Biomethane : WBA's Charlotte Morton on why methane leakage is a business problem

The World Biogas Association contributed to the IEA's 2025 Outlook for Biogas and Biomethane, which documented methane leakage rates of 0.1-12% depending on the stage. What was your reaction to those findings, and how did they influence your certification work? 

The findings from the IEA’s 2025 Outlook for Biogas and Biomethane were not unexpected. However, some of the higher leakage rates came from older AD plants, while newer and bigger plants showed better performance on methane leak mitigation.

Minimising methane leakage has long been a priority for WBA since the industry’s reputation and licence to operate depend on doing so. Well-designed and operated plants ensure that methane slip and leakage are minimised. The Anaerobic Digestion Certification Scheme International (ADCS Intl), which is the first global certification scheme dedicated specifically to enhancing the health, safety, environmental, and operational performance of biogas plants, already covers this, emphasising the risks that methane leaks pose both to the environment and to the financial performance of AD plants. 

A new module entitled “Air Emissions Monitoring and Mitigation” is scheduled to be incorporated into the next update of the ADCS International. In addition, the WBA published an Operational Guidance Note (OGN) providing practical advice on how to detect and reduce methane leaks in AD plants.

The International Anaerobic Digestion Certification Scheme is now live. Can you describe what a certified facility looks like operationally and what the key requirements are? 

The scheme is structured around multiple levels of certification, ranging from Starter to Elite. A facility certified at the Starter level will meet all the core criteria, including safe operations, high gas quality and production standards, and environmental compliance while demonstrating active efforts to improve its performance across health, safety, environmental, and operational parameters. An Elite-certified site, by contrast, represents a model of best practice for AD facilities worldwide. 

ADCS International standards are designed to set minimum health and safety, environmental and operational performance standards to protect all stakeholders and ensure good performance.

>>> From denial to detection: How biogas is confronting its methane problem

Your scheme emphasises sealed tanks, proper digestate storage, and leak detection programs. What does implementation actually look like in practice? 

Of course, all tanks on site that are actively producing methane must be sealed; methane produced on site, the desired product, needs to be captured , not released to the atmosphere. Environmental Agencies in the UK are targeting open storage tanks and mandating covers here, followed by leak detection, and that’s for the benefit of both the environment and the benefit of the operator – methane is the product, and so should be captured and used as a valuable resource to replace fossil methane. 

Implementation for the tanks is simple: cover the lagoon with a non-permeable roof, then capture and use whatever gas is produced within the tank, which can be done by using the gas in an engine or upgrading to biomethane. 

 Leak detection is also straightforward, usually involving a special camera survey in addition to good operator training. There are multiple service providers that can offer this, or in some cases, a plant may be able to do most of the leak detection work itself.  

Does your certification scheme aim for zero leakage, or is there an acceptable threshold? How did you determine what "good performance" looks like? 

Ideally, all AD plants should operate with zero leakage, not only to safeguard the environment but also to ensure optimal plant performance and revenue generation.  

However, the operational reality is that small leaks do occur. Provided that sites have robust leak mitigation processes in place and can detect and repair leaks in a timely manner, a threshold of 1–3% is generally considered best practice, in line with benchmarks used in European gas networks. Zero methane emissions from site are simply not practical. The acceptable threshold may vary depending on the country and its average gas network leakage rate, but for ADCS-certified facilities, the aim is to keep it as low as practically achievable, 1% or less. 

What monitoring technologies does the certification scheme recommend, and how accessible are these for facilities of different sizes and budgets? 

The scheme does not endorse or recommend any specific technology, as available options vary considerably in terms of cost, granularity, and effectiveness depending on geographical and operational factors. We acknowledge that Optical Gas Imaging (OGI) cameras are becoming increasingly popular and accessible to operators; however, as an international scheme, we encourage sites to follow their national guidance and engage with their respective environmental agencies; particularly where specific monitoring methods may not be recognised by permitting authorities in certain regions, despite being recommended in others. 

The OGN we published last year on Pollutant Gases and Leak Detection and Repair (LDAR) references technologies such as LiDAR, OGI cameras, and Flame Ionisation Detection (FID) as examples, given that these are the methods most widely deployed across the EU, UK, and US. However, we do not limit acceptable detection methods to these alone, recognising that they may be prohibitively costly or less widely available in certain parts of the world. 

Beyond environmental benefits, what economic advantages have facilities seen from better methane management? 

Improved methane management and reducing leaks to near-zero levels hold significant potential for facilities to recover thousands of pounds in lost revenue, with only a fraction of that amount required to invest in operational expenditure for LDAR methods. 

 A recent financial analysis we conducted in the UK illustrated this clearly. Assuming a biomethane injection rate of £6.69p/kWh (the standard support scheme rate in the UK), a large-scale plant producing 500m³ of biomethane per hour with a simple unrepaired leak of 5% could lose approximately £150,000 in annual revenues. For leaks exceeding 20%, the losses could surpass half a million pounds per year. 

Implementing proper LDAR methods and continuous methane monitoring represents a compelling business case when one considers the scale of methane and revenue that is effectively being lost through undetected or unrepaired leaks. 

Are there financing mechanisms available to help facilities invest in leak detection equipment and improvements? 

Not that I am aware of, especially on an international scale. 

