ECONOMYNEXT – Sri Lanka shut down a coal plant from April 11, using the maximum possible rooftop solar, as factories closed for the traditional New Year holiday using the maximum possible rooftop solar, state-run Ceylon Electricity Board said.
The CEB said it shut the third coal plant Friday night at 21:57 hours, and had deloaded the remaining two.
The CEB had asked rooftop solar users to voluntarily shut down their units, during the holiday season as demand falls, to maintain grid stability with sufficient generators providing ‘inertia’ to absorb shocks.
The utility said it had curtailed commercial solar units above 100kW, operating on ‘net plus’ and ‘net plus, plus’ contracts to maintain grid stability.
Though rooftop solar is not visible to the CEB’s system control centre, there is 1,500MW capacity, which will generate energy based on the intensity of the sunlight.
Overall daytime demand was above 1500MW.
“This suggests a significant contribution from rooftop solar units. Additionally, large synchronous generators played a vital role in maintaining system inertia, ensuring grid stability throughout the day,” the CEB said.
The CEB had run its large hydro plants, during the night peak and also daytime.
On April 12, a Naptha (heavy fuel) plant that was running overnight after the coal plant shut down was shut at 9.16 am to absorb solar energy.
“No oil-fired power plants operated the rest of daytime,” the CEB said.
“Only two coal units operating at minimum power and larger hydro power plants maintained grid stability.”
Though rooftop solar tends to destabilize the grid and battery storage to store them is expensive, some storage is taking place through the conservation of water in CEB’s large hydros as well as reduced coal use. (Colombo/Apr15/2025)