Solar-Powered Groundwater Irrigation: Risks and Opportunities

In a Policy Forum, Soumya Balasubramanya and colleagues argue that the carbon emissions reductions gleaned from the rapidly expanding transition to solar-powered groundwater irrigation by low-and-middle-income countries (LMICs) may not meet expectations. What's more, the transition could lead to increased groundwater extraction. The declining cost of solar technologies and growing government commitments to clean energy are driving a boom in the use of solar-powered groundwater irrigation in LMICs. This has led to more than 500,000 solar pumps across South Asia and an estimated similar number installed across Sub-Saharan Africa over the last decade. Given this rapid expansion, there is emerging interest in incorporating emissions reductions from solar pump use into carbon credit programs. However, according to Balasubramanya et al., the benefits of the transition to solar-powered irrigation, including the associated emissions reductions, are complex to assess and could come with risks. Although total replacement of electric or diesel pumps with solar pumps would reduce greenhouse gas emissions, it is not guaranteed. Farmers may continue to use their former pumps, particularly if they have unmet irrigation needs, and agricultural land use change could affect net energy use in different ways. Moreover, even if solar-powered irrigation leads to net zero emission, increased adoption could accelerate the groundwater boom in LMICs and exacerbate groundwater depletion, threatening the viability of many aquifers already at risk of running dry. Balasubramanya et al. argue that an interdisciplinary understanding of water, energy, and land-use changes is needed to develop a policy framework capable of managing solar irrigation's potential risks and opportunities.