Can We Power the Whole World with Solar Power?

There's a good chance that you've heard somewhere that "there's more than enough energy coming from the sun to power all of humanity". Today, what I'd like to do is look a bit more closely at that statement to see if it is true, and then put it in perspective.

Of course, if we wanted to power the whole world with solar power, there would be many problems to solve. What to do at night (this might be a solution)? Long distance transmission lines? centralized, or decentralized? Solar thermal, or photovoltaic? Where to put the solar power plants (on commercial rooftops, maybe)? etc.

But lets leave all of those questions for another time and focus on just two aspects for now: How much solar energy is hitting the Earth, and how much land would it take to power the whole world with solar power?

As you can see in the image below, there's a lot of solar energy potentially available to us. Even wind power (which is also caused by the sun) is a lot compared to total world energy consumption:

Now, lets look at how much land it would take to harness enough of that solar energy to power the whole world. That might seem like a straightforward question, but the answer will depend on the assumptions you make. Below are images from two different studies.

The first one is from Germany and assumes solar thermal power plants in the African desert.

The three red squares, in order from left to right, represent what would be required for the whole world, for the 25 European countries, and for Germany. Of course, if we were to really do this, not all solar power plants would be centralized like that, but as I said in the intro, we're just looking at how much land it would take, not at the details.

The second study spreads the solar power plants in 6 "hot spots" around the world: North-America, South-America, North Africa, the Middle-East, Central Asia and Australia. It assumes a conversion efficiency of 8% (which is conservative, we can do much better).

The colors in the map show the local solar irradiance averaged over three years from 1991 to 1993 (24 hours a day) taking into account the cloud coverage available from weather satellites
I think that's enough to give you a sense of scale. It's a lot of land, but if it was spread among a few deserts (for solar thermal power) and already existing rooftops (for photovoltaic), it would be manageable.

In future articles we'll look at some of the most promising new clean energy technologies.

Comments

[research]

There is also a breakthrough in low cost solar cells from http://www.nanosolar.com/

less then one dollar per installed watt.

Thin film allows it to cover every roof, car top, etc..

[sheila]

Please do not consider our wilderness areas as "fair game" for some massive, wasteful, centralized "solar solution." If we have not learned anything else over the past century, we have at least learned about the cumulative effects of destroying perfect ecosystems to increase profits. And despite the marketing of Big Energy, especially the crooks in Big Renewables, the deserts are not some blighted wasteland with nothing living and no ecological functions. They are crucial in thousands of ways, some known, others to be discovered (hopefully not after Big Energy irreversibly destroys them and we have yet another "woops, we didn't know" moment).

Every structure should be built and/or retrofitted to be as close to "net zero" for water and power as humanly possible. The Rocky Mountain Institute can show you how. Many, many developed properties can be used as oversized renewable power generators (like every structure in the Mojave), and should be allowed to PROFIT from their capacity, rather than be punished, as current CA law does. the existing grid can be used as a large load-balancing center for excess power generated at these point-of-use facilities, and NO new transmission or wasteful, destructive remote generation facilities are needed.

This is ready NOW - we just need to divert all the taxpayer resources (power buy-back contracts, cheap capital, tax breaks, subsidies, etc.) we are shelling out to Big Energy back to ourselves, so WE can do the right thing without breaking the bank.

[research]

converting all electrical generation to solar would be cheaper than the trillion dollar Iraq war crime for oil.

There are much better solar cell up to 45% now.

[mergina]

Of course there is.

[Ajita]

Excellent! This is the kind of thinking we need. Please give us more analysis on the efficacy of solar power, Mr. Richard.