When solar-powered irrigation pumps made their debut on the Indian agricultural scene three years ago, they were hailed for three reasons – for being 'cheap', 'clean' and 'timely'. It was expected then that they would revolutionise the sector.

However, despite some progress, the desired ‘solarisation of Indian agriculture’ has not happened.

Today, some 25,000 solar-powered pumps irrigate the fields; in contrast, there are 20 million irrigation pumps driven by electricity and another eight million powered by diesel.

And why is this so? According to agri experts, the problem lies in the cost factor. Farmers are simply not able to finance solar irrigation pumps, despite the subsidy offered on them.

Take a look at the economics. It costs a farmer no more than ₹30,000 to buy a conventional, grid-powered pump. In contrast, a solar pump costs a lakh of rupees a horse-power, so the typical 5 hp power would be billed for ₹5 lakh. While the central and state governments offer subsidies, financial constraints are a natural limiting factor.

The Centre, for instance, has sanctioned ₹353.50 crore for 2014-15 for 100,000 pumps. Up till now, 63,436 pumps have been sanctioned to various state governments and another 30,000 through NABARD.

There are other obstacles as well in the way. Solar irrigation pumps could easily substitute the eight million-odd diesel-powered irrigation pumps. They could also be preferred over the other 20 million pumps powered by freely-supplied electricity as it is released inconveniently only in the night. Farmers could therefore be encouraged to purchase solar pumps, but banks are not willing to lend.

Karnataka experiment

Though the funding challenge for solar pumps remains unmet, there is an experiment that could show the way -- Karnataka's Surya Raitha scheme that is now being piloted in the Ramnagara district.

The scheme allows farmers to sell surplus energy from solar pumps to the grid. Since farmers need to use the pumps only for a few hours a day, and not all days of the year, the pump lies idle a lot of the time and can be a source of income.

The pilot scheme covers 250 solar pumps. The state electricity supply company arranges a loan to cover the unsubsidised part of the pump’s cost, and the farmer pays back the loan out of the money he makes by selling power. He gets a higher tariff if he waives the subsidy.

Solar experts say this model might be the way forward. In future, ‘electricity savings companies’ could install a solar pump at the farmer’s place, supply him the water and sell power for a few years and then hand over the pump to the farmer. Hence, simply using the idle capacity of the solar pump could be the answer.