The Government has acknowledged an oversupply of solar power to the national grid, particularly on Sundays, and is working with engineers and the Ceylon Electricity Board (CEB) to find solutions to stabilize the system.
Cabinet Spokesman and Minister Dr. Nalinda Jayatissa stated that small-scale solar power producers contribute to an imbalance in supply and demand on Sundays, making the grid more vulnerable to disruptions. He explained that the high penetration of solar energy has resulted in low system inertia, meaning even minor incidents—such as an animal interfering with power lines or a fallen tree—could trigger widespread disconnections and potentially lead to a total power failure.
Unlike hydro and thermal power generation, solar power cannot be regulated in the same way, adding to the challenge. Engineers are currently investigating ways to stabilize the grid and prevent further disruptions.
The issue became evident during the nationwide power failure on 9 February 2025. The CEB reported that the failure was triggered by a disturbance at the 33kV Panadura grid substation, causing a sudden voltage drop. At the time, over 50% of the national electricity demand was met by 800 MW of solar photovoltaic (PV) generation, alongside 470 MW from the Lakvijaya Power Plant in Norochcholai and 130 MW from hydropower plants. The high proportion of non-synchronous solar PV generation led to a lack of system inertia, making the grid susceptible to faults.
As part of its response, the CEB plans to curb ground-mounted solar PV generation during low-demand periods to reduce instability risks. However, rooftop solar installations will not be affected by this measure.