In his January working paper, "The Market Value and Cost of Solar Photovoltaic Electricity Product," Borenstein also found that, even after considering that the panels reduce greenhouse gases, their costs still far outweigh their social benefits.

The bottom line, Borenstein argues in his paper, is that solar PV panels are not ready for widespread installation. Rather than subsidizing residential solar PV installations, as many states do, he favors more state and federal funding for research and development.

"We need a major scientific breakthrough, and we won't get it by putting panels up on houses," he said in a recent interview on campus. "It is going to come in the labs."