Co-firing technology using ammonia may produce more emissions

A new study by California-based Breakthrough Institute suggests that co-firing technology, which produces power by using ammonia and hydrogen alongside coal, may generate more emissions than just coal or gas.

Using ammonia and hydrogen alongside fossil fuels in power plants may result in more emissions than simply burning coal or gas, a new study found, adding to scepticism over a decarbonisation technology being embraced by some Asian nations.

Countries including Japan and South Korea are betting on co-firing technology to achieve reductions in carbon emissions from electricity generation in the next decade. But the plans have drawn criticism for being costly and inefficient, while the process could increase air pollution.

Among recent projects, Japanese trading house Mitsui & Co in June concluded a sales agreement to supply ammonia in large-scale co-firing at Jera Co’s Hekinan Thermal Power Station. Meanwhile, South Korea is aiming to use hydrogen and ammonia in its existing coal power plants, with the two fuels making up more than 7 per cent of the power mix in 2036.

South-east Asian countries including Indonesia have also signed agreements to research domestic co-firing potential.

Proposals to co-fire ammonia or hydrogen in power plants to replace 20 per cent to 30 per cent of coal or gas burned still leave 70 per cent to 80 per cent of fossil-fuel emissions, the Breakthrough Institute said. The benefits shrink even further after considering the energy required to manufacture and transport ammonia and hydrogen.

Further, significant electricity is needed for the compression and liquefaction of hydrogen for transoceanic shipping, and 10 per cent to 20 per cent of the hydrogen cargo may be lost during a long voyage.

If suppliers produce the ammonia and hydrogen using fossil fuels, co-combustion can result in “considerably more carbon emissions than if the power plants were to burn only pure coal or natural gas”, the report said.

Projects supplying hydrogen markets in the Asia-Pacific region use fossil-fuel feedstocks to produce hydrogen and subsequently synthesise ammonia. But currently operating and announced pilot projects in the region have made only vague, non-binding commitments to install carbon capture equipment, the report said.

Even with best-case, low-carbon hydrogen and ammonia production, co-firing yields little climate benefits and represents a “wasteful use of valuable low-carbon hydrogen and ammonia”.