Urgency to update Germany’s coal mine methane emission factor

Introdução

A Alemanha subestima suas emissões de mineração de carvão

Ember Avaliou os dados de emissão de metano de carvão da Alemanha, que não tem sido a mina de linhagem de que a escala significativa de 532 em que a escala significativa de preenchimento de preços de linha de emissões não tenha sido adequada ou avaliada. Minas, representando 44% da produção de carvão total de linhita EUS de 2022. No entanto, a Alemanha relatou apenas emissões ativas de CMM de 1,39 mil toneladas, a saber, 1% do total de emissões de CMM de superfície ativa do Total na UE em 2021.

In 2022, Germany mined 131 million tonnes of lignite coal from surface mines, representing 44% of the 2022 EUs total lignite coal production. However, Germany only reported active CMM emissions of 1.39 thousand tonnes, namely 1% of the total EU’s reported active surface CMM emissions in 2021.

Ember analisou as medidas de metano da linhita polonesa e descobriu que as emissões podem ser 184 vezes maiores que os relatórios da Germania atualmente. Isso mais que dobraria as emissões de metano de 2021 da Alemanha de todo o setor energético, representando um aumento de 14% nas emissões nacionais de metano. A Alemanha não pode reivindicar ser um líder climático, enquanto subnote simultaneamente suas emissões. A próxima regulação do metano exigirá “fator de emissão de metano de mina de carvão específico de depósito estabelecido“ trimestralmente ”e levando em consideração“ emissões de metano dos estratos vizinhos ”. A Alemanha deve dar um exemplo sobre a "prática das melhores práticas" CMM MRV. Para fazer isso, exigirá uma revisão da metodologia existente e existente da Alemanha. Tomar:

Germany’s current methods, which use a single emissions factor, are considered inadequate by EU standards. The upcoming Methane Regulation will require “deposit-specific coal mine methane emission factor” established “on a quarterly basis” and taking into account “methane emissions from surrounding strata“.

As a Global Methane Pledge Champion, and the largest EU surface coal mine producer, Germany’s oversight on measurements and verification must be rectified. Germany should set an example on “best practise” CMM MRV. To do this will require an overhaul of Germany’s outdated and lax existing methodology.

By establishing a rigorous MRV standard, Germany has the potential to significantly enhance the effectiveness of emissions reductions from surface coal mines, both within the EU and globally, as the Methane Regulation mandates importers to attain MRV equivalence.

Ember highlights 3 recommendations which Germany can take:

1. Medida: requer minas de superfície para medir diretamente e modelar suas emissões atuais e futuras de metano, inclusive após o fechamento
2. Evite: sem expansões de minas de carvão e eliminar as minas mais gás. Emissões relatadas pelo governo para três estimativas independentes da Agência Internacional de Energia (IEA), Global Energy Monitor (GEM) e Shen et al. (2023). Os estudos dependem de métodos de baixo para cima e de cima para baixo, descritos nos materiais de apoio. A análise anterior de Ember constatou que a Alemanha era o país com a maior disparidade entre emissão relatada e estimada de forma independente na UE. As maiores estimativas (por gem) sugerem que a Alemanha emite 300.000 toneladas adicionais de emissões de metano anualmente.
3. Mitigate: Require methane mitigation at active and closed coal mines

Comparison of Estimates

Ember compared government-reported emissions to three independent estimates from the International Energy Agency (IEA), Global Energy Monitor (GEM) and Shen et al. (2023). The studies rely on bottom-up and top-down methods, described in the Supporting Materials.

Findings from all three studies agree that Germany is underreporting its CMM emissions, although there are significant differences in the scale. Ember’s previous analysis found that Germany was the country with the largest disparity between reported and independently estimated emission within the EU.

The studies indicate that Germany emits between 28 to 220 times as much as it officially reports from active coal mining operations. The largest estimates (by GEM) suggest Germany emits an additional 300,000 tonnes of methane emissions annually.

Using methane’s short-term climate impact over 20 years (GWP 20), this would mean Germany’s CMM emissions are between 3-25 million tonnes of CO2e, equivalent to some of the country’s dirtiest coal power plants. Using methane’s 100 year climate impact, CMM emissions would be equivalent to 1-9 million tonnes of CO2e.

