The demand for power is rising steadily, with the economy doing well. This has resulted in companies scrambling to either hike capacities or expand on the renewable front — with pumped storage hydropower being an area of interest. Before we get into how this technology works, let us look at how it can benefit the sector?

How will pumped storage hydropower benefit the power sector?

According to Sumit Kishore, Executive Director, Capital Goods, Power and Infrastructure, Axis Capital, India's peak electricity demand reached a fresh record high of around 233 GW earlier this week. He said the average electricity exchange prices are hovering around Rs 9 on an average for the day. Vikram V, VP and Sector Head, Corp Ratings, ICRA, said the overall electricity demand this fiscal is expected to grow 5-6 percent.

There are two peaks of power demand daily — morning and evening. The morning peak is met by solar energy, but managing the evening peak is becoming fairly challenging and is likely to remain so for the next few years, Kishore said.

"There is a growing realisation in the power sector that intermittent renewable installed capacity alone could cross or come close to India's peak demand in the next 3-4 years. To manage these grid intermittency issues that this may trigger, given that we have a thermal-heavy generation mix in India, there is a very big push for hybrid wind, solar, as well as renewable electricity storage solutions," Kishore added.

What is pumped storage hydropower and how does it work?

Pumped storage hydropower (PSH) is a scalable battery storage solution which helps in dealing with grid intermittency issues, mainly the evening peak deficit dilemma that the power sector finds itself in.

PSH is a configuration of two water reservoirs at different elevations that can generate power as water moves from the upper to the lower reservoir, passing through a turbine. This is known as the batteries discharge phase. The now pumped storage hydro also requires the water to be pumped back into the upper reservoir to recharge the battery. The recharging process requires green power — solar or wind power — during off-peak hours, which can recharge the battery. "During peak hours, you can discharge the battery and benefit from this whole operation," Kishore said.

Pumped storage hydropower technology — cost, potential, India's target

According to Kishore, the PSH technology is almost 30-40 percent cheaper than the prevailing prices in the battery energy storage system.

India is targeting close to 19 GW of PSH projects through 2032. However, the country has the potential to generate over 100 GW, Kishore said, citing data from the Ministry of Power.

JSW Energy, NHPC, Torrent Power and Tata Power have outlined plans for PSH in India. Greenko has taken the lead in the private sector, so far. It is an unlisted company, but is at an advanced stage of setting up a 1.2-GW PSH project in Karnataka, Kishore said.

JSW Energy has tied up with almost 10-kW capacity in MoUs with almost seven states.

Tata Power is looking at setting up 2.8 GW of PSH in Maharashtra, where they have an existing rain-fed water reservoir, Kishore said.

He added that Torrent too is interested in the PSH technology. Meanwhile, SJVN and NTPC have locations to set up the projects over the medium term.

"Pumped hydro is a proven technology. We have had pumped hydro projects for a number of years in the country as well. But the quantum was very small, at about 3.3 gigawatt being operational. But now the government is talking about is much larger number to mitigate the risk associated with this intermittent nature of wind and solar power generation and to ensure that the grid is balanced, and we don't face the challenges of going forward," Vikram V said.

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(Edited by : Shoma Bhattacharjee)