With a population of 15,000 pigs, the farm sources its power from the methane gas emitted by the pig manure.

The wastes are collected in a pond connected to a digester with huge, thick polyethylene sheets, where the methane gas is trapped as it moves to big pipes into the generator before being converted into energy with the remaining wastes used as organic fertiliser.

The 70-square-meter-wide bio-methane gas converter and seven-meter deep digester, and generator area provide the electricity for the 14-hectare piggery, producing 300 kilowatts per day.

Teresita Pascual, general manager of the Cecilia Stock Farms, said that the biogas generator is a "build, operate, and transfer" (BOT) project.

Ms Pascual said the operation of the biogas plant is also a move to support the campaign for reducing emission of greenhouse gases.

"Methane, a gas coming from animal waste, is 21 percent more potent than carbon dioxide, so when released into the atmosphere, this poses an environmental hazard," she said.

She said that the firm contracted Philippine Bio-Sciences Co.,Inc (PHILBIO), a Manila-based company which deals in trapping methane gas, to build, fund, and operate the project for seven years, after which the ownership is transferred to Cecilia Stock Farms.

The project was first planned in 1999, but due to financial constraints, it is only now that the project has come to fruition.

"Before we tapped PBS, we had to ask for the go signal of the Davao Light and Power Company (DLPC) since we were given a special power grid. And it is only this year when DLPC agreed that we pursue with the project," Teresita Pascual said.

At present, Ms Pascual reported that the farm is paying DLPC more than P300,000 a month in electricity bills. Using the biogas generator, the farm will be independent of its power. However, once the supply of waste is depleted, a double-throw button in the generator can be turned off to allow electricity from DLPC.

Ms Pascual said that the farm and PBS will sign a power purchase agreement soon. "As of now, PBS is still trying to see how stable the supply of manure is," she said.

CSF started operations in 1980. Presently, the company has about more than 150 employees and operates in partnership with the Pig Improvement Company based in the UK.