This article, originally written by Ryosuke Hanabusa and published on September 8, 2017 by the Nihon Keizai Shimbun, is republished here courtesy of The Japan Times in translation by Ken-ichi Aika, Professor Emeritus of Tokyo University. Chugoku’s ammonia co-firing technology was earlier described in Ammonia Energy articles, from March 2017 and August 2017, and research underpinning the project will be presented at the NH3 Fuel Conference on November 1, 2017. Dr. Aika reports that ammonia co-firing technology could have an important impact: if every coal-fired plant in Japan were to co-fire at the rate of 20% by energy content, the country’s carbon footprint would be reduced by about 3%.
Coal-fired power plants have negative environmental impacts, not least of which is the emission of large amounts of carbon dioxide (CO2). Japan’s electric power companies are working to change this state of affairs. Chugoku Electric Power Company announced today that they have filed a patent application for a clean-power technology that involves co-firing ammonia with coal. The novel approach is attracting widespread interest.
Ammonia, with a chemical formula of NH3, contains hydrogen and burns without releasing CO2. Ammonia can be liquefied by compression at room temperature or by cooling to minus 30 degrees C. In its liquid state, ammonia can carry large amounts of hydrogen energy.
With support from the Japan Science and Technology Agency, Chugoku Electric Power Company conducted an initial test from July 3 through July 9, 2017 at its Mizushima power plant in Kurashiki City in Okayama Prefecture. Ammonia was added continuously to the 155 MW coal-fired plant at the rate of 450 kg/hour. The company confirmed that the addition of the ammonia did not cause the plant’s power efficiency to fall. On the basis of energy content, the added ammonia represented 0.6-0.8% of total fuel. At this ratio, a decrease in carbon dioxide emissions was observed. The Chugoku demonstration was the first time that ammonia was burned in a commercial power plant in Japan.
It was also found that when the plant’s output was throttled back to 120 MW, the added ammonia led to a decrease in the generation of nitrogen oxides (NOx). Chugoku has plans to co-fire with mixtures of up to 20% ammonia in the future. Further research is underway.
While mainly used as a fertilizer, ammonia is also used as a reducing agent for NOx in coal-fired power plants. Energy companies are thus already accustomed to handling it and investment in new infrastructure – such as storage equipment – is less than would otherwise be the case.
Coal-fired power technologies may be experiencing a kind of “Galapagos” evolutionary process within Japan’s electric generation industry. Besides Chugoku’s co-firing technology, the industry has been working to develop coal gasification technology for electric power generation. The result is that Japan may become an exception to the global movement away from coal as an energy source for electric power generation.
“Japan seeks clean technologies” will become an important part of the country’s message to the world.