Thailand is close to completing one the world's biggest hydro-floating solar hybrid projects on the surface of a dam, part of steps towards boosting renewable energy production after years of criticism for reliance on fossil fuels.

Over 144,000 units of solar panels are being installed on a reservoir in the northeast province of Ubon Ratchathani, where workers are completing the last of seven solar farms covering 121 hectares of water area.

Authorities are aiming to complete the project in June.

The state-run Electricity Generation Authority of Thailand says the pilot project is one of the world's largest hybrid hydro-solar power ventures. It aims to replicate it at eight more dams over the next 16 years.

Thailand has long relied on coal for its power, but plans for new coal-fired projects have been met with opposition over health and environmental risks, including two proposed southern coal plants shelved in 2018.

The country is aiming to draw 35% of its energy from non-fossil fuel sources by 2037, according to its latest Power Development Plan.

Since November, EGAT has been putting together floating solar platforms at the Sirindhorn dam, one of the country's largest hydropower dams, which it says should have capacity to generate 45 megawatts of power.

An Energy Management System will be used to switch between solar and hydropower, depending on which has more strength to generate electricity, a hybrid system project chief Chanin Saleechan said allows continuous power generation.