Earth-Policy Institute, by Lester R. Brown, January 6, 2009

Dramatically ramping up energy efficiency would allow the world to not only avoid growth in energy demand but actually reduce global demand to at least 6 percent below 2006 levels by 2020. For example, retrofitting existing buildings with better insulation and more-efficient appliances can cut energy use by 20 to 50 percent. If everyone around the world turned to high-efficiency home, office, industrial, and street lighting, total world electricity use would fall by 12 percent. Recycling plastics and producing them more efficiently could cut petrochemical energy use by close to one third. Adopting the most-efficient blast furnaces and boosting recycling can cut energy use in this industry by close to 40 percent.

http://www.earth-policy.org/Books/Seg/PB3bp_ss2.htm