The nausea-inducing energy source that lurks beneath our feet

Fatbergs – congealed masses of cooking grease and other unsavoury items such as baby wipes flushed down drains – are the grim byproduct of our high-fat, wasteful lifestyles.

Many are the size of buses, lurking under our feet in sewers all over the place. They are the bane of treatment plants and cost companies millions of dollars to clean up.

However, UK biodiesel producer Argent Energy has found an innovative use for fatbergs – it wants to convert them into green fuel.

How does it work?

Tankers would collect fatbergs from processing plants and sewers and transfer them to a specialist plant. They would be heated to melt the fats and solids and water would be removed using a high-tech filtering system. The company would then syphon off a fairly clean oil, to which various chemicals would be added to produce biodiesel.

About 25-40% of the mass collected would be reclaimed as oil for biodiesel, which is about 80% cleaner than normal diesel.

Thames Water, a UK utilities company, has previously said that removing the oil from London’s fatbergs could produce more than 130 gigawatt hours of energy a year – enough to power about 40,000 homes.

Fatbergs are usually sent to landfill or broken down and put back through the system.

Initially Argent trialled the scheme with one Birmingham-based treatment plant, removing some 30 tons of fatbergs a week. The company’s one plant has capacity to produce 90 million litres of biodiesel a year – more than all the sustainable biodiesel used in the UK in 2016. And with 8999 treatment works in the UK, the potential could be huge.