Conventional wisdom states that renewable energy cannot cover 100 percent of the world's needs: It's too expensive and too scarce, and switching would be inefficient while hydrocarbon resources are still plentiful. A group of 28 U.S. scientists and engineers has attempted to make the opposite case.
The group focuses on California, arguing that the state could move its industry, transportation and housing entirely to wind, water and sunlight energy by 2050 -- and gain from it economically. By U.S. standards, the state is relatively energy-efficient to begin with: It consumed 201 million British thermal units per capita in 2012, the third-lowest after New York and Rhode Island. It's energy-hungry, though, compared with the global average consumption of about 75 million British thermal units per capita.