Japanese oil companies are stepping up efforts to produce sustainable aviation fuel, or SAF. The goal is to help airlines cut greenhouse gas emissions in the years ahead.

SAF is made from used cooking oil or plant-based materials. It emits as much as 80 percent less carbon dioxide than conventional fuel.

The major refiner Cosmo Oil set up a company earlier this month to produce SAF with engineering firm JGC Holdings and others.

A production facility will be built at Cosmo Oil's refinery in Osaka, western Japan. Operations are planned to begin in around two years.

JGC Holdings is collaborating with the real estate developer Mitsubishi Estate. They plan to collect used cooking oil from tenants in central Tokyo.

Another oil major, Eneos, has teamed up with TotalEnergies of France. They aim to start making SAF from around 2025.

And Idemitsu Kosan aims to start making plant-based jet fuel the following year.

The government has set a target of having airlines replace 10 percent of their aviation fuel with SAF by the end of the decade.

But SAF can cost anywhere from two to 10 times more than conventional fuel. So there is a long way to go to find efficient ways to get raw materials and cut costs.