State-run Electricity Generating Authority of Thailand (Egat) is planning to reduce the power generation capacity reserve to 15% from 40% of total capacity, in a move to curb high power costs.
Decommissioning some power plants early, electricity sales to neighbouring countries and greater use of electricity in agribusiness will be carried out to allow for reductions.
Without these actions, the national power reserve would rise above 40% because of lower electricity demand during the economic recession, said Viboon Rerksirathai, Egat's governor.
The more energy is stored in the grid, the more expensive power becomes for users.
The 2018 power development plan (PDP) projects future electricity demand as a factor of GDP, projected to grow by between 3-5% over the next decade. The outbreak, which has led to lockdown measures worldwide, has made that estimate untenable.
Authorities cannot delay the operations of existing power plants or those under construction, but they can accelerate decommissioning of some ageing plants whose 25-year concessions are going to expire.
Mr Viboon did not name which plants are targeted for early decommissioning, saying the decision will depend on selection criteria and discussions with operators.
Under the PDP, plants with a capacity of 241 megawatts are scheduled to be decommissioned next year, followed by 1,250MW in 2022, 1,050MW in 2023, 700MW in 2024 and 4,170MW in 2025.
Without early decommissions, the country's power generation capacity will rise from 51,390MW to 54,026MW in 2025.
Another option to reduce electricity reserves is sales to Myanmar and Cambodia, said Mr Viboon.
This requires upgrading transmission lines, but it would be worth the investment, he said.
The power surplus can also be used for chilling fruit and vegetables to prolong their shelf life before sale, said Mr Viboon.
Egat subsidiary Ratch Group said it is ready to discuss early decommissioning if it does not negatively affect the company's earnings as it is committed to paying shareholders and creditors.
Ratch chief executive Kijja Sripatthangkura said two thermal generation plants, with a combined capacity of 1,400MW, are set for decommissioning in 2025.
He said Egat should delay its development plans for power plants, including the gas-fired South Bangkok Power Plant and coal-fired Mae Moh Plant, to reduce power reserves.