Consultation: draft of the 2nd amendment to the Site Development Plan 2025 (BSH, 19 June 2026) — options N-10.1 / N-10.2 / SEN-1. Statement — AquaVentus Förderverein e.V.
20 July 2026. The AquaVentus Förderverein would like to thank you for the opportunity to comment in the consultation on the 2nd draft amendment to the Site Development Plan 2025. As the representative of member companies along the entire offshore hydrogen value chain, a healthy and competitive offshore wind industry matters to us just as much as the long-term ramp-up of offshore hydrogen production — because without economically viable wind farms there is no renewable electricity for offshore electrolysis. In the short term, the economic viability of wind farms can be improved through better site delineation, with the resulting reduction in wake effects, and through a functioning contract-for-difference regime; these efforts by the industry and by regulators have our full recognition. In the long term, however, offshore wind developers need additional revenue streams to secure viability beyond the mere sale of electricity — in particular through the possibility of storing wind energy as hydrogen during high-yield, low-price hours instead of curtailing it. Offshore electrolysis is therefore not a counter-proposal to the wind industry but its necessary second revenue stream and complementary to it. We therefore assess the three options put out to consultation from the perspective of the industrial scaling of offshore electrolysis and of securing SEN-1 in the long term as a central demonstration and scaling location. In addition to this individual statement, AquaVentus has co-signed the joint statement of the SEN-1 group, which sets out at a technical and infrastructural level how a combined connection concept for SEN-1 can be implemented in concrete terms (see our explanation under Q3 and Q4). The present AquaVentus statement is consistent with that joint position and supplements it with association-policy aspects, in particular the generic demand under the Offshore Wind Energy Act for sector coupling on sites (not only in areas), as well as the outlook for Zones 4 and 5.
The AquaVentus Förderverein unanimously rejects Option 3. We regard an adjusted Option 2 — with the full build-out capacity of 2,000 MW on N-10.1 and up to two 250 MW electrolysis platforms — as the best solution. Implementation via Option 1 would be an equivalent alternative, provided it achieves the same target configuration. The association's central demand is to enable up to two demonstration projects of 250 MW each on SEN-1 and/or surrounding sites, as well as combined connection concepts (electricity and hydrogen) — not only in areas, but on sites as well.
Q1: Are the options presented fundamentally suitable for increasing the economic attractiveness of sites N-10.1 and N-10.2?
Yes, in principle all three options are suitable for increasing the attractiveness of N-10.1 and N-10.2 through reduced power density. AquaVentus points out, however, that the economic attractiveness of the wind sites must not be assessed in isolation from the development prospects for SEN-1. Increasing the attractiveness of N-10.1/N-10.2 at the cost of dissolving SEN-1 entirely or largely merely shifts a siting problem instead of solving it, and at the same time jeopardises the build-up of the offshore hydrogen industry, for which no alternative, equally well developed location exists in the FEP to date.
Q2: Are the options presented suitable for achieving a sufficient expansion of offshore electrolysis?
In the view of AquaVentus, the suitability of the options for expanding offshore electrolysis depends directly on retaining a sufficiently large SEN-1 site: • Option 1 retains SEN-1 in full and thus enables, in perspective, two demonstration projects of 250 MW each on SEN-1. However, to achieve this Option 1 provides for a reduction in the build-out capacity of N-10.1 in order to keep grid connection capacity on NOR-10-1 free for SEN-1. This reduction is to be rejected for cost-efficiency reasons and is also unnecessary. • Option 2 reduces SEN-1 in its original form to approximately 32 km². In adjusted form, however — with optimised site delineation, full build-out capacity of N-10.1 (2,000 MW) and a separate connection via low-cost 66 kV cables to the NOR-10-1 converter (see Q3) — Option 2 can enable up to two 250 MW demonstration projects on SEN-1 without diminishing the grid connection capacity of N-10.1, and is from the AquaVentus perspective the preferred solution. It is decisive that the site be delineated in such a way that the option of a second 250 MW project remains technically and spatially secured. • Option 3 eliminates SEN-1 entirely and makes offshore electrolysis in Zone 3 impossible. Relocation to Zone 4 comes too late for the timely demonstration of sector coupling that is needed, and cuts AquaVentus projects off from the infrastructure planning already in place (AquaDuctus connection, converter station). AquaVentus position: AquaVentus calls for a site configuration that enables two demonstration projects of 250 MW each — or that at least expressly keeps open the technical and spatial possibility of a second 250 MW electrolyser. Option 3 is rejected as not expedient.
Q3: How large would the wind farm and electrolysis capacity ideally to be installed on SEN-1 be, taking account of the electricity transmission capacity available in each case via NOR-10-1?
