New technique gives hydro power generation a leg-up

A hydro power system which generates more power by recycling water "cost-effectively" is increasingly finding favour with companies as the country struggles with a peak power shortage of 12 per cent.

The pumped storage plant (PSP) involves recycling of water between reservoirs. Surplus off-peak energy available in the grid (thermal or nuclear) is used to pump water from the lower reservoir back to the upper reservoir for generation during peak hours.

A Central Electricity Authority (CEA) study has identified 56 sites with a combined capacity of 94,000 Mw where the system can be installed. The process involves an investment of about Rs 6 crore per Mw, compared with Rs 5-5.5 crore required for a conventional hydro power plant.

The Nuclear Power Corporation of India Ltd (NPCIL) and Tehri Hydro Development Corporation (THDC) recently set up a joint venture company for implementing PSP schemes.

However, it will take another five years before the technique is implemented across the country. "It is not the government's priority at the moment," said a senior government official.

The system helps in meeting peak demand and provides a balancing load to base load thermal power plants during off-peak hours (base load thermal power plants operate continuously, stopping only for maintenance or unexpected outages).

The western region alone (Gujarat, Maharashtra and Madhya Pradesh) has 25 sites with a capacity of 38,000 Mw where the system can be set up, according to the CERC study.

The northern region has seven such sites with a capacity of 13,000 Mw, while the southern region has eight sites with 16,600 Mw capacity. In the east, six sites with a capacity of 9,000 Mw have been identified.

Power Secretary Anil Razdan said the concept should have been taken up 10 years ago by big players like National Hydro Power Corporation (NHPC). He added that Maharashtra had a few sites that could be taken up for immediate implementation by the joint venture company of THDC and NPCIL.

The sites in Maharashtra, which are being considered for PSPs, are Humbarli and Malshay Ghat. The estimated cost for these projects is Rs 1,600 crore and Rs 1,400 crore, respectively.

Neighbouring states like Bhutan and Nepal have also shown interest and approached the Indian government for PSP schemes. Nepal has three such projects with 1,300 Mw capacity.