When it comes to power, density is the key. Energy density. The reason that solar power, wind power, and ethanol are so expensive is that they are derived from very diffuse energy sources. It takes a lot of energy collectors such as solar cells, wind turbines, or corn stalks covering many square miles of land to produce the same amount of power that traditional coal, natural gas, or nuclear plants can on just a few acres.
Each of these alternative energy sources is based on mature technology. Agriculture and fermentation have their roots in prehistory, windmills date back at least to 65 B.C., the photovoltaic effect was discovered in 1839. Yet nowhere in the world are these technologies serving as primary energy sources without significant government subsidies. While incremental improvements can be expected, what is needed for them to become viable is an order of magnitude increase in productivity.…