Harnessing the sun to pump water

The answer to low agricultural productivity made worse by the climate crisis is simple: water. But the challenge has always been to find the energy to pump water to rain-fed terraces.

Now, rapid advancement solar panel efficiency and falling costs have made it an attractive option for pumping water for irrigation for higher and sustainable agricultural yield.

Solar powered water pumps in fact have the potential to lift Nepali families from subsistence agriculture and poverty, which has been exacerbated by  climate induced water shortage and the economic fallout of the pandemic.

Solar power has become a necessity to shift to higher-value crops and transform livelihoods of subsistence and smallholder farmers. This is why it has become the Nepal government’s priority to promote solar irrigation to address the food-energy-water nexus and its climate interlinkages.

As of August 2019, Nepal had already installed 1,600 solar irrigation systems worth $8 million all over the country. More than 75% of these were financed by the Alternative Energy Promotion Centre (AEPC), an apex body on renewables promoting solar irrigation under the Renewable Energy Subsidy Policy (2016) and Subsidy Delivery Mechanism Guidelines (2016).

Collectively, these systems irrigate 550 hectares of farmland and generate 2.5 megawatt of energy. In a nation where only a quarter of the 3.5 million hectares of cultivable land is irrigated, and two-thirds of farms depend on the rains, solar irrigation systems are crucial for expanding acreage. 

There is great potential for solar irrigation systems as a solution to food security for  smallholders because it can increase agricultural production to keep pace with food demand while at the same time adapting to changes in weather patterns due to climate change. 

This in turn will lead to improved livelihoods and help in poverty alleviation. The use of clean energy also removes expenditure for diesel used in pumps, and reduces Nepal’s petroleum import bill.

Much of the effort so far has been concentrated on improving access to solar technologies through innovation in infrastructure and financial instruments. There is now a need for concurrent investment in optimisation of energy generated through solar irrigation systems. Appropriate technologies could  translate excess energy generated by solar systems beyond irrigation.

A solar irrigation facility in Devchuli Municipality of Nawalpur district shows that, on average, only 30% of 22.4KW energy generated is used for pumping water and the rest is wasted. An estimated $188,727 worth of valuable energy goes down the drain.

There are at least three ways to use the energy generated by solar irrigation systems for economically productive and socially valuable outcomes. First, we could sell back excess energy to the utility for feed-in tariff as long as the feed-in tariffs and the cost of net metering are feasible. 

Secondly, irrigated water could also be sold to other farmers as long as they are nearby, the timing of local needs is compatible, and the availability of diesel-powered tubewells. 

Third, and most importantly, the energy that is presently being wasted could be used more productively by introducing innovation in the agricultural value chain. We call this ‘enhancing the social value of energy’.

Market-based solutions such as post-harvest processing are contenders to improving energy utilisation and add greater value for the farmer. Innovations in agro-processing technologies can expand opportunities for local communities to improve their livelihoods and better respond in the times of crises like climate and Covid-19.

Greater attention to innovation, both social and technological, is critical in ensuring the full benefits of solar irrigation systems. Proponents of Nepal’s solar energy need to move away from the traditional priority given to techno-centric strategies to find ways to efficiently use up the excess energy.

Usha Maskey Manandhar is with MinErg and works with gender and social inclusion on energy and environmental issues. Jeevan Baidya of Sunbridge Solar Nepal and Netera Chhetri, professor at the School for Future Innovation at Arizona Stte Univerity also contributed to this report.