OPINION: ‘UK government should do more to promote anaerobic digestion’

OPINION: The United Kingdom faces a critical juncture in its approach to mitigating climate change. Methane, a potent greenhouse gas, contributes significantly to global warming, with a heat-trapping capability far exceeding that of carbon dioxide over short periods. With the agricultural sector, particularly livestock farming, being a major source of methane emissions, it is imperative for the UK to adopt more robust policies promoting anaerobic digestion and biogas production. Other nations have demonstrated the efficacy of such measures, and it is time for the UK to follow suit.

The case for anaerobic digestion

Anaerobic digestion (AD) is a process where organic materials, such as animal manure, are broken down by microbes in the absence of oxygen, producing biogas. This biogas primarily consists of methane and carbon dioxide. When purified, the methane, known as biomethane, can be used as a renewable energy source, providing a viable alternative to fossil fuels.

The benefits of AD are multifaceted. Firstly, it addresses the urgent need to reduce methane emissions. Farms are significant methane producers due to the decomposition of manure. By using AD, we can convert this waste into energy, thus preventing methane from escaping into the atmosphere from slurry lagoons, manure piles, and similar sources. Research highlights that anaerobic digesters can, and are, reducing methane emissions from dairy, swine, and chicken waste affordably and efficiently. Numerous other organisations such as the Anaerobic Digestion and Bioresources Association (ADBA) and the World Biogas Association make a similar case. Energy Vision, a US research organisation, points out that AD systems can reduce methane emissions 12 times more than if all 2.1 million abandoned oil and gas wells stopped plugging in the US, and at approximately half the cost.

Secondly, AD produces renewable natural gas (RNG), contributing to energy diversification and security. RNG can be used for heating, electricity generation, and as a vehicle fuel, reducing reliance on carbon-intensive fossil fuels. This aligns with the UK’s climate goals and the broader global commitments, such as the Global Methane Pledge, which seeks to cut methane emissions by at least 30% by 2030. The deployment of AD technologies directly supports these targets by improving manure management and generating clean energy.

International examples of success

Many countries are ahead of the UK in leveraging AD technology. The United States, for instance, has seen significant advancements in this area, particularly in states like California, where policies like the Low Carbon Fuel Standard (LCFS) incentivise the production and use of RNG. These policies not only help reduce greenhouse gas emissions but also improve air quality by cutting down on pollutants like ammonia and nitrogen oxides.

Similarly, Germany has been a pioneer in biogas production, with thousands of AD plants operating across the country. The German Renewable Energy Sources Act (EEG) has played a crucial role in this success, providing financial incentives for biogas production. This has not only reduced methane emissions but also supported rural economies by creating jobs and providing farmers with an additional income stream.

Benefits beyond emissions reduction

The advantages of AD extend beyond reducing greenhouse gas emissions. AD improves air quality by capturing methane and reducing odours associated with manure management. It also produces digestate, a nutrient-rich byproduct that can be used as a natural fertilizer, enhancing soil health and potentially increasing crop yields. This can reduce the need for chemical fertilizers, further benefiting the environment and promoting sustainable farming practices.

Water pollution is another significant concern addressed by AD. By preventing manure lagoon runoff, AD systems help protect water bodies from contamination, safeguarding aquatic ecosystems and public health.

Addressing criticisms and misconceptions

Critics argue that promoting biogas plants might lead to the expansion of large farms, potentially harming small-scale farmers. However, it’s essential to understand that the trend towards larger farms has been driven by broader economic factors, such as economies of scale and market dynamics, rather than the adoption of AD technology alone. Previous UK governments have also limited their AD support to large farms, something not to be repeated.

Furthermore, policies can be designed to ensure that the benefits of AD are accessible to all farm sizes. Subsidies and incentives should be structured to support small and medium-sized farms, helping them adopt this technology and reap its benefits. Most dairy farms in the UK, like those in the US, are family-owned and thus might follow the Danish model of forming biogas cooperatives. With the right support, these farms can implement AD systems without compromising their operations.

To avoid the possibility of any negative impact on food production UK rules must follow the example of Germany where their AD industry until recently consumed significant output of whole crop maize, and where food crop subsidy has been removed.

Concern has been rising that in England the high allowable plastic content permissible in organic compost and manures would be unacceptably increased by land spreading of increased biogas plant fertiliser. However, there is every prospect that this shortcoming will be addressed by more stringent standards applied as a result of current waste industry Defra consultations, and there is now also source separated organic waste depackaging equipment available to the UK market that can achieve the anticipated new standards.

Visitors to the RWM exhibition at the NEC, Birmingham in September 2024 will be able to visit this depackaging equipment at Stand No. EN-F61 where the Drycake Twister Depackager and Separator, plus their Seditank plastic and grit removal equipment will be featured.

Policy recommendations

To harness the full potential of AD, the UK government should implement several key policy measures:

1. Incentives and Subsidies: Financial incentives, similar to those in Germany and California, should be introduced to encourage the adoption of AD technology. These could include grants, low-interest loans, and reinstating feed-in tariffs and better use of CfDs for biogas production. The rules for subsidy under the existing Green Gas Support Scheme (GGSS) need to be made less restrictive to raise the number of projects within the scheme.
2. Research and Development: Increased investment in R&D is crucial to advancing AD technology and making it more efficient and cost-effective. This includes developing better microbial cultures, improving biogas purification methods, and enhancing digestate management practices.
3. Regulatory Support: Streamlined regulatory processes can help accelerate the deployment of AD systems. This includes further simplifying permitting procedures and providing clear guidelines for the construction and operation of biogas plants.
4. Education and Outreach: Raising awareness about the benefits of AD among farmers and the general public is essential. Educational programs and technical support can help farmers understand how to integrate AD into their operations effectively.
5. Integration with Climate Policies: AD should be integrated into broader climate and energy policies. This includes recognising biogas as a key component of the UK’s renewable energy strategy and formally incorporating it into national greenhouse gas reduction targets.

Conclusion

Promoting anaerobic digestion and biogas production is not just a technological solution; it is a strategic imperative for the UK. By following the example set by other nations, the UK can reduce methane emissions, produce renewable energy, and support sustainable agriculture. The benefits are clear: improved air and water quality, enhanced soil health, and economic gains for farmers. It is time for the UK government to take decisive action and implement policies that will unlock the full potential of anaerobic digestion, contributing to a cleaner, healthier, and more sustainable future.

Find out more at the Resources & Waste Management Management Expo on 11-12 September in Birmingham.