Electric power to supply the water electrolysers installed in the solar hydrogen facility at Neunburg vorm Wald, Germany, is generated in two photovoltaic (PV) power systems with a combined module power rating of 277 kWp. Since they were commissioned in January 1990, operation of the PV systems has been accompanied by a test programme. To date, both PV systems have fulfilled expectations with regard to utilisation factor and reliability. Based on these experiences six further developed PV systems were installed at the end of 1993/beginning of 1994.