Big biogas plans after project’s success

Bhutan will have at least 4,600 homes running on biogas for cooking or lighting by the end of next year.

Department of Renewable energy (DRE) officials said the success of the current biogas programme has raised their hopes and have proposed to establish another 5,000 plants in the 12th Plan.

DRE director Mewang Gyeltshen said that the Bhutan Biogas Project (BBP), an ADB funded project that is likely to be extended to early next year, has made huge progress in reducing the burden on imported fuel.

The biogas project that failed two decades ago has returned to replace imported liquefied petroleum gas (LPG) and firewood in thousands of rural homes across the country today.

A family of seven in Trashigang today uses only one LPG cylinder a year against a dozen earlier. Officials said that a household using biogas is expected to save 2,000kg of firewood, 2,555 litres of kerosene, 164.25kg of LPG, and 1,460 kilowatts of electricity a year.

Bhutan consumes about 1.2 million tonnes of fuel-wood a year, about 70 percent of that is used by households for cooking and heating. The country has one of the world’s highest monthly per capital fuel-wood consumptions, burning 97.3 kilogrammes as of last year.

Biogas is produced by fermenting cattle dung, which has the same characteristics as human sewage or agricultural residues, and is rich in methane and has the same characteristics as natural gas.

As of September this year, the project has built 4,173 plants across the country except for Thimphu, Trongsa and Zhemgang dzongkhags. Samtse with 677 plants has the most number of plants and Gasa has the least with seven.

SNV and ADB studies on biogas potential in the country showed that at least 16,000 households have the potential to use biogas plants cost-effectively.

The project has trained 547 masons and more than 200 supervisors.

Chief engineer of the alternative energy division, Chhimi Dorji said biogas was introduced in the country in the early 1980s. He said that however, most of the biogas technologies were abandoned because of poor technical designs and lack of spare parts and maintenance.

The plant’s design comes in four sizes: four, six, eight, and 10 Cubic Meters (CuM) costs ranging between Nu 30,000 to Nu 50,000. Mewang Gyeltshen said that the most popular size with villagers is the six CuM plant that costs about Nu 45,000.

The project provides one-third of the cost of the plant and the BDBL provides another one third as collateral free loan at 10 percent interest payable in three years. “The proponent only needs to invest one-third of the cost upfront,” he said.

The biogas programme, through the BBP, was reintroduced in Bhutan in 2011 with support from ADB to reduce destruction of forests and to bring down greenhouse gas emissions.

The project confronted numerous challenges. Given the subsidies on electricity, free 100 units of electricity in rural villages, LPG, and the easy availability of firewood, people do not take the opportunity to construct biogas plants, officials said.

The other constraint of the project is that most villagers are engaged in field works most of the year and don’t have time for construction of such plants.

“It’s only during winter that most farmers have time to build which is why we’re trying to extend the project by a few months until spring next year,” Mewang Gyeltshen said.

“We try to reduce people’s dependence on imported fuel and firewood through building biogas plants, wind and solar plants,” Mewang Gyeltshen said. “We’ve to create awareness among consumers on using energy efficiently.”

Tshering Palden 

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