The rising sun: analyzing potential of energy efficient solar photovoltaic water pumping systems in India

Central and state governments have been successful in recent years in getting farmers to buy new solar photovoltaic (PV) pump systems or to replace current diesel or electric pump sets through policies involving capital subsidies that range from 30% to 90%. While the subsidy policies support installation of more solar pump systems, the policies make little or no mention in their technical criteria of the degree of energy efficiency of the pump sets. Installation of energy efficient solar PV water pumping systems under the Indian government's "Solar Pumping Program for Irrigation and Drinking Water" scheme could result in about 600,000 MWh of additional energy savings and about 500,000 tCO2e of greenhouse gas (GHG) emissions reductions during the life of the systems. These savings would be in addition to the savings from the 100,000 solar pump systems that are currently planned under the government's scheme. The additional savings would be achieved because over 30,000 additional solar pump sets could be installed within the proposed budget of $67 million for providing subsidy to farmers if energy efficient pump sets were used. A solar pump system that includes an efficient pump (for e.g., a Bureau of Energy Efficiency (BEE) five-star rated pump set) for water delivery would require a smaller PV array to deliver the required amount of water. Due to the reduced size and cost of the PV array, such a system is more cost effective despite the fact that highly efficient pumps are somewhat more expensive than the average electric pumps. This research recommends reexamining the technical criteria for receiving subsidies and considering the cost and benefit of requiring a minimum efficiency equivalent to BEE's five-star level. The research shows that using five-star rated pumps reduces net costs by $1,700 per pump and the subsidy requirement by $1,500. Hence for the same amount of total subsidy, over 30,000 additional solar pumps can be installed, leading to both greater energy savings and greater GHG emissions reductions.