Solar panels capture energy from light and convert it to electricity. This is the most visible form of energy harvesting, but it is hardly the only one. Energy harvesting captures energy lost as heat, light, sound, vibration, or movement. Devices that harvest or scavenge energy can capture, accumulate, store, condition, and manage this energy into electricity for consumption. That’s important, because our existing electricity infrastructure is extremely wasteful in its use of energy. For instance, today’s technologies used in electricity generation are not energy efficient. Traditional gas or steam-powered turbines convert heat to mechanical energy, which is then converted to electricity. Up to two thirds of that energy input is lost as heat. Those old incandescent bulbs (technology invented by Thomas Edison in 1879) were real energy losers too. Ninety percent of the electricity flowing into incandescent bulbs ends up as waste heat. That’s lost energy, which is why smart federal legislation banned incandescents in favor of more energy efficient sources of lighting starting in 2012.
Glycon Garcia on 16 May 11The electricity sector accounts for almost 35 percent of greenhouse gas (GHG) emissions in the United States, and 40 percent of the carbon dioxide (CO2) emissions. Over 80 percent of GHG emissions associated with electricity generation are from the combustion of coal, with nearly all the rest due to natural gas and petroleum combustion. U.S. electricity sales are split among the residential (37 percent), commercial (36 percent), and industrial (27 percent) sectors, where primary uses vary by sector. Over the past 30 years the U.S. electricity sector has become less carbon intensive, and the U.S. economy has grown less electricity-intensive.
