A joule is one watt of power for one second. An exajoule is 10 to the 18th power joules. Current estimates are that the world demand for energy in a year is 428 exajoules. Right now, the best guess is that 4 percent of those 428 exajoules are satisfied by clean, renewable energy sources.
How much higher can we go? Last week, readers got stirred up when I took issue with a particular tenet of peak oil doomer philosophy: the idea that only a fraction of our current energy use will ever be accounted for by renewable energy. Yesterday, while researching carbon trading, I ran across several studies focusing on exactly that issue.
The most interesting figures came in a paper submitted at a conference on renewable energy held in Germany in 2004. In "The Potentials of Renewable Energy" there is a chart that estimates the technical maximum energy possible from various forms of renewable energy. Hydropower, 50 exajoules a year. Biomass energy, 250. Solar, 1,600. Wind, 600. Geothermal, 5,000. The total, some 7,500 exajoules a year, or 17 times current demand.
Sure, there is a certain amount of magic-wand waving to come up with such numbers. And getting from here to there will be quite a feat, and won't be accomplished in a decade or two. It will require a vast realignment of government priorities and considerable technological advancement. And even the most optimistic of projections don't hold out promise of renwables accounting for more than 50 or 60 percent of world energy demand by 2050.
But with the right kind of political will, we could make a serious difference. Current estimates of government subsidies for the fossil fuel industry range from $50 billion to $250 billion a year. If that funding was diverted to subsidizing renewable energy, solar and wind and biofuels would fast become cost-competitive with oil -- even when priced at lower than the current $60 a barrel.
As study after study points out, small-scale renewable energy installations are increasingly appropriate for deployment in impoverished nations where millions still live far from the electricity grid. Widespread rollout would create jobs, fend off the pressures of peak oil, combat global warming and, best of all, decrease the influence that Big Oil currently exerts on world affairs. It's pretty easy to conclude: Nothing could be more important.
There's a story today in an East Bay newspaper, the Contra Costa Times, that profiles a biodiesel pumping operation in my home town of Berkeley, Calif. It's just one pump in a garage, run by a collective of five women -- which is about as Berkeley as you can get. On weekends, says the reporter, there's usually a short wait for a turn at the pump. That's a market opportunity, if I ever saw one, and some small reason for hope.