The importance of national legal metrological control in EU emissions trading

Introduction

The EU Emissions Trading System (EU ETS), launched in 2005, remains a central pillar of EU climate policy. Over the past two decades it has required major emitters in energy and industry to report and pay for their greenhouse gas (GHG) emissions, delivering a 51% reduction across covered sectors since 2005 [1] The system has expanded to include aviation and maritime transport and now operates across all EU Member States plus Iceland, Liechtenstein, and Norway. 

A major reform in 2023 introduced a parallel system, commonly called ETS2, which extends emissions trading to CO₂ emissions from fuels used in buildings, road transport and small industries not covered by ETS1. Unlike ETS1, which focuses on emissions measured at the point of combustion or production, ETS2 regulates fuels as they are placed on the market. This design aligns the system with existing fuel‑measurement infrastructure and greatly widens the number and type of measurement points involved in monitoring, reporting and verification (MRV). Currently ETS2 is focussed on monitoring, reporting and verification with financial obligations to commence in 2029 for 2028 emissions. 

Robust measurement data – an essential requirement

The EU ETS – both ETS1 and ETS2 – depends on robust data. The Monitoring and Reporting Regulation (EU) 2018/2066 requires entities to ensure the accuracy of emissions reporting, minimise potential inaccuracies and apply the highest achievable measurement quality. While some installations use continuous emissions monitoring, most rely on calculation methods using data from fuel and material measurements and applying approved emission factors. Because of this, measurement quality directly underpins the credibility of the entire system.

This is where National Legal Metrological Control (NLMC) becomes essential. Under ETS1, measurement instruments may be located where fuels or raw materials actually enter combustion or industrial processes – for example, flow meters on fuel lines, weighbridges at industrial sites or building management system meters used to track stored fuel and these are used in conjunction with fuel/materials invoices. In ETS2, measurement shifts upstream to instruments used when fuels are released for consumption – such as road loading gantry meters for liquid fuels, domestic gas meters for natural gas supplied to households, or bagging scales used for packaged solid fuels in the residential heating market.

NLMC reduces the administrative burden

Because ETS2 applies to such a diverse range of fuels, suppliers and measurement environments, the number of instruments involved in MRV increases substantially through the introduction of ETS2. The system sets tighter uncertainty thresholds for operators and entities with larger emissions or more significant fuel streams. NLMC provides a structured basis for meeting these uncertainty requirements. When an instrument is subject to NLMC, the entity may use the maximum permissible error in service defined under metrological legislation as the uncertainty value without needing to provide further justification. This avoids duplicated assessments, reduces the administrative workload, and ensures consistent measurement quality across a highly varied system. 

In Ireland, the Environmental Protection Agency has been designated the Competent Authority for both ETS1 and ETS2 implementation. Effective engagement with national standards bodies responsible for metrology is therefore essential to ensure the system operates as intended and that regulated entities have confidence in the measurement infrastructure they rely on. 

Conclusion

Accurate MRV is the foundation of trust in the ETS: a tonne reported must equate to a tonne emitted. Since its inception, the EU ETS has generated over €250 billion in auction revenues, €39 billion in 2024 alone, with all revenues legally required to support climate action and energy transition measures [2]. With ETS2 and maritime transport now included, carbon pricing mechanisms extend to 75% of the EU’s greenhouse gas emissions, making the role of reliable measurement and NLMC more important than ever. 

References

[1] European Environment Agency “Greenhouse gas emissions under the EU Emissions Trading System” published 06 Nov 2025, Available at https://www.eea.europa.eu/en/analysis/indicators/greenhouse-gas-emissions-under-the

[2] European Environment Agency “Climate Action Progress Report 2025” published 06 Nov 2025, Available at https://climate.ec.europa.eu/eu-action/climate-strategies-targets/progress-climate-action/eu-climate-action-progress-report-2025_en