Of course, the very heterogeneous nature of DG renders such analyses especially difficult. The appropriate numerical representation of DG is clearly complex. Nevertheless, in order to assess the contribution of DG to energy (and other) policy goals, we need to understand the system-wide economic, environmental and social impacts of increased penetration of DG. Increased decentralisation of the UK energy system via DG technologies would likely have substantial impacts through construction expenditures, infrastructure adaptations, employment changes in ‘green’ industries and environmental impacts. Such effects could have important implications for economies at all spatial scales, and are of interest to local, regional and national governments. There are also potentially important impacts of DG policy on fuel poverty in particular and equity in general, as well as issues relating to the potential displacement of emissions across local areas, from centralised ‘out of town’ plants to urban locations. This highlights the complexity of, but also the need for, emissions attribution analyses that recognise geographic boundaries (and accommodate trade flows) appropriately. System-wide economic-energy-environment modelling can, we believe, enhance the evidence base for DG policy formation and implementation.