Americans used more solar, nuclear, biomass and wind energy in 2008 than they did in 2007, according to the most recent energy flow charts released by the Lawrence Livermore National Laboratory (LLNL). The nation used less coal and petroleum during the same time frame and only slightly increased its natural gas consumption. Geothermal energy use remained the same.

The estimated U.S. energy use in 2008 equaled 99.2 quadrillion British thermal units (Btus), down from 101.5 quadrillion Btus in 2007.

“This is a good snapshot of what’s going on in the country. Some of the year-to-year changes in supply and consumption can be traced to factors such as the economy and energy policy,” said A.J. Simon, an LLNL energy systems analyst who develops the energy flow charts using data provided by the Department of Energy’s Energy Information Administration.

Simon said the increase in wind energy is due to investments in technology and better use of existing turbines.

Nuclear energy also saw a slight increase from 8.41 quadrillion Btus in 2007 up to 8.45 quadrillion Btus in 2008. No new nuclear power plants came online in 2008; and existing plants had decreased down time, continuing a 20-year trend.

The chart also shows the amount of energy rejected by the United States. Of the 99.2 quadrillion Btus consumed, only 42.15 quadrillion Btus ended up as energy services. Energy services are things that make our lives better, Simon said.

The ratio of energy services to the total amount of energy used is a measure of the country’s energy efficiency. The remainder, explained Simon, is simply rejected.

“For example, some rejected energy shows up as waste heat from power plants,” Simon said.

“I’m really excited about the renewed push for energy efficiency in this country,” he said. “Because once that energy is rejected, it’s no longer useful.