Record-breaking device uses sunlight to produce hydrogen at 15% efficiency

Scientists at KU Leuven in Belgiumhave developed a device that combines incoming solar energy and water vapor from the surrounding air to produce a record-breaking daily average of 250 liters (66 gal) of hydrogen throughout the year. According to the researchers' estimations, an array of 20 such panels paired with an underground pressurizedtank could provide the totality of a household's entire electricity and heating needs for a modest price.

Goingsolar comes with a couple of significant drawbacks, particularly whenit comes to managing your reserves. First, storing an energy bufferfor a rainy day is all but cheap: a home battery pack will run you upthousands of dollars, and its charge will keep you off the grid for a fewextra days at most. Secondly, lithium-ion batteries lose capacity withuse, and slowly self-discharge with disuse.

ProfessorJohan Martens and his team have turned to hydrogen for a cheaper,year-round green energy alternative. Their device has been under development for a decade, and can currently reach a energy conversion of 15 percent.

Commercial solar panels can easily surpass that figure, often reaching 18 or 20 percent, but the advantage of this approach is thatlarge amounts of hydrogen can be stored in an underground pressurizedtank (at a pressure of approximately 400 bar) without the inevitable losses in capacity that come with battery technology. Using fuel cells, the reserves from the tank can then be converted at will into heating, electricity, or fuel for a hydrogen-powered car with a 90 percent conversion efficiency.

Hydrogenis often produced from non-green sources such as gas and oil, and it'salso expensive to produce and store. This project aims to buck thetrend thanks to a combination of high conversion efficiency and theuse of small-scale systems designed to work at the local scale.

"Wewanted to design something sustainable that is affordable and can beused practically anywhere," says Martens. "We're using cheapraw materials and don't need precious metals or other expensivecomponents."

Theresearchers estimate that an array of 20 panels and four cubic metersof pressurized storage would meet the energy and heating needs (inBelgium) of a household throughout the year, with the assumption thatthe reserves will build up during the summer months and last throughthe winter.

Aprototype of this setup will soon begin field testing on a propertyin the rural Belgian town of Oud-Heverlee. Over the next two years, the researchers are will be focusing on testing the panels for household, agriculture and retail applications, with the eventual goal to massproduce and commercialize the system.

Source: KU Leuven