On 15 October 2026, a study commissioned by Environmental Defense Fund Europe put a price on the fight over the EU's hydrogen rules. Relaxing additionality and hourly matching together would cut the levelised cost of hydrogen by only €0.10 to €0.25 per kilogram in the short term, while adding more than 15 Mt of EU greenhouse gas emissions in 2035 (EDF Europe) [2].
Meanwhile, the Commission's targeted review, announced in April for the second quarter of 2026, had still not been published as this article went live (Stibbe) [3]. We covered the review itself in The RFNBO Rules Are Being Rewritten.
This article covers the rule in force today. Delegated Regulation (EU) 2023/1184 sets the RFNBO additionality rules, and they decide which wind and solar farms a grid-connected electrolyzer can contract, when, and on what terms. Here is what the text says, which dates drive commissioning schedules, and what to design for while Brussels deliberates.
What RFNBO additionality actually requires
Additionality is one of three tests for grid-connected electrolyzers, alongside temporal correlation and geographic correlation. Under Article 4(4), all three apply together only when none of the simpler pathways described below is available (Delegated Regulation 2023/1184) [1].
Article 5 breaks additionality into three conditions [1]:
- Volume. You produce at least as much renewable electricity in your own installations as you claim, or you hold direct or intermediated renewables power purchase agreements (PPAs) for at least that amount. The contracted plants must actually produce it.
- Age. Each renewable plant came into operation no earlier than 36 months before your electrolyzer.
- No support. The renewable plant has received no operating aid or investment aid. Four exclusions apply: support received before repowering, financial support for land or grid connections, support that is not net support (such as aid fully repaid), and support for plants supplying research, testing and demonstration installations.
The rules are not limited to European plants. Article 1 applies them regardless of whether the fuel is produced inside or outside the Union, and bidding zones are read as "an equivalent concept for third countries" [1]. A project in Chile, Oman, Australia or Morocco selling RFNBO hydrogen or ammonia into the EU faces the same test. Our export corridor analysis covers the logistics side.
Four routes where additionality does not apply
Before you plan around Article 5, check whether your site qualifies for a simpler route [1]:
| Route | What you must show | Additionality test? |
|---|---|---|
| Direct connection (Art. 3) | A direct line, or generation and electrolysis in the same installation; smart metering proving no grid electricity was used | No Article 5 test, but the renewable plant must still be no more than 36 months older than the electrolyzer |
| High-renewables zone (Art. 4(1)) | Bidding zone renewable share above 90% in the previous calendar year; production hours capped at that share | No |
| Low-carbon grid (Art. 4(2)) | Bidding zone emission intensity below 18 gCO2eq/MJ, plus renewable PPAs, plus temporal and geographic correlation | No |
| Redispatch (Art. 4(3)) | Consumption in a settlement period when the grid operator redispatched renewable generators downwards, reducing redispatch by the same amount | No |
Two details matter for engineers. First, the direct-connection route carries its own 36-month age rule, so it does not let you pair a new electrolyzer with an old wind farm. Second, the 90% route is narrow: as of 2023, only Sweden's bidding zones qualified [3]. Once a zone passes either the 90% or the 18 gCO2eq/MJ threshold, it keeps that status for the following five calendar years [1]. For reference, 18 gCO2eq/MJ equals 64.8 gCO2eq/kWh.
The 36-month rule in practice
The age test runs backwards from your electrolyzer's commissioning date. A wind farm that came into operation on 1 March 2025 can supply an electrolyzer that comes into operation up to 1 March 2028. A renewable plant built after the electrolyzer passes automatically.
The text adds three clarifications that shape real contracts [1]:
- Added capacity. Capacity added at the same site within 36 months of the original plant's start date counts as part of that plant.
- Replaced PPAs. If a compliant PPA with a fuel producer ends, the renewable plant is treated as coming into operation at the same time as the electrolyzer under the new agreement. A good contract can be re-signed without losing eligibility.
- Repowering. "Come into operation" includes restarting after a repowering that required investment exceeding 30% of the cost of a similar new installation.
The practical risk is schedule slip. If your PPA counterparty's solar farm is already running, every month your electrolyzer is late eats into the 36-month window. Check the commissioning date and support history of every plant in your PPA portfolio before signing, not after. A plant with a feed-in tariff or an operating-aid contract for difference fails the no-support condition outright.
The 2028 cliff and the 2038 grandfather clause
Article 11 is the most important date in the regulation for anyone building now. The age and no-support conditions do not apply until 1 January 2038 to electrolyzers that come into operation before 1 January 2028. The exemption does not cover capacity added after 1 January 2028 [1].
