AquaVentus Förderverein e.V. represents member companies along the entire offshore hydrogen value chain with the aim of developing offshore wind energy and offshore electrolysis as complementary building blocks of an integrated North Sea strategy, and took part in the Hydrogen Market Survey 2026 with a cut-off date of 13 March 2026.
This statement addresses guiding questions 3, 4, 7 and 11 of the accompanying document of August 2026. AquaVentus comments separately in the same proceedings on the corresponding passage in the draft Electricity Scenario Framework (chapter 3.4, p. 61).
The key points:
– The statement that offshore electrolysers are “only relevant for the Gas and Hydrogen Grid Development Plan, as they do not require a grid connection” (p. 95) does not apply to SEN-1. The draft itself contradicts it in footnote 1 on the same page, and its legal basis ceased to exist with the cabinet decision on the WindSeeG amendment of 2 September 2026.
– For the offshore volumes of the joint electrolyser list – around 30 percent of reported capacity according to table 39 (p. 60) – the annual values, maturity level and landing point published for all other project categories are missing.
– The SEN-X entry is the only expansion stage in the entire list that is not marked for the joint scenario despite the project status “design planning”. The only decisive factor for this is the legal basis – and it was created with the cabinet decision of 2 September 2026. The marking must be reassessed before approval and set to “yes”.
– In the draft, the design of AquaDuctus at 20 GWh/h (p. 69) rests equally on two strands: hydrogen volumes from the German North Sea and international volumes via the cross-border point. Both lines of justification should remain side by side – and precisely for that reason, the domestic strand must not be treated elsewhere as irrelevant for modelling.
1. Correction required: offshore electrolysis needs a grid connection (on question 7)
Passage concerned
Chapter 3.3.2.2 “Plausibility check of the electrolyser list”, p. 95:
“Offshore electrolysis is handled as in the Gas and Hydrogen Grid Development Plan 2025: these projects are part of the electrolyser list and are marked as ‘offshore electrolysis’, as they are only relevant for the Gas and Hydrogen Grid Development Plan, since they do not require a grid connection.”
Facts
This does not apply to the SEN-1 project named in the same paragraph. Its connection concept is hybrid: the hydrogen is transported via the AquaDuctus pipeline, and the electrical connection runs via the electrical infrastructure of the neighbouring converter platform of the offshore grid connection system NOR-10-1. The only correct point is that no dedicated offshore grid connection system is provided for SEN-1 in the site development plan – an efficiency feature of the concept, not a renunciation of the grid connection. The project is structured in four tranches of 250 MW each of PEM electrolysis; tranche 1 targets commissioning in 2033.
The draft contradicts itself here – and the legal premise has ceased to exist
Footnote 1 to the same paragraph expects the 2026 WindSeeG amendment to provide an improved legal basis for integrated offshore electricity and hydrogen production, “in particular for combined connection concepts of subsea cable and hydrogen pipeline”, and considers this relevant “above all for far-offshore sites in zones 4 and 5”. Combined connection concepts of subsea cable and hydrogen pipeline are the opposite of “do not require a grid connection”.
This expectation has since been met. The draft amendment to the WindSeeG adopted by the Federal Cabinet on 2 September 2026 replaces, in section 3 no. 9, the words “which are in each case not connected to the grid” with “in particular electrolysers”; in section 4(3) sentence 1 the same restriction is deleted. The explanatory memorandum makes clear that this enables “both feeding into the electricity grid and using electricity from the onshore grid”, and names the other energy generation areas – “currently exclusively SEN-1” – as the place for industrial testing. The deletion of section 5(2a) sentence 2 will in future allow the site development plan to designate routes for cables that carry energy from other energy generation areas into the grid – according to the explanatory memorandum “against the background of the [...] fundamental decision to open the other energy generation areas to grid connection”.
The draft reflects the status of June 2026; approval takes place after the consultation has closed. The legal situation at the time of approval should therefore be decisive. Anticipating future law is in any case common practice in these proceedings: on p. 77 the Electricity Scenario Framework expressly anticipates the crediting of capacity from neighbouring EEZs, which is not yet in force – on the basis of a ministerial draft. Here there is a cabinet decision.
Effect
The marking has effects beyond the Gas and Hydrogen Grid Development Plan: the Electricity Scenario Framework adopts it and concludes that the project is “not relevant for power system modelling” (p. 61). Two points are directly affected for hydrogen modelling:
– Operating behaviour: a grid-connected PEM plant can also produce when wind output is low if electricity prices are low. Its injection profile into the hydrogen network therefore differs markedly from that of a pure island solution.
