The court decided local officials do not have the authority to issue a building licence for the plant.
A group of 290 plaintiffs from tambon Pak Phraek filed a complaint with the Central Administrative Court on Dec 13, 2012. The complaint asked the court to nullify a provincial appeal committee order that allowed tambon Pak Phraek's administrative organisation to grant a construction licence for the plant.
The defendants were the Prachuap Khiri Khan governor, the provincial appeal committee and the Bang Saphan Noi Biomass company.
The court ruled that tambon Pak Phraek's administrative organisation did not have the authority to issue the licence for the project as this was the duty of the Energy Regulatory Commission under the Energy Ministry.
The local administrative organisation can only give recommendations to the commission, it said.
"This means the company must go back to square one and get permission from the commission, not the local organisation. The project cannot proceed without the licence," said Srisuwan Janya, president of the Stop Global Warming Association, who is among the 290 plaintiffs.
Bang Saphan Noi Biomass company submitted a proposal for the 9.5 megawatt-biomass power plant to the local administrative organisation in November 2010. Villagers protested against the project due to concerns about environmental impacts and competition for water resources.
Villagers were also unhappy that according to regulations, a small power plant with less than 10 megawatts of production capacity does not require an environmental impact assessment study. It only needs a primary environmental impact assessment study which has less stringent conditions.
The company has bought the land on which the plant was to be built but has not yet started construction.
The local administrative organisation first decided not to issue the licence to the company in March 2011, but the company filed a case with the provincial appeal committee which ordered the local organisation to reverse its decision that July.