The Ceylon Electricity Board (CEB) has urged all rooftop solar owners to voluntarily switch off their systems from 9:00 AM to 3:00 PM daily until April 21, in order to safeguard the national power grid during the Sinhala and Tamil New Year holiday period.
The appeal follows a significant drop in electricity demand due to factory and office closures, coupled with high solar output under clear skies. This mismatch has created a serious risk of grid instability, as solar systems continue generating power without responding to demand levels.
Unlike traditional power plants, rooftop solar installations cannot be controlled by the CEB in real time and do not contribute to the critical “inertia” needed to stabilize electricity frequency. Inertia, typically provided by large spinning generators like hydro or thermal plants, helps prevent blackouts by absorbing fluctuations in supply and demand.
Data from April 12 shows that without CEB intervention, system inertia would have dropped to a dangerous 34%—well below safe operating limits. CEB managed to keep it at 56% by shutting down solar and carefully managing plant operations.
Until Sri Lanka deploys advanced grid-forming technology or large-scale battery storage, the country’s electricity system will remain dependent on conventional power plants for stability. With only 100,000 rooftop solar owners out of 7 million total electricity consumers, CEB says this temporary curtailment is essential to avoid risks to the entire grid. (Newswire)
