Evaluation of a 5 kWp photovoltaic hydrogen production and storage installation for a residential home in Switzerland

The performance of a privately owned photovoltaic (PV) hydrogen production and storage installation in a one-family house at Zollbrück i. E. in Switzerland (altitude 630 m, latitude 46.9°N) has been studied. The manually controlled system has operated since 1991 and was built by its owner (M. Markus Friedli) mainly from commercial components. It consists of an array of roof mounted PV solar panels (65 m2 surface, 5 kWp average peak power, 8.4% average efficiency), a DC–DC converter (95% efficiency), an alkaline membrane electrolyzer (5 kW, 62% average electrolyzer efficiency), a hydrogen purification unit, a compressor, and two metal hydride storage tanks, a fixed one (capacity: 15 Nm3) for in-house storage to operate household appliances running on hydrogen such as a stove and a laundry machine, and a mobile one (capacity 16 Nm3) for running a hydrogen operated minibus. In-situ measurements during operation on three typical summer days and computer modeling based on standard meteorological data suggest a yearly hydrogen production of 1100 Nm3 (16 Nm3/m2 year), corresponding to an average efficiency of 3.6% for converting solar energy into hydrogen fuel for seasonal energy storage.