Tapping the Unused Energy Potential of Solar Water Pumps in India.

India seeks to deploy millions of solar water pumps to farmers who often lack access to electricity or face an unreliable power supply. Improving the use of this technology can bolster sustainable agriculture and expand clean energy services. We investigate farm-level impacts and opportunities with primary survey data ( = 292 farmers) and a large real-time pump operational data set ( = 1106 pumps). By modeling the potential solar generation of off-grid solar water pumps, we estimate 300-400 kWh/month of unutilized solar energy per pumping system, representing up to 95% of potential generation. While farmers report increased revenues and ease of pump operation, unsolved challenges concerning the lack of panel cleaning and tracking remain. Pump operational data show pump usage in the summer and monsoon seasons and an expansion of irrigation to grow crops in the winter. Relative to emissions associated with the use of diesel pumps, solar pumps that are highly utilized reduced life cycle CO-eq emissions by 93% on average, while the pumping systems with the lowest use result in a net increase of 26% relative to the diesel alternatives. Based on observed usage rates, approximately 70% of pumps had positive environmental benefits. The high share of unutilized solar energy provides a significant opportunity to use the energy for nonpumping purposes.