Christian Science Monitor: Where solar power can't fly, artificial photosynthesis might
... One emerging option [for aircraft fuel] is artificial photosynthesis – after all, if fuel is a better way to store energy, then why not turn sunlight directly into fuel instead of electricity?
Nathan Lewis, a chemist at the California Institute of Technology in Pasadena, has built PV cells that split water molecules to generate hydrogen gas, a fuel. His cells convert sunlight into chemical energy 10 to 40 times more efficiently than most crops.
"It's reasonable to say that within our first five years we will have working prototypes that can be manufactured at scale," says Mr. Lewis.
The challenge will be combining that hydrogen with carbon dioxide to form hydrocarbons found in diesel or jet fuel. It's chemically possible, but might require a dozen steps. ...