New AD plant in Kent, UK connected to the national grid

A new anaerobic digestion (AD) plant in Kent, UK has been connected to the national grid. The plant, which cost £14,460,400 (€17 million), converts food and agricultural waste from the region into biogas and electricity.

Developer Farm Renewables has said the plant on the Isle of Sheppey will produce 500 cubic metres per hour of biomethane for the national grid, enough to heat almost all the homes on the island, which has an estimated population of around 40,000. Malcolm McAllister, chairman of Farm Renewables, said: “The plant is also producing 499 kWh of electricity, 50% of which is being used to power the AD plant, while the remainder is exported to the grid.

“As to be expected, there is also a significant amount of heat produced during the ad process, which we’re planning to use to heat our landowner’s commercial grain storage and drying operation, greatly reducing the amount of diesel required.”

The Sheppey plant, which was fully-funded by specialist energy from waste funder Privilege Finance, will use 15,000 tonnes of maize, 6,000 tonnes of straw, 6,000 tonnes of poultry manure and 6,000 tonnes of fruit waste from the area annually to produce renewable energy. The resulting digestate will be spread on local arable fields, providing nutrients and organic matter to boost soil quality.

Innovative technologies have been implemented at the facility, such as its unique straw processing unit. “This technology allows straw bales to be broken down, via a hammer mill into fine pieces, which are then compacted and made into briquettes,” said McAllister. “Rather than using straw in its raw form, the uniformity of the briquettes aids the digestion process inside the plant, helping to increase efficiency and gas production per tonne of straw.”

Marc Graham, project lead at Privilege Finance, added: “We support projects that enable the development of local circular economies at an appropriate scale, so taking agricultural waste and fruit waste from within the area and using it to produce renewable energy for the national grid is a perfect fit.”