Wattanapong Kurovat said the formula used for calculating the price might have to be revised.

The office expects to complete a revision of the Power Development Plan (PDP 2018) in the next three months, he said, and little change is likely regarding the details of contributions from the major power plants – unless the Electricity Generating Authority believes it can commence operations at its Surat Thani plant earlier than the forecast 2027.

The PDP revision is expected to maintain a 20-per-cent contribution from renewable-energy plants, but they might be allowed to sell power to the national grid earlier than previously planned, Wattanapong said.

The contribution from solar panels on the rooftops of private homes might be lowered from the current projection of 10,000 megawatts per year.

Wattanapong was speaking at a seminar on the Energy Ministry’s “smart grid” master plan, the preparation phase for which took place in 2015-2016 and the short-term development phase is ongoing from 2017-2021.

A medium-term phase is set for 2022-2031 and a long-term phase for 2032-2036.

The master plan approved by the Cabinet in 2015 lays out guidelines for state electricity agencies and the private sector to invest in the scheme.