IHI Corp., a Japanese maker of heavy equipment, is promoting a method to increase the ratio of woody biomass that’s able to be burned at coal-fired power plants amid increasing pressure to curb the carbon dioxide emissions that result from power generation.
By retrofitting the mills that grind coal in preparation for burning so that they’re also able to use more wood pellets in the fuel mix, Tokyo-based IHI says it’s able to boost the ratio of biomass to as much as 25 percent.
“Retrofitting the mills can be done easily and they can be remodeled back” to grinders for coal, said Shinobu Nakamura, deputy division director of the energy systems center for IHI.
The process of retrofitting is made easy so that mills for wood pellets can be switched back to grind coal when woody biomass supplies run low.
Some coal-fired plants are already mixing wood pellets and chips using mills intended to grind coal. In such co-firing, biomass typically accounts for less than 10 percent of the heat generated, with the remainder contributed by coal.
The push to use more biomass to generate electricity comes as an international agreement on climate change reached at the United Nation’s COP21 meeting last year in Paris encourages a shift to more clean energy.
Pressure on Coal
Environmentalists have criticized Japan’s plans for new coal plants at the same time some developed nations such as the U.S. and U.K. are shifting away from the most polluting fossil fuel.
IHI conducted a pilot project at a 149-megawatt coal-fired plant operated by Nippon Steel & Sumitomo Metal Corp. in the northern prefecture of Iwate allowing the generator to use wood pellets for as much as 25 percent. The ratio could feasibly be raised to more than 50 percent, according to a company statement.
The Ministry of the Environment provided about 560 million yen ($4.8 million) in funding for the project.
Additional costs related to retrofitting mills can be recouped in “several years” for power producers who sell biomass power under Japan’s incentive program for clean energy, Nakamura said. The program, which began in July 2012, buys electricity from renewable sources at higher rates to boost investments in clean energy.
Nippon Paper Industries Co. is among companies planning to mix woody biomass for its new coal-fired power plans under development.
“It is easier to run plants that only burn coal in terms of securing fuel and operating them,” said Yoichi Horikawa, head of the paper company’s energy business division.
“As the COP21 meetings indicated and as seen in the example of the U.K. plan to phase out coal, however, we began to recognize we can no longer stick to coal only,” he said.
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