Contribution of solar photovoltaic to the decarbonization of wastewater treatment plants in China

Abstract

As the decarbonization of wastewater treatment plants (WWTPs) progresses, leveraging photovoltaic (PV) systems to reduce greenhouse gas (GHG) emissions has received increasing attention. This study is, for the first time, to comprehensively summarize and analyze the deployment of PV + WWTPs. Since 2019, hundreds of PV + WWTP projects have been built and are currently in operation nationwide, with the majority located in the Yangtze River Economic Belt. According to 31 case projects, the adoption of PV systems can, on average, supply about 20 % of the electricity required annually. As a result, they achieved an average GHG emission reduction of 11 %. This performance is strongly correlated with the panel coverage and local solar radiation. Regarding economic performance, the initial investment of PV systems is high but can be recovered, on average, within 7 years, resulting in a marginal abatement cost of −30 $/t CO_2-eq. Overall, the contribution of PV systems to emission reduction in the water sector is limited, despite the economic advantages. As PV at WWTPs is projected to increase, a critical evaluation and feasibility analysis are strongly recommended in future planning. Most importantly, the adverse environmental impacts of PV, particularly during the disposal stage, should also be considered.