Posted: 16/08/2019

Anaerobic digestion becoming a more popular whey to go

Wensleydale Creamery’s decision to send whey for anaerobic digestion will create enough energy to heat 800 homes for a year

Cheesemakers have long struggled with the question of what to do with leftover whey, using it in everything from pig feed and fertiliser to butter and ricotta, or just paying for it to be disposed of. 

But a growing number are now using anaerobic digestion (AD) to turn the by-product into energy, reducing bills and cutting carbon in the process.

The Wensleydale Creamery recently signed a deal to send whey permeate (whey with the protein removed) to a local AD facility, where it is converted by bacteria into enough methane to generate over 10,000 MWh of energy a year – the equivalent of heating 800 homes. 

Iona Capital, which owns the Lemming biogas plant, told FFD it is in discussions to source whey from other cheesemakers, and would be open to working with artisan producers. 

“The Wensleydale story has sparked a lot of interest,” said Mike Dunn, co-founder of Iona. “Whey permeate can be classed as a ‘Goldilocks’ feedstock (just right) for anaerobic digestion. It has a high energy content and is easily digested by the anaerobic bacteria. In most cases, the energy produced will directly supply the cheese production facilities, so creates a circular economy. Smaller artisan cheesemakers also have the opportunity to supply waste and by-products to generate renewable energy.”

Some cheesemakers are taking matters into their own hands, investing in AD systems fed with slurry and whey to generate electricity and heat water. Stephen Temple, co-owner of Mrs Temple’s Cheeses in Norfolk, invested £800,000 in a digester 10 years ago, which generates 170 kW of electricity for the grid and the farm. 

Somerset cheddar-maker George Keen also installed an AD plant 18 months ago and expects to achieve payback in the next 6-8 years. “As energy becomes more expensive and we become more ecologically minded, it was the right time,” he said. 

At AD specialist Clearfleau, marketing director Richard Gueterbockin said new modular digesters were being developed, which would lower prices, while the government’s commitment to net zero UK carbon emissions by 2050 will also drive the market.

“The landscape is changing with greater pressure to reduce carbon and be more sustainable,” said Gueterbockin. “If tech suppliers can develop smaller scale AD solutions – and there are some already – there’s a future for gas from cheese.”

This story appeared in the August issue of Fine Food Digest. You can read more on the digital edition here.

Read more of the latest news from Fine Food Digest here

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