Enviro-Friendly Housing Estate Opens In Sydney

SYDNEY, AUSTRALIA - APRIL 13: An air-conditioning unit is tested in a revoloutionary and environmentally-friendly housing estate April 13, 2007 in Sydney, Australia. 16 houses in the estate use technology that converts natural gas into electricity. Utility provider Grid X claims that each house generates a third less greenhouse gas than houses that use coal fired electricity. (Photo by Ian Waldie/Getty Images)