The state-run Electricity Generating Authority of Thailand (Egat) will open a new bid for the first hybrid power from hydro and solar at Sirindhorn dam in Ubon Ratchathani within a few weeks.
Egat will issue terms of reference (ToR) in mid-June for the 45-megawatt floating solar array at Sirindhorn dam. The project is worth an estimated 2 billion baht.
The ToR issuing schedule has been delayed for a month because Egat adjusted the bidding details and conditions after conducting public hearings.
Energy Minister Siri Jirapongphan said each interested bidder has to provide services in engineering, procurement and construction.
A screening process will commence in October and the first project will start operations by 2020.
The auction is using international competitive bidding because installation of floating solar panels requires double-glass panels.
"This auction aims to seek the best solar technology from the global market," Mr Siri said. "The construction will include smart power supply management."
After the National Energy Policy Council approved new power generation of solar resources in early 2019, Egat was assigned the world's largest hybrid power scheme from hydro and solar, totalling 2,725MW.
This solar power generation is planned as floating hydro-solar hybrid projects at nine dams by 2037.
Egat is preparing human resources and related infrastructure to invest in solar power at all nine dams: Sirindhorn (Ubon Ratchathani), Ubol Ratana (Khon Kaen), Bhumibol (Tak), Srinakarin (Kanchanaburi), Vajiralongkorn (Kanchanaburi), Chulabhorn (Chaiyaphum), Bang Lang (Pattani), Ratchaprapha (Surat Thani) and Sirikit (Uttaradit).
Egat forecasts a development cost of US$1 million (31.5 million baht) per MW.
Two power generation resources are not in stable mode because of limited resources, so Egat has to stabilise the power supply system and reduce power generation costs.
Viboon Rerksirathai, Egat's governor, said the eight other dams will start new bidding rounds after Sirindhorn commences floating solar operation.
The power transmission line for the hydropower projects has a utilisation rate of 40% because the dam's key priorities are draining water for agricultural areas and water resources for communities. The nine dams cannot generate power all day and night.
"The floating solar farms are designed to fulfil a partial gap in leftover power capacity of nine dams," Mr Viboon said.
He said Egat plans to install energy storage for the nine floating solar farms once the development cost of lithium-ion batteries and solar panels are viable and competitive with fossil fuel-based power generation.
Egat is also teaming up with Siam Cement Group to research and develop suitable materials to build floating solar panels at a capacity of 250 kilowatts.
The site is located at Tha Thung Na dam in Kanchanaburi.