Solar irrigation: A boon or bane for groundwater?

Md Faiz Alam:

In Ishnav, a small village in Anand district in Gujarat, solar panels shine bright in the farmers’ field. The energy generated by these solar panels is used by farmers to run pumps for irrigating their fields. However, there is more to these solar panels. When not irrigating, farmers can sell the solar energy generated, thus providing an impetus to their income. This can also be rightly termed as Solar Power as a Remunerative Crop.

This story is unfolding in more than 100 villages across Gujarat. The state government in 2018 started implementing the SKY (Suryashakti Kisan Yojana)” scheme. To get solar panels under the scheme, farmers pay a 5 % down payment, whereas the rest is covered as part of the loan (65 %) and subsidy (30 %). For a 10 HP, this down payment cost is around INR 30,000. In return, farmers earn Rs. 3.5 for each unit of electricity sold. Further, the government of Gujarat gives another Rs. 3.5 for each unit for seven years to boost farmer’s’ repayment capacity on the capital cost loan. A more detailed design of the scheme can be accessed here. The Government of India, recently launched an ambitious solar scheme, KUSUM (Kisan Urja Suraksha evam Uhaan Mahaabhiyan) that will be implemented  pan India, although with some modifications.

Is Free Power a Threat to Groundwater?

One persistent nagging question regarding solar irrigation concerns most of us, i.e., “Won’t farmers with free solar energy pump more?”.

India has 20 million groundwater irrigation pumps that support about two-thirds of the total irrigated area. Of these 20 million pumps, about 14 million use electricity as energy source. And electricity for agriculture is provided either completely free or at very subsidized rates. This has led to unfettered groundwater overexploitation in large parts of the country. This threatens agriculture’s sustainability, and research suggests that this unsustainable groundwater use can decrease India’s cultivated area by 20 %. This will impact both India’s food security and the livelihoods of farmers.

 

A farmer’s field showcasing solar panels and dug well in Parmeshwar feeder, Botad, Gujarat
Photo: Md Faiz Alam/IWMI

So, does the same fate awaits solar irrigation?

This intricate link of water with energy to produce food, often termed as Water-Energy-Food nexus, is central to the long-term sustainability of all three domains. This requires innovative integrated solutions. The aforementioned SKY scheme is implementing one such solution. The scheme while promoting solar irrigation also incentivizes farmers to not waste water by providing them the opportunity to sell generated electricity. For example, a farmer with 7.5 HP pump can potentially earn as much as 24000 INR/year (upto 7 year during loan term) and 51000 INR/year after 7 years. With this incentive design, the hope is that farmers will use energy (and thus water) more cautiously and efficiently to maximize their income from selling energy.

But is the scheme working? The International Water Management Institute (IWMI), as part of the Solar Irrigation for Agricultural Resilience in South Asia (SoLAR) project in partnership with INREM foundation, Gujarat Energy Research and Management Institute (GERMI), and Gujarat Urja Vikas Nigam Limited (GUVNL) is trying to find this out.

Measuring Farmers Groundwater Abstraction: A Herculean Task

The project will be comparing groundwater use of solar and non-solar farmers. But measuring the quantity of water pumped out by thousands of farmers across the state is a herculean task. Thus, the project uses an innovative way to do the same, i.e., converting farmers energy consumed data to water abstraction. Each unit of energy used is associated with a certain amount of water abstracted. This relationship between farmers’ energy use and water abstraction differs among farmers depending on their pumps, wells, and aquifer types. To develop this relationship, the project team is conducting extensive research and fieldwork by testing out different pumps, wells, and aquifers.

 

Water being pumped to an overhead tank for irrigation (Ishnav Feeder, Anand)
Photo: Md Faiz Alam/IWMI

The project will benefit from the state-of-the-art monitoring system of the SKY scheme that measures the energy used and energy sold by farmers. Also, most of the other non-solar farmers have electricity meters, though with subsidized tariffs. With the availability of energy use data and developed relationships, the project will compare the irrigation behaviour of solar and non-solar farmers across Gujarat.

 

An installed flow meter [Parmeshwar Feeder, Botad district], Gujarat
Photo: Md Faiz Alam/IWMI

Currently, research is being undertaken in Botad and Anand districts in Gujarat. They were chosen for the distinct hydrogeology they provide. Anand is underlain by highly productive alluvial aquifers with deep and year-round groundwater availability. On the other hand, Botad consists of low storage hardrock aquifers where groundwater availability is very limited post-monsoon. Once the relationship is developed and tested, we can upscale it elsewhere to assess whether the SKY scheme has brought a change in farmers’ irrigation behaviour. The research will provide insight on the implication of solar irrigation on groundwater and will also lead to cheap indirect ways of measuring water through energy use.

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