PEC House: a solar hydrogen cell project According to the BE de l'Adit
While it is not yet a usable energy source strictly speaking, hydrogen is nevertheless of capital interest as a means of storage. However, the main current difficulty is to be able to produce it in a “green” way. The Swiss Federal Institute of Technology in Lausanne (EPFL) recently embarked on the development of a photoelectrochemical cell (PEC) capable of breaking down water into hydrogen and oxygen on the very surface of the electrodes. Unlike current systems, which consist of associating a solar cell with an electrolyser, the main drawback of PECs is their low efficiency. However, EPFL hopes to achieve yields of around 4,5% in 2009 and 7% in 2011.
The project is coordinated by the EPFL Energy Center and piloted by the Photonics and Interfaces Laboratory directed by Professor Michael Grätzel, inventor of the solar cells of the same name which are inspired by the photosynthesis of plants for convert solar energy into electricity. This work follows on from those carried out at the end of the 90s in collaboration with professors Jan Augustynski in Geneva and Gion Calzaferri in Bern and which had allowed the construction of a photoelectrochemical "tandem cell", the results of which were promising. This cell combined a semiconductor with a dye cell, which increased the electrical input required for the water dissociation reaction.
The new project, called PECHouse, will try to improve this device by developing more stable materials. Indeed, the main obstacle to the development of this type of cell is to find materials which resist corrosion while maintaining an affordable price. With a budget of around 3,1 million euros, PECHouse is supported by the Federal Office of Energy and will be able to benefit from the expertise and skills of EMPA, the federal laboratory dedicated to materials.
PECHouse website: http://pechouse.epfl.ch
Michael Grätzel, Laboratory of Photonics and Interfaces, EPFL - tel: +41 21 693 31 12 - email: michael.graetzel @ epfl.ch
Source: "EPFL is embarking on the race for solar hydrogen" - Le Temps - 17/06/2008