What is the difference between methanation and methanisation?

Methanisation is a natural process whereby biogas is produced from organic waste. The process at work is called anaerobic digestion. The organic matter is heated in a low-oxygen atmosphere, which encourages its breakdown by bacteria and produces methane. That biogas, after treatment, can be injected into the natural gas grid in the form of biomethane, to be used for the same purposes.

Methanation, meanwhile, is an industrial process, the purpose of which is to create a chemical or biological reaction by combining hydrogen with carbon dioxide or carbon monoxide. The resulting product is a gas referred to as synthetic methane.