Photo/IllutrationThe digestion gas power plant in Utsunomiya which began commercial operation on April 1 (Provided by the Utsunomiya city government)

UTSUNOMIYA--One of Japan’s largest power plants using biogas emitted from treating sewage has started operations here, boasting a power generation capacity of 840 kilowatts.

Around 1.7 billion yen ($16 million) was spent to set up the plant within the compounds of the Kawada Mizu Saisei Center, a water purification station located in the capital of Tochigi Prefecture in eastern Japan.

With eight phosphoric acid fuel cell power generators, the plant can produce a maximum 7.17 million kilowatt-hours a year, enough to power 2,000 regular households.

Commercial operations of the plant began April 1, following an opening ceremony on March 28 attended by Utsunomiya Mayor Eiichi Sato. Sato pushed the switch to bring the plant online.

Known as digestion gas, the fuel used by the power station is a flammable gas mainly comprising methane emitted during sewage treatment.

The biogas had been used as fuel for a sludge incinerator operating in the wastewater treatment plant, but the aging furnace was shut down in March.

The operator of the facility turned to power generation as a way not to waste the biogas.

2016 marks 100 years since the start of the water supply service and 50 years since sewage treatment began in Utsunomiya. The city government wanted the biogas power station--a special project--to kick off in the landmark year.

Using the central government’s feed-in tariff program, the operator will be able to sell the generated electricity for 20 years, creating up to 300 million yen in benefits for the local economy.

The electricity produced at the plant will be sold to trading house Marubeni Corp. for the first fiscal year.

According to the Tochigi prefectural government’s urban development section, digestion gas power generation is currently spreading across Japan.

The latest facility is the sixth one set up in the prefecture. It is also the fourth power plant in Tochigi Prefecture that uses fuel cells, following the three facilities in Kaminokawa, Nikko and Tochigi that began commercial operations between February and April last year.

Fuel cells generate electricity through a chemical reaction of hydrogen from digestion gas and oxygen in the air.

Other methods of digestion gas power generation include those using gas engines and gas turbines.

The two plants that began commercial services in the prefecture’s Otawara in May 2015 and Kanuma last June both use the gas engine method.

Another gas engine-driven digestion gas power station also started full-scale operations in Sano, Tochigi Prefecture, in April.