India's grid gets ready to deal with 'too much' green energy risk

As unprecedented amount of RE flows in, grid managers devise ways to prevent supply disruptions

With significant addition of renewable energy (RE) capacity over the past two decades, the grid is now devising ways to handle “too much RE”. RE sources — which include solar, wind, small hydro, and others — are intermittent in nature, and their sudden spikes and drops can cause massive grid disruptions, including outages. 

To address this, arms of the Union Ministry of Power — Grid Controller of India (Grid-India), the Central Electricity Authority (CEA), and the Central Electricity Regulatory Commission (CERC) — are drafting various plans to schedule, forecast, and manage RE efficiently, while keeping thermal power as the base supply. 

The current RE capacity stands at 224 gigawatt (Gw), with India’s total power generation capacity at 470 Gw. 

Managing RE to avoid blackouts 

Last month, Spain faced a power outage credited to a sudden drop in RE in its grid, which relies heavily on green power. Senior executives said while India’s RE capacity has not reached such levels yet, it has the potential to cause imbalances in the grid. 

 

As India still lacks large-scale RE storage, managing infirm RE sources becomes difficult when they are fed into the grid.

Senior executives at Grid-India said they are looking at a two-pronged approach. 

“One is that we run thermal power in two shifts — first during the morning hours, then take it offline during solar hours, and then sync it again just before sunset. The other is to run thermal power at a heat rate of 40–55 per cent and then ramp it up whenever RE supply falls during the daytime and for night hours,” said an executive. 

Grid-India is the electricity grid operator of the country. 

The executive added that CERC is expected to introduce regulations that would provide compensation to thermal power generators for reducing their heat rate. 

As RE’s contribution increases every year, the Indian grid is facing a “duck curve” problem. India’s electricity load earlier peaked during the daytime — i.e., office hours or commercial electricity demand. But in recent years, a new peak has emerged during the evening hours, driven by domestic electricity demand, with more electrified households and increased use of electronic appliances — especially air conditioners and refrigerators — in both rural and urban areas.

 

“When the demand peaks during evening hours, solar and wind are not available. And during the morning and afternoon when solar is available, demand isn’t as high. This duck curve — when supply is high and demand is low — could become precarious in the coming years as RE’s share rises,” said a grid executive, adding that energy storage will be crucial in addressing the duck curve problem. 

 

Disciplining green energy

 

Another issue faced by the grid is the erratic scheduling of RE sources.

 

According to a study by Grid-India, RE pockets in the country showed large and complex voltage fluctuations during solar hours in high-demand months of 2024. These zones also witnessed large deviations in RE supply schedules. The government is now considering stricter provisions for RE scheduling and forecasting.

 

“It is being observed that RE-rich regions are facing twin issues of voltage variability and active power variability. Voltage variability is a function of how reactive power response is being created by RE assets. Active power variability is a function of scheduling and forecasting errors due to sudden weather changes, which forecasting technology can miss. Both events could disrupt grid stability,” said Vishal Pandya, cofounder of REConnect Energy, a leading technology solutions provider for grid and RE management.

 

Pandya said the government is actively tweaking policies on both fronts. Reactive power management has started to be priced under the new Indian Electricity Grid Code (IEGC ’23), which includes incentives and penalties for RE assets responding to the grid’s reactive power needs. The CEA is providing technical support and updated grid data for the IEGC.

 

Likewise, under the deviation settlement mechanism (DSM) by CERC, much higher forecast accuracy is now expected from renewables, conventional generators, and distribution companies.

 

“Deviations from schedule are becoming expensive for all stakeholders. This is also reflected in DSM charges at the national grid, which increased by 103 per cent from 2020–21 to 2023–24. From 2026 onwards, even tighter DSM rules are planned, which could further escalate DSM charges for all grid-connected entities,” Pandya said.

 

Sector executives said stricter measures would help all stakeholders reduce their losses from DSM charges. They added that it would also help grid operators improve grid stability through better demand-supply management. 

How Spain’s grid buckled on cloudy day 

During the last week of April, Spain and Portugal faced their worst blackout on record. Initially, authorities pointed to power transmission issues, but it soon became clear that a sudden drop of renewable energy (RE) supply into the grid led to its collapse. 

While an official report is still underway, several independent reports have cited that the blackout across the Iberian Peninsula was triggered by a sudden and steep drop in solar power generation in Spain. This caused a chain reaction of frequency drops in the grid, activating automatic systems designed to prevent overloading. Several experts have highlighted the vulnerability of electricity grids to the erratic nature of infirm RE. Last year, several solar-rich states in India saw localised outages due to drops in RE supply during peak summer demand. 

 

India’s months of high RE supply also coincide with its high-demand summer season.