Will power generation with ammonia play leading role in decarbonization?

Yomiuri Shimbun file photo
Satoshi Onoda, President of JERA Co., In Chyuo Ward, Tokyo, October 2021.

Along with hydrogen, ammonia, which does not produce carbon dioxide when burned, is attracting attention as a new fuel that is expected to play a key role in decarbonization. The public and private sectors need to work together to overcome technical problems for the practical use of power generation with ammonia.

The government has included power generation with hydrogen and ammonia in the energy mix for the first time in the draft of its strategic energy plan compiled in July this year.

At existing coal-fired thermal power plants, vaporized ammonia will be mixed with powdered coal and then burned as a fuel to generate electricity. The reduction in carbon dioxide emissions is proportional to the amount of ammonia gas added.

About 1.1 million tons of ammonia, a compound of hydrogen and nitrogen, is already used annually in Japan, mainly as a raw material for chemical fertilizers. Ammonia is less flammable than hydrogen but is more easily liquefied and easier to handle. Transport and storage infrastructures for ammonia are also in place.

Ammonia can be said to be more suitable for practical use than hydrogen. The benefits will be significant if it can be used as a fuel for thermal power generation without constructing new facilities.

JERA Co., which is jointly funded by Tokyo Electric Power Company Holdings Inc. and Chubu Electric Power Co., has started a feasibility project at a power plant in Aichi Prefecture. In fiscal 2024, JERA plans to replace 20% of the coal it uses to generate electricity with ammonia. Efforts should be made to improve a technology in which Japan is leading other countries.

There are strong calls worldwide for the abolition of coal-fired thermal power generation, but it cannot be eliminated at once considering a stable supply of electricity. Coal power generation also has a role in supplementing renewable energy, which is an unstable power generation source.

By gradually expanding the use of ammonia through the mixed combustion method, greenhouse gas emissions can be reduced while using coal-fired thermal power. It is hoped that the resources will be effectively utilized.

In addition, the government said it is aiming to realize power generation solely with ammonia in 2050.

However, there are many challenges to be solved before the technology can be widely adopted.

If ammonia accounted for 20% of the mixed fuel burned at one coal power plant, the annual amount of ammonia needed would be 500,000 tons. Two plants would be equivalent to Japan’s entire current ammonia consumption. Domestic production will not be sufficient to meet the demand. A global procurement network must be established.

Burning ammonia emits air-polluting nitrogen oxides. It is essential to improve the performance of combustion equipment that reduces emissions of nitrogen oxides and the performance of equipment that removes such air pollutants.

According to a government estimate, the cost of power generation with ammonia is much lower than that of hydrogen but is higher than that of coal or natural gas. It is important to lower the cost.

As the production of ammonia consumes a large amount of energy, it is also important to establish a method of producing it using renewable energy.

Cooperation with other countries that are highly dependent on thermal power should also be considered.

— The original Japanese article appeared in The Yomiuri Shimbun on Aug. 20, 2021.