– Load cases (question 4): the draft justifies the requirement that entry capacities must cover exit capacities partly with the case “in which electrolysers do not produce hydrogen due to low generation of electricity from renewable sources” (p. 111). This does not apply in the same way to a grid-connected offshore electrolyser. The load cases should therefore distinguish between island concepts and grid-connected hybrid concepts.
Proposed wording (replacing the sentence concerned on p. 95)
“Offshore electrolysis is handled as in the Gas and Hydrogen Grid Development Plan 2025: these projects are part of the electrolyser list and are marked as ‘offshore electrolysis’. The reported connection concepts are differentiated: plants without a grid connection are relevant exclusively for the Gas and Hydrogen Grid Development Plan; plants with a grid connection – for example via the electrical infrastructure of a neighbouring offshore grid connection system – are additionally relevant for power system modelling and are included there as a load at the associated grid connection point. For the offshore project AquaVentus SEN-1, an electrical connection via the offshore grid connection system NOR-10-1 has been reported.”
2. The offshore volumes lack the data published for all other categories (on questions 3 and 7)
The draft shows the reported electrolysis capacity by federal state and states: “Around 40 % of the capacity is accounted for by these three federal states in total. A further 30 % of the capacity is located offshore.” The “Offshore” row shows 16 GW of electrical capacity and 11.7 GWh/h of injection capacity (table 39, p. 60), making it the largest single item in the breakdown. In the joint electrolyser list this corresponds to seven expansion stages with the federal state “North Sea”.
The electrolysis reports are consulted separately via the joint electrolyser list; the two AquaVentus projects can be found there in rows 233 (SEN-1) and 234 (SEN-X). By contrast, they are not included in the likewise published “Overview of all project reports in the market survey on infrastructure needs for electricity and hydrogen” (annex 4) – this overview contains 913 data rows, located exclusively onshore, and not a single electrolysis report. For every exit point, storage facility and other entry point reported onshore, it publishes annual values from 2027 to 2045 and for 2050, the project status and the FID status. The electrolyser list contains none of this: neither annual values nor maturity level, neither landing point nor entry zone.
This means that precisely for the largest single item on the list, the data needed to verify two central assumptions of the draft are missing: the design of AquaDuctus (p. 69, see point 4) and the north-west entry load case. This load case is set as a modelling result of the Grid Development Plan 2025 (p. 159); the German offshore volumes feed into this zone, and this is exactly why their ramp-up and landing point must be available for modelling. In addition, on question 3: the maturity level is not published for the electrolyser list, although the draft attaches considerable importance to it in regionalisation and, for power plants, combines it with the project status into a consolidated project status (p. 93).
A correction is also required for the projects reported by AquaVentus. An offshore electrolysis capacity of 1 GW (SEN-1) was reported. The 10 GW entry for SEN-X, by contrast, corresponds to the reported offshore wind capacity of the total potential of zones 4 and 5; no electrolysis capacity of that size was reported. The list nevertheless shows these 10 GW as the electrical capacity of an electrolyser with 7,400 MW of injection capacity. The statement that around 30 percent of reported electrolysis capacity is located offshore therefore also rests to a considerable extent on confusing wind and electrolysis capacity – which third parties cannot verify, because the underlying reports are not published. The figures should be reconciled with the project developer before approval.
Demand
– Publish the offshore electrolysis reports in the same structure as the other project reports: annual values of injection capacity and volume, project status, FID status, landing point and entry zone.
– Clarify the title of annex 4, which, contrary to its name, contains no electrolysis reports, and state the maturity level for the electrolyser list as well.
– Reconcile the capacity figures of the offshore entries with the data actually reported, in particular separating reported offshore wind capacity from reported electrolysis capacity.
3. SEN-X must be taken into account in the joint scenario (on questions 3 and 7)
The draft formulates the inclusion rule twice. Chapter 3.3.2.3, p. 95:
“The draft Scenario Framework 2027 takes into account all projects with at least the status ‘design planning’.”
Chapter 4.3.2, p. 158:
“Scenario 2: the scenario takes into account at least all electrolysis sites of the joint, cross-scenario electrolyser list that, according to the project status reported by the project developer, are in the phase of ‘design planning’, ‘detailed planning’, ‘procurement of materials and services’ or ‘commissioning’ (minimum capacity).”
The joint electrolyser list applies this rule consistently: all 113 expansion stages with the status “design planning” or better are marked for the joint scenario – with a single exception. It is the offshore entry SEN-X (federal state “North Sea”, status “design planning/regional planning procedure”), which is also the largest single entry in the list.
The draft names the legal situation as the criterion: SEN-1 is taken into account “as the legal planning basis is already fully in place today” (p. 95). For SEN-X the reverse applies – its exclusion therefore rests solely on a missing legal basis, not on project maturity, data quality or plausibility. This very basis was created with the cabinet decision of 2 September 2026 (see point 1): the other energy generation areas are opened to grid connection, and the explanatory memorandum expressly names the designation of further such areas as the scaling pathway. The key argument for the “no” has thus ceased to apply before the scenario framework is approved.
