Increasing energy efficiency is the most important action that can be taken to combat climate change. The International Energy Agency declared in 2010 that “[i]ncreasing energy efficiency, much of which can be achieved through low-cost options, offers the greatest potential for reducing CO2 emissions over the period to 2050. It should be the highest priority in the short term… Decarbonising the power sector [is] the second-largest source of emissions reductions.”1 The United Nations Foundation has calculated that if the G8 countries (United States, Canada, France, Germany, Italy, Japan, Russia, and United Kingdom) doubled their historical rate of energy efficiency improvement, that would avoid the need for 2,000 coal-fired power stations and would make it possible to keep CO2 concentrations in the atmosphere below 550 parts per million.2 One study has shown the potential to meet all of the greenhouse gas (GHG) emission reduction goals for 2020 under the climate legislation that passed the House of Representatives in 2009 through energy efficiency measures.3
Much potential remains for further improvements in U.S. energy efficiency. Only 42 percent of the energy used in the U.S. actually provides energy services; the rest is lost.4 The National Academies of Science have concluded that the U.S. could reduce its energy use by 17-22 percent by 2020 and 25-31 percent by 2030, mostly using existing technologies that are already in commercial use, and delivering the same services as their less efficient counterparts.5
