The air smells fruity, slightly alcoholic. Against the strong hum of machinery, 175 cows are eating hay. As their dung drops to the slatted floor, a machine sweeps it through and it runs underneath the barn to a futuristic dome outside.
The Heegs’ 75-hectare family farm in remote Friesland, in the north-west of the Netherlands, where cows outnumber people almost two to one, marks the start of a national experiment to encourage farms to turn their manure into biogas.
The process is simple: the dung is broken down by bacteria into biogas in an anaerobic digester. Other machines then extract nitrates and phosphates to make fertiliser, leaving organic matter, which is spread on the Heegs’ farm.
Masterminded by FrieslandCampina, the country’s largest dairy collective which buys milk from 13,500 of the Netherlands’ 17,000 dairy farmers, the project has established an initial target of getting 1,000 large farms across the country to make power from cow manure within four years.