How the world would benefit if we could simply switch over to 100% renewable energy, but perhaps it’s not that easy.
Well, we’ve always known that renewable energy wasn’t the easy choice, once you throw in economics, efficiency, and political costs. The problem is that renewable energy, while all around us, is in such diffuse form that it requires some kind of harvesting technology to concentrate it into a usable form. Earth, receives some 23,000 TWh/yr (terawatt-hours per year) of solar radiation, while all of our energy expenditures only add up to 16 TWh/yr. Wind, it is estimated, could account for between 25 and 70 TWh/yr.
Surely, with enough solar panels, wind turbines, and backup power supplies, couldn’t we power all of mankind’s energy needs with renewable energy? Even wind power alone might be able to provide all of our energy needs, so why isn’t it happening? Why are we still counting on the 900 TWh of reserves that are still buried in the ground, such as natural gas, petroleum, or even uranium?
The problem has to do with how easy it is to convert diffuse renewable energy sources, such as solar and wind, into concentrated energy forms, such as electricity or liquid fuels. Fossil fuels already come in concentrated form, so the technology to convert them into something useful is actually fairly cheap, in comparison to renewable energy.
For example, solar power may be able to provide some 6 Wh/m2 (watt-hours per square meter), but an oil well may be able to generate nearly 30 Wh/m2. Since the oil well is cheaper, per m2, to operate, and crude oil is closer to a useable fuel than solar or wind power is, the bottom line gets it. Until conversion factors become cheaper or more efficient, thanks to some upcoming technological breakthrough, no one has any financial impetus to invest in renewable energy systems. We’re getting there, but we still have a long way to go.
Image © Richard Perez & Marc Perez, SUNY Albany
