The CNN report says the waste - stomach and intestines primarily, but also udders, blood and parts of the liver and kidneys – would normally be discarded. It quotes Carl Lilliehook, Managing Director of Svenska Biogas, as saying that they are getting as much as 80-100 kilograms of material from each cow which would otherwise be incinerated or disposed of in landfill.

To put the value of the waste into perspective the report calculates the yield in terms of powering Amanda, a biomethane powered train running between Linkoping and Vaster. The entrails of one cow, it is estimated, are enough to fuel the train for four kilometers, making Linkoping-Vastervik a 29-cow one-way journey, or a 58-cow return. Two thirds of the biomethane produced at the Linkoping plant powers the city’s fleet of 70 buses, with the remainder of the fuel being used in other transport applications such as cars, refuse trucks and the biomethane train.

Biogas production is slowly catching on around the world. It’s estimated that in Argentina alone, the waste from more than 35 million cows is dumped in landfill each year.