The carbon payback of micro-generation: An integrated hybrid input-output approach

Feed-in Tariffs (FiTs) in the UK have been introduced to stimulate growth in small-scale renewables such as photovoltaics and micro-wind. They form one of the UK’s key policies to decarbonise electricity by 2030. However, the evidence used to inform the policy was predominantly related to costs, capacity and deployment; not contribution to meeting decarbonisation targets. This paper employs an integrated hybrid lifecycle assessment method, which overcomes boundary limitations of traditional process-based assessments, to measure the full lifecycle emissions of solar PV and micro-wind technologies eligible under FiTs. Environmental assessments of policies often do not take account of the lifecycle emissions of technologies, therefore underestimating their emissions contribution and overestimating the success of policies towards decarbonisation targets. Considering the full lifecycle emissions, the paper assesses the effectiveness of FiTs for driving the UK’s low carbon transition. The results demonstrate that, while there is still significant variation and uncertainty with such estimates, even with the most conservative figures, both the technologies can offer substantial emission savings compared to fossil fuel alternatives when installed in suitable locations. However, the renewable resource of installation sites is critical to the carbon intensity that the technologies can offer. Under a poor renewable resource their impacts can be as high as fossil fuels alternatives. As FiTs makes no distinction between installation sites this should form part of the assessment of funding. Finally, despite their potential for carbon reduction, with the full lifecycle of the considered technologies taken into account, a target of 50 gCO2e/kW h is not possible with the current technology generation efficiencies. The paper concludes that a complete re-assessment of the role of technologies in the decarbonisation of electricity is required to take into account the full lifecycle impacts to gain a more realistic picture of the mitigation potential.

Bush RE; Jacques DA; Scott K; Barrett J (2014), Applied Energy, 119, pp.85-98.