mental_floss magazine
SUBSCRIBE >
GIFT SUBSCRIPTIONS >
DIGITAL SUBSCRIPTIONS >
subscriber services >
Where Knowledge Junkies Get Their Fix
How much surface area would we have to devote to solar cells in order to power the whole world? A physics professor at Berkeley named Mattias Loster decided to extrapolate some answers. Assuming the entire world uses about 18 terrawatts per year (which we do) and the solar cells installed had just 8% efficiency (a low average), the black discs represent the surface area needed:
For technical and political reasons (and certainly economic as well), it probably doesn’t make sense to build solar cells that average 150,000m in diameter, but it’s an interesting thought nevertheless.
Via Ecogeek and Loster’s homepage.
Comments (11)
Comment
- Follow mental_floss
Very thought-provoking. Imagine what would happen to the global economy if solar cell roofs came into widespread use. Some experimenting with amorphous silicon (ie sand) was showing encouraging results a few years ago. Wouldn’t that be a kick?!
posted by Tom on 4-10-2007 at 3:15 pm
i hope i hope. there’s always people saying that solar and wind will never fully replace fossil fuels. i.e. my geography teacher. Then there is info like this which completely conflicts that.
posted by Bronwen on 4-10-2007 at 6:24 pm
This reminds me of a figure i saw for corn ethanol. If it was correct, the use would have about 90% of its real-estate covered in corn to support current vehicle usage. Does this seem reasonable? If so maybe we should stop wasting energy on developing that system.
posted by Josef on 4-10-2007 at 6:50 pm
When you try to verify Loster’s work, the references don’t give you the data you need, and he doesn’t show how he made his calculations.
A back-of-the-envelope sanity check on what he says shows him to be wrong, and not by a little. If you covered the entire state of New Mexico with a canopy of photo cells, and then covered the entire state of Arizona with a canopy of photo cells, you still would not have half the energy we need.
We can’t afford to be sidetracked by such clowns as this. It’s hard enough figuring out what to do, even if we use the real facts.
posted by Paul Ding on 4-10-2007 at 8:22 pm
It would have been nice if Loster’s analysis was a bit more extensive, but Paul’s response also leaves a bit to the imagination. Occam’s razor would help the surface wattage rating, and when I multiply even 28 watts by the number of square meters in a square mile, I get 72.5 million.
No one is suggesting that the photovoltaics be centralized. The map is an illustration, and if it is flawed, the matter should be taken up with the author. Scientists do differ on matters such as this, but such issues are usually resolved empirically. I am glad to see attention focused on our energy use and what to do about it.
posted by Tom on 4-11-2007 at 7:35 am
They can have my back yard… I hate mowing…
posted by Truth on 4-11-2007 at 10:04 am
Eat THAT Al Gore!
posted by Korin on 4-11-2007 at 11:54 am
Has anyone ever driven the Interstate 15 corridor between Los Angeles and Las Vegas? There are hundreds of square miles of otherwise non-viable real estate that gets endless amounts of free sunshine.
To think globally, there’s the Sonoran desert in Mexico, the Gobi desert in Asia, the Sahara and the Namib desert in Africa, etc.
Solar panels have no moving parts, so maintenance is minimal, mostly cleaning. Installation can be engineered to be quick and inexpensive, given a little forethought.
The environmental impact in such an area would also be minimal, given the scarcity of organisms in those environments. What organisms there are would still receive sunlight, both directly and indirectly.
A significant portion of the states of Nevada, California, Utah, Arizona, New Mexico, and Texas could generate enormous amounts of electricity. There’s a lot of desert in those areas, and I know because I’ve lived in a couple of those states and visited the rest.
The carbon footprint of solar collection processes can’t be that different than that of any other power production method, and has to be lower than a coal-burning power plant.
So, instead of running around poking holes in people’s theories simply to decry them, how about trying to devise a solution to the flaws? You know, be part of the solution, not part of the problem.
Oh, and regarding the ethanol issue, is corn the best choice for ethanol production? Has any significant research been done to determine what plant has the highest yield per bushel/pound or other unit of measurement?
Does the cornstalk contribute to the overall production? If it’s only the ear on corn, that’s a lot of nutrients and water to grow a 6 foot stalk for 8-12 ounces of corn. Potatoes seem to produce large, starchy lumps with a lot less byproduct.
Any monkey can criticize attempts to solve problems. The trick is to come up with a better option.
posted by Melanin Junkie on 4-12-2007 at 11:51 am
I’ve heard that Brazil uses sugar cane for it’s fuel supply. I don’t know if it’s true but also heard they no longer need to import oil or gas and can supply enough fuel for thir country with cane.
posted by Sgmagain on 4-12-2007 at 5:35 pm
It seems to me that one possible solution lies in utilizing even a fraction of the solar output that radiates to no one all the time. Just the light/energy available in Earth’s orbital plane (to keep things simple) would potentially have to be 364 times what we receive each day.
“Solar collectors” in space can be as big as the designers can make them as long as they don’t block the sunlight we normally use (or frustate astronomers’ observations), and the energy ought to be convertible for transport via lasers to intermediary satellites, and from there to earth stations. It’s an old concept, but maybe now is the time to implement it.
posted by Cryptonym on 4-12-2007 at 10:12 pm
Global warming solves the energy crisis!
posted by Bryan on 4-13-2007 at 5:58 pm