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ajm101 (31.93)

How many solar cells it would take to supply the entire earth's electricity needs?



October 31, 2009 – Comments (20)

A picture representing the surface of the Earth that would have to be covered in solar cells to generate all the world's electrical needs was posted as part of a post rebutting Superfreakonomics, here.  The image itself is here.  The author includes all of his calculations and assumptions in the post.

Remember that when you hear people talking about how infeasible it would be to wean ourselves from a coal economy.  Coal is almost exclusive used to generate electricity in the US, and coal power plants produce about half of the electricity the US consumes (which itself is about 40% of the energy used by the US per year).  It's even more realistic when you consider wind power and efficiency improvements.  

20 Comments – Post Your Own

#1) On October 31, 2009 at 1:42 PM, rofgile (99.40) wrote:

Nice posting.  Solar energy is a great possibility for total energy.  And it doesn't have to be photovoltaic, it could be concentrated solar instead.

The real truth is we could rely 100% on solar and drop fossil fuels, which is amazing.


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#2) On October 31, 2009 at 2:24 PM, ajm101 (31.93) wrote:

Thanks, rofgile, I'm glad for your comment.  I had just come back after reading the very insightful comment #12 in this silly thread to emphasize that I think this is a highly investable idea, not a political diatribe (how global warming could be considered a political topic is a subject for another forum).  I couldn't write about it any better than so I will just say that I like efficiency and grid upgrades most (JCI, BGC, and MXWL are current holdings and I have an eye on LED-related companies and ABB) and on more renewable weighted producers like Iberdrola and FPL.

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#3) On October 31, 2009 at 2:38 PM, portefeuille (98.50) wrote:

and I have an eye on LED-related companies

You might want to have a look at this post.

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#4) On October 31, 2009 at 2:53 PM, ajm101 (31.93) wrote:

I didn't mention it by name (it was in the LED-related bucket), but AIXG has been right on my radar since that post, port :)  I've had mediocre experiences with semiconductor equipment makers before (BRKS) so I'm loathe to chase it...  I'm disappointed that this correction hasn't given me a better entry point.  Another I didn't mention is a small piggyback speculative long on TIMNF.PK based on BravoBevo's writeup, which is essentially an 'anything but WFR' silicon producer position for me.

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#5) On October 31, 2009 at 2:58 PM, binv271828 (< 20) wrote:

Excellent post ajm! Thanks man!!

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#6) On October 31, 2009 at 3:40 PM, JaysRage (87.05) wrote:

I do think that solar will eventually be king, but I also think that wind will have a brief and profitable reign before solar takes over for good.   Wind companies are much much better prepared to execute on a large scale in the near term, and we are already seeing massive investment in it right now, resulting in profits to be seen in 2010.

Once wind peaks, I'll be looking to move out of wind and into solar, just as it begins to make its move and become the final energy king.   I'm not there yet.   I think money moved there now will be dead for 2-3 years.   Not a bad long term investment, but why not use that money in the mean time and still get the gain?  

Fossil fuels will survive the wind revolution, but they will not survive solar.  

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#7) On October 31, 2009 at 4:50 PM, rofgile (99.40) wrote:

I second JaysRage comment.  Wind is a great investment now, solar is still yet to come.

I am currently invested in wind power through Vestas shares, and solar through FirstSolar.  Wind energy will be growing for quite some time, the technology and companies are quite mature and the industry is consolidated.  It is difficult for a new company to come along with an upstart wind technology that would make your investment worthless.

Solar is the opposite.  My FirstSolar shares could become completely worthless for a variety of technological reasons.  Examples: silicon becoming dirt cheap = cheaper competition and terrible margins.  New thin film competitors such as NanoSolar could obselete FirstSolar's product.  Or an alternative chemistry could be developed that is dramatically more efficient an obseletes all PV companies.  Further, a model of deployment of PV panels is yet to be established.  Will we put them in fields?  On roof tops in cities?  Do people lease them, buy them, or rent-to-buy panels?  Etc.  I think solar won't be a mature business model for 20 years.  

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#8) On October 31, 2009 at 5:48 PM, ajm101 (31.93) wrote:

@ JaysRage, binve - thanks!  I think wind will lead solar, too, but my inclination would be either wind power producers (ie FPL) or secondary plays like grid infrastructure.  Time to attend to trick or treaters, have a happy Halloween.

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#9) On November 01, 2009 at 11:01 AM, pixelmoney (< 20) wrote:

Although I am a big supporter, and previously an investor, of Photovoltaic as well as other non-food based Alternative Energy technologies it is imperative to point out that 53,333 square kilometers of PV's is not realistic.


Beside capital the big point I'd like to make is there may well not be enough silicon and/or other rare earth minerals to actually manufacture 53,333 square kilometers worth of panels. Don't get me wrong, I personally am installing a 4 Kw system in the next few months - I'm not against this idea. But like the electric car, fusion or sea algae - none of them can scale up to current let alone "growth" needs. That I'm afraid to say is a fact.


Now, if we all can get off the grand ponzi scheme called capitalism and power way down then just maybe we can make human life the ultimate currency.

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#10) On November 01, 2009 at 11:48 AM, rofgile (99.40) wrote:


 We have enough materials to make concentrated solar fields that large, no sweat.   Maybe that is a better solution than PV for the large fields?  PV could be nice when the technology becomes ultra-efficient - for use only in cities on rooftops perhaps.  

