SET-listed Ratchaburi Electricity Generating Holding Plc (Ratch), Thailand's biggest private power producer, hopes to build another unit at the Hongsa power plant in Laos to make use of an abundance of lignite underground.
It would be the coal-fired power plant's fourth unit and have the same specifications as the previous three with 626 megawatts of power-generating capacity, says Ratch president Phongdit Potchana.
The company and partner Banpu Plc began a mining project late last year and found up to 577 million tonnes of lignite reserves.
That is far more than the 371 million tonnes needed as a power source for the entire 25-year concession (2016-41).
"We are thinking about building a new unit to make use of the excess lignite we have found, and I have already talked unofficially with relevant Laotian authorities about the possibility of adding a new unit to the Hongsa power plant," Mr Phongdit said.
The US$3.71-billion-baht power plant's first unit is due to start commercial operations on June 2, the second unit on Nov 2 and the third on March 2 next year.
About 490 MW of the total capacity of 626 MW will be sold to the Electricity Generating Authority of Thailand (Egat), while 100 MW is expected to be used in operations at the power plant. Some 34 MW will be sold to the Laotian government, with two MW expected to be line losses.
While the chances of building a fourth unit are good, some obstacles and limitations must be tackled and agreements reached with relevant agencies.
"We have to negotiate with the Laotian government over how much additional power it would need if we generated more power from the fourth unit," Mr Phongdit said.
The Hongsa power plant is 40% owned by Ratch, 40% by Banpu and 20% by the Laotian government.
RATCH shares closed Friday on the SET at 59.25 baht, down one baht, in trade worth 41.7 million baht.