‘Smart solar pump’ solution gains foothold in India

In Karnataka state in arid southwest India, the local electric company is required to buy back surplus solar power from farmers – similar to programs in parts of Germany, Japan and the United States.

The buyback policy, signed by Karnataka’s governor last September, is consistent with recommendations by scientists at the International Water Management Institute (IWMI) to treat solar power as a ‘cash crop.’ The rationale is that if farmers can make money by selling excess power, they then will have an economic incentive to irrigate their crops efficiently, thus helping to conserve groundwater and energy use.

“Many Indian states have been heavily subsidizing the cost to buy solar irrigation pumps as a green energy solution,” said Tushaar Shah, an IWMI senior fellow based in India. (IWMI leads the CGIAR Research Program on Water, Land and Ecosystems). “However, runaway growth in solar pumps actually can result in as much groundwater over-exploitation as free electric power has done so far in India. The best way to halt/avoid this threat is by paying farmers to ‘grow’ solar power and sell it back to the grid rather than use it to pump water.”

For example, a farmer with a 10kwp solar power system (10 kilowatts at peak performance or full sun) can earn nearly 50,000 rupees a year (800USD) selling back excess power, according to Karnataka government documents attached to the September order.

Groundwater over-exploited despite impressive canal system

Despite inheriting the world’s largest canal irrigation network built during British colonial rule, India has become the biggest groundwater irrigation economy, with nearly 20 million electric and diesel pumps irrigating more than 67 million hectares of land a year.

Heavily-subsidized pumps have driven groundwater depletion in western India and other parts of the country. An unreliable electric grid, bankrupted utilities and power theft have contributed to the problem.

IWMI’s solar pump work grew in response to India’s National Solar Mission, which aspires to develop 22 gigawatts of solar power by 2020, largely by constructing massive solar power plants. Shah said India could achieve its solar goal with 2 million solar irrigation pumps instead and “put cash in farmers’ hands” in the process.

Researchers combine the power buy-back with a lower solar panel subsidy

Currently, many Indian states offer subsidies of 80 to 90 percent for buying solar panels. IWMI research funded by Tata trusts, the social arm of the Indian Tata Group conglomerate, showed that heavy subsidies create unintended incentives for the solar industry to maximize its gains by constantly raising solar panel prices. An open market is thereby limited, elites tend to capture the subsidies, and there is ripe potential for groundwater over-extraction.

IWMI’s ‘smart solar pump’ policy recommends a lower, flat subsidy, readily available bank financing to help farmers buy pumps, the abolishment of pump size restrictions and, overall, a solution tailored to local conditions.

Karnataka’s new Surya Raitha policy with a solar buyback provision is a further step in the right direction. But Shah said he believes Karnataka’s policy still has flaws including a too-high 90 percent subsidy for buying solar panels. The scheme also needs tamper-proof meters and strong farmer cooperatives to stem electricity theft, he said.

Shah said he believes IWMI’s “smart solar pump” policy has applicability to both the dry and wet areas of India.

In dry areas such as Karnataka state, the goal is to wean farmers from grid power. In eastern India where aquifer resources are prolific, the idea is to stimulate a local irrigation service market and “green revolution” which has stagnated because of soaring diesel prices. (Diesel prices have risen 10 times faster than the prices of agricultural commodities since 1990, according to studies).

IWMI has been working with a variety of partners on its proposed solution, including the Indian government, solar power companies such as SunEdison India and Tata Solar and the Sir Ratan Tata Trust.

Challenges exist, but solar pump potential in South Asia is high

One of the issues utilities have, Shah said, is the cost to meter each farm. He recommends that farmers form “solar farm cooperatives” with a single connection to the grid to sell back and meter the excess power. The CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) has shown interest in supporting IWMI to pilot that idea.

IWMI researchers say their “smart solar pump” proposal also has application to other parts of South Asia, such as Bangladesh, Nepal and Pakistan where farmers are hamstrung by an unreliable grid power and high diesel costs.

“Solar pumps can unlock India’s energy-irrigation logjam – and other parts of South Asia as well – if the right incentives are made to farmers to manage groundwater resources sustainably,” Shah said. “A key incentive is to encourage farmers to grow solar power as a cash crop.”