Irrigation in a farm (Image: Asadwarraich, Wikimedia Commons; CC BY-SA 4.0)
India's dependence on groundwater has grown alongside the expansion of irrigated agriculture. Around 23 million pumps are used for irrigation, and groundwater's share of the country's irrigation has risen from about 30 per cent in the 1950s to 64 per cent today. Cheap electricity and improved drilling technologies have contributed to this expansion, while declining aquifers are increasingly putting pressure on farming and food security.
Solar irrigation is being promoted as one response to this water and energy challenge. But replacing electricity-powered pumps with solar systems raises another question: could cheaper pumping encourage farmers to extract more groundwater?
A study by Mohammad Faiz Alam and others from Gujarat, published in Energy Nexus, examining grid-connected solar irrigation offers a more nuanced picture. It finds that solarisation can encourage farmers to use less irrigation water in areas with productive aquifers and suitable economic incentives. However, the same approach does not necessarily reduce water use in regions where rainfall and limited groundwater storage already constrain farming.
The findings suggest that the effect of solar irrigation depends not only on the technology itself but also on the aquifer beneath farmers' fields, the crops they grow and the incentives attached to the electricity they generate.
The government has promoted solar irrigation through the PM-KUSUM programme, launched in 2019. The programme aims to install 34,800 MW of solar capacity by March 2026 through small-scale solar plants and the solarisation of irrigation pumps. Scaling up solar irrigation, however, faces challenges including high infrastructure costs, limited technical and maintenance capacity, land scarcity, fragmented land holdings and policy misalignment.
There are also concerns about groundwater. Solar power has virtually no marginal cost once the system is installed, raising the possibility that farmers could pump more water and intensify groundwater extraction.
Grid-connected solar irrigation offers a different model. Existing electric irrigation pumps are solarised and connected to the electricity grid. Farmers can continue using electricity for pumping, while excess solar power can be exported to the grid through net metering.
The model creates a financial incentive to use less electricity for pumping and sell unused electricity instead. PM KUSUM aims to solarise one million grid-connected agricultural pumps under this approach. Until now, there has been limited systematic assessment of how solarisation affects irrigation and energy use. The Gujarat study examines this question by comparing farmers using solar and non-solar pumps.
There has been no systematic assessment of the impact of solarisation on irrigation and energy use. This study assesses how solar adoption has altered farmers' irrigation practices and its implications for groundwater sustainability under the grid-connected solar model in the state of Gujarat.
Gujarat has implemented grid-connected solar pumps under the state scheme, Suryashakti Kisan Yojana (SKY). More than 90 agricultural feeders covering 4500 farmers have been solarised since 2018, with over 75% of farmers’ irrigation pumps now being powered by solar energy in the feeders. The state scheme provides 7 INR/unit (kWh) of excess energy that can be sold to the grid as an incentive structure for farmers to efficiently use water and save energy.
The incentive consists of a Feed-in-Tariff (FiT) at 3.50 INR/kWh, along with an additional 3.50 INR/kWh as an evacuation-based incentive (EBI) for the first seven years to support loan repayment against the capital subsidy and the loan taken by the government on behalf of farmers.
For this study, data on farmers’ groundwater withdrawal was collected from four agricultural feeders – two solar and two non-solar – located in the districts of Anand and Botad. The two districts were chosen for their contrasting hydrogeological characteristics. Anand in central Gujarat is underlain by high-storage productive alluvial aquifers which are recharged by the canal irrigation systems, whereas Botad in Saurashtra has hard rock aquifers, with little inter-year storage and is highly responsive to both pumping and recharge.
Irrigation water application and energy consumed were higher in Anand as compared to Botad. Irrigation water application in Anand was 3 to 4 times higher compared to Botad, while energy consumed while using pumps in Anand was twice that of Botad, reflecting differences in cropping patterns, cropping intensity, and aquifer capacity.
Anand has high cropping intensity and is dominated by water-intensive crops of paddy in the monsoon (kharif) season, followed by tobacco and wheat in the post-monsoon (rabi) season. This high cropping intensity and water use are sustained by shallow (6-12 m) productive alluvial aquifers that are recharged by good rainfall in the monsoon and a canal network during other times. Water can be accessed via medium-depth tubewells (~70 m), typically powered by 10–20 HP pumps.
In contrast, Botad has lower cropping intensity, as it has to heavily depend on annual rainfall and the shallow hard rock aquifers in the region that have limited recharge capacity and can be accessed through large-diameter dugwells (~18–20 m deep), restricting access to deeper groundwater reserves. Cropping patterns are dominated by kharif cotton and groundnut, with chana (chickpea) covering most of the rabi area. In 2021–22, a favourable monsoon with good pre-monsoon showers in May helped moderate cropping intensity, as there was sufficient groundwater recharge, critical for post-monsoon cultivation in the region. However, in 2022–23, poor rainfall significantly reduced cropping intensity with limited post-monsoon season cropping due to depleted groundwater levels.
In Anand, farmers with solar-connected pumps consistently used less irrigation water than those without solar connections. Both groups grew paddy in the monsoon over 90% of the area. In winter (rabi), solar farmers spread their land more evenly between wheat and tobacco, while non-solar farmers leant heavily on tobacco. In summer, both grow bajra (pearl millet). Many farmers sold water (65–79%), but solar farmers adjusted their irrigation needs to irrigate larger buyer areas and thus ended up irrigating more land overall. While both solar and non-solar farmers had access to shallow water tables, non-solar wells were deeper.
