Volume 1: Energy Innovations: Accelerated Deployment, New Concepts, and Emerging Technologies

Practical routes for the integration of rooftop PV in the UK, and their economic and environmental costs Richard Johnson, Martin Mayfield

Abstract

With the recent removal of the Feed in Tariff, and an imminent increase in VAT, the purchase and installation of solar PV on the domestic scale has become significantly less economic. Despite this change, no organization or individual has been able exhibit the magnitude of subsidy that will still be required to ensure a return on investment that encourages further uptake of rooftop PV, nor consider how this changes with the addition of further revenue streams (such as P2P trading or PPA-like agreements). Furthermore, concerns over methods for local voltage and thermal constraint management, and the environmental and economic costs of such methods, have developed as localized areas of very high PV penetration have been increasingly observed. In this paper, we determine the subsidy that should be provided to encourage an uptake rate of 0.5% homeowners/year under different revenue streams, determine the environmental and economic costs of local constraint management, and compare the results to avoidance of installation. The problems were solved using a combination of time series analysis, NPV calculations, power flow simulations, and optimization processes. It was found that none of the examined alternative revenue streams could currently provide the return on investment required (i.e. a FiT type subsidy is still required), that the required FiT would likely be insignificant on a national scale (provided P2P trading is employed), that simple reconductoring is the most economically and environmentally effective constraint management strategy, and that all constraint management strategies provide a large environmental benefit when compared to avoiding installation.

Keywords Solar PV, P2P trading, LV network management, Feed-in tariff