There is also a transparency point: on p. 95 the draft states that further offshore electrolysis reports in zones 4 and 5 are “also part of the electrolyser list and may be included in the Gas and Hydrogen Grid Development Plan depending on the scenario or load case”. The marking “no” does not reveal whether this happens and with what capacity. If SEN-X – as would be appropriate on the merits – is included in scenarios 2 and 3 with substantial parts of the reported capacity, this should be stated explicitly in the approved scenario framework.
Demand
– The SEN-X entry must be reassessed before approval and set to “yes”, now that the legal basis decisive for this has been created with the cabinet decision of 2 September 2026 – with the capacity figure to be reconciled under point 2.
– Binding statement of the scenarios and load cases of the Gas and Hydrogen Grid Development Plan in which SEN-X is included and with what capacity.
4. The design of AquaDuctus rests on two strands (on question 11)
For the AquaDuctus (offshore) cross-border point, the draft assumes injection capacities from the United Kingdom, Denmark and the Netherlands and then states on p. 69:
“In conjunction with the expected offshore hydrogen production volumes from the German North Sea reported via the market survey, full utilisation of the pipeline capacity of 20 GWh/h is assumed for AquaDuctus in the long term.”
AquaVentus shares this assessment. In the grid development plan, the design at 20 GWh/h is justified and secured equally by two strands: by hydrogen volumes from the German North Sea reported via the market survey, and by the cross-border point for further international volumes from the North Sea corridor. Both strands should stand side by side in the scenario framework and not be played off against each other. Assigning fixed shares is neither necessary nor appropriate for this: it would make the capacity shown vulnerable as soon as one of the two strands is called into question. Capacity reservation and marketing take place outside the grid development plan in any case.
This leads to the actual point: if domestic offshore hydrogen production is one of the two supporting strands of this design, it cannot at the same time be treated elsewhere as irrelevant for modelling (point 1), remain without the necessary data (point 2) and have its largest project excluded from consideration (point 3). On question 11: identical hydrogen injection capacities in scenarios 1 to 3 are appropriate for AquaDuctus, precisely because the capacity is supported by both strands. It must be ensured, however, that the domestic strand is not weakened by the treatment of offshore electrolysis in the two scenario frameworks.
5. Summary of demands
1. Correct the statement on p. 95 that offshore electrolysers do not require a grid connection, in line with the proposed wording; differentiate the reported connection concepts into island concepts and grid-connected hybrid concepts.
2. Take account of the legal situation at the time of approval: the cabinet decision of 2 September 2026 opens the other energy generation areas to grid connection. The anticipation principle that the Electricity Scenario Framework applies on p. 77 on the basis of a ministerial draft should apply here in the same way.
3. Distinguish load cases by connection concept: for grid-connected offshore electrolysers, the assumption that no hydrogen is produced when renewable electricity generation is low does not apply in the same way as for island concepts.
4. Publish the offshore electrolysis reports in the same structure as the other project reports and explain why power-to-gas reports are not part of the “Overview of all project reports”; state the maturity level for the electrolyser list as well.
5. Reconcile the capacity figures of the offshore entries in the joint electrolyser list with the data actually reported: for SEN-X, 10 GW of offshore wind capacity was reported, not electrolysis capacity of that size.
6. Reassess the marking of SEN-X before approval and mark it “yes”: its exclusion rests solely on a missing legal basis, which was created with the cabinet decision of 2 September 2026. In addition, a binding statement of the scenarios and load cases in which SEN-X is included and with what capacity.
7. Retain the design of AquaDuctus at 20 GWh/h, supported by both lines of justification – domestic offshore hydrogen production and international volumes via the cross-border point – without assigning fixed shares in the scenario framework.
AquaVentus is available for a technical discussion to go into the technical and economic foundations in more depth.
Study references
– Frontier Economics: “Effiziente Integration von Offshore-Windenergie durch Offshore-Wasserstoffproduktion” (Efficient integration of offshore wind energy through offshore hydrogen production), 24 November 2025, commissioned by AquaVentus Förderverein e.V. https://aquaventus.org/en/leitstudien/frontier-economics-2025
– E-Bridge Consulting: “Bewertung von Anschlusskonzepten für weit entfernte Offshore-Windgebiete in der deutschen Nordsee” (Assessment of connection concepts for far-offshore wind areas in the German North Sea), September 2024, commissioned by AquaVentus Förderverein e.V. https://aquaventus.org/downloads/studien/kurzstudie-2024-de.pdf