But as I said before, any methane leaking from a site is a loss of valuable product, so it really is in the operators' best interest. ADBA published an article earlier last year, reviewing a study that showed a UK biogas site reducing its rate of methane emissions from over 10% to around 1-2% (compared to overall production levels), and this would save the site over one hundred thousand pounds – each molecule of methane is that valuable. 

Can you share examples of facilities that have implemented these best practices successfully? What results did they achieve? 

We are currently in the process of gathering data from some of our UK ADCS sites, which have shown an increase in performance.  An additional study conducted by the UK government showed that adopting best practices, such as conducting a Leak Detection survey followed by repairs and maintenance (particularly the digester roof), considerably reduces leaks on site. One of the surveyed plants showed a reduction from 22% to 5%  of fugitive emissions following an LDAR survey. Ideally, the leak reduction process does not just end after the repair; the site would have implemented proper monitoring and mitigation techniques alongside further repairs and achieve rates closer to 0-1% leakage. 

Which countries or regions are leading on methane management in biogas, and what can others learn from them? 

EU Member States and the United Kingdom are at the forefront of efforts to address methane leakage, driven in large part by robust policy frameworks such as the Urban Waste Water Treatment Directive (UWWTD) in the EU and the UK’s Guidance for Reporting Fugitive Methane Emissions for the Green Gas Support Scheme, as well as their respective Methane Action Plans, which set ambitious targets for reducing methane emissions. 

The key lesson for other regions is that a combination of enforceable methane reduction regulations and clear, accessible guidance on best practices is essential for preventing fugitive methane emissions and ensuring that waste management facilities operate at peak performance without compromising environmental safety. 

Denmark and other European countries have implemented methane regulations for biogas. How does your certification scheme work alongside these emerging government regulations? 

The ADCS International was developed with reference to the regulatory frameworks, guidance documents, and best practice standards of over 50 countries. Regulations from European countries such as Denmark were indeed considered when drafting the scheme’s criteria. A facility that meets the ADCS International standard will, in most cases, already be following the vast majority of Danish or broader European regulatory requirements. 

That said, adherence to ADCS International criteria does not exempt facilities from following their national regulations. Given the global and necessarily broad nature of the scheme, certain criteria may not be fully aligned with granular national rules. This is precisely why the ADCS International is designed to serve as a blueprint that is then adapted to national regulatory contexts in the countries where it is being implemented, for example, India, and Brazil, which form part of our initial engagements. 

The certification scheme has been designed for global deployment. What's been the uptake so far, and what feedback are you receiving from operators? 

The scheme was first piloted and successfully deployed in the United Kingdom, where it has achieved strong initial uptake. We are currently in ongoing discussions with national regulators regarding its progression towards a recognised national voluntary certification. 

Internationally, our primary target markets for implementation are India and Brazil, where we are working closely with local stakeholders on the adaptation phase. This involves using the ADCS International as a blueprint and tailoring it to each country’s regulatory and industrial context. We are optimistic that the first plants will be audited within this year with support provided during the process to achieve accreditation. 

The Global Methane Pledge depends significantly on biogas to deliver emissions reductions. How confident are you that the industry can meet these expectations while addressing leakage? 

That’s absolutely right, the WBA produced a report in 2022 that demonstrated the global biogas sector alone could deliver half of the Global Methane Pledge – humans generate 105 billion tonnes of organic wastes every year which release harmful methane into the atmosphere when they decompose but the biogas industry can harness these wastes and recycle them into renewable energy, a valuable biofertiliser, bio-CO2 that could be used in industry or stored for carbon negative emissions and other valuable bio-products – all while preventing methane and displacing their fossil equivalents! 

So it is a must that the industry scales and it is already happening, the industry is growing steadily worldwide with top performer biomethane markets reaching 14–28%+ per year – indeed recent years show a clear trend in favour of biomethane upgrading. 

Nonetheless, it is clear that current growth rates are far short of what we need to see to deliver the full potential of the industry and achieve the GMP. For this reason, we launched the #MakingBiogasHappen programme, which is a global renewable gas market accelerator and catalytic platform designed to unlock the full potential of the industry. The programme provides regulatory de-risking, technical standardisation, and structured project pipeline development, transforming underdeveloped waste sectors into bankable renewable gas markets with the potential to mobilise billions in private capital. A key focus of the programme is reducing methane leakage so that we scale a high-performing and sustainable industry.  

What gives you the most optimism when you look at where the industry is headed on methane management? 

The industry is clearly heading in the right direction. There has been something of a watershed moment in 2025 regarding methane emissions and the recognition that fugitive emissions must be addressed as a matter of urgency.  

We have seen a proliferation of Methane Action Plans, increasingly stringent regulations, policy incentives that reward lowering carbon emissions – specifically clean fuel and renewable gas credits increasingly dependent on lifecycle carbon intensity, and national governments committing to measurable methane reduction targets, all of which underscore the critical importance of effective methane management.  

What's your message to waste management operators who are concerned about methane leakage but unsure where to start? 

My advice would be to start by engaging with your local environmental agency. These bodies exist not only to enforce regulations but also to provide guidance and support. Scheduling a leak survey and addressing the associated repair costs may seem daunting and could have an impact on quarterly financial reports, but these are valuable long-term investments. 

To put this in perspective: the cost of a survey and repairs for a medium-sized leak can typically be offset within just a few weeks of leak-free operations. The business case is clear and compelling, and facilities that invest in proper leak management will see returns not only in environmental performance but also in their bottom line.