Fatberg

A ‘fatberg’ in the sewers? What a waste

For much of history, the fat found in a giant ball clogging London sewers would have been put to a surprising array of uses

The fatberg – a 15-tonne lump of fat and other debris – coagulated inside a London sewer. Photograph: AP

A colossal “fatberg” of wet-wipes, sanitary products and food fat clogging a Kingston sewer threatened to send raw sewage spurting into London streets and homes in late July. Looking like some kind of B-movie monster, this 15-tonne abomination reminds us that waste is getting harder to keep underground.

But for most of history, a fatberg would have been a valuable commodity. Rather than shooting high-powered water-jets at the monster, the green solution would have been to make it into tallow candles – the chief source of light for most people before gas or electricity. Hence the job of “grease-dealer” – a person who made their living by collecting the grease of domestic kitchens, scraping it into a tub, and presently re-selling it. Once, you made energy from anything you could – including, sometimes, your pets: “My old dog Quon was killed … and baked for his grease, of which he yielded 11 pounds,” wrote a Dorset farmer in 1698.

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London’s cooking waste to fuel power station

Thames Water and 2OC in deal worth £200m over 20 years to turn ‘fatbergs’ clogging capital’s sewers into energy for sewage works and homes

Chips in a deep fat fryer. Thirty tonnes a day of ‘fat’ waste will be collected from leftover cooking oil supplies at eateries and manufacturers, fat traps in kitchens and pinchpoints in sewers to fuel the power plant. Photograph: Antonio Olmos for the Guardian

Cooking waste from thousands of London restaurants and food companies is to help run what is claimed to be the world’s biggest fat-fuelled power station.

The energy generated from the grease, oil and fat that clogs the capital’s sewers will also be channelled to help run a major sewage works and a desalination plant, as well as supplying the National Grid, under plans announced by Thames Water and utility company 2OC.

The prospect of easing the financial and logistical problems of pouring £1m a month into clearing the drains of 40,000 fat-caused blockages a year is being hailed by the companies as a “win-win” project. Thirty tonnes a day of waste will be collected from leftover cooking oil supplies at eateries and manufacturers, fat traps in kitchens and pinchpoints in the sewers – enough to provide more than half the fuel the power plant will need to run. The rest of its fuel will come from waste vegetable oil and tallow (animal fats).

The deal, worth more than £200m over 20 years, has made possible the building of the £70m plant at Beckton, east London, which is financed by a consortium led by iCON Infrastructure. It is due to be operational in early 2015. No virgin oils from field or plantation crops will be used to power it, says 2OC.

The plant will produce 130 Gigawatt hours (GWh) a year of renewable electricity – enough to run just under 40,000 average-sized homes, say the planners.

 

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