Sudden dip in solar power raises alarm about grid stability

Clouds over vast swathes of North India have caused abrupt dips in solar power production, raising worries about the stability of the power grid that serves millions of Indians.

- Rituraj Baruah

The national grid operator asked all electricity companies in February to be on alert mode and supply power to preserve the grid's stability, two people aware of the matter said.

"There have been instances of a dip in power generation, which puts the grid under strain. In mid-February, it went below the requisite range and hit 49.5 Hz, raising a concern. A balance needs to be made in terms of renewable energy and other sources power, mostly coal," one of the people mentioned above said on the condition of anonymity.

Queries sent to the Grid Controller of India and the Union power ministry remained unanswered till press time.

Grid frequency is a key indicator of the network's stability, and must remain within a tight band of 49.9-50.2 Hz to ensure that the grid functions smoothly. Sudden changes in power production or demand can disturb the frequency and potentially destabilize the grid, and in extreme cases, spark outages across vast areas. Grid frequency fell below safe levels several times in February, the two people said.

Solar and wind power are considered infirm sources of power since production depends on unpredictable sunshine and wind. When production from such sources fall, coal- and gas-based power plants amp up supply to maintain frequency and stabilize the grid.

Clouds and fog common in winters cut off sunshine and curb solar power generation, especially in northern states such as Rajasthan, which have large solar capacity. When accurate weather forecasts are available early, authorities can crank up production from other sources, the second person added.