Cheaper and increasingly more powerful solar-powered water pumps are lifting more than groundwater in parts of India. They are also lifting farmers out of poverty by enabling them to better irrigate their crops more affordably, with less dependence on electric and diesel-powered pumps. But while it is clean energy, will they bring environmental costs?
Typically, power supply is either too poor or non-existent for farmers to adequately irrigate their fields. A long-established system involved distributing irrigation canal water to farm ponds once every two or three weeks. Farmers would extract this water with shallow, electric or diesel surface pumps to irrigate their fruit orchards, flower and cotton fields. A steady decline in this on-off supply of canal water has led to increasing irrigation water stress. Even this would be suspended once a year for canal maintenance work for up to 40 days, leaving farmers literally high and dry.
Solar Powered Pumps
To supplement the intermittent and inadequate canal supply, many farmers have also dug tubewells. Throughout India, 20 million small electric or diesel-powered pumps have been installed to date by 55-60 per cent of the population. For farmers, waiting two to three years for connection to the national grid only adds to their woes. Looking for solutions to the poor electricity distribution and spiralling costs of diesel, they have been demanding solar power to meet the shortfall in energy to irrigate their fields.The technology has been around for two or three decades but it’s not a perfect solution for powering irrigation. Too expensive for most farmers, the panels were only available in one or two horsepower (hp) output and inadequate for groundwater extraction from deeper tubewells.
Subsidies make solar pumps a viable option for more farmers
A new study by Nidhi Prabha Tewari for the IWMI-Tata Water Policy Program highlights a scheme by the Rajasthan Government offering massive (86 per cent) subsidies on 3 hp solar pumps costing $11,000. To date, over 7,000 have popped up across India, generating enough energy to irrigate small plots of 1 – 1.12 hectares. New providers in the market are producing solar integrators which have brought the cost of a similarly powerful pump, down to $3,000. With costs plummeting and savings on diesel as much as $1 – 2,000 a year, the cheaper solar pumps are suddenly a viable option for many more farmers. But the lack of power storage facilities and cloudy or rainy weather means solar pumps are still supplementary to normal pumps.
Solar pumps are not only emerging as an answer with huge potential for the agriculture sector’s energy problems. They are also bringing savings to farmers for whom they are pumping as well as energy solutions.
Innovating at domestic level, individuals are adding inverters and batteries to leverage the technology, providing more energy for their domestic or cottage industry use such as small mills. Solar pumps are not only emerging as an answer with huge potential for the agriculture sector’s energy problems. They are also bringing savings to farmers for whom they are pumping as well as energy solutions.
Will this spark excessive groundwater extraction?
Groundwater irrigation has been a major factor in raising many from poverty in developing countries. But with growing awareness of the groundwater-energy nexus, comes concern for the management of solar-powered groundwater extraction. With the previous state management of water supply for farm irrigation, there was a great deal of control. Will increasing installations of solar pumps lead to unsustainable groundwater extraction, sinking water tables and water quality?
With electric or diesel pumps, farmers could quantify the cost which was a financial control on pumping. Once the initial cost of solar pumps was recovered (usually a year or so), running costs disappeared. The situation isn’t helped by famers complaining that 3 hp is not enough and are demanding 5 and 10 hp solar pumps. As pumping groundwater becomes cheaper and easier, researchers are mindful of its environmental impact. IWMI’s Nidhi Tewari says, “Although policy makers don’t fully appreciate the implications, they have tried tying the subsidised solar pumps to drip irrigation.” But will it lead to excessive extraction? Tewari thinks it’s too early to say. “Solar pumps installed at tubewells in farms not supplied by canal water are a bigger concern.” She adds, “It would be great to promote solar surface pumps in eastern India which is rich in water and deficient in electricity.”
It will be interesting to see whether the new lower cost pumps on the market will affect the subsidised State scheme and whether it will be rolled out elsewhere. So while India’s farmers look forward to more prosperous lives, the Government must look for innovative answers to management that doesn’t remove those hard-earned benefits.
(Dharshani Weerasekera is an independent science writer who has just completed her M.Sc in Science Communication at Imperial College, London).
Source : Agriculture and Ecosystems blog