Gas and nuclear in the EU taxonomy: rules and claim risk
In 2022 the European Commission brought certain natural gas and nuclear energy activities within the EU taxonomy, subject to conditions. It did so not by amending the Taxonomy Regulation itself but through a complementary delegated act. That choice shaped both the substance and the proceedings that followed. On 10 September 2025 the General Court of the European Union upheld the act. This article deals with the instrument: what it is, which conditions apply and what legal route was taken.
The short answer
- The complementary act is Delegated Regulation (EU) 2022/1214 of 9 March 2022. It was published on 15 July 2022 and has applied since 1 January 2023.
- It amends two existing delegated regulations: the one containing the climate criteria and the one containing the disclosure rules.
- Gas and nuclear energy count only under strict conditions that are limited in time.
- Companies and financial parties must make these activities separately visible in their reporting.
- Austria challenged the act before the General Court. That action was dismissed on 10 September 2025.
What a delegated act is
The Taxonomy Regulation contains the system, not the technical detail. It names six environmental objectives and, in Article 3, sets four requirements for an environmentally sustainable activity. The activity must contribute substantially to at least one objective and do no significant harm to the others. Minimum social safeguards and technical screening criteria apply in addition.
The Commission adopts those technical screening criteria in delegated acts. That is a form of delegated legislation. Parliament and Council have no right of amendment, but they do have a right of objection within a set period. If they do not use it, the act enters into force.
It is precisely that mechanism which explains the political tension. A contested choice was routed past the ordinary legislative procedure. More on the system itself can be found under the taxonomy regulation.
What the act provides
Delegated Regulation (EU) 2022/1214 adds six activities to the climate criteria. Three concern nuclear energy and three concern fossil gas.
For nuclear energy these are research into and development of advanced technology, the construction of new installations, and life extension of existing installations. For gas they are electricity generation, high-efficiency combined heat and power, and heat generation in district heating.
These activities are included as transitional activities. That is a separate category in the Taxonomy Regulation for activities for which no low-carbon alternative is yet available. Transitional activities are by definition temporary and subject to stricter conditions.
The conditions
The act contains no general approval. It contains a set of cumulative requirements.
| Subject | Condition |
| Gas emissions | Direct greenhouse gas emissions below 270 grams of CO2 equivalent per kilowatt hour, or an alternative limit expressed in kilograms per kilowatt over twenty years |
| Replacement | The installation replaces an existing installation running on solid or liquid fossil fuel |
| Alternative | It must be shown that renewable capacity is not available in sufficient measure |
| Switching | A commitment to switch to renewable or low-carbon gases |
| Nuclear waste | An operational final disposal facility for low and intermediate level waste, and a plan for high level waste |
| Funding | Separate funds for waste management and decommissioning |
| Fuel | Use of accident tolerant fuel |
| Deadlines | Construction permit for new nuclear plants by 2045 at the latest; permit for life extension by 2040 at the latest |
Each condition must be demonstrated separately, with verification by an independent third party. In practice that is a heavy burden of proof. Inclusion in the taxonomy also says nothing about whether a project can be permitted. National environment and planning law applies undiminished for that. See environment and planning law.
Separate disclosure
The act also amends the disclosures regulation. Companies and financial market participants must state the extent to which their activities or products relate to gas and nuclear energy.
Specific templates apply for this. The thinking behind it is transparency: anyone presenting taxonomy figures must make visible what share of them comes from these two sources. The reader can then judge for themselves what the figures are worth.
Since the Omnibus I package entered into force in March 2026, the reporting obligation has fallen away or become voluntary for part of the corporate population. The specific disclosure on gas and nuclear energy continues to apply to those who do report.
Why the route was contested
The legal criticism was not directed at the desirability of gas or nuclear energy but at the construction chosen. Three objections recurred.
The first concerned the scope of the delegation. Critics argued that a choice of this political weight belongs in the regulation itself, not in a technical elaboration.
The second concerned the do no significant harm principle. For nuclear energy that turns mainly on long-term storage of radioactive waste. For gas it turns on continued emissions over the lifetime of the installation.
The third concerned the coherence of the system. A taxonomy derives its value from strict delineation. Every exception reduces the instrument’s power to distinguish.
The General Court considered these objections and rejected them. The dispute is therefore settled in law, not in substance.
The legal proceedings
Action was taken against the act along two lines.
The first line was political. In July 2022 the European Parliament voted on an objection to the delegated act. Rejection required a majority of its members. That majority was not reached, and the act entered into force.
The second line was judicial. Austria brought an action for annulment before the General Court of the European Union. That case is known as Case T-625/22.
On 10 September 2025 the General Court, sitting as a Grand Chamber, dismissed the action. It held that the Commission had remained within the limits of its delegated power. According to the Court, certain activities in the nuclear and gas sectors can, under specific conditions, contribute substantially to climate change mitigation and adaptation. A number of Austria’s objections, including those on accident risks, were considered too speculative.
A judgment of the General Court may be appealed to the Court of Justice, on points of law only. The period for doing so is two months and ten days.
What this means
Three conclusions matter in practice.
- The act is valid and applies. Anyone reporting applies the criteria and the separate disclosure.
- The conditions are strict and time-limited. Inclusion in the taxonomy is not a permanent qualification.
- The dispute about the instrument has been settled in law, but the debate about the investment side has not. We deal with that separately.
Frequently asked questions
Have gas and nuclear energy now been declared green?
No. They have been included as a transitional activity under strict conditions. That is a temporary category, not a general qualification.
Can the act still fall away?
The General Court dismissed the action. Beyond that, change is possible only through a new delegated act or through amendment of the regulation.
Does the taxonomy apply to unlisted companies as well?
Only if they fall within the reporting obligations. After Omnibus I that group has become considerably smaller.
Do you have questions about taxonomy criteria, disclosure or the consequences of Omnibus I? Contact Law & More. We assess your obligations and the substantiation behind your figures. Our offices in Eindhoven and Amsterdam work in Dutch and English.
