About
This report takes methane emissions and mitigation assumptions from the West Cumbria Mining Limited’s (WCML) application for the Whitehaven coal mine and compares them with UK and international benchmarks for similar coal mines.
Executive summary
Whitehaven coal mine approval jeopardises UK’s Methane Pledge
In 2021, the United Kingdom alongside 100 countries signed the Global Methane Pledge, committing to reduce methane emissions by 30% this decade. Just over a year later, it approved the UK’s first underground mine in over 30 years.
Tony Bosworth Friends of the Earth
We already knew that the Cumbria mine would have a major climate impact - that’s why the Climate Change Committee criticised the decision to approve it. But this new analysis shows that the impact could be even more damaging than previously thought. It’s yet another reason why the mine shouldn’t go ahead. Ministers must end their support for projects like this and invest in green energy solutions that will cut emissions and give areas like West Cumbria the jobs they so urgently need.
Background
The UK commits to a coal mine at the same time as signing the Global Methane Pledge
“An immediate and significant change in the pace and scale of methane action is needed to achieve reductions consistent with international climate objectives” IEA Global Methane Tracker 2023
The UK has positioned itself as one of the leaders in the fight against global methane emissions. At COP26 in Glasgow, the UK government alongside 100 other countries signed the Methane Pledge, promising to work together to reduce methane emissions by at least 30% from 2020 levels by 2030, thereby eliminating over 0.2˚C of warming by 2050.
In addition, the UK has signed the Joint Declaration from Energy Importers and Exporters on Reducing Greenhouse Gas Emissions from Fossil Fuels, where the signatories committed to take “immediate action to reduce the greenhouse gas emissions associated with fossil energy production and consumption, particularly to reduce methane emissions”.
Underestimation of emissions
Cumbria’s coal mine will emit three times more methane than estimated
Using official UK emissions factors, the Cumbria coal mine would generate 21 cubic metres of methane per tonne of coal produced. In contrast, WCML provided estimates of 3-7 cubic metres.
The comparison of different benchmarks show that the numbers proposed by WCML are very low and must be treated with caution. WCML makes estimates from the methane content of coal core samples from the mine, but that does not take into account all the methane emissions associated with coal mining, as the mining process also disturbs methane holding strata adjacent to the mined seam.
Research by Kholod et al. suggests that coal methane content derived from core samples should be multiplied by an emission factor to account for this discrepancy. They state that globally this number is on average 1.7, but with huge uncertainties and discrepancies, which increase with mining depths (ibid.). For this reason, we do not believe that it is appropriate to use WCML’s methodologies for measuring gas content.
The IPCC guidelines for estimating coal mine methane emissions recommend the use of regional emission factors unless actual mine measurements are possible. This approach is mirrored in the UK government’s guidance for evaluating greenhouse gas emissions from new projects, which also call for the use of emission factors that are supplied by the National Atmospheric Emissions Inventory (NAEI).
The NAEI emission factor is much more in line with what we would expect from a mine of Cumbria’s depth and we therefore believe that the number that should have been used to evaluate the Cumbria proposal.
Using the NAEI number means that if unmitigated, the mine would emit 3.5x more over its lifetime than what is assumed by WCML.
Overestimation of mitigation
Mine’s mitigation volumes are unrealistic
WCML’s application states that it will destroy over 95 per cent of coal mine methane produced by the Cumbria mine. However, the International Energy Agency’s assessment is that only 69% mitigation would be expected from the mine.
Evidence from documentation indicates that the Inspector did not understand the technologies proposed by the mine. In his decision, he said 95% of the methane would be drained:
“95% of the methane generated by the mining operations and underground crushing processes would be captured by the methane drainage system. This methane would be drawn out of the mine in a system of integrated pipes into methane pumps and into the methane plant located on the surface.”
This shows a misunderstanding of the scheme, as the mine documentation states that it would drain and utilise just 12 percent of the methane, with the remainder coming through VAM destruction.
This is a totally different technology, that is technically proven but is rarely seen in real world operations due to its cost. Renewable Thermal Oxidisers are highly niche technologies, with only four mines globally known to operate them. Three of the mines are in China and one in the United States.
In their Proof of Evidence, WCML referred to a US based project, showing generalised brochures. The project operated since 2014 and WCML states in their proof of evidence that as of December 31 2017 the project had registered 1,045,923 tCO2e in emission reductions.
There is no public data available for the three VAM destruction projects in China, but the US based project, Marshall Mine, reports its methane emissions. In the period of 2014 when it installed the VAM destruction equipment until end of 2017, it has emitted over 8 million tonnes of CO2 equivalent of methane, meaning it only destroyed 12% of the methane it emitted.
We cannot comment on the viability of the methane mitigation plans, as they are lacking detail. Therefore, it is important that the Mine Gas Mitigation Plan has much more detail about the proposed measures to destroy methane emissions.
It must at the very least include:
- Detailed geological analysis, demonstrating the basis of mine’s methane emissions forecasts;
- Modelled hourly gas flows from the mining process;
- Detailed information about VAM oxidation technology used, including its manufacturer, footprint, technical characteristics, safety and impacts on the local environment.
It must also be put into the public domain, with experts being invited to scrutinise it.
Total methane impact
Total methane impact 15x greater
More emissions and less mitigation means the Cumbria mine’s methane impact will be 15x greater than suggested.
Based on WCML’s estimates the impact on UK methane emissions in 2030 would be just 0.3 kilotonnes compared to a total of 22 kilotonnes of methane from other sources.
Based on Ember calculations using the official NAEI emission factor and IEA’s mitigation estimates, the mine would produce 12 kilotonnes in 2030, more than half the emissions from other sources. If the Cumbria mine fails to implement any mitigation, it risks producing 39 kilotonnes of methane in 2030, almost tripling the UK’s total methane emissions from oil, gas and coal production in 2030.
If taken over the mine’s lifetime, the differences become substantial. WCML’s estimates for mitigated lifetime emissions total 22 kilotonnes of methane, whilst using Ember calculations the number would be 334 kilotonnes, rising to 901 kilotonnes if unmitigated.
Supporting Material
Acknowledgements
Train transports coal in Greenholme, Cumbria.
Credit: Avalon/Construction Photography / Alamy Stock Photo
