Estimation of energy production and net metering of Grid connected rooftop photovoltaic system in Rajasthan

Ministry of New and Renewable Energy, Government of India in the year 2015, revised the target of solar power generation to 100 GW under National Solar Mission. But out of this 100 GW, target of power to be generated through grid connected rooftop photovoltaic power plants is 40 GW till the end of the financial year 2021-22. For achieving this ambitious target of 40 GW, a large number of rooftop systems are being installed. This paper discusses the guidelines and technical specifications of various components of grid connected rooftop photovoltaic systems that are specified by Rajasthan Renewable Energy Corporation Ltd for projects being implemented in Rajasthan state of India. Net metering and grid connectivity guidelines and procedures of distribution company of Rajasthan are also discussed. The paper also analyzes the feasibility of a 100-kW grid connected rooftop photovoltaic power plant at Rajasthan Technical University, Kota, Rajasthan. Energy production estimations are calculated using RETScreen Expert and PVWatts software using the solar radiation data files of Kota, that are available with the two software. Using the prevailing tariff of electricity for government educational institutions, an estimate of annual cost savings is calculated. The annual energy production estimations from RETScreen Expert is 174.667 MWh and that calculated using PVWatts is 180.740 MWh. The capital cost of Rs. 6 million for installation of 100 kW will be recovered in less than 5 years. Considering the life of grid connected rooftop photovoltaic power plant as 25 years, for the next 20 years, the university will generate additional revenue of Rs. 2.62 crores (Rs. 26 million) to Rs. 2.71 crores (Rs. 27 million) at the present rates of tariff for electricity in Rajasthan.