x drop, after 4 GWatts are installed.  Even without a 10x drop, a 3x drop would make Ivanpah solar cheaper than the California cost of solar PV or wind.

In the same way as it is not possible to accurately measure the torque on a nut that is not turning, it is also not possible to measure the cost of a technology which is not in volume production (and for power plants, that means multi-GWatt scale).

Feel free to criticize the studies, or criticize the Ivanpah project management.  If you foresaw issues that NREL did not, then great.  But it is not fair to criticize them for costing more than natural gas, since the cost reduction in gas occurred after the Ivanpah plant was planned; and solar PV has recently surged dozens of GWatts ahead of CSP power towers, so even that is not a fair comparison.

Nathan Wilson's picture
Nathan Wilson on Apr 10, 2014 5:04 am GMT


I’m sure you are aware that manufacturing and disposal of PV arrays will necessarily involve disposal of toxic chemicals?

And perhaps you’re aware than much of our current nuclear power comes from dismantled nucear warheads.  Of course the ultimate goal of the pro-nuclear movement is closed cycle reactors, such as the IFR which could supply all our electricity needs for 400 years using just the uranium that has already been mined, or the LFTR which can supply our electricity many times over using the thorium waste from the rare-earth mining industry.

Of course today’s light water reactors will require mining, but given that they get 10,000 times more energy from a pound of mined uranium than a thermal plant can get from a pound of fossil fuel it should come as no surprise that uranium mining is relatively low impact (even when the uranium is just a small fraction of a percent of the ore).  Dredging up old mining horror stories from the 1940 is no more relevent to today than looking at wind turbines or chemical waste disposal practices from the 1940.

Similarly, nuclear waste disposal need not use much land.  It’s no problem to temporarily store 60 years of waste at the power plants.  And given that the final waste repositories will be underground (with eventually unrestricted use of the surface land), you could say it requires no permanent land.

donough shanahan's picture
donough shanahan on Apr 10, 2014 12:45 pm GMT

The one problem I see is this comparison of the built environment and a solar farm. A solar farm will probably have its panels replaced every 20-30 years and in reality, this is the main element of the structure. Biuldings on the other hand have an average lifetime of 60 ish years. However the structures are often still available for reuse or recycling. There are also a lot of outliers on the building lifetimes with many victorian era buildings around (at least in the UK) and skyscrapers above 100 years old. Life extensions are thus possible though not for panels.

Clayton Handleman's picture
Clayton Handleman on Apr 10, 2014 12:47 pm GMT

Deleted – It posted same thing twice.

Clayton Handleman's picture
Clayton Handleman on Apr 10, 2014 12:46 pm GMT

“I’ve personally proposed sparse arrays of solar PV panels held in a “tensegrity” space frame 30 feet above orchards and agricultural fields in the California’s Central Valley.”

An interesting idea.  Are there photos of test sites or architectural drawings.  I would be interested to learn more about it.  How do costs look compared to other mounting approaches.

People have also looked at pole mounting with the poles high enough that there is a similar effect minimizing shading.

Clayton Handleman's picture
Clayton Handleman on Apr 10, 2014 12:49 pm GMT

“But it is not fair to criticize them for costing more than natural gas, since the cost reduction in gas occurred after the Ivanpah plant was planned;”

And BTW, the downside to gas is that the price goes back up as anyone in the Northeast will tell you.

Bas Gresnigt's picture
Bas Gresnigt on Apr 10, 2014 9:24 pm GMT

That power density of 8.7 W/m² for Ivanpah, is rather bad compared to PV.

A good quality PV panel (e.g. Sunpower) on the roof has a capacity of 200 W/m² (yield >21%).
With an average utilisation of 20% (sunny area) that delivers a power density of ~40 W/m².
And no land use at all, as it is on the roof.


Paul O's picture
Paul O on Apr 11, 2014 1:40 am GMT

I thought I said this before. NNdir stated his reasons, please feel free to go and debate him if you must.

Furthermore, calling an industry frauds is not uncivil. It may be inaccurate, it may be unwise, it may even be uninformed or hypocritical.  On the other hand, if I called you, or another particular individual a fraud, that there is patently uncivil and possibly even libelous.

