Some of the biggest industrial companies in Japan are working on a project that could trigger a wave of investment into one of the most controversial forms of carbon capture: methanation.

Shipping giant Mitsui OSK Lines Ltd. (MOL) is leading a working group of nine Japanese companies including steelmakers Nippon Steel Corp. and JFE Steel Corp. to assess the viability of producing and using methane to power “zero-emission ships” instead of liquefied natural gas or other fossil fuels, including a fleet of new vessels that would transport carbon dioxide for processing.

Methanation is “the most realistic solution” for MOL to achieve net-zero emissions by 2050, Takeshi Hashimoto, chief executive officer said in an interview. “The challenge for the next 1-2 decades is whether the company could turn the technology into a sustainable and practical solution” by reducing the cost, he said.

Discovered over a century ago by French chemists, methanation is a two-part process to convert carbon dioxide and hydrogen into methane. The hydrogen can be produced by splitting water using renewable energy such as wind or solar power. The hydrogen is combined with CO2 and the resulting methane can be used as a fuel in ships or power plants.

Yet the costs of producing and transporting the gases and the technical hurdles have so far kept the process largely at an experimental level. That may change as demand for carbon-neutral energy increases.

One of methane’s advantages over alternative fuels such as ammonia and hydrogen is that it can more easily use existing natural gas infrastructure, said Hashimoto. Another is that it can effectively store excess energy created by solar and wind power as methane. When the gas is burned to produce power, the CO2 captured earlier is released back into the atmosphere, making it carbon neutral.