The EU launched the European Green Deal in line with the Paris Agreement goals, setting out the objectives to achieve a carbon neutral economy by 2050.

[10] As of now, the EU taxonomy is considered one of the main pace setters which aids the financial system redirect capital towards a low carbon economy conforming to the Paris Agreement.

[11] Upon findings by the Technical Expert Group (TEG), the EU taxonomy has undergone various testing in both private and public sectors which includes the European Investment Bank and BNP Paribas asset management.

[12] The preparatory work started in 2018, when the Commission set up a Technical Expert Group on Sustainable Finance, to assist in developing the EU Taxonomy, with the OECD as an observer.

[13] In the case of Taxonomy, the main task of the TEG was to develop technical screening criteria that would be used to determine whether an activity is environmentally sustainable.

[16] The TEG mandate, which was originally supposed to end in June 2019, was extended until September 2020, due to the high volume of feedbacks received after the publication of the first report.

[21] It played the main role at the preparatory stage, when was tasked with developing recommendations to the Commission regarding both the overall structure of the Taxonomy and the technical screening criteria.

Therefore, both institutions are only involved at a later stage with no powers in shaping the content of the DAs, which is largely determined by the Commission and the expert groups.

In addition to the concerns raised on the democratic legitimacy of the delegated acts in general,[26] also with specific regard to the taxonomy this mechanism and the lawmaking process have been subject to criticism by some.

In its preamble is stated that for nuclear energy the assessment is still ongoing, and natural gas will be included in a future delegated act if it fulfilled the requirements to be considered a transitional activity.

The inclusion of such activities follows the publication of two reports, one from the TEG in 2019 and the second from the Joint Research Committee (JRC), in 2021, as well as consultations with the PSF and the Member States Expert Group, that led to different conclusions.

[39] The debate about the inclusion of certain nuclear and gas activities in the green taxonomy was complemented by two reports that preceded the Complementary Climate Delegated Act: one from the Technical Expert Group (TEG), mostly including institutions from the finance sector,[40] and one from the Joint Research Centre, whose role is to provide independent scientific advice to EU policy and which conducts research on nuclear safety and security for Euratom.

Also, the PSF noted, the technical screening criteria applied to new nuclear power plants would cover installations receiving the construction permit by 2045.

Austria and Luxembourg have even threatened to sue the Commission in the Court of Justice if it included the two power sources into the taxonomy, on the ground that it would weaken its credibility.

[53] On the other hand, France is promoting the inclusion of nuclear power into the taxonomy, supported by Bulgaria, Croatia, Czechia, Finland, Hungary, Poland, Romania, Slovakia and Slovenia.

[54] The economy and energy minister of these countries published a joint opinion article on 11 October 2021 to defend the role of nuclear power in the fight against climate change.

[55] Furthermore, a joint letter to the Commission from Finland and Sweden asked to remove the deadline for investment in nuclear energy and criticized the stringent criteria for waste disposal, which in their view fail to account the advances achieved in the two countries.

[57] The compromise between gas and nuclear has been eased by the fact that the Commission opted for the inclusion of the two controversial energy sources in the taxonomy in one single delegated act, implying that Member States and European Parliament can either refuse the whole proposition or adopt it.

[53] On 6 July 2022 the European Parliament voted against a resolution to reject the Third Delegated Act regarding the inclusion of nuclear power and natural gas in the taxonomy.