Ember update to GEM estimate

Ember estimated Germany’s methane emissions, following the peer-reviewed Model for Calculating Coal Mine Methane (MC2M) methodology, as used by GEM and described in the Supporting Materials. We compiled company data on coal production for the latest reported year (2022 when available, otherwise 2021), coal mine depth as described in company reports or academia, and used data from Polish lignite samples to estimate the gas content of German lignite at varying depths, as plotted below.

Applying this methodology, Ember estimated Germany’s coal mine methane emissions at approximately 256,000 tonnes annually. While this figure aligns with the upper range of independent emission estimates, it remains within the uncertainty range established by Shen et al.’s analysis of Germany’s CMM emissions from TROPOMI satellite data.

Addendum: Satellite sees Germany’s CMM

The TROPOMI instrument onboard Sentinel-5P provides methane concentration measurements globally. Using Google Earth Engine, Ember calculated average methane concentrations from 2022-2023 from repeat daily overpasses.

TheTROPOMI data indicated strong methane enhancements over the lignite mines. Further analysis by the SRON Netherlands Institute for Space Research found that the enhancements are caused by high surface reflectivity and are not correlated with wind direction. Due to this limitation, we cannot conclude how much methane is present over the mines using the TROPOMI data. Observations from other satellite sensors and ground-based observations would help to quantify this.

CMM Underreporting

The problem with Germany’s current emission factor

Germany uses a single emission factor, measured in 1989, to calculate the methane emissions from all of its lignite coal mining operations throughout the country. This single emission factor lacks verification, is significantly different to lignite coal measured in Poland, and does not take into account methane emissions from surrounding strata. Here we highlight why the emission factor used by Germany is not adequate for estimating its coal mine methane emissions.

Inadequacy of single emission factor

A single emissions factor is insufficient for estimating surface coal mine emissions because the methane intensity of coal mined is not constant in time. Methane emissions are affected by factors such as the mines’ location, depth, and change in the permeability of coal seams as overburden is removed. This level of variability is not captured with a single emission factor.

However, Germany currently relies on a single emission factor, based on a 1989 study by Rheinbraun AG, a lignite mining company. The German Lignite Industry (DEBRIV) states that methane content from borehole samples was measured, ranging from 0.00 m3/t to 0.05 m3/t, and that the average methane content was 0.015 m3/t.

Single emissions factors are not an appropriate starting point for effective methane measurement or management at surface mines. Awareness of this issue is increasing in other countries that mine coal. For example, this has also been highlighted by the Australian Climate Change Authority, who have called for a review “with respect to sampling requirements and standards estimation methodologies for fugitive methane emissions” when applied to surface coal mines “as a matter of urgency”.

40-100 times lower than lignite coal from Poland

Ember analysed the methane emission factor reported by Germany, and compared it to in-situ gas content, and depth measured from lignite samples in Europe (data was available for Poland and Greece, see data here).

Germany considers its lignite coal to be comparable to that from Poland, as stated in the National Inventory Report (NIR), and confirmed by Betzenbichler et al. in 2016.

No entanto, a Alemanha avalia o teor de metano de seu carvão como significativamente menor. Dependendo da profundidade da amostra de carvão, o fator de emissão da Alemanha está entre 40 a 100 vezes menor que as medições in situ de linhita polonesa.

Em geral, a intensidade do metano de uma mina aumentará em relação à profundidade do carvão extraído. Embora existam exceções a essa regra, pois a intensidade do metano do carvão pode variar significativamente entre regiões, bacias e minas de carvão. O fator de emissão da Alemanha não leva em consideração variações de profundidade ou variações na geologia do carvão em todo o país. Na Polônia, a bacia de carvão da Silésia superior cobre uma área menor que 2% do tamanho da Alemanha, mas o teor de metano varia significativamente tanto vertical quanto horizontalmente. Somente em costuras rasas, o teor de metano pode variar de acordo com um fator de 100 (entre 0,01 e 1 m3/t de carvão). (Referenciado no NIR da Alemanha), destaca a mesma preocupação e afirma que, depois de solicitar mais informações do DeBriv, não houve mais atualizações para os dados. As diretrizes do IPCC afirmam “para explicar o metano que migra dos estratos circundantes, o fator de emissões assumido deve ser baseado em variáveis ​​medidas, como conteúdo de gás e características qualitativas, como a permeabilidade”. Sob Burden (U.S. EPA, 2016). não é o caso. Nenhuma das referências fornece informações para determinar a aplicabilidade ou robustez do programa de amostragem geológica utilizada. Informações sobre o número de furos, técnicas de amostragem, profundidade de amostras, porosidade e teor de metano não foram divulgadas publicamente. Campeão

Rhine Basin cannot be assumed to be representative of all of Germany

In-situ gas contents can vary greatly within a country as there is often a large spatial variability of methane content of coals, even within a basin. In Poland, the Upper Silesian coal basin covers an area less than 2% the size of Germany but methane content varies significantly both vertically and horizontally. In shallow seams alone, the methane content can vary by a factor of 100 (between 0.01 and 1 m3/t coal).

