PV, or not PV: using backcasting to explore policy, market and governance implications of local decarbonisation pathways such as urban PV

Abstract

Since 2018, over three quarters of UK local governments have signed climate emergency declarations signalling a new phase in local climate action. Many areas are developing climate action plans and considering what policies could be adopted to increase the use of distributed energy resources, such as building-integrated photo-voltaic (PV) generation. In this paper we demonstrate how city-scale backcasting can be used as a tool to go beyond technical feasibility and explore the policy, market and governance implications of decarbonisation pathways across the local and nation scales. Using urban PV as an example we model three scenarios for increasing installed capacity in the UK city of Bristol and demonstrate how, in each case, PV switches from being a minor ‘negative load’ on the energy system to being the dominant factor determining the volatility and predictability of the energy demand during daylight hours. Current approaches to integrating distributed energy resources into the wider system tend to focus on predictive modelling and half-hourly pricing to drive demand-side response. Our analysis indicates the risks of relying on these non-real time methods and suggests that more granular techniques such as triggering local DSR based on changes in electricity system frequency could better manage the variability of high levels of PV deployment at the local scale. We also demonstrate the importance of developing new local approaches to system integration that bring together network operators, local authorities and other local actors to deploy renewable generation and flexibility assets in coordination.