Abstract/Summary

The electricity sector is one of the largest sources of greenhouse gas emissions and the study of electricity grid carbon intensity has a key role in meeting the Climate Change targets. Evaluation of grid carbon intensity, typically measured in gCO2eq/kWh, is fundamental to footprint calculation. The UK government (DEFRA) provides guidelines and annual grid carbon intensity figures for companies to report their emissions, but the use of a single annual value for grid carbon intensity introduces several key uncertainties into carbon assessment. This study examines the uncertainties that arise from using single annual values for carbon accounting and reporting purposes. Half-hourly UK grid carbon intensity values have been calculated and analysed for the years 2009-2017. Additionally, a power system (UC / ED) model of the GB power grid has been built. This model is being used to explore the sensitivities of grid carbon intensity to variable renewable energy and capacity assumptions. Grid carbon intensity is shown to widely vary not only inter-annually and intra-annually but also from one hour of generation to the next. Hence, the use of a single annual average figure raises doubts over the accuracy of the estimations. Finally, high resolution grid carbon intensity is being used to inform demand side management schemes and identify potential carbon benefits on the domestic and business level.