Life Cycle Assessment of solar energy systems: Comparison of photovoltaic and water thermal heater at domestic scale

This study is concerned with the results of a Life Cycle Assessment comparison between photovoltaic – silicon based modules and thin film modules – and solar thermal systems, as technologies which are usually installed for partially covering household energy demand. Several studies focused on energy and environmental performances of photovoltaic and solar thermal collectors, however they have been always analysed separately. This study proposes the comparison of different systems to exploit the solar energy, producing different energy types. The comparison was done referring to one square meter of roof surface occupied by the equipment. The environmental burdens were calculated according to the indicators proposed by Eco-indicator'95 method. The results showed that the system based on thermal solar collector obtained the major number of more favourable indicators: eight out of ten, in the case of no-recycling of materials after dismantling phase, and six out of ten in the case of recycling of materials after dismantling phase. The thin film modules and solar thermal collector showed the lowest values of energy payback time and CO2eq payback time. Results clearly show that photovoltaic and solar thermal collector can effectively provide comparable environmental and energy benefits as regard to domestic scale installation. •Photovoltaic and solar thermal were compared by Life Cycle Assessment.•For a domestic roof which is the best option for solar energy exploitation?•Results show that solar thermal system collects the major number of best scores.•If materials are recycled at the end-of-life photovoltaic results are improved.