Every year, the Lawrence Livermore National Laboratory (part of the Department of Energy) releases an energy flow chart showing how much and what types of energy were consumed in the U.S. in the past year. In recent years there have mainly been small increases in energy use each year, but in 2015, that trend reversed and Americans actually used less energy than in the previous year.
Compared to 2014, Americans used 0.8 quadrillion BTU (quads) less energy in 2015. A BTU or British Thermal Unit, is a unit of measurement for energy and 3,600 BTU is equivalent to about 1 kilowatt-hour. Natural gas use increased by 3 percent while coal use decreased by 12 percent and it's that shift that could have had the biggest impact on the numbers since natural gas power plants are far more efficient at producing electricity than coal-fired ones.
The better news is that renewable energy use has continued to grow with wind energy use up 5 percent, geothermal up 11 percent and residential solar up 11 percent. The biggest increase was in utility-scale solar use which rose 25 percent thanks to a few major projects finally starting to feed into the grid in 2015.
The milder winter helped with the energy consumption too. People ran their home's heating systems less, leading to less residential natural gas use. Commercial and industrial energy use fell, too, but the decreases were much smaller than residential.
The other good news is that the energy wasted was down by one percent. Every year, more energy is generated than is actually used, but improvements in the efficiency of electricity generation and transmission are helping to bring that number down, if even just a little.
While all areas of energy use -- electricity, transportation, industrial, residential and commercial -- all saw decreases in 2015, petroleum use continues to increase along with economic growth. The two are tied together because when employment and income increases, driving increases, as does commercial and industrial shipments from people buying more things.
The positive things to get from this report are that renewable energy continues to grow and if efficiency gains in both electricity generation and consumption can keep increasing, a downward shift in fossil fuel consumption will be a permanent trend. Now, if electric vehicles could become a greater portion of the vehicles on the road, we could see those petroleum numbers go down, too.