Tip of the ‘fatberg’: Sewer sludge fires up Grand Designs guru

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TV design guru Kevin McCloud is switching from green energy to brown after plumbing the depths of London’s sewers to find a foul new fuel.

Viewers will see the Grand Designs presenter wading through sludge as he seeks out piles of congealed grease to heat homes for a new Channel 4 series.

In the first episode of Kevin McCloud’s Man Made Home – to be screened on Sunday – he will be seen foraging below the streets of the city to provide power for a Ford Transit van and to run lamps.

For the show, in which he builds a bespoke home in the woods out of recycled materials, he explores alternative sources of energy and hits upon “fatbergs” – huge masses of used cooking fat which are tipped down the sink and collect in the sewers in dense sticky outcrops.

They trap other materials and can create major blockages – accounting for three-quarters of the 200,000 sewer blockages in England and Wales each year – and are often packed with hair, wet wipes and used condoms.

The presenter harvests two buckets of the stuff from a fatberg, which he says was “the most disgusting thing I’ve ever seen”.

Under the guidance of Professor Matthew Davidson from the University of Bath’s chemistry department, he turns it into biodiesel.

Viewers will see him run the van for 20 minutes and illuminate a lamp for an hour using one bucket of the gathered sludge.

He said: “It might be difficult to get hold of, but if we don’t stop wastefully chucking all our cooking fat and oil down the drain, cars and homes powered by sewer fatbergs might well become a thing of the near future.”