 All you need for concentrated solar is:

 Large mirrors (could be highly polished stainless steel, we have unlimited iron and carbon on the planet).

 A material to absorb the solar energy with high heat capacity (oil / salt).

 Steam turbines (we already are making these for the coal and nuclear plants).


 Solar is very practical, we just need to invest in it as a nation.


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#11) On November 01, 2009 at 12:59 PM, Rasbold (89.69) wrote:

Ok, we all love to love solar, but keep in power, once installed, requires no maintenance....which means, no maintenance people. No jobs. One the install is complete, you only need to change the battery plant after five years, pv panels should last up to twenty years, unless physically damaged.

This would destroy a very large part of the global economy. Electrical energy production is a vast industry. I am not against economical and ecological solutions to our power problem, hell, I am an electrical contractor, I install the damn things myself!

The solar solution is wonderful for houshold (less than 4kW) solutions. Businesses and manufacturers will require many megawattes to function, making solar installations not realistic on the premises. A concentrated solar plant will not work because of transmission losses, esp for DC. -The copper required just to get to the inverters would tax even the mines of Utah!

We need nuclear - It puts people to work and is 100% reliable. We have the technology to exit nuclear waste into space, no more underground chilled storage.

Also, it is about 1000 times cheaper than solar cells. - and clouds aren't a problem!!


Good Luck, and May Your Dow Never Jones!

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#12) On November 01, 2009 at 1:04 PM, Rasbold (89.69) wrote:

One more thing-

 The concentration of any nation's resource is a huge security problem. We don't keep stockpiles of ANYTHING in one spot! Imagine flying a payload of rocks over this massive solar plant -- all of the sudden, half the country has no power??

Osama's Dream!!


NOW Your Dow Will Never Jones!

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#13) On November 01, 2009 at 1:20 PM, portefeuille (98.50) wrote:

not be enough silicon and/or other rare earth minerals

really funny!

Measured by mass, silicon makes up 25.7% of the Earth's crust and is the second most abundant element in the crust, after oxygen.

(from here)

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#14) On November 01, 2009 at 1:42 PM, Rasbold (89.69) wrote:

#13 - true.

Silicon does not exist as the poly or mono crystalline structures needed for pv applications. That is why they are 'grown' in the lab.

The 25.7 pc is great for the glass industry!

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#15) On November 01, 2009 at 8:48 PM, ajm101 (31.93) wrote:

There are plenty of jobs to be had in solar for the foreseeable future... lots of new infrastructure to build to distribute power from the southeast US, lots of science jobs in maturing the technology... even if jobs are lost, the standard of living will be raised.

As for the resource constraints, I don't know.  I understand thin film requires rare earth metals, and I understand the politics behind that resource (I have a smallish speculative long in Lynas).  But there's also concentrated PV, which would reduce the materials required.


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#16) On November 07, 2009 at 9:40 AM, PdoBear (24.42) wrote:

Um... are any of you factoring in transmission losses?

How about energy ROI? It takes quite a while just to recoup the energy that goes into building, transporting, and integrating a solar panel. 

They also are subject to being damaged easily. Solar panels in Florida and the Caribean?

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#17) On November 07, 2009 at 10:01 AM, CFOTOCEO (63.32) wrote:

We will not shift fully to an alternate source until the money is bleed dry from oil and coal.  Too many dollars invested in these areas. 

I agree the technology is there today but there is no money in the short term and thus few are even looking to play in the alternate fuel source game,  A shame we will be dead before we see what was displayed in the image above.  Humans are like crows, they like shiney things.

You are more likely to see another country develope and use to near full capacity alternate fuel source.  My best bet is an Asian nation.

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#18) On November 07, 2009 at 11:29 AM, Teacherman1 (< 20) wrote:

I am not against "Green" by any means, but it does tend to cost.

What's wrong with NG?

Not posting this as a challange, but would really like to know form those who appear to be very sold on Wind and Solar, who I assume have done some in depth and critical thinking on this subject.


Have a nice weekend.

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#19) On November 08, 2009 at 11:38 AM, ajm101 (31.93) wrote:

@PdoBear - I should have been clearer that the author's article and image were aimed at disproving a claim in Superfreakonomics that solar cells wouldn't prevent global warming because of how much of the sun's energy they absorb and radiate back out as heat.   It wasn't a practical suggestion that we should build a 50K sq km solar farm in the heart of Saudia Arabia... that was a just a part of the exercise to show how much area would be required to generate all the world's electricity (in order to then calculate the waste heat it would generate).  I thought it was an interesting way to visualize how feasible alternative energy is, though.  Obviously you're right about location risk and transmission losses.

@CFOTOCEO - maybe - hopefully sooner than later before we really alter the climate.  if you consider the costs there, it doen't look so bad.

@Teacherman1 - Increasing NG usage would improve things.  You can see how much CO2 would be reduced by considering the ratio of hydrogen to carbon in the molecules (methane is 4:1, butane is 2.5:1, petroleum approaches 2:1 asymptotically as chain length increases, and coal has branches and sheets so it is closer to 1:1).   It's still not renewable and contributes to global warming, though.

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#20) On November 09, 2009 at 2:06 AM, lucas1985 (< 20) wrote:

NG is useful as a low-cost bridge fuel for coal plants. NG is cleaner (sulphur emissions, particulates, mercury, etc) than coal in every part of the production chain (i.e., from mining to waste disposal) and it's less CO2 intensive as ajm101  pointed out. However it still emits GHGs and it's non-renewable.

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