If solar irrigation is over-drawing groundwater, you’re doing it wrong
India's flagship agricultural solar programme, PM-KUSUM, has installed over 2.5 million solar irrigation pumps for farmers over the past five years, using subsidies to make them affordable for smallholders.
The government is preparing PM-KUSUM 2.0, the next phase of the scheme, with an expanded focus on feeder-level solarisation of the agricultural grid.
A key design challenge has emerged: standalone solar pumps make the marginal cost of pumping groundwater effectively zero once installed, creating an incentive for farmers to over-extract rather than conserve.
Experts argue the risk is not inherent to solar irrigation itself but to a policy design that fails to pair pumps with demand-side measures such as micro-irrigation, water metering, or grid buy-back options.
PM-KUSUM Scheme (2019) — Structure and Components
The Pradhan Mantri Kisan Urja Suraksha evam Utthaan Mahabhiyan (PM-KUSUM) was launched by the Ministry of New and Renewable Energy (MNRE) in 2019 to promote solar energy use in agriculture while providing farmers a supplementary income source and reducing subsidy burden on grid electricity.
Key Details
- Component-A: Setting up of 10,000 MW of decentralised, ground/stilt-mounted grid-connected solar or other renewable power plants on barren/agricultural land, with surplus power sold to DISCOMs.
- Component-B: Installation of 14 lakh standalone solar-powered agricultural pumps, replacing diesel pumps in areas without grid access.
- Component-C: Solarisation of 35 lakh grid-connected agricultural pumps, including feeder-level solarisation, allowing farmers to use solar power for irrigation and sell surplus to the grid.
- Central financial assistance covers 30% of the benchmark cost (or tender-discovered price, whichever is lower) for Component-B and individual pump solarisation under Component-C, with the state government providing a subsidy and the farmer bearing the balance.
- Scheme target: 34,800 MW of solar capacity by March 2026, backed by central financial support of approximately ₹34,422 crore.
PM-KUSUM 2.0's design choices — particularly whether it favours Component-B (standalone pumps, no grid tie-in) or Component-C (grid-connected, buy-back enabled) — directly determine whether the scheme worsens or mitigates groundwater stress.
Central Ground Water Board (CGWB) Assessment Categories
The CGWB, under the Ministry of Jal Shakti, periodically conducts a Dynamic Ground Water Resource Assessment classifying India's groundwater assessment units (blocks/mandals/talukas) based on the ratio of annual groundwater extraction to annual extractable recharge.
Key Details
- Four categories: Safe (extraction below 70% of recharge), Semi-Critical, Critical, and Over-Exploited (extraction exceeds annual recharge).
- The 2024 Dynamic Ground Water Resource Assessment Report found 73.4% of assessed units "Safe," while 11.1% were classified "Over-Exploited," 3.05% "Critical," and 10.5% "Semi-Critical."
- India is the world's largest extractor of groundwater, using more than the United States and China combined, overwhelmingly for irrigation.
- Over-Exploited categorisation triggers restrictions: future groundwater development in such blocks must be linked to water conservation and artificial recharge measures.
Uncontrolled expansion of standalone solar pumps in already Critical or Over-Exploited blocks — without metering or recharge safeguards — can accelerate a unit's slide into the Over-Exploited category, undermining the CGWB's conservation framework.
The Energy-Water-Agriculture Nexus and Subsidy Design
The interaction between free/subsidised electricity (or, in this case, near-zero-marginal-cost solar energy), unmetered groundwater extraction, and agricultural power subsidies is a well-documented policy problem in Indian water governance, distinct from the technology itself.
Key Details
- Because groundwater in India is governed largely as a private property right attached to land (rather than a regulated common resource), and electricity/energy costs are the primary check on extraction, removing that cost check (via free power or free solar energy) removes the only practical brake on pumping.
- Policy correctives suggested by researchers include: pairing solar pumps with micro-irrigation (drip/sprinkler) to cap water use, promoting grid-connected models (Component-C) that let farmers earn income by selling surplus power rather than pumping more water, and community-level water budgeting.
- The International Water Management Institute (IWMI) has piloted grid-connected solar irrigation models that create an incentive to conserve water and sell surplus electricity instead of pumping continuously.
The article's core argument — "if solar irrigation is over-drawing groundwater, you're doing it wrong" — reflects this established distinction: the problem lies in subsidy and metering design (favouring standalone, ungoverned pumps), not in solar technology itself.
- PM-KUSUM launched: 2019, by the Ministry of New and Renewable Energy.
- Over 2.5 million solar pumps installed under the scheme in the past five years.
- Central subsidy: 30% of benchmark/tender cost for standalone and individual grid-pump solarisation.
- Component-B target: 14 lakh standalone solar pumps; Component-C target: 35 lakh grid-connected pump solarisation.
- CGWB 2024 assessment: 11.1% of India's groundwater assessment units are "Over-Exploited," 3.05% "Critical."
- India accounts for the largest share of global groundwater extraction, exceeding the combined extraction of the US and China.