Anybody can draw a red square on a map of Africa: filling it with solar is the $64 trillion question.


 “We could power the WHOLE WORLD with a solar array the size of the biggest red box? That square is so tiny…it’s only the size of West Virginia, which is the 9th smallest state!” That’s a compelling story, and you can see why it has been going viral on my social media feed lately. But the graphic is badly misleading.

First, while the red square looks small, Algeria (the country on which it drawn) is the biggest country in Africa, and 10th biggest in the world at nearly a million square miles.

Next, solar arrays are normally measured in square feet (or meters), not square miles or kilometers. That small red box is around 25,000 square miles, which is indeed about the size of West Virginia (24,230 mi2.)

The West Virginia Division of Highways is responsible for 72,000 lane miles, which are 90% of the roads in the state. A lane is 12 feet wide, so that amount of roadway covers 164 square miles, or about 0.7% of West Virginia’s surface area. Repaving a road – with asphalt, AKA waste petroleum and dirt – costs about $125,000 per lane mile, or $55 million per square mile. And this is how affordable they find that:


Currently, a 600 square foot solar array costs about $55,000 installed, or $92 per square foot. At 5,280*5,280 that means that a square mile of solar array would be $2.56 billion. And the biggest red box on the graphic above would cost $64 trillion. Trillion.

That seems like a lot of money…and it is. It’s equivalent to ALL of US GDP for the next four years.

Put another way, global spending on all new electricity generating capacity will be about $400B in 2014, of which renewables are already 60%. In order to fill our red square with solar arrays, we would need to take the entire global capital expenditure on power plants, devote it to this one task…and keep doing it for the next 160 years.

By the way, the reason the red box is drawn in North Africa isn’t random chance: the energy figures supplied ONLY work for a place where there is almost never any cloud cover and that is close to the tropics. Which is fine, except that isn’t where the world needs electricity. Not only do we need to spend $64 trillion in the middle of the desert (the shipping and construction costs will not be cheap) but we now need to transport that electricity to the places where it will be used. That will be at least another $30 trillion, or 75 years of global spending.

Then there is the cost of storage: the electricity isn’t necessarily being generated at the time of day when it is needed. The (very) rough rule of thumb is that storage adds 25-50% to the cost.

We are now up to about $125 trillion, and I am being very optimistic on the costs.

Please don’t get me wrong. I am not saying that solar doesn’t work, or that it won’t have a larger role as a percentage of global electricity production. But I am saying that running the graphic with the headline “This map shows how little space we’d need to power the entire world with solar panels” is deceptive. It confuses people about energy and the real numbers, and in turn that will lead them to making bad choices in their lives and at the ballot box.

In 2014, being energy-literate is as important as being able to read, write, or do math.


Special thanks to my friend Byron Berry who started this conversation, and Brian Piccioni who helped with some of the research. All errors and opinions are purely my own, of course.

[Detail only for energy geeks. The chart that has been going around was originally from a 2005 Diploma Thesis for Nadine May at the Technical University of Braunschweig. The full thesis is here, and the map appears as Figure 12 on page 12. Despite the headline that accompanies the graphic talking about “powering the world with solar panels” May’s thesis was referring to solar thermal, not solar photovoltaic. However, since thermal costs 30-50% more than PV, all it means is that the idea is even less practical than the image would suggest. Which May knew full well: “These considerations only serve to point at the large potential of this energy resource and technology respectively. It should not give the impression to be the only option for the expansion of renewable energies.”]




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