Areva bought the Mountain View, Calif. company Ausra, a company that has developed a system of reflectors that concentrates and directs sunlight to create steam and spin a turbine.
But how much electricity a system can generate will depend greatly on the locations and the amount of sunlight available manufacturers tend to provide power generation numbers based on a set of standard parameters.
Panasonic's artificial photosysnthesis system has a simple structure with highly efficient CO2 conversion, which can utilize direct sunlight or focused light.
Having an open system may make it easier for people to "game" the system, but Mr Wales thinks it also means abuse is dealt with sooner, "Sunlight is the best disinfectant, " he said.