Sri Lanka temporarily shut down one of its coal power plants during the Sinhala and Tamil New Year holidays, relying heavily on rooftop solar energy and reduced electricity demand as many factories closed for the season. The move marked a significant shift in the country’s energy management strategy, highlighting the growing role of decentralized renewable power.
The Ceylon Electricity Board (CEB) confirmed that it shut down the third coal unit on April 11 at 9:57 p.m., and scaled back the remaining two units. The decision came as daytime power demand dipped, aided by a surge in rooftop solar generation, estimated at over 1,500 megawatts (MW) in capacity.
“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 in a statement.
However, the CEB also noted challenges in managing grid stability during such periods. Since rooftop solar installations operate independently and are largely invisible to the system control center, the utility asked solar users to voluntarily switch off their systems to avoid overloading the grid. Commercial-scale solar generators operating under ‘net plus’ and ‘net plus, plus’ contracts were also curtailed temporarily.
Despite these limitations, the increased solar output helped the CEB conserve fuel and water resources. On April 12, a naphtha-powered thermal plant, which had been running overnight, was shut down at 9:16 a.m. to make way for solar generation. No oil-fired plants were used for the remainder of the day.
Only two coal units were kept running at minimum capacity, while large hydropower plants supported the grid and maintained system balance, especially during night-time peaks.
Though battery storage for solar power remains financially unviable at scale, Sri Lanka is effectively “storing” solar energy by conserving water in reservoirs and reducing coal use, a move that contributes both to energy efficiency and emissions reduction.