SAN FRANCISCO – FEBRUARY 24: A dog goes to the bathroom behind a bush at Ft. Funston February 24, 2006 in San Francisco. San Francisco is on its way to being the first city in the nation to convert dog waste to alternative energy by ingesting discarded dog feces into a methane digester, a device that uses bugs and eat the material and emit methane, which would be trapped and burned to power a turbine to make electricity. Dog waste accounts for 4 percent of garbage picked up at San Francisco homes. (Photo by Justin Sullivan/Getty Images)