Sophia Haussener, director of the Renewable Energy Science and Engineering Laboratory of the Faculty of Engineering at the Ecole Polytechnique Fédérale de Lausanne (EPFL), said the work is based on preliminary research that demonstrated the concept at laboratory scale using the LRESE high-flux solar simulator. The parabolic dish, located on the EPFL campus, has become an artificial tree that produces renewable hydrogen, thanks to the installed reactor, which uses sunlight to convert water into renewable hydrogen, oxygen, and heat.
The "tree" can generate more than 2 kilowatts of power, a high efficiency rate for this system.
It works by concentrating the sun's rays, then pumping water to its focus point, which has an integrated photoelectrochemical reactor. Inside this reactor, photoelectrochemical cells use solar energy to electrolyze or split water molecules into hydrogen and oxygen.
The system not only produces hydrogen, but also generates heat, which is passed through a heat exchanger for use rather than being released as a loss from the system. Oxygen molecules released by the photoelectrolysis reaction are also recovered and utilized. The oxygen generated can be used in medical applications and is not considered waste.
What is the project's roadmap? This system is already in commercial use, at a Swiss-based metal production facility to build a demonstration plant at a scale of several 100 kilowatts that will produce hydrogen for metal annealing processes, oxygen for nearby hospitals, and heat for water needed in the factory.
The EPFL campus system is capable of supplying more than half of the annual heat demand of a typical Swiss household of four people at a production level of about half a kilogram of solar hydrogen per day.
EPFL stated that the system provides a better idea of energy efficiency if the entire system is considered, not just the device itself. In addition, the system has the ability to store energy in the form of hydrogen, making it a viable solution for power generation during peak demand hours or when solar production is limited, not to mention that it is clean and sustainable energy, since when hydrogen is burned to generate power, the only byproduct is water, making it a source of energy.
Although the system has yet to be perfected for mass adoption, the results obtained are very encouraging and demonstrate that solar hydrogen could have an important role to play in the future of clean and sustainable energy.
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09 de Mayo, 2023