17 April 2020

In perhaps the largest electricity experiment the world has ever seen, India’s hydropower sector was heralded last week for restoring electricity to tens of millions of households following a huge plunge in demand.

The fall in demand of 31,089 megawatts (MW) – equivalent to the entire power demand of Pakistan – came after Prime Minister Narendra Modi called for Indians to switch off their lights for nine minutes at 9pm on 5 April, to express solidarity amid the Covid-19 pandemic.

While the Prime Minister’s aim was to unite citizens during a time of crisis, the move presented a huge challenge for power operators, who are charged with managing grid stability.

India is the world’s third largest consumer of electricity and, according to IHA’s 2019 Hydropower Status Report, has the sixth largest hydropower sector by installed capacity.

Hydropower’s role in grid stability

India’s Power System Operation Corporation (POSOCO) had anticipated a much smaller reduction of 12,000 to 14,000 MW in the nine-minute period than the 31, 089 MW which ultimately took place.  

Following Modi’s announcement, the state-owned company reportedly held a conference call with all state load despatch centres and major hydropower stations on 4 April, and began mock exercises on hydro ramping almost immediately.

As the country reached closer to the lights-off vigil, hydropower generation was maximised. When people began switching lights off between 8.45pm and 9.10pm, hydropower generation was then quickly reduced from 25,559 MW down to 8,016 MW to match the demand reduction.

Thanks to hydropower’s unique flexibility, the stations were then able to ramp up within seconds to meet the increased demand, as Indian households began switching their lights back on.

“In managing a staggering 31 GW ramp down on demand in matter of minutes, hydro resources helped the grid managers like a rock star,” Debashish Mishra, a partner at Deloitte India told The Mint newspaper. “Kudos to POSOCO and the LDCs (load despatch centres) for pulling off this spectacular event within the technical range of system frequency.”

In a preliminary report, POSOCO thanked hydropower operators, as well as thermal, gas and wind power operators, for their support and co-operation in meeting “this unprecedented challenge”. “The event was managed smoothly without any untoward incident while power system parameters were maintained within limits,” POSOCO said.

“This experiment provides a good example of how hydropower can provide flexibility and stability to the grid system under extreme circumstances,” said Nicholas Troja, a Senior Hydropower Analyst at the International Hydropower Association (IHA). “It again highlights the need for greater investment in flexible generation sources, particularly pumped hydropower storage.”

Professor Arun Kumar of the Indian Institute of Technology Roorkee said: “The support provided by the flexibility of hydropower resources to meet the rapid drop and rise in the demand on 5 April 2020 triggered policy-makers to seriously think of installing hydropower projects, along with pumped storage.”

Read IHA’s working paper on pumped storage and our pumped storage tracking tool for more information.