Cornwall Council is piloting ground-breaking, highly innovative technology - developed by a Cornish company - to turn methane, derived from organic waste, into renewable fuel. Working with six of its farms, the project turns methane into 'better than Net Zero' carbon biomethane.
The challenge
Agriculture accounts for 21% of Cornwall’s carbon emissions. The Council owns 58 of the 427 dairy farms in the county. All of these have open slurry lagoons emitting methane into the atmosphere. Many Cornish farms are unable to participate in the biomethane market due to the entry costs associated with scale and having no mains gas connection. This project aims to address that challenge by supporting a technological solution, to eventually progress towards being more commercial.
The solution
Clean energy company, Bennamann developed a solution for small, off-gas-grid dairy farms. This £1.58 million biomethane pilot is fully funded by the Council and equips farms with new, fully covered slurry lagoons capturing 100% of the biogas produced. Bennamann extracts and upgrades the biogas on a weekly basis, taking away liquified biomethane. It then pays the Council for that biomethane and sells onto Corserv, a Council-owned organisation managing our fleet. Eventually, all 77 of the Council's road maintenance trucks will run on farm-produced green energy.
Biogas is captured by enclosing the slurry lagoon and processed into biomethane on the farm. The company aggregates volume from several farms and sells on to local customers. Completely burning the methane in an engine stops it from being released into the atmosphere. The amount released in the exhaust is the same as is released by grass in the first place. Material left in the lagoon (digestate) is made into a biologically enhanced conditioner that helps improve soil quality - negating the need for artificial fertiliser. It is distributed on the soil using a method that stops gases from being released into the air, establishing a circular-based, better than a Net Zero economic model.
The construction phase is underway, with one farm nearing completion. Biomethane went on-line in February 2021, the further five lagoons will be installed before autumn 2022. Trials are underway for the processed biomethane in a tractor and Cormac’s fleet of tarmac hot boxes.
The pilot is just one strand of Cornwall’s transition to a zero-carbon vehicle fleet by 2030, and part of the wider Climate Change Action Plan and builds on the Energy Independent Farm research and development project, part-funded by the European Regional Development Fund, a collaboration between Bennamann, Exeter University and Chynoweth Farm Partners.
The impact
- The pilot will prevent 16,591 tonnes of CO2e from being released every year.
- Plans to transition 77 trucks to biomethane fuel will offset a further 752 tonnes CO2e per year.
- Each pothole repair unit converted to fugitive biomethane could reduce CO2e emissions by five tonnes per year. That’s an equivalent volume to an average hot air balloon and would take five native broadleaf trees to offset over their lifetime (approximately 100 years).
This project could generate enough income, over 20 years, to cover the Council’s £1.58m capital and borrowing costs. Farmers will receive income from biogas sales, save on energy and fertiliser bills, have access to better slurry storage and be responsible for reduced environmental impacts from methane, NOx and ammonia. Initial reductions in emissions may be small, but the project has the potential to help large numbers of farmers reduce their carbon footprint, create ‘green jobs’ and support the ambition for more sustainable farming.
The impact forecasted is based on findings from two-years of a three-year single farm research and development project. The aim is to prove that this business model can take an energy-independent farm towards being fully commercially viable and replicable.
How is the new approach being sustained?
This project should generate enough income, over 20 years, to cover the Council’s capital and borrowing. Farmers will receive income from biogas sales, save on energy and fertiliser bills, have access to better slurry storage and see reduced environmental impacts from methane, NOx and ammonia.
The project has the potential to help large numbers of farmers reduce their carbon footprint, create ‘green jobs’ and help the shift towards more sustainable farming for the long term.
Lessons learned
Current legislation and regulation is changing, with Defra's Clean Air Strategy set to make covered slurry lagoons a mandatory requirement by 2027.
With the need for slurry lagoons to be covered and future-proofed the scale of opportunity is huge, being replicable across similarly sized dairy farms in Cornwall, across the UK and beyond putting Cornwall at the centre of a local clean energy revolution.