Industries like the Autombile Industry, the Oil and Gas Industry, the Nuclear Industries, have all been called all kinds of names in the past by people who favor renewables, and they will likely be called even more names in the future. Even if I dislike it, this concerns me far less than when a living, breathing human being were called names.

Friend, everything I have said above seems self-obvious to me. I frankly think that what’s really happening is that you are used to being freely dismissive toward others without being called out on it.

Roger Arnold's picture
Roger Arnold on Apr 11, 2014 2:18 am GMT

No nice pictures that I can get my hands on at the moment.  I may have something in the backups for a defunct web site that I could ressurect.  But it’s not hard to picture it, once you have the general idea of a tensegrity structure.  What I proposed was much simpler and more regular than the complex structures that you’ll find in an image search on “tenegrity structure”, or on this gallery site.  

In what I proposed, the compression elements were all verticle members that served as elevated posts for mounting the panels.  They were positioned in a flat hexagonal array, with each post connected by tension wires to its six surrounding neighbors.  There were six horizontal wires and six diagonal wires at the top of each post, with a corresponding six horizontal and six diagonal wires at the bottom.  

That’s for the interior cells; those on the periphery would have fewer surrounding neighbors.  In place of the missing neighbors, they’d have tension links to the boundary poles that held up the tensioned array. The boundary poles would slant outward slightly, and be  guyed to ground anchors for providing tension to the whole array.  The poles would be 30 – 40 feet high, leaving clearance below the array for tractors and farm equipment.

Clayton Handleman's picture
Clayton Handleman on Apr 11, 2014 3:05 am GMT

Sounds a bit like a solar tent : )

Interesting idea.


Roger Arnold's picture
Roger Arnold on Apr 11, 2014 3:37 am GMT

Regarding the comparison to natural gas, we’ve been talking about capital cost, not O&M.  The capital cost of gas combustion turbines and combined cycle units hasn’t changed quickly or dramatically over the last 40 years.  Efficiency and flexibility have improved, but the capital cost per MW of rated capacity hasn’t changed all that much — certainly not in the time since Ivanpah was planned.

The cost of fuel — sunlight being free — justifies a higher capital cost for solar, per annual MW-hour delivered, than for any fossil-fueled plant.  Depending on the cost of capital and the cost of fuel, a solar installation might be financially attractive at 3x the cost of a natural gas plant, when gas is as cheap as it has been for the past few years.  If natural gas recovers to the $6 – $8 price needed to sustain production and if interest rates remain low, than a capital cost of 5x for solar might be attractive.  But definitely not 30x.

I would love to know more about why the cost of the Ivanpah facility was so high.  As I said, if someone can show why future projects drawing on its experience will be 10x cheaper, I’ll happily take back my negative comments.  But a 10x reduction is far outside the normal learning curve from a mere rampup of production volume.  It’s more the difference between a hand-built prototype and a factory-produced unit. With ca. 350,000 heliostat mirrors, Ivanpah was far from a hand-built prototype.  It pushed no technology envelopes, and seems like it should be a fair benchmark for the cost of that technology in large-scale application.  Perhaps I’m wrong, but show me.  

BTW, I’m not against solar thermal power in general.  I’m familiar with the Sargent and Lundy study that was highly favorable.  But that was for parabolic trough designs, with integrated thermal storage.  Right now, it seems that the tens of thousands of large stepper motors, sensors, and controls for precision pointing of all those polished heliostat mirrors are likely an inherent limiting factor for the economics of power towers.

Clayton Handleman's picture
Clayton Handleman on Apr 11, 2014 5:01 am GMT

I think you offer a great case in point to one of Robert’s statements:

“”We often imagine that things are bad, so we oppose them, but often we should be asking instead if something is better or worse than the alternatives.”

I have found this metastudy helpful in gaining some perspective on the relative environmental impact of different energy sources.


Clayton Handleman's picture
Clayton Handleman on Apr 11, 2014 5:53 am GMT


It was not my intent to do a direct comarison between nuclear and solar or to say one was better than the other. 

