Life-cycle air emissions from PV power systems

This paper addresses the air emissions of grid supply versus grid-connected and off-grid photovoltaic power generation, using the framework of life-cycle assessment, in the concert of rural household energy supply in Australia. Emissions of carbon dioxide, sulphur dioxide and nitrous oxides are calculated for the three life-cycle stages of manufacture, use and disposal. Sensitivities to materials and data inputs, as well as to component efficiencies, lifetimes and sizing are discussed. For each supply option, demand management options, including insulation and appliance choice, and the substitution of solar heating or bottled gas for electricity, are considered. The best option in all cases, in terms of life-cycle air emissions, is a grid-connected photovoltaic system used to supply an energy-efficient household with a mix of solar, gas and electric appliances. However, in financial terms, with current Australian energy prices, this option represents a high capital and life-cycle cost. Additionally, for the grid options, electricity costs do not significantly disadvantage the high demand scenarios. Both results provide a clear illustration of current Australian energy-pricing policies being ill conflict with long-term environmental sustainability. (C) 1998 John Wiley C Sons, Ltd.