Optimal investments into rooftop solar and batteries for a distribution grid company and prosumers: A case study in India

Rooftop solar power plants, hereafter rooftop solar, have good potential to decarbonize local energy systems in countries like India. This paper investigates optimal sizing of rooftop solar together with lithium-ion batteries from the perspectives of distribution grid companies and prosumers. For this, a techno-economic analysis is performed on a case study in Delhi using an optimization tool, the Multi-Vector Simulator. Results indicate that with current incentives it is an economically attractive option for domestic consumers to invest in rooftop solar to become prosumers, while investments in battery storage do not lead to economic benefits. However, the availability of upfront investments and roof areas could limit the growth of prosumers. For distribution grid companies growing prosumers means a reduction in revenues. By investing in rooftop solar, distribution grid companies can improve their profitability and self-meet their obligation to purchase renewable energy. For policymakers, it is important to design policy instruments that support both the prosumers as well as the grid operators.