Article 21 of the EU ETS Directive requires all EU ETS implementing countries to submit an annual report on the application of the Directive in their country ("the Article 21 reports" or "country reports" hereinafter). The main focus of these reports is the implementation of the requirements on Monitoring, Reporting, Verification and Accreditation (MRVA), permitting and inspection and enforcement. Based on these country reports the Commission publishes a technical report on the application of the EU ETS Directive. The Article 21 reports are provided on the basis of a questionnaire adopted by the European Commission - the Article 21 questionnaire. Lessons learned from analysing the country reports have been taken forward in the update of the questionnaire that was made in parallel to writing this technical report. This present technical report takes into account the reports for the reporting year 2020, which were submitted in the year 2021. As 1 January 2021 marked the end of phase 3 of the EU ETS, the report also shows, where relevant, trends over the entire phase 3 period, drawing lessons learned on the quality of reporting and potential improvements for phase 4 of the EU ETS. Information provided for 2013-2019 addresses all countries that implemented EU ETS in that period, being the EU-27, the UK, Norway, Iceland, and Liechtenstein. The UK was still part of the EU ETS in the year 2020 but was, because of UK's withdrawal from the EU as from 1 January 2021, not required to provide its 2020 Article 21 report in June 2021. However, as the EU ETS continues to apply to electricity generation located in Northern Ireland according to the Protocol of Ireland, the technical report analysing the 2020 country reports includes the data for Northern Ireland. For practical reasons, this report uses the term EU ETS countries or just countries to refer to the countries that operated the EU ETS in the years reported on. According to the EUTL and including the UK in 2020, 10,412 installations were covered by the EU ETS, with total emissions of 1,355 Mt CO2eq. This is 11.4% lower compared to 2019 and almost 29% lower than in 2013. The number of aircraft operators (AOs) was 311, with total emissions of 25.1 Mt CO2. Both the number of AOs and their total emissions are considerably lower compared to 2019, 38% and nearly 64% compared to 2013. The strong reductions in the aviation sector are caused by the COVID-19 pandemic.
