- Case Studies
Edina Group supplies and installs leading efficiency and performance biogas combined heat and power (CHP) at Biffa’s flagship Anaerobic Digestion (AD) plant in Cannock, Europe’s largest waste processing plant capable of handling over 120,000 tonnes of food waste per year.
As a landfill operator of many years’ experience, BIFFA put forward proposals to create an AD facility at its landfill site in the West Midlands. Aware that the thousands of tonnes of food waste could be put to better use and in response to the UK’s National Waste Strategy a plan was devised whereby waste food could be delivered to an enclosed warehouse, sorted and then used for AD all at one site.
Costing £24million to develop, the Poplars AD plant was intended to mainly treat commercial and industrial food and organic waste from the likes of Sainsbury’s and Bakkavor.
Edina supplied three MWM manufactured TCG 2020 V20 biogas CHP engines providing 6.5MWe capacity. All three engines were containerised at Edina’s manufacturing facility based in Lisburn, Northern Ireland and delivered to site. Biffa are now in the process of installing an additional 500kW engine at its Poplar’s site.
In terms of the process, waste is pumped into one of the five digester tanks, which is then heated to 70 degrees Celsius, allowing the AD process to work and produce the methane gas.
The plant uses CHP boilers which produce both heat and electricity. About 15% of the electricity is used by the plant, but the rest is sold back to the National Grid. The heat generated on the other hand is reused in the plant across Biffa’s operations.
Biffa’s flagship plant in Cannock was opened in April 2011. The site is the biggest in Europe handling 120,000 tonnes of food waste annually and although an existing landfill site, BIFFA worked hard with suppliers and the local residents to lessen the impact of its activities on the area and allay any concerns about the AD facility.
Due to the plant being located near the landfill site, Biffa used its existing waste management infrastructure to exploit efficiencies, such as a ready supply of suitable feedstock to allow them to produce large volumes of gas, which can be combusted to produce electricity.
The UK generates around 15million tonnes of food waste per year, with businesses accounting for just under half of this in the food production sector.
Much of this food waste is currently sent to landfill sites where it is slowly broken down into methane and carbon dioxide, which are both powerful greenhouse gases.
This project aligns to the Government’s strategy of recycling waste to be used to produce renewable energy. One of the by-products of the digestion process is high quality soil, which can then be sold onto farms and local gardening centres in the West Midlands.
In addition, the Poplars AD plant further demonstrates its environmental credentials by helping the local community manage waste by: recycling food waste from supermarkets; digesting food and drink from manufacturers; taking waste from hotels, restaurants, caterers and homes, which is then delivered to the site from Biffa’s collection network.
The AD plant was one of the first (of the few) AD plants in the UK to achieve PAS 110 accreditation. PAS 110 is an industry standard accreditation which signifies that the digestate is of the highest quality available to farmers and can be applied to agricultural land.
Biffa’s general manager at the plant, Chris Savage, comments, “The bio-fertiliser produced at Poplars is ‘liquid-gold’ for farmers as it offers the agricultural industry an effective organic alternative to chemical fertiliser.
It is wonderfully rich in nutrients such as nitrogen, phosphorus and other elements required for healthy plant growth and fertile soil.”
This plant is the most efficient food waste processing AD plant in Europe, generating up to 6.5MW of electricity – enough energy to power 15,000 homes.
The plant is best in class, providing a single point waste disposal solution for packaged and unpackaged food waste.
Over the past three years (Jan 2013 to Jan 2016) the plant has had a generation plant availability of 95.5% with an average output of 90%. That is an average of 8350 hours per machine each year.
Within the past three years all three machines have each had an E50 and E60 major services, the time taken for each service is counted in the average 430 hours unavailable hours each year.
This is a remarkable achievement for such a large plant with a very mixed commercial waste feedstock.
Cannock, United Kingdom
3 x 2MWe TCG 2020 V20 and 1 x 500kWe TCG 2016