Methane leaks recorded at Danish biogas plants 

Evidence of leaks detected by the Changing Markets Foundation and Deutsche Umwelthilfe includes a Shell-owned plant historically linked to dairy giant Arla.

Copenhagen/London – An investigation by the Changing Markets Foundation and Deutsche Umwelthilfe has found significant methane leaks at two Danish biogas plants, raising urgent questions about the climate credentials of so-called ‘green’ energy projects tied to the dairy sector. 

The methane emissions were detected using industry-standard instruments, including an optical gas imaging camera and trace gas analyser, conducted by a thermo-imaging expert (1).

Main findings: 

• • At the Shell-owned Nature Energy plant in Videbæk (formerly part-owned by Arla), methane concentrations reached over 5,000 parts per billion (ppb), more than double the regional atmospheric average (2,077 ppb).
  • The leak was observed on consecutive days at different times of day, with the measuring instruments capturing both the methane levels and the source of the leak from a compressor stack –indicating intentional rather than accidental venting.
  • At Arla’s Arinco processing facility, originally linked by a pipeline to the Vidabæk plant, we filmed a methane release from a chimney.
  • A Freedom of Information request by Greenpeace Denmark shows the Videbæk plant has a record of significant to major leaks, and that mismanagement of documentation on the feedstock used has allowed unsubstantiated sustainability claims to be passed down to consumers. However, some information about agricultural feedstocks was withheld (2).

• At the Tønder biogas plant, one of Europe’s largest, we detected atmospheric methane levels outside the facility, spiking at nearly 35,000 ppb, around 16 times higher than background levels. While the source couldn’t be pinpointed, such elevated levels raise serious concerns about methane leakage in the region. 

“By exposing methane leaks from biogas, our investigation is helping to make the invisible, visible,” said Alma Castron-Davila, Senior Campaigner, Changing Markets Foundation. “Big meat and dairy companies love to market biogas as a green fix, but they clearly aren’t telling the whole story. Our findings raise serious questions about the viability of the industry regulating itself.”

Methane is 80 times more potent than CO₂ in the short term, and agriculture is the largest human-made source of methane, accounting for around 80% of the emissions, primarily from meat and dairy production. The agricultural industry often promotes biogas from manure as a solution to its methane emissions. As a renewable energy source, biogas is supported by public subsidies and subject to weaker regulations than fossil gas when it comes to leaks.

By providing a recent snapshot of two biogas plants on different days, the investigation supports evidence that methane leakage is potentially a persistent and widespread problem.

“Finding such significant leaks in such short inspection indicates that this is a systemic issue with biogas production,” said Jens Hürdler, Senior Expert Agricultural Emissions, Deutsche Umwelthilfe (DUH). “These findings in Denmark are not isolated. We have monitored agricultural methane leaks at more than 20 biogas plants in three countries over the last two years. It is clear that much stronger and well-enforced regulation is needed to identify and prevent leaks.”

In recent years, academic studies have demonstrated that methane leaks from biogas can potentially undermine the climate benefits of this technology. This includes a global study which found that biogas plants may leak up to twice as much methane as previously estimated, and a Danish-specific study showing an average leakage rate in Denmark of 2.5% (with a variance of between 0.3 and 40%) of total biogas production, one-and-a-half times higher than the Danish Energy Agency’s recommended limit of 1%(3).

Denmark is one of the largest biogas producers per capita in Europe. In 2023, the country introduced regulations aimed at reducing methane leaks at biogas plants. While this is a positive step, the requirements are limited to just one independent third-party audit, with the rest relying on the industry’s self-monitoring and reporting.

“This investigation raises serious questions about whether we have a handle on leakage from Danish biogas plants”, said Christian Fromberg, Agriculture and Nature Campaign Lead, Greenpeace Denmark. “When such a large methane leakage is measured around a facility that on paper has minimal leakage, it’s an obvious problem. When we as a society channel billions in subsidies to the biogas industry, it’s to achieve climate benefits – not to pay for hot air.” 

As many countries and companies turn to biogas and biomethane as ‘green’ solutions to agricultural emissions and an alternative to fossil gas, gaps in current policies must be recognised and addressed. While the EU has regulations to reduce methane leaks from fossil fuel production, such as oil and gas plants, the provisions do not currently extend to biogas production. Denmark currently holds the EU Presidency, and with this, the opportunity to not only strengthen regulation at home, but across the EU.

Contact

Jo Kuper, Communications Director, Changing Markets Foundation: +44 7577 462 824, jo.kuper@changingmarkets.org

DUH-Newsroom:+49 30 2400867-20, presse@duh.de

Notes to Editors 

Video footage and a background briefing paper detailing the investigation are available here: Methane Unmasked

(1) The investigation took place on 13 and 14 May 2025, with the trace gas analyser used on the first day.

(2) Greenpeace Denmark requested information on the feedstock received by Nature Energy’s Videbæk plant, but the company requested that the Danish Energy Agency withhold it on the grounds of business competitiveness. After Greenpeace pressed for disclosure, the information was released in a heavily redacted form, preventing any determination of the amount or origin of manure entering the facility.

(3) The papers referenced are:

• Bakkaloglu, S., Cooper, J. and Hawkes, A. (2022). Methane emissions along biomethane and biogas supply chains are underestimated. One Earth. www.cell.com/one-earth/pdf/S2590-3322(22)00267-6.pdf
• Anders, M.F., et al. (2023). The Danish national effort to minimise methane emissions from biogas plants. Waste Management. www.sciencedirect.com/science/article/pii/S0956053X22006304

The Changing Markets Foundation is a non-profit organisation dedicated to exposing irresponsible corporate practices and driving sustainable market change. Our campaigns focus on holding companies accountable for environmental impacts and accelerating the transition to sustainable business models.

Deutsche Umwelthilfe is an independent, non-profit environmental organisation. It is politically independent and also active in the field of consumer protection. Its key areas of work include nature conservation, transport and air quality, climate and the energy transition, recycling, and consumer protection.