What would be the ideal ratio of wind farm, electrolysis and transmission capacity in the case of a combined connection of SEN-1, from a business perspective and from a system cost perspective? Please explain with regard to Options 1 to 3 and name the advantages and disadvantages.
From a business and system cost perspective, AquaVentus argues for the following key parameters: • Option 1 (adjusted): wind farm capacity SEN-1 up to 500 MW, electrolysis capacity of 2 × 250 MW possible, electricity connection via NOR-10-1, hydrogen connection AquaDuctus scaled accordingly. • Option 2 (adjusted): full build-out capacity of N-10.1 of 2,000 MW — not using the NOR-10-1 converter, already designed for 2,000 MW, at more than 1,750 MW would be macroeconomically nonsensical, since grid capacity already paid for and passed through in the cost base would remain unused. Wind farm capacity SEN-1 / site N-10.1 up to 500 MW on up to two platforms of 250 MW each, electrolysis capacity accordingly up to 2 × 250 MW, electricity connection for each platform separately via a 66 kV cable to NOR-10-1 (approx. 80–100 MW per platform), hydrogen connection AquaDuctus scaled accordingly. Advantages of Option 1: greatest economies of scale, highest flexibility between hydrogen generation and electricity export, room for two parallel demonstration projects, maximum learning and cost degression effects. Disadvantages of Option 1: increased attractiveness for N-10.1 achievable only through reduced power density (no site enlargement at the expense of SEN-1).
Advantages of Option 2 (adjusted): improved economic viability of N-10.1 through a larger project site at full build-out capacity of 2,000 MW (no unused grid capacity); with optimised site delineation and a separate, cost-efficient 66 kV connection it enables the same target configuration of up to two 250 MW demonstration projects as Option 1, without requiring the complete SEN-1 site and without diminishing the capacity of N-10.1. Disadvantages of Option 2: limited to one demonstration project without site optimisation (see Q4); realising the second platform presupposes a corresponding site adjustment. Option 3 offers no basis for a robust answer to the business question, since no electrolysis capacity remains.
One central principle, irrespective of the option chosen: an upper limit for the ratio of wind farm capacity to electrolysis capacity is sensible and defensible in regulatory terms; a lower limit, by contrast, is not necessary and should be left to the market, that is, to the project developer's business decision.
Technical feasibility: connecting the electrolysis platforms does not require a complete, parallel grid connection, but merely a limited electrical backup for minimum operation during periods of low wind. A comparatively low-cost 66 kV cable with a transmission capacity of around 80 to 100 MW per electrolyser platform suffices for this and can be connected to reserve connection sockets already present on the NOR-10-1 converter. Even though the converter has already been ordered and is under construction, no adjustments to the existing converter design are necessary for this — connecting SEN-1 is therefore possible without additional technical risk to the realisation of N-10.1. Precisely because this cost-efficient connection option is tied to the NOR-10-1 converter station already under construction, SEN-1 should be retained at its current location — relocation would nullify this cost advantage. The detailed technical arrangement is set out in the joint statement of the SEN-1 group, which AquaVentus has co-signed.
Q4: In your view, which of the options presented offers the greatest advantages overall and should therefore be implemented? For what reasons?
From the AquaVentus perspective, an obvious configuration is missing from the three options presented: the construction of a second 250 MW electrolyser platform on site N-10.1 itself — technically and spatially a hybrid of the electrolysis capacity of Option 1 (2 × 250 MW) and the site delineation of Option 2. Such a configuration would combine the scaling logic of Option 1 (two parallel 250 MW demonstration projects) with the site enlargement of N-10.1 already provided for in Option 2, without requiring the complete retention of the SEN-1 site. This possibility is reflected in none of the three options submitted, because under the current Offshore Wind Energy Act sector coupling is permissible exclusively in areas (such as SEN-1) and not on sites such as N-10.1 (see our fundamental demand under Q5). AquaVentus suggests including this hybrid configuration in the further examination as a fourth variant that may well prove preferable. The SEN-1 group likewise notes in its statement that a second platform could in perspective also be realised on N-10.1 or on neighbouring sites — this accords with the hybrid approach outlined here.
Site optimisation under Option 2: with the delineation as it stands, Option 2 makes a total of only around 256 km² available for energy generation across sites N-10.1, N-10.2 and SEN-1, compared with 278 km² under Option 1 — a difference of around 22 km² that would remain unused under the current proposal. If this loss of area is avoided by optimising the delineation and the area is allocated to the SEN-1 site, a second 250 MW demonstration project could be realised there instead of a single one. The site adjustment specifically proposed for this includes a north-west to south-east orientation of SEN-1, which allows a route that does not cross N-10.1.
Q5: Do you see further effects of the options, not presented here, for instance on other sites or other uses, that would need to be taken into account in the amendment?
