Since the oil shocks of the 1970s, governments around the world have paid plenty of lip service to renewable energies such as wind and solar power. But only a few governments have been able to engineer policies that have begun to bring alternative energies into wider use. Renewable fuels provided 18% of the world’s total electricity supply in 2004, according to figures from the International Energy Agency, a Paris-based intergovernmental organization. Almost all of that, though, came from hydropower, a source with limited growth potential because of geographic constraints. The use of wind and solar power is growing, but they still generated only 1% of global electricity production in 2004, the latest year for which figures are available.