My comments about nuclear power were directly in reference to and frustration with these from Nadir’s comment and the tedious thread of bickering that they provoked:

“In the following link, note the difference between “capacity” which is always fraudulently represented by the so called “renewable energy” industry and energy.  “

“San Onofre produced in two small buildings, covering a surface areas too trivial to compare to the state’s land area.”

In that, he conveniently left out the environmental footprint of the mining and processing required to fuel the nuclear plant.  So what he said is true but contexturally disingenuous.  This is exactly analagous to the solar industry making true statements about capacity.  One can make a reasonable arguement that what they say is contexturally disingenuous and probably often done intentionally to take advantage of the general public’s lack of energy literacy.  However it is accurate and in no way is it fraudulent. 



Robert Wilson's picture
Robert Wilson on Apr 11, 2014 9:05 am GMT


Again, I will repeat, this is tiresome. My piece does not “rant” against environmentalists who give a rat’s ass about tortoises. Your misreading of it is rather unbelievable in fact. Are you actually capable of reading, or do you just filter everything through your prejudices?

You seem to imply that I am attacking people for thinking about criticising solar projects. You read it “as an endorsement of the idea that environmentalists have their heads up their butts if they criticize solar energy projects.” Seriously? I open the piece by criticising a solar project, and I later take a rather negative view of building solar in Germany. By your own misreading of the piece then I am saying that my head is up my own ass. 

I also state clearly that I am not adjudicating on the environmental benefits of Ivanpeh, yet you think I am dismissing its impact of tortoises. In fact I am stating no view either way, simply expressing that we maybe do not know the answer. 

You also make it seem that I dismiss the issue of land use for renewables. This is again nonsense, and I suggest you re-read the piece, or in fact read anything I have written about the subject. My final paragraph has this sentence: “The size of renewable energy power plants will soon start, and already are in some cases, causing problems.” However you believe that I am dismissing the issue!

It’s a bit tiring to have to come into the comments and deal with this type of misrepresentation, but there it is. 

But at least it is good to get a tribalist coming at me from the other end. Normally I get hardline pro-renewables people coming along and calling me “anti-renewables”. It’s refreshing to have gone from being “anti-renewables” to being someone who does not question renewables.


Nathaniel Pearre's picture
Nathaniel Pearre on Apr 11, 2014 9:17 pm GMT

While this comment does not significantly change the comparison to a building, consider that the PV panels themselves only make up about a third of the PV farm by capital cost.  

Robert Wilson's picture
Robert Wilson on Apr 11, 2014 11:19 pm GMT

How tiresome do these energy debates need to be? The piece is about solar power, yet half of the commenters have brought up nuclear energy.

A bunch of men (and it is always men who behave in this way) engaged in a dick measuring contest, to put it bluntly.

We could of course try to have a discussion about the land impacts of solar power that actually discussed the issue, and that did not devolve into vacuous pro-solar, anti-solar, anti-renewables, pro-renewables, renewables versus nuclear debates. But hardly anyone seems capable of tolerating such discussion.

Bob Meinetz's picture
Bob Meinetz on Apr 12, 2014 12:28 am GMT

Clayton, let’s talk numbers, because your statement fairly proves N Nadir’s point.

Whether renewables advocacy is guilty of fraud or ignorance hardly matters. The fact is that nuclear’s mining footprint is not only tiny compared to coal – it’s infinitesimal compared to solar. For example: currently, the State of Virginia is considering relicensing uranium mining in the state after a 32-year moratorium. A 3000-acre mine proposed for Pittsylvania County is estimated to yield 119 million pounds of uranium ore, which will deliver 6.3PWh of energy – more than all of the energy contained in Virginia’s offshore oil reserves.

The solar farm at Ivanpah, which is a bit larger at 3,500 acres, would have to run continuously for 50.8 million hours, or 5,800 years, to deliver that amount of energy.

With any kind of luck we will come to our senses, scrap this worthless misadventure, and build a nuclear reprocessing facility in its stead. Or a home for wayward tortoises, or a shopping mall…anything with value.

