Less coal, petroleum and natural gas were used last year compared to 2008, while more solar, hydro and geothermal power were used, the Laboratory reports. But the change isn't only because Americans want to live a greener lifestyle.
"Energy use tends to follow the level of economic activity and that level declined last year," said A.J. Simon, an energy systems analysts for the Laboratory.
"At the same time, higher efficiency appliances and vehicles reduced energy use even further. As a result, people and businesses are using less energy in general," Simon added.
The estimated U.S. energy use in 2009 equaled 94.6 quadrillion BTU's, down from 99.2 quadrillion BTU's in 2008, according to data from the U.S. Energy Information Administration. (A quadrillion usually means a thousand million millions, or a 1 followed by 15 zeros, says the website mathisfun.com.) The average American household uses some 95 million BTU's a year.