Performance of two photovoltaic arrays in the UK

Abstract

There are numerous conflicting reports into the economic and embodied energy return of photovoltaic (PV) arrays installed in the UK. Using actual performance data measured on two PV arrays installed on the Zicer building at the University of East Anglia, this paper attempts to resolve some of the issues arising from earlier predictions made using theoretical test bed performance data. A PV model using the monitored data, in combination with solar radiation and geometry data from across the UK, was used to predict the average annual electricity output from the installations over a range of tilt angles, orientations and geographical locations. Six separate capital cost scenarios are considered and the predictions of the unit cost for electricity range from £0·10 (€0·14) per kWh under the most favourable conditions to £2·68 (€3·83) per kWh. At a mean solar radiation of 1000 kWh/ m2 per year, typical of many locations in the UK, the energy yield ratio (EYR) ranges from 4·3 to 5·1 depending on whether the cells are monocrystalline or polycrystalline and the assumptions made in the scenarios. Even on a vertical west-facing face, an EYR of over 2·5 is achieved.