Often people have a knee jerk reaction in which they announce their expectation that renewable energy will save the day. What is typically missing in these discussions, which often begin with accounts of the installation of renewable capacity reported in in
peak power units of "kilowatts" or "megawatts," is a sense of scale.
To the extent that renewable technologies are available, one can applaud them without imagining that they are anywhere near sufficient in scale to address our actual requirements.
This link gives the break down of all types of renewable fuels produced in the United States. It includes hydropower, biomass, wind, geothermal and solar energy:
http://www.eia.doe.gov/cneaf/solar.renewables/page/rea_data/table2.html#fpNote that the links give energy units in Quads, which is 10^15 BTU's. For reference I have provided the conversion to exajoules, the SI unit, by multiplying by 1059 and dividing by 10^18 to account for the "exa" prefix.
Note also that in the link the use is broken down by sector, ie, industrial, commercial and residential. Note that in each heading the "biomass" heading is not independent of the wood, landfill gas, municipal solid waste and (curiously) burning tires, but instead represents the sum of these sources.
Some striking, but not surprising - at least to me, features. The renewable industry is dominated by hydroelectric power, with 2.7 Quads, or 2.9 exajoules. The next most important renewable source is, unsurprisingly, biomass, accounts for 2.124 Quads, or 2.25 exajoules, excluding the ethanol business in the transportation sector, which produces 0.22 quads, or 0.22 exajoules, a completely trivial amount of energy given all the hype and subsidies that the ethanol industry entails.
The much hyped solar industry is too tiny to even be discussed seriously. It is just this side of useless in the crisis at hand. Wind power, at 0.108 quads (0.114 exajoules) does better than thermal and PV solar, but it's impact on US energy production and consumption is still way too small to account for much of an impact.
All tolled, the total renewable energy output of the United States, including hydroelectric power, and burning biomass, accounts for 6.131 quads, or 6.5 exajoules. Note that there isn't much more available to the biggest player, hydroelectric power, nor in my opinion, should there be.
The United States, the world's largest energy consumer, consumed 98.8 quads, or 105 exajoules of energy in 2003.
http://www.eia.doe.gov/pub/international/iealf/tablee1.xlsPersonally I would be thrilled if all of our renewable fantasies were achievable, but it is time to think very seriously about energy and the environment. There will be
no future without a sober, rational, and realistic assessment of our options. There are renewable technologies that can
help but none in the immediate future can do more than scratch the surface. The crisis is NOT in the immediate future. It is NOW.