Yale Environment 360: For homeowners in 46 of the 50 largest cities in the U.S., investing in a residential solar power system would yield better returns than putting money in the stock market, according to an analysis by the North Carolina Clean Energy Technology Center at North Carolina State University. For 21 million owners of single-family homes in the U.S., solar energy already costs less than current local utility rates, the report says, as long as the system can be purchased with low-cost financing of 5 percent...