The consequence is binary. An electrolyzer commissioned in December 2027 can contract existing, even subsidised, renewable plants for ten years. One commissioned in January 2028 needs new, unsubsidised capacity from day one. The volume condition still applies to both, and so do temporal and geographic correlation.
Additionality does not move alone. Temporal correlation tightens on its own timeline [1]:
| Date | What changes |
|---|---|
| 1 July 2027 | Earliest date a member state may impose hourly matching on its territory, after notifying the Commission |
| 1 January 2028 | Age and no-support conditions apply to newly commissioned electrolyzers; capacity added after this date is not grandfathered |
| 1 July 2028 | Commission report due on the impact of the requirements (Art. 10) |
| 1 January 2030 | Monthly matching ends; production must match renewable generation within the same hour |
| 1 January 2038 | Grandfathering of pre-2028 electrolyzers ends |
One relief valve applies throughout. Any hour when the day-ahead price in the bidding zone is at or below €20/MWh, or below 0.36 times the EU carbon allowance price, counts as compliant with temporal correlation [1]. For hourly matching, this is where a battery and a well-shaped hybrid profile earn their keep. See our posts on battery storage for green hydrogen and hybrid solar-wind capacity factor.
What could change in the review
The pressure to move these dates is real. In late March 2026, energy officials from Germany, Spain, the Netherlands, Austria and Poland proposed moving the additionality cutoff to 1 January 2035, grandfathering for up to ten years beyond that (until 2040), and monthly matching until 2035 [3]. On 22 April 2026, the Commission said it would propose a targeted review in the second quarter of 2026, ahead of the 2028 review [3].
Industry followed. A joint letter to DG ENER dated 8 July 2026 asked to "extend the transition phase for the additionality requirements from 2028 to at least 2035", to protect first movers "for the lifetime of a project", and to complete the amendment by the end of 2026 (joint industry letter) [4].
The other side has numbers too. The EDF Europe study estimates that relaxing additionality and temporal correlation together could raise EU average marginal power prices by up to 2% in the short term, and by more than 4% in France, Poland and Belgium in some 2035 scenarios, without speeding up renewable hydrogen output [2].
How to design a project around the rules today
Until a revised act is published in the Official Journal, the text above is the law. Five practical steps follow:
- Treat 1 January 2028 as fixed. If your commercial operation date sits within 12 months of the cliff, add schedule float, and quantify what slipping past it would cost you in PPA terms.
- Audit every PPA counterparty. Record commissioning date, repowering history and any operating or investment aid. Keep the evidence: Article 8 requires producers to provide reliable information showing every requirement is met [1].
- Price the post-2028 case. If you miss the cliff, you need new, unsubsidised capacity with hourly matching from 2030. Run that as your base case and treat relaxation as upside. The EDF estimate of a €0.10 to €0.25/kg cost difference suggests no project should depend on it [2].
- Check the simpler routes first. A direct connection, a low-carbon grid or a high-renewables zone may remove the additionality test altogether.
- Write regulatory change into contracts. Change-in-law clauses in offtake and PPA contracts protect both sides whichever way the review goes. Our guide to hydrogen offtake agreement structure covers the clauses.
The cost side of these choices runs through capacity factor. If tighter sourcing cuts your full-load hours, our analysis of electrolyzer capacity factor and LCOH shows how fast unit cost rises.
Conclusion
RFNBO additionality comes down to three questions: is the renewable plant new enough, unsubsidised, and producing at least what you claim? The answers depend on one date. Commission before 1 January 2028 and you get a decade of flexibility; commission after it and you need new, unsubsidised capacity from the start.
The review may move those dates, but nobody can bank on it yet. Design for the rules as written, and model the relaxed case as upside.
Hyzen's platform runs RFNBO compliance checks alongside renewable input modelling and electrolyzer sizing, so you can see early whether a site and sourcing plan pass. Start with the free Site Screener.
References
[1] European Commission. Commission Delegated Regulation (EU) 2023/1184 of 10 February 2023, consolidated text. Official version on EUR-Lex (2023).
[2] EDF Europe. New study finds relaxing EU renewable hydrogen rules could raise electricity prices and emissions without delivering significant production boost. Environmental Defense Fund Europe (2026).
[3] Stibbe. Renewable hydrogen in the EU: a framework under pressure. Stibbe (2026).
[4] Joint industry signatories. Joint letter to DG ENER calling for a speedy targeted amendment of Delegated Act (EU) 2023/1184. Hydrogen Europe (2026).