A Japanese research group has made a major advance in the generation of solar energy. Professor Takeo Saito of the Graduate School of Environmental Studies, Tohoku University have developed a small, highly efficient solar power system with a solar energy conversion efficiency between 16 and 20 percent. It's power generation is double that of solar cells and 1.5 times that of fuel cellls.

This system uses the Rankine cycle system, in which water heated by solar energy heats up hydrochlorofluorocarbon (HCFC) fluids to between 120 to 200 degrees Celsius. The vaporized HCFC is sprayed through a small nozzle at a supersonic speed of Mach 2 to 3 to drive the turbine and generate electricity. The group spent 12 years to develop this system, achieving high efficiency through a combination of over ten features, including the rotor shape.

The developers hope to lower the power generation cost to about $1835 per kilowatt from the current cost of photovoltaic power generation at about $6,422 per kilowatt. If the system is installed at home, water heated during the daytime can also be used for a 24-hour hot water supply and room heating system.