Representational image.

Moushumi Basu, Reuters

Tucked away in the Himalayan foothills of northeast India and frequently battered by strong winds and landslides, the isolated village of Hengbung is well-accustomed to prolonged power cuts. But the village’s challenging terrain — it is mountainous, hard to reach, and criss-crossed by streams — is now proving an opportunity to ensure reliable electricity for the community. A pumped-storage hydropower system fitted with solar-powered pumps started operating in the village last July — the first such project in India to integrate hydro with solar. Built on a stream, the facility features two interconnected reservoirs and essentially acts as a giant water battery, which stores renewable power for release later during grid outages or when demand is higher.

At least 350 people in Hengbung —located in Manipur state — now have consistent lighting in their homes and streets as a result of the system, said the Foundation for Environment and Economic Development Services (FEEDS), a local NGO involved in the initiative. “The project has made a sea change in the lives of our villagers by fighting out darkness while keeping the environment clean,” said FEEDS founder, Haokholet Kipgen, who is a Hengbung resident and the wider area’s local political representative. The project — a collaboration between FEEDS, the NB Institute for Rural Technology (NBIRT) and Visva-Bharati University, with central government funding of 29 million rupees ($353,195) — is part of a drive to boost India’s renewable energy capacity.

One of the top global emitters of greenhouse gases, India wants to increase its renewable generation to 500 gigawatts (GW) by 2030, from an output of about 120 GW, government data shows.

Hydropower has been earmarked as a key part of this, as it can provide continuous power when other green power sources — such as solar and wind — are limited by poor weather conditions. But as renewable energy generation grows, particularly from solar power, energy storage is also needed to ensure the nation’s grid remains stable around-the-clock and outages are avoided. India’s total operational battery storage capacity is about 50 megawatt hours (MWh), according to the India Energy Storage Alliance (IESA). A recent study by the Council on Energy, Environment and Water (CEEW) estimated that the country’s need would be 327 gigawatt hours (GWh) by 2030. Energy experts say that pumped-hydro storage projects (PSP) could be a key solution, and India’s power ministry recently published draft guidelines to promote the technology.

Currently there are eight operational PSPs in India with about 4.7 GW capacity overall, most drawing their main operating power from the national grid. But India’s government has identified about 120 sites for the technology, with the total storage potential of 103 GW. Nine further PSPs have been commissioned, with three now under construction, and energy analysts said private power firms are now looking to combining hydro power with clean energy, following the example of the landmark system in Hengbung. “Such projects show the way in transitioning to a sustainable energy future by integrating renewable energy with hydroelectric power and storage,” said Santi Pada Gon Chaudhuri, NBIRT’s founder and an energy advisor to the central government.

The PSP in Hengbung has two interconnected reservoirs with a total capacity of 1.9 million litres of water, equivalent to about three-quarters of an Olympic swimming pool. During power outages - which are often caused by snapped transmission wires or transformer breakdowns during monsoon rains and in winter — the upper reservoir releases stored stream water to operate a turbine, feeding green power to the grid. That released water then accumulates in the lower reservoir, until it is later pumped back upstream, using solar power, to make it available for power generation again. During monsoons, when there is plenty of stream water to drive the turbine and restock the upper reservoir, excess solar power is fed into the national grid. Energy experts said PSPs have a longer lifespan, lasting for at least six decades, than lithium-ion or lead-acid batteries. “Pumped water storage systems can be a dependable option ... especially when renewable sources such as the sun or the wind may not be available to match the electricity demand,” said Disha Agarwal, senior programme lead at CEEW, a think-tank.

Major hydroelectric facilities being built across other Himalayan areas and regions of India have sparked huge protests from residents due to the environmental and social impacts.