This raises the concern that the current emission factor, based only on samples from the Rhine basin, may not be representative for all of Germany’s coal.

The 2016 study by Betzenbichler et al. (referenced within Germany’s NIR), highlights the same concern, and states that after requesting further information from DEBRIV, there were no further updates to the data.

Additional methane from the surrounding strata

During the excavation of coal at a surface mine, the methane within the mined coal seam will be released, as well as methane within the surrounding (unmined) strata. The IPCC guidelines state “To account for the methane that migrates from surrounding strata, the assumed emissions factor should be based on measured variables such as gas content, and qualitative characteristics such as permeability”.

To account for these additional emissions, the U.S. Environmental Protection Agency multiplies coal production by a gas content emission factor and a 150-percent emission factor to account for emissions from over- and under-burden (U.S. EPA, 2016).

There is no indication that Germany has taken into account methane emissions from the surrounding strata within their emission factor estimates.

Emission factor lacks verification

Germany’s National Inventory Report (NIR) claims that secondary references substantiate the findings of the 1989 Rheinbraun AG study, however, this is not the case. None of the references provide information to determine the applicability or robustness of the geological sampling program used. Information on the number of drill holes, sampling techniques, depth of samples, porosity, and methane content have not been publicly disclosed.

For more detail on the references included within the NIR, and why they do not substantiate the emission factor, see the Supporting Materials.

Recommendations

Germany claims to be a climate action champion. O país também é signatário da promessa global de metano e, portanto, se comprometeu a medir e reduzir o metano, mas só pode fazer isso se entender suas emissões. Cabe ao governo alemão implementar um plano robusto para medir e reduzir rapidamente suas emissões de metano de mina de carvão. Ao fazer isso, a Alemanha tem a oportunidade de definir um ambicioso padrão da indústria de melhor prática na UE e globalmente. Minas

Ember recommends urgent changes that Germany should make to quickly get a grip on their methane emissions from surface mines, highlighting best practice measurement, and a pathway for how to avoid and mitigate future emissions.

Best practice measurement for surface mines

Medição de práticas recomendadas para minas de superfície combina várias tecnologias para gerar um modelo de entrada múltipla. A abordagem deve levar em consideração a variabilidade do metano, fatores espaciais e climáticos e mudanças na permeabilidade da costura de carvão, bem como os principais eventos de poluição. Para operações de superfície, que são verificadas por um corpo independente; lagos.  

In brief, Ember suggests the following should be considered:

• Measurements of geotechnical cores to establish the methane content across all the gas bearing strata, combined with field coal gas models, to derive a site-specific emission factor for surface operations, which are verified by an independent body;
• Complementary total site-level measurements should be conducted to ensure site-level reconciliation with source-specific measurements.

Decommissioned surface mines

Surface mines should be required to undertake direct measurements and model their emissions after closure, including reliable gas measurements from waters of pit lakes.   Um estudo de 2017 no pit lake Vollert, na Alemanha, também encontrou concentrações elevadas de metano na água. Isso é particularmente importante, pois os lagos de poço podem ser mais suscetível a erupções limnicas, representando um risco de segurança grave. Os drones são uma abordagem emergente para a verificação de inventários nacionais, e os reguladores devem considerar a calibração de observações de satélite com dados de sistemas de monitoramento terrestre. Ao eliminar a mineração de carvão nas minas de carvão mais gastas. Evitar emissões dessas fontes pode ser feito utilizando métodos alternativos de reabilitação. Universidade de Queensland

Verification

Reporting entities should have a formal quality assurance program, including independent review of emission reports prior to submission, as stated in the upcoming EU Methane Regulation.

Satellites and drones are an emerging approach for the verification of national inventories, and regulators should consider the calibration of satellite observations with data from land-based monitoring systems.