Central demand — sector coupling on sites as well, not only in areas: under the current Offshore Wind Energy Act, offshore sector coupling (combined electricity and hydrogen production) is permissible exclusively in areas (such as SEN-1) and not on regular sites such as N-10.1. In the view of AquaVentus this distinction is a considerable structural obstacle to the ramp-up of the offshore hydrogen industry — irrespective of which of the three options is ultimately implemented: • Should the entire SEN-1 site be absorbed into N-10.1 under Option 3, the possibility of sector coupling on this site would automatically fall away — irrespective of the technical and infrastructural conditions actually present there (proximity to AquaDuctus, converter station).
– AquaVentus therefore calls for an amendment to the Offshore Wind Energy Act that explicitly enables combined connection concepts (electricity and hydrogen) on sites as well — not only in areas. This concerns site N-10.1 specifically but should not be limited to this individual case. • This demand is of fundamental importance for site development in Zones 4 and 5 of the EEZ as well: there too, no sites (only potential future areas) are so far provided for offshore sector coupling. Without an amendment to the Offshore Wind Energy Act permitting sector coupling generically on sites, today's siting problem will repeat itself with every future update of the FEP for the outer zones.
Balanced power density across N-10.1, N-10.2 and SEN-1: when optimising the sites, N-10.1 and SEN-1 should not be considered in isolation — N-10.2 too already has a lower power density today and can be used as a further lever for increasing attractiveness. Concentrating the optimisation exclusively on N-10.1 at the expense of SEN-1 falls short if unused potential exists in N-10.2 at the same time. AquaVentus therefore suggests examining, for all three options, the extent to which a balanced power density across N-10.1, N-10.2 (sites) and SEN-1 (area) can contribute to increasing attractiveness, instead of carrying out the necessary reduction in power density one-sidedly at the expense of SEN-1. Such a balanced view across sites could help both to increase the economic attractiveness of N-10.1/N-10.2 and to preserve a greater share of the SEN-1 site.
Further aspects: • Innovation and scaling effects: the loss or severe reduction of SEN-1 limits the transfer of demonstration findings (among others from neighbouring projects) into industrial scaling steps. • Utilisation of the converter station and grid infrastructure: a converter station that is only partly utilised is uneconomic, since it is very costly in macroeconomic terms; the site configuration should enable optimal utilisation through overplanting (as suggested by the BSH in March 2025) and the flexible use of free connection capacity. Offshore electrolysis offers particular potential in this respect, especially on SEN-1 with the surrounding converter stations. • Energy resilience: SEN-1 enables offshore wind electricity to be complemented by offshore hydrogen and thus strengthens the diversification and resilience of the German energy system.
Q6: Regarding Options 2 and 3: the area in which site N-10.1 is extended to include parts of the current SEN-1 will not be centrally pre-surveyed before the site is tendered; in particular, no survey of the subsoil has been carried out in that area. The geological exploration must therefore be supplemented independently by the project developer. The BSH assumes that the project on the enlarged site N-10.1 can nevertheless be implemented within the deadlines of the Offshore Wind Energy Act for the plan approval procedure and in good time for the specified commissioning date. Are there compelling reasons in this respect that would need to be taken into account, such that different timing provisions for commissioning might have to be made for the area extended into the current SEN-1?
AquaVentus sees fundamentally comprehensible reasons for greater flexibility in timing in the areas additionally incorporated into N-10.1 from the previous SEN-1 site. The absence of a central pre-survey (particularly of the subsoil) increases project risk and planning uncertainty compared with fully pre-surveyed sites; depending on the results of subsequent geotechnical investigations, adjustments to foundation design, plant layout and cable routing may become necessary. AquaVentus proposes providing appropriate regulatory flexibility on commissioning dates for the sub-areas additionally incorporated, without this leading to a fundamental abandonment of the incorporation of SEN-1 site portions or hindering an optimal combination for trialling offshore sector coupling. The long-term advantages for the ramp-up of the offshore hydrogen industry clearly outweigh the additional survey effort.
Summary of the core AquaVentus demands • Option 3 is rejected — the complete elimination of SEN-1 is incompatible with the objective of the offshore hydrogen ramp-up. • An adjusted Option 2 — with N-10.1 at the full build-out capacity of 2,000 MW and up to two 250 MW electrolysis platforms on SEN-1 / site N-10.1 with a cost-efficient 66 kV connection — is supported as the best solution. • Option 1 (large-scale retention of SEN-1) represents an equivalent alternative, provided it achieves the same target configuration of up to two 250 MW demonstration projects. • The target figure is 2 × 250 MW of electrolysis capacity, irrespective of the option chosen.
– Amendment to the Offshore Wind Energy Act: enable sector coupling on sites as well — not only in areas. This concerns site N-10.1 specifically and, in perspective, all sites in Zones 4 and 5 of the German EEZ.