Cars run on cowpats

The fuel – for cars, buses and lorries which have engines able to run on petrol and gas, with separate tanks for each – could lead the way for more projects of this type.

In 2015, France set a target of 10% of its gas coming from bio-gas by 2030 but this was lowered to 7% this year.

By mid-2016, there were 463 bio-gas projects producing electricity and around 40 producing gas for the Gaz de France network, such as the one from the farmers in Mortagne-sur-Sèvre in the Vendee, which has been running since 2014.

The unit can supply gas for around 500 homes to use as heating. Damien Roy, spokesman for the farmers’ project, said: “We set up a fuel pump in 2017, and established a separate company to do so.

“We have 15 public service vehicles – one bus and the rest works vans – and around 15 cars which use it regularly.”

He said the advantages of the fuel pump for the bio-gas plant were practical, as well as diversifying their revenue stream.

“In summer there is very little gas used at the weekends and it is more difficult to inject gas into the network,” he said. “By loading the fuel station, we can use gas which would otherwise have to be stored, which makes running the plant easier.”

Another advantage is that the farmers have found the fuel pump has improved their image with their neighbours.

“It is a relatively large site and requires at least two or three lorries or tractors a day to supply it, so neighbours did not see an advantage,” Mr Roy said.

“Now they know they can get cheap green fuel for their cars [it sells for €0.85 a litre] and that a local bus runs on it.”

At the moment, only certain Fiats and Volkswagens can run on natural gas, and cars equipped for the GPL gas found at service stations cannot do so.

Some 15 years ago, Citroën and Gaz de France ran a natural gas trial near Toulouse, where clients could have connections in their garage to fill C3 hybrid fuel cars, but it was abandoned due to a lack of interest.

Mr Roy hopes the pump will stimulate interest in natural gas as a vehicle fuel again.

“It is clean, comes from renewable sources and running costs are between 30% and 50% cheaper than petrol or diesel cars,” he said.