Clifford Goudey's picture
Clifford Goudey on Apr 12, 2014 1:39 am GMT

Robert, I hate to be the one to break the news but you need to revise your calculations.  Your power numbers are correct but you used the area of the entire site rather then the that used by the mirror array.  Rather than the 14.2 square kilomtres [sic] you pulled from the project press release, the heliostat solar-field aperture area is 2,600,000 m² or a mere 2.8 square kilometres. See:

I’ll let you re-do your own calculations, adjusting your numbers by a factor of five.  You may also want to revise your conclusions, but given your usual disdain for renewables, I don’t really expect it.

Nathan Wilson's picture
Nathan Wilson on Apr 12, 2014 2:35 am GMT

The article is not about how much glass is required, but how much land is required.  The roads, building, and gaps between mirrors are required, so why exclude them from the calculations?

Nathan Wilson's picture
Nathan Wilson on Apr 12, 2014 3:01 am GMT

Sure, but it’s not an apples-to-apples comparison.  I know many people have limitless faith in future breakthroughs, but as of today, while solar PV may work fine as a supplement to other energy sources, we simply do not know how to power a modern society using only solar PV.  

In contrast, if we chose to do so, we could fill the world’s deserts with CSP plants using thermal energy storage and fuel synthesis, and meet all of our energy needs (hence the importance of discussing the land use).  We could even supplement such a grid with a lesser amount of rooftop PV.

I’m sure people that don’t live near a desert don’t like to think about this, but that doesn’t make it any less true.

Clifford Goudey's picture
Clifford Goudey on Apr 12, 2014 3:01 am GMT

So when you calculate the size of a roof-top PV array would you use the lot size?  Or when you capculate the foot print of a wind turbine would you include the acres of corn field that surrounds it?

Nathan Wilson's picture
Nathan Wilson on Apr 12, 2014 4:28 am GMT

Come on Robert, do you really think it makes sense to ignore the elephant in the room?  The sole purpose for the renewable movement is encourage a non-nuclear alternative to fossil fuels, because historically, nuclear power in combination with hydro is the only combination that has been successfully used to fully replace fossil fuels at the national level.  

If we don’t allow any discuss of why we are considering CSP, of what we get in exchange for the land use, of how CSP compares to nuclear, then what is the relevance of the discussion?

I agree that the solar/nuclear discussion is too often vacuous and poorly executed, but that does not mean it is not an important discussion to have.

Nathan Wilson's picture
Nathan Wilson on Apr 12, 2014 5:25 am GMT

I suppose it depends on the intended purpose of the calculation.  If it is to judge how much land is “visually impacted”, then for trough CSP go 100 yards past the fence, for wind farm area go one mile from each turbine, 100 yards around each home or building with PV, one mile around a nuclear plant, etc.

If the purpose is to calculate how much land is removed from other uses, then for wind we’d want the turbine foundation plus roads, for CSP or nuclear we’d go to the fence, for rooftop PV maybe it’s zero.

Robert Bernal's picture
Robert Bernal on Apr 12, 2014 6:58 am GMT

Please re-inform yourself about the different (and proven) nuclear reactor designs, if you are to stray… (sorry about doing that myself!)

Robert Bernal's picture
Robert Bernal on Apr 12, 2014 7:12 am GMT

It required more mass because it is far more diffuse than nuclear, especially of the closed cycle. Therefore the costs must intrinsically be more expensive, especially since it has such a low capacity factor. Still, though (in the absense of the better nuclear options), It would be better to have 1% of any land covered by mirrors, molten salt and steam generators… than to keep going backwards using hydrocarbons. Any planetary civilization must learn to deal with some minimal amount of subsidy if we wish to prevent the Holocene from becoming a holocaust…

Bas Gresnigt's picture
Bas Gresnigt on Apr 12, 2014 7:26 am GMT

The reason you now see far more PV farms in deserts and not CSP, is simple: PV is at least 30% cheaper. 
The Austin deal in which the utility did buy electricity from a PV solar farm for <$50/MWh show it.

Take into account that PV-panels have no moving parts, so they can last a century or more (if well designed), and hardly need any maintenance. Only some cleaning for which there are robotcars that do the job fully automated.

Bas Gresnigt's picture
Bas Gresnigt on Apr 12, 2014 7:35 am GMT

“… historically, nuclear power in combination with hydro is the only combination that has been successfully used to fully replace fossil fuels at the national level.”

