A Swedish company claims that this small-scale concentrated solar energy system—which leans on ideas from a 19th-century Scottish clergyman—converts 34 percent of sunlight into electricity. That could make it the most efficient solar system in the world.


The Guardian reports that the system—currently being tested by its makers, RiPasso Energy, in the Kalahari Desert—uses 100 square-meter dishes to focus the sun’s light to a single, hot point. The heat then drives a Stirling engine, first developed by Robert Stirling in 1816, which uses alternate heating and cooling of a closed volume of gas to drive a piston and, in turn, flywheel to generate electricity. The dishes swing on their axes during the day in order to capture as much light as possible.



Tests show that each dish could generate between 75 and 85 megawatt hours of electricity per year. For a little context, the same amount of electricity generated by coal-fired power station would create 81 metric tonnes of CO2. The claimed efficiency of 34 percent compares incredibly well with other solar techniques, too: traditional photovoltaic cells currently manage around 23 percent at best.


While the financial side of things remains unclear—and potentially prohibitive—RiPasso now claims to have secured funding to first large-scale installation. It’ll be interesting to see if it can hit its claimed 34 percent efficiency at scale. [Guardian, RiPasso Energy]

Image by RiPasso Energy