Solar farmers in Anand thus used less irrigation water because of the way in which the solar scheme changes farmer behaviour through:
Financial incentives: Solar farmers could sell surplus electricity back to the grid. This made it profitable to irrigate less and export more energy.
Water markets: Many solar farmers sold water to others. Solar water sellers irrigated larger buyer areas, so they managed their own irrigation needs more carefully to maximise earnings from electricity sales.
Changes in cropping patterns: Solar farmers spread their winter (rabi) crops more evenly between wheat and tobacco to reduce their irrigation needs, as tobacco is a water-intensive crop, while non-solar farmers leant heavily on tobacco.
Efficiency response: Water buyers, who pay by the hour, often reduce irrigation hours or apply water more efficiently when prices rise.
Aquifer access: Solar feeder wells are shallower, making water easier to access, but the incentive structure still encourages moderation in use.
Thus solar incentives shifted the cropping mix, reduced water use per hectare, and expanded irrigated area through water markets in Anand.
However, in Botad, rainfall and aquifer limits mattered more than solar incentives. Solar farmers used more water per hectare in drought years but could not expand cropping because groundwater recharge was too low. Thus, during a normal year in 2021–22, solar and non-solar farmers used about the same amount of water, and the cropped area was similar. However, during the dry year in 2022–23, rainfall was poor, so the cropped area shrank and post-monsoon crops almost disappeared.
Solar farmers actually used more water per hectare to protect cotton, while non-solar farmers stayed at ~440 mm because their shallow wells ran out of water sooner. Even with solar pumps, farming was limited by rainfall and the hard rock aquifer. Solar feeder farmers irrigated cotton more intensively despite reduced cropped area, but aquifer limits + poor rainfall constrained overall production.
The study findings underscore the importance of considering the underlying hydrogeological conditions when assessing the impacts of irrigation technologies on groundwater use. This is because results showed contrasting patterns of irrigation water use across two districts underlain by different aquifer types, i.e., hard rock and alluvial. In low-storage aquifer regions, water availability, not energy, was the limiting factor and constrained farmer cropping practices based on the available water.
The results of this study indicate that grid-connected solar irrigation can help alleviate concerns about its likely negative impact on groundwater. However, its effectiveness in promoting groundwater conservation is strongly influenced by the local context, particularly the characteristics of the underlying aquifer, cropping practices and Feed-in-Tariff (FiT) incentive provided.
While the incentives provided by the grid-connected solar model changed the pumping behaviour of farmers in Anand in favour of reduced water application, the effectiveness of this mechanism is dependent on the attractiveness of the feed-in tariff. Under the national PM-KUSUM solar scheme, tariffs in many states remain considerably lower than those offered under the SKY scheme in Gujarat, which may weaken the behavioural incentive that makes grid-connected solar potentially useful as a groundwater management instrument. An appropriately calibrated tariff must be decided that takes into account local cropping systems, prevailing electricity prices, and the degree of groundwater stress if it is to meaningfully influence farmer pumping behaviour, crop choices, and the adoption of water-positive agricultural practices.
This highlights the need for groundwater management policies and incentive structures that reflect local hydrogeological and agro-climatic conditions. Scaling up grid-connected solar irrigation also requires addressing institutional and equity challenges. Evidence shows that solar irrigation schemes in India face recurring constraints, including high upfront capital costs, dependence on subsidies, and institutional and infrastructure gaps.
Grid instability, voltage fluctuations that cause inverter tripping, and differences in DISCOM capacity can also affect scheme performance and farmer earnings across regions. Feed-in tariffs under the national scheme have declined, reducing incentives for farmers to export surplus power rather than expand groundwater-intensive cultivation. Viability has so far been demonstrated only in specific agro-institutional contexts.
Improved financing, stronger grid infrastructure and context-specific tariff design will therefore be important to ensure that grid-connected solar irrigation supports both livelihoods and groundwater sustainability.
Future research should focus on four areas:
Long-term groundwater impacts: Longitudinal studies tracking groundwater levels, water market dynamics and farmer behaviour across multiple seasons are needed to determine whether the short term reductions in water use observed here translate into sustained aquifer conservation, particularly in alluvial regions where water markets are active and groundwater depletion is acute.
Long-term scheme performance: Research should examine operation and maintenance challenges, changes in farmer behaviour over time and feed in tariff design across different agro-climatic and institutional settings.
Hydrogeological suitability: Further work is needed to identify the most suitable solar irrigation configurations for different hydrogeological settings.
Livelihood impacts: Research should examine how solar irrigation affects crop diversification, yield stability and livelihood resilience under national programmes such as PM KUSUM.
The Gujarat evidence shows that the effects of solar irrigation on groundwater use depend on local water conditions, farming systems and incentives.
In Anand, where productive alluvial aquifers, water markets and financial incentives operate together, solarisation was associated with lower irrigation water use among solar farmers. In Botad, where groundwater recharge is limited and aquifers have low storage capacity, rainfall and water availability constrained farming regardless of whether pumps were solar powered.
The findings suggest that solar irrigation can influence how farmers use water, but its effectiveness as a groundwater management tool depends on the conditions of the aquifer and the incentives surrounding it. Technology cannot create groundwater where storage capacity is limited.
As India expands solar irrigation to address the energy and water needs of agriculture, the Gujarat experience points to the importance of aligning financial incentives, farming practices and groundwater policies with local aquifer conditions.