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From Farm to Factory – The Role of Biomethane in Fuelling a Greener Future
2 minute read
As the world accelerates its shift toward sustainable energy, biomethane is emerging as a critical solution, especially in agricultural regions like Northern Ireland.
With a farming landscape dominated by livestock—home to over three million cattle, sheep, and pigs—Northern Ireland generates vast amounts of manure, approximately nine million tonnes each year. While valuable as fertilizer, this manure also poses significant environmental risks, including water pollution and high ammonia emissions. Although Northern Ireland makes up a small portion of the UK in terms of population and land area, it disproportionately contributes to the nation’s ammonia output.
To address these environmental challenges and meet ambitious climate targets, Northern Ireland’s 2021 Energy Strategy, “Path to Net Zero Energy,” is designed to overhaul the energy system by 2050. With agriculture accounting for nearly a third of the region’s greenhouse gas emissions, biomethane plays a key role in this strategy, offering a pathway to reducing emissions and meeting the requirements of the Climate Change Act (Northern Ireland) 2022, which mandates a 48% reduction in greenhouse gas emissions by 2030.
What is Biomethane?
Biomethane is a carbon-neutral energy source that offers a sustainable alternative to fossil fuels, produced through a process known as anaerobic digestion. In this method, organic waste—such as food scraps and manure—breaks down without oxygen, thanks to microbial activity. This process not only captures methane, a potent greenhouse gas that is 23 times more effective at trapping heat in the atmosphere than carbon dioxide, but also manages manure more effectively, reducing the release of ammonia and phosphorus which can lead to water pollution and eutrophication.
After impurities and carbon dioxide are removed, the purified methane becomes biomethane—a renewable gas that can be used just like natural gas for heating, electricity, and even transportation. Its production plays a crucial role in cutting down reliance on fossil fuels while enhancing energy security. Furthermore, biomethane supports a circular economy by turning waste into energy and producing valuable byproducts like digestate, a natural fertilizer that cuts down the need for synthetic alternatives, and biogenic CO2, which can be used in industrial applications. This aligns with global efforts to promote regenerative practices, reduce waste, and extend the lifespan of resources.
Tullyweel Farm + AG
At AG, sustainability drives everything we do, and a key part of that commitment is sourcing 100% of our manufacturing energy from renewable resources. At the heart of this effort is our collaboration with Tullyweel Farm, a family-run dairy farm in Fivemiletown, located next to our head office. Managed by Wilfred Bothwell and his sons, Stephen and Rodney, the farm plays an essential role in our sustainability strategy by providing locally generated renewable energy that aligns perfectly with our business practices.
Tullyweel Farm’s journey into renewable energy began in 2013, when fluctuating milk prices prompted them to diversify by investing in renewable energy under the Northern Ireland Renewables Obligation (NIRO) scheme. This move not only allowed them to generate electricity for their own use but also to feed surplus power into the Northern Ireland Electricity grid. As a result, the farm gained financial stability, reduced energy costs, and insulated itself from the unpredictability of the agricultural market.
In 2017, AG seized an exciting opportunity to partner with Tullyweel Farm, harnessing their biomethane production to power some of our operations. This collaboration has transformed key aspects of our business, providing renewable energy for our electric vehicle (EV) chargers and our wash plant at our Fivemiletown facility. The wash plant plays a crucial role in our production process, where raw aggregates from our quarry are meticulously cleaned and refined to ensure that our paving and building products consistently meet the highest standards of quality and durability
This partnership has had far-reaching effects beyond environmental sustainability, delivering remarkable financial benefits as well. Over the past year alone, switching to biomethane has reduced electricity costs at our wash plant by 23%. These savings have enabled us to expand our product range, including the introduction of Crescent flagstones, an affordable, entry-level addition to our renowned premium line-up. By harnessing locally produced biomethane, we’re not only cutting our carbon footprint but also fuelling economic growth within the community, proving that sustainability and business success can go hand in hand.
How is Biomethane made?
At Tullyweel Farm, biomethane is produced through a meticulously controlled four-stage process that transforms organic waste into a valuable renewable energy source for both their farm and AG.
1. Feedstock Collection
The journey begins with collecting a diverse range of organic waste materials, including slurry, farmyard manure, silage, and whey—a byproduct of cheese production.
2. Anaerobic Digestion
The mixed feedstock is then transferred to anaerobic digesters, large, sealed tanks where the real transformation occurs. Inside these digesters, microorganisms break down the organic material at controlled temperatures between 40-45 degrees Celsius. This biological process generates raw biogas, rich in methane.
3. Biogas Cleaning and Upgrading
The raw biogas is then subjected to a cleaning and upgrading process. Impurities such as hydrogen sulphide and carbon dioxide are removed, resulting in high-quality biomethane with a high methane content. This purified biomethane is now ready for a range of applications. It can be injected into the natural gas grid, used as a clean fuel for vehicles, or employed in combined heat and power (CHP) systems for generating both electricity and heat. A dedicated gas line runs 1200 meters from Tullyweel Farm to our Fivemiletown facility which powers an engine that produces electricity.
4. Digestate Management and Utilisation
The residual liquid from the digestion process, called digestate, is rich in nitrogen and serves as an excellent plant nutrient. More effective than undigested slurry at enriching soil, digestate plays a key role in the circular economy and supports sustainable farming practices.
In summary, biomethane production represents a pivotal advancement in Northern Ireland’s journey toward a sustainable and resilient energy future. By transforming agricultural waste into valuable renewable energy, this process adheres to the principles of a circular economy—converting potential pollutants into economic assets. The partnership between AG and Tullyweel Farm exemplifies how integrating biomethane production into local farming operations can drive economic growth, enhance rural livelihoods, and support energy security.
As Northern Ireland continues to embrace biomethane technology and develop supportive policies, it stands to gain from reduced reliance on imported fossil fuels, improved air quality, and a stronger commitment to climate goals. With ongoing innovations and investments in biomethane, Northern Ireland can emerge as a leader in renewable energy, setting an example for others and ensuring a more sustainable, prosperous future.
Learn more about how AG is dedicated to leaving behind a Low Carbon Legacy.