Will Renewable Energy Ever Meet All Our Energy Needs?

...on how you look at the problem.

Cover every roof in the United States with photovoltaics at today's efficiency levels and you'll generate roughly as much energy as the entire civilization consumes. And lots of places in the world have roofs other than just the United States....

But, though there's no problem with resource availability, there are two huge practical concerns. First, such a project would be massively expensive. Second, it generates electricity, which is not readily useable for transportation with today's infrastructure.

Neither of those problems are insurmountable. Though solar photovoltaics aren't cheap, they're not as expensive as many petrochemical alternatives being seriously considered, such as tar sands. That is, we might not be able to afford widespread PV adoption, true...but, if we can't afford it, we won't be able to afford anything else when the existing wells run dry.

(As a side note, we're already scraping the bottom of the oil barrel. Remember Deepwater Horizon? Imagine you're standing on the shore of the Colorado River in the middle of the Grand Canyon. A mile above you is the rim; that's how far below the ocean surface the wellhead was. Several miles above the rim is an airliner flying past. That's how far through solid rock the well was bored before it reached the oil deposits. That's how desperate we already are today for oil...loooooong gone are the days when you had to be careful in Texas with a pickaxe lest you start a gusher. Yes, we've got lots of oil left -- about half as much as the planet's total original reserves, in fact. But -- duh! -- we went for the easy-to-get-to, high-quality half first, and what's left increasingly fits the definition of, "dregs.")

The problem with transportation fuels is more pressing. At the very least, with enough input energy, you can extract CO2 from the atmosphere and turn it into fuel (via the Fischer-Tropsch process, for example) that you can put back into a tank to burn it again, so we have alternatives. The catch, of course, is that it takes a lot of excess energy to do so, and so won't be cheap.

TL/DR: Yes, we can run our society on solar power. No, it won't be cheap. No, we won't have any better alternatives. Yes, that means we're facing some tough times in the not-too-distant future.

Cheers,

b&

P.S. Even worse than the looming transportation fuel shortage is the looming petroleum-based fertilizer shortage. That double whammy is going to result in lots of people starving to death. b&

Source: http://rss.slashdot.org/~r/Slashdot/slashdotScience/~3/qhjpYmrXpBk/story01.htm

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