Solar power produces, per unit of energy, only about one-tenth as much carbon dioxide and other harmful emissions as does conventional power generation, a new study shows.
Solar panels don't release harmful gases during use, but making the solar cells does consume materials and energy—mainly from conventional power sources such as coal-fired power plants, which in turn produce emissions. Industrial techniques for making glass and other materials in solar panels also produce gases such as carbon dioxide.
In the 1970s, manufacturing a solar cell required about as much energy as the cell could produce over its 20-year lifetime, so using solar power provided little if any energy gain. Also, as recently as 10 years ago, total emissions from solar cells were about twice what the new study shows. "Solar power has been criticized in the past" for requiring too much energy to produce, says Vasilis M. Fthenakis of the Brookhaven National Laboratory in Upton, N.Y. "But what