How Many Energy-Efficient Light Bulbs Does It Take to Close 705 Coal Plants?

Image Gallery Of the estimated 4.7 billion light sockets in the United States, close to 1 billion now have CFLs (compact fluorescent light bulbs). ISTOCKPHOTO/RICHARD COTE

The lighting sector is on the edge of a spectacular revolution, a shift from the century-old, inefficient incandescent light bulb to far more efficient technologies. Perhaps the quickest, most profitable way to reduce electricity use worldwide — thus cutting carbon emissions — is simply to change light bulbs.

The first advance in this field came with compact fluorescent light bulbs (CFLs). Replacing old-fashioned, inefficient incandescent bulbs that are still widely used today with new CFLs can reduce the electricity used for lighting by three fourths. Over its lifetime, each standard (13-watt) CFL will reduce electricity bills by roughly $30. And though a CFL may cost twice as much as an incandescent, it lasts 10 times as long. Each one reduces energy use compared with an incandescent by the equivalent of 200 pounds of coal over its lifetime. For perspective, the energy saved by replacing a 100-watt incandescent bulb with an equivalent CFL over its lifetime is sufficient to driving a Toyota Prius hybrid car from New York to San Francisco.

CFL production in China, which accounts for 85 percent of the world total, climbed from 750 million units in 2001 to 3 billion units in 2007. Sales in the United States climbed from 21 million CFLs in 2000 to 397 million in 2007. Of the estimated 4.7 billion light sockets in the United States, close to 1 billion now have CFLs.

The world may be moving toward a political tipping point to replace inefficient light bulbs across the board. In February 2007, Australia announced it would phase out the sale of incandescents by 2010, replacing them with CFLs. Canada soon followed with a 2012 phase-out goal. In early 2009, the European Union (EU) approved a phaseout of incandescent bulbs, one that will save the average EU consumer 25 to 50 euros each year.

Brazil, hit by a nationwide electricity shortage in 2000 to 2002, responded with an ambitious program to replace incandescents with CFLs. As a result, an estimated half of the light sockets there now contain these efficient bulbs. In 2007, China — working with the Global Environment Facility — announced a plan to replace all of its incandescents with more-efficient lighting within a decade.

Retailers are joining the switch too. Wal-Mart, the world’s largest retailer, began an ambitious marketing campaign in 2007 to boost its cumulative U.S. sales of compact fluorescents to over 260 million. Currys, Britain’s largest electrical retail chain, went further — discontinuing sales of incandescent light bulbs in 2007.