The Somerset Waste Partnerships governing board has approved plans for Viridor to develop a large-scale anaerobic digestion facility to treat all of the household food waste collected in the county.
The Somerset Waste Board, which includes councillors from all Somersets six councils, voted on Friday (September 23) to task the Taunton-based company with funding, developing and running the facility, which would be built at Walpole, near Bridgwater.
At the same meeting, the board voted to approve proposals to extend a charging scheme in operation at four of the countys household waste recycling centres for another 12 months (see letsrecycle.com story).
Viridor committed to build the anaerobic digestion (AD) facility under part of its long-term contract to manage Somersets waste, which began in 2006 and runs until March 31 2022 (see letsrecycle.com story).
The facility will be designed to accept up to 30,000 tonnes-a-year of separately collected food waste, at least 19,000 tonnes-a-year of which will be guaranteed by the Somerset Waste Partnership. The remainder is expected to be filled by food waste from the countys food waste processing firms, catering services, restaurants, pubs and shops.
Food waste collections
Kerbside food waste collections were first introduced for Somerset residents in 2004, with the majority of material collected currently being sent to a Viridor-run in-vessel composting (IVC) facility at Dimmer, near Castle Cary.
However, a report considered at last weeks waste board meeting explains that the SWP and Viridor have known for several years that IVC is not an ideal process for pure food waste.
In particular, the need to top up the material with garden waste for it to compost effectively has led to a capacity shortfall, with material being sent to various third party AD and IVC outlets in Dorset, Devon and Shropshire to compensate for this.
Gate fee
To address this, Viridors proposals for an AD plant involving it paying the capital costs of getting the plant up-and-running and the SWP paying a gate fee for every tonne of material delivered to the plant.
The report explains that Viridor first proposed an AD facility at the Walpole landfill site in 2007, and has already secured planning permission. However, initial negotiations with the SWP stalled because, it explains: The gate fee originally proposed was considered uneconomic by SWP and negotiations failed to find an acceptable price per tonne.
Viridor then returned to the market in early 2011 and came back to the SWP with a more economic proposal. According to the report, using the facility to treat the countys food waste will be 191,000-a-year cheaper than continuing with existing options for the material.
Somerset county council, which is taking the local authority risk on the project, will also benefit from a share of super-revenues if the income generated from the facility exceeds an agreed threshold. This could be because the amount of energy generated exceeds the guaranteed level provided by the manufacturer or income exceeds the assumptions in the model, the report explains.
Pay back
But, the project could also see the county council have to pay Viridor the value of the facility. This is because, Viridors contract with the SWP runs until March 31 2022, but the time needed to fund capital costs of developing the AD facility mean that one of the conditions of developing the plant is that Somerset sends material there until March 21 2031.
If Somerset chooses to stop doing this before 2031, then, the report explains, the county council will repay to Viridor the value of the facility and associated equipment at the net book value of the assets
Now the proposals for the plant have been approved, it could be operational by mid-2013. Almost all of Somersets 249,000 households are expected have kerbside food waste collections soon.
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