Check the list of 100% renewable electricity countries at Wikipedia.
No country that uses nuclear belongs to that substantial list. 

Bas Gresnigt's picture
Bas Gresnigt on Apr 12, 2014 7:56 am GMT

…solar farm will probably have its panels replaced every 20-30 years…
There are no moving parts, the technology is similar to that of transistor or old solar cells. Those last already ~50years.

Quality PV-panels are now guaranteed (incl. yield) for 25years (e.g. check at Sunpower). There is no build in mechanims the kill those panels after 30years or so.
So you may assume they last at least four times the guarantee period (as much other equipment). That implies a century.

The other issue is whether they are still economic after 30years.
Assuming the yield progress of 0.5%/year since ~35years continues (no reason why not, Dutch solar car had panels of ~40%), the panels may be replaced on the roof after 30year for others that have a yield of ~35% in stead of the present 20%, which implies the roof delivers 75% more electricity.

Bas Gresnigt's picture
Bas Gresnigt on Apr 12, 2014 8:46 am GMT


The future of solar is PV-solar on your roof in combination with some cheap battery that saves the electricity for the evening. Just check Germany; ~70% of all is small rooftop.
No footprint at all.
Less electricity transport lines/capacitiy needed.

PV-panel production per m² goes up each year with 0.5% yield improvements (may end at ~40%, we now have ~20%. So production by a roof will double).
Costs of batteries are going down fast. Especially since Germany started creating a mass market for this application last year.

Robert Wilson's picture
Robert Wilson on Apr 12, 2014 9:11 am GMT


l really do not see how the “sole purpose” of the renewables movement is to encourage a non-nuclear alternative. 

And why would we not want to pursue non-nuclear alternatives? Has nuclear energy shown itself to be a wonderful source of energy? It seems to have no shortage of problems, problems that the many tribalists at Energy Collective prefer to ignore. 

So, we are told that we must put our faith in small modular reactors and new fast reactors. Perhaps they may work. But it is just faith based thinking to pursue these things while ruling out everything else, which is what some people seem to want to do. Some nuclear advocates tell me that these technologies are “winners”, and the thorium crowd is similar. But not one of these things has been proven commercially.

And the same goes for those who want to crowd out nuclear.

Robert Wilson's picture
Robert Wilson on Apr 12, 2014 9:28 am GMT

Right. So I am now being told that the piece was partial analysis as part of my anti-renewables campaign. Earlier I was told it was arguing that we should not criticise solar. Perhaps I need to finish with bullet points explaining what the article says so that dogmatists do not misunderstand.

Robert Wilson's picture
Robert Wilson on Apr 12, 2014 9:35 am GMT


For wind farms I prefer to look at the size of the entire farm. Some people only want to look at the small bit of land below the turbine. This tells you little of great importance.

Here in Britain there are now considerations of banning onshore wind farms. Irrespective of the merits of doing this it is clear why it is happening: low power density. Simple calculations will tell you how much land needs to be covered in wind turbines to get, say, 100% of UK electricity from onshore wind. And that calculation will tell you that it is not politically and socially easy to do it. Focusing on the area under a turbine will not tell you this. 

Bob Meinetz's picture
Bob Meinetz on Apr 12, 2014 11:26 am GMT

Robert, I think you’ve answer the question of why we would not want to pursue solar by pointing out ithat tiling anything close to 1% of the entire land area of California with panels is not practical.

You make similar points about wind in other articles  of The Energy Transition. In fact, nearly every one of your recent articles describes significant shortcomings of renewables quite accurately and convincingly. So I don’t understand your frustratration with the direction discussion takes when readers want to suggest alternatives.

Quite a few here believe nuclear has indeed shown itself to be a wonderful source of energy by any standard of safety, despite inflated fears of some activist groups and media. It’s robust enough to provide the power which the world will be generating, one way or another, and potentially do it in a way that’s responsible.

I would love to see you put aside the childish implications that nuclear advocates are only impotent men seeking a virility fix, and instead direct your considerable talents to an article on the problems of nuclear power. Don’t be surprised if renewables advocates make their case – that’s the nature of internet debate, and embracing it will prove far more satisfying than trying to keep it on some predestined course.


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