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In the U.S. Department of Energy's most recent EIA "Monthly Energy Review" on December 22, 2010, the share of renewable energy is 10.89 percent of all primary energy produced in the U.S. during the first nine months of 2010.

Meanwhile, nuclear power's share was 11.39 percent of the total during the same period.

The "Monthly Energy Review" is published by the United States Department of Energy's Energy Information Agency.

With a little injudicious rounding, those numbers can be made to look like the two energy sources match at 11 percent. In fact they are separated by a spread of 223 trillion Btus or 65,458 megawatt-hours. That's close to half of what wind energy contributed (505 trillion Btus) in the report period. (The figures in this article are rounded to the number of decimal places it provides. When the first digit being cut off is 5 or above, we round the number up; if it is 4 or below, we round down.)

The EIA figures reflect the contributions of each energy source to the total energy produced, not generating capacities or consumption. "Primary energy" refers to the energy value of raw fuels before they are converted to other forms of energy.

Renewables

Renewables are up and nuclear is down, according to this set of EIA figures. By comparison, in the first nine months of 2009, renewables had a 10.47 percent share; nuclear had an 11.62 percent share.

Renewable energy capacity is expanding, especially in states with favorable policies such as renewable energy portfolio standards. Nuclear power production tends to increase in years when fossil fuel commodity prices are high, among other factors. Through the years since 1990 the nuclear contribution has risen gradually from 8.61 percent to 10.99 percent in 2000, and 11.73 percent in 2005. (Remember that the percentage contribution from any source is a factor of total energy produced that year, regardless of capacity.)

Renewable energy sources include hydroelectric, geothermal, solar/photovoltaic, wind and biomass.

The end of 2010 is right around the corner, but the EIA's figures for all of 2010 won't arrive until March, 2011. Even then, they will be projections subject to revision. As of this writing, the figures for 2009 are still labeled as "projections," and almost all of EIA's 2008 production figures were revised.

Source: "Monthly Energy Review," EIA, December, 2010.

Nuclear power caught up to and surpassed renewables in the late 1980s, and widened their lead as renewables declined in the late 1990s. The nuclear lead has been narrowing, but renewables remain slightly behind, as of EIA's December 2010 report.

Natural gas

Coal's share of primary energy production has been declining, while that of natural gas has been rising. If the figures in this partial-year EIA report carry through to the annual figures, in 2010 natural gas (29.61%) will have surpassed coal (29.81%) in energy production. Natural gas burns relatively cleaner than coal, and that has led to the fuel conversion of some coal plants to use natural gas, instead.