Reducing Methane Emissions

Avoid

A clear pathway to avoiding methane emissions is for Germany to cease approving coal expansion projects, and focus on phasing out coal mining at the gassiest coal mines first.

For closed mines, Germany must reassess its legislation on the rehabilitation of surface coal mines via the creation of pit-lakes. Avoiding emissions from these sources can be done by utilising alternative rehabilitation methods.

Mitigate

Whilst existing mines continue to operate, there are methods available to mitigate methane emissions.

Best practice methane mitigation in surface coal mines is pre-mine drainage, as indicated in a recent study from the University of Queensland. O método é amplamente utilizado em toda a indústria de mineração e envolve projetar e implementar uma série de poços planejados para explorar ou utilizar o metano drenado antes da mineração. Para os melhores resultados possíveis de mitigação, esse processo começa meses à frente da mineração em um domínio de mineração específico e continua ao longo da vida da mina. Pit-Lakes,

This practice has a twenty year history in the mining industry, especially in the USA, where surface mines are often found to have relatively lower gas content to those of underground mines.

At pit-lakes,  Extração e utilização de metano pode ser considerado uma opção de mitigação. Isso significa que eles devem usar o fator de emissões com base no depósito de carvão e, especificamente, os regulamentos afirmam; Stratos ao redor. Como o maior mineiro de carvão superficial da UE, é a responsabilidade da Alemanha liderar o esforço de determinar e implementar MRV preciso em minas de superfície. Melhorar os padrões de MRV nas minas de superfície na UE pode ter um impacto positivo substancial globalmente, uma vez que o carvão importado deve estar em conformidade com os requisitos de equivalência de MRV da UE. Rastreador de minas para estimar as emissões de metano em minas individuais em todo o mundo, agregando os dados sobre escalas nacionais e globais. Eles fornecem estimativas de linha de linha para as emissões de metano da mina de carvão, que utilizam dados de atividade no nível da mina, como produção, profundidade de operação, teor de metano em profundidade e um fator de emissão para contabilizar o metano de excesso e sob o ônus, seguindo a metodologia | Estima que as emissões das minas de superfície da Alemanha possam chegar a 307.000 toneladas por ano. O teor de gás aplicado GEM para brasas “marrons” em seus cálculos após A

EU Methane Regulation Opportunity

As highlighted previously, in line with the upcoming EU Methane Regulation, Germany is required to update the current MRV methodology for surface mines. This means they must use the emissions factor based on coal deposit and specifically, the regulations state;

“As regards surface coal mines, mine operators shall use deposit-specific coal mine methane emission factors to quantify emissions resulting from mining operations. Mine operators shall establish those emission factors on a quarterly basis, in accordance with appropriate scientific standards and take into account methane emissions from surrounding strata. “

European standardisation organisations will be requested to draft harmonised standards for measurement and quantification of methane emissions from coal mines. As the largest surface coal miner in the EU, it is Germany’s responsibility to lead the effort to determine, and implement accurate MRV at surface mines.

Although surface mines in Europe are exclusively for lignite coal, globally surface mining is commonly employed for methane-intensive hard coal, including coking coal. Improving MRV standards at surface mines in the EU can have a substantial positive impact globally, since imported coal must comply with the EU’s MRV equivalence requirements.

Downloads

Methodology

Supporting Materials

Independent estimate by Global Energy Monitor

Global Energy Monitor employs its Global Coal Mine Tracker to estimate methane emissions at individual mines worldwide, aggregating the data on national and global scales. They provide baseline estimates for coal mine methane emissions, which utilise mine-level activity data, such as production, operating depth, methane content at depth, and an emission factor to account for methane from over and under burden, following the peer-reviewed Model for Calculating Coal Mine Methane (MC2M) methodology.

Using the MC2M methodology, GEM estimates that the emissions from Germany surface mines could be up to 307,000 tonnes per year. GEM applied gas content for “brown” coals in their calculations after a  Estudo polonês mostrado Emissões de 2,5 dcm3/kg a uma pressão de 10 bar para linhita. Essa estimativa pode, portanto, superestimar as emissões CMM da Alemanha.

Estimativa independente de Shen et al. 

O estudo de Shen et al. As emissões nacionais e globais estimadas de CMM usando a metodologia de cima para baixo. O estudo utilizou 22 meses (maio de 2018 a 2020) de observações de satélite do instrumento Tropomi para quantificar melhor as emissões nacionais de combustíveis fósseis em todo o mundo. A faixa do percentil 95 é notavelmente ampla, variando de 6.000 a 280.000 toneladas, indicando uma incerteza significativa de -95% a +155%. Esse alcance considerável ressalta a incerteza ligada às emissões de metano do setor de carvão na Alemanha. Em comparação, as emissões de metano da indústria de petróleo e gás foram estimadas em 200.000 toneladas anualmente, com uma faixa de percentil 95 mais restrita de 160.000- 240.000 toneladas, mostrando uma margem muito menor de +/- 20%. Fator

The study estimated annual coal methane emissions from Germany to be 110,000 tonnes. The 95th percentile range is notably wide, ranging from 6,000  to 280,000 tonnes indicating a significant uncertainty of -95% to +155%. This considerable range underscores the uncertainty linked to methane emissions from the coal sector in Germany. In comparison, methane emissions from the oil and gas industry was estimated at 200,000 tonnes annually, with a more constrained 95th percentile range of 160,000 – 240,000 tonnes, showing a much smaller margin of +/- 20%.

Emission factor lacks verification

Not all studies referenced in Germany’s NIR substantiate the CMM emission factor

Texto: “Este fator de emissão é baseado em um estudo de 1989 do RWE Rheinbraun AG (DeBriv, 2004)”

DeBriv. (2004, 15. Setembro de 2004) Mitteilung vom Deutscher Braunkohlen-Industrie-Verein E.V. Um Das Ikp Stuttgart/Entrevistador: I. Stuttgart. DeBriv.

Fonte Substitui o fator de emissão? O teor médio de metano foi de 0,015 m3/t. Menciona o instituto de Öko mediu um teor de metano de 0,02 m3/t.Source não inclui outras medições, dados ou evidências para apoiar a EF. (1992). Ansatzpunkte und potentiale Zur Minderung des Treibhauseffektes aus sicht der Fossilen Energieträger PARTLY

Source says: In 1989 Rheinbraun AG measured methane content from boreholes ranging from0 to 0.05 m3/t. The average methane content was 0.015 m3/t. Mentions the Öko-Institute Measured a methane content of 0.02 m3/t.Source does not include any further measurements, data or evidence to support EF.

Text: “..and has been substantiated by publications of the German Society for Petroleum and Coal Science and Technology (DGMK) (DGMK, 1992)”

DGMK. (1992). Ansatzpunkte und Potentiale zur Minderung des Treibhauseffektes aus Sicht der fossilen Energieträger

Fonte substancia o fator de emissão?  NO

Fonte diz: declara que o fator de emissão é de 0,015 m3/t, mas não comprova o fator de emissão com outros estudos ou informações. 2016b). ”

Text: “This conclusion was also reached by a report prepared by VERICÖ (Betzenbichler et al., 2016b).”

Betzenbichler, W., Kolmetz, S., & Randall, S. (2016b). ERARBEITUNG WISSCHAFTLICH-METHODISCHER GRUNCLAGEN ZUR Umsetzung der Empfehlungen aus den Internationalen Inventarüberprprüfungen-verbesserung des qualitätsmanages e derivikation der deutschen emissionsinventare. Freising, Dessau-Roßlau: Verico.

Fonte substancia o fator de emissão?  NO

Fonte diz: confirma que a Alemanha é semelhante à Poland com respeito ao tipo e metaneemissões de carvão. Perguntas, apresentação do uso do estudo “antigo” de 1989, com sede no Vale do Reno para a Alemanha. Afirme que, depois de perguntar a desbriv para obter mais informações, eles nunca mais atualizam sobre EF. revisou e aprimorou o relatório. Agradecemos também a Julian Schwarzkopff (Deutsche Umwelthilfe) por revisar o relatório e fornecer seus comentários e sugestões.

Acknowledgements

Contributors

Sarah Shannon who analysed the satellite data, Reynaldo Dizon for all the data visualisation, Christiane Yemen who checked data and aided translations, and Eva Mbengue and Eleanor Whittle who reviewed and improved the report.

Our appreciation also goes to the Global Energy Monitor (GEM) for valuable inputs during the writing of this report. We also thank Julian Schwarzkopff (Deutsche Umwelthilfe) for reviewing the report, and providing their comments and suggestions.

Image credit

Wojciech Stróżyk / Alamy Stock Photo