Integrated appraisal of micro-generators: methods and applications

A range of integrated appraisal techniques have been utilised to study the comparative performance of various domestic micro-generators that have been proposed as possible decentralised energy resources for 'low carbon' buildings. Energy, environmental impact and cost-benefit analysis methods, employed on a 'whole systems' basis, are described. The application of this 'toolkit' is illustrated by way of the evaluation of three microgenerators: a micro-wind turbine; a (generic) solar photovoltaic array; and a solar hot water system. It is estimated that all three generators, in appropriately sited installations, have energy and carbon paybacks well within their lifetimes. Significant life-cycle environmental impacts are associated with the use of aluminium to fabricate both the solar hot water unit and the microwind turbine. All three domestic micro-generators were found to be economically unattractive in the present liberalised British energy markets from a societal perspective. Increased production volumes and technical innovations in the next generation of devices, such as improvements in their manufacturing processes and operational efficiencies, are necessary in order to render micro-generators economic propositions. However, there are likely to be many external and unpredictable changes to the global energy market during the years to 2050. These could dramatically alter the prospects for distributed generation.