AquaVentus Förderverein e. V. takes the opportunity to comment on the second draft of the Grid Development Plan Electricity 2025–2037/2045 (NEP Strom). As the representative body of member companies across the entire offshore hydrogen value chain, AquaVentus pursues the goal of developing offshore wind energy and offshore electrolysis as complementary pillars of an integrated North Sea strategy. This statement focuses on five points that, in AquaVentus’s view, require correction or addition in the draft plan.
1. Confirmation of Zone 4 ONAS Based on an Incomplete Planning Foundation
The Federal Network Agency (BNetzA) classifies five offshore grid connection systems for the N-14 and N-16 areas in Zone 4 (NOR-14-1, NOR-14-2, NOR-16-1, NOR-16-2, NOR-16-3) with commissioning dates of 2036–2037 as eligible for confirmation. AquaVentus takes note of this confirmation but considers it premature and based on an incomplete planning foundation.
The core problem: the confirmation of these five ONAS rests on the implicit premise that all energy output from offshore wind farms in Zone 4 must be transported to shore as electricity. Offshore hydrogen production – generating H₂ via electrolysers directly at sea – structurally reduces the need for expensive HVDC cable capacities: wind power converted into hydrogen on-site does not need to be transported ashore as electricity. Each GW of offshore electrolysis capacity in Zone 4 correspondingly reduces the required ONAS expansion.
This is not a theoretical argument but the core principle behind SEN-1 and SEN-X: a single HVDC cable system (2 GW) costs all-in approximately 13–15 million EUR/km; the equivalent H₂ pipeline capacity (20 GW₂, DN 1200) is approximately 10–14 million EUR/km – at ten times the transport capacity. Confirming five additional ONAS for Zone 4 without first analysing the impact of offshore electrolysis on ONAS demand cements an infrastructural path whose macroeconomic merits have not yet been sufficiently demonstrated.
Four independent studies – E-Bridge (2024), Fraunhofer IEE (2024), Frontier Economics (2025) and Ramboll (2026) – reach the same conclusion: the hybrid path (fewer ONAS supplemented by offshore H₂ pipelines) is economically superior in all scenarios. Confirming five ONAS without conducting this analysis means ignoring potential savings of billions of euros for electricity consumers and the energy system without scrutiny.
AquaVentus demands: the BNetzA conduct a sensitivity analysis before finally confirming the Zone 4 ONAS, quantifying how different shares of offshore electrolysis capacity in Zone 4 affect ONAS requirements.
2. Offshore Hydrogen as Off-taker Must Be Included in the NEP 2027 Scenario Framework
The current NEP Strom 2025 does not account for offshore electrolysers and dedicated offshore H₂ pipelines in Zones 4 and 5, but excludes them entirely from the planning horizon. This is at odds with the federal government’s energy and climate policy objectives and with the planning framework of the NEP Gas and Hydrogen 2025 (revised draft, 01 June 2026), which provides for 186 km of new offshore hydrogen pipeline routes.
AquaVentus calls on the BNetzA to add an offshore sector-coupling pathway to the NEP 2027 scenario framework. An offshore H₂ pipeline (DN 1200, 100 bar, 20 GW₂ capacity) costs approximately 10–14 million EUR/km – corresponding to approximately 0.51–0.70 million EUR/(GW·km) against approximately 7.0 million EUR/(GW·km) for an HVDC cable system. Even with full reconversion to electricity, the H₂ pipeline route is more than five times cheaper per GWₑₗ·km.
3. Equal Treatment of Offshore Electrolysers and Onshore Flexibility
The BNetzA acknowledges that onshore electrolysers, as flexible loads, can reduce grid expansion needs. The approved scenario framework includes electrolyser site lists; common assumptions for the electricity NEP and gas/H₂ NEP have been harmonised for the first time. The same logic is not applied to offshore electrolysers, even though the physical mechanism is identical: an offshore electrolyser activated at times of high wind output reduces the volume of electricity fed into the grid, thereby reducing redispatch requirements and the load on ONAS.
AquaVentus demands equal treatment: offshore electrolysers must be considered as flexible loads in grid planning, in the same way as onshore electrolysers. This is a question of methodological consistency, not technological feasibility.
4. Market Survey Data as a Binding Planning Basis
AquaVentus submitted the following project data to the transmission system operators (TSOs) in the official market survey for NEP Strom 2025 on 13 March 2026: SEN-1 (1 GW offshore wind capacity, target commissioning 2032 and later) and SEN-X (10 GW offshore wind capacity, total potential Zones 4+5, target commissioning 2037–2045). These data receive no adequate consideration in the second draft of NEP Strom.
AquaVentus demands: the TSOs and BNetzA explicitly state, in the context of NEP 2027, how the market survey data for SEN-1 and SEN-X have been incorporated into planning or why they were not taken into account. Transparency over the planning basis is a prerequisite for meaningful consultation.
5. WindSeeG Amendment as a Necessary Prerequisite
The legal basis for offshore sector coupling is not enshrined in the current Offshore Wind Energy Act (WindSeeG). Offshore sector coupling requires at minimum: an amendment to the WindSeeG enabling dedicated offshore electrolyser areas and combined operation of offshore wind farms and electrolysers at sea; an adjusted tender model for SEN-1; and a clarified regulatory framework for interfaces between the offshore wind farm operator, electrolyser operator, electