The carbon intensity of electricity: How many kgC per kWhe?

Abstract

While it is relatively easy to describe how a change in electricity demand causes a change in carbon emissions from a system of grid-supplied power, it is by no means easy to quantify this. The following have all been used to determine the carbon emissions from changes in electricity demand: the system-average carbon intensity (that is, the ratio between all carbon emitted to all power distributed); the carbon intensity of the typical marginal plant; and, the carbon intensity of new plant built or avoided. All of these are valid in certain circumstances, but in others can give misleading results. This paper brings together existing information and new results of modelling a limited number of situations to propose, pro tem, a working set of figures for England and Wales, together with recommendation for their application. Further modelling and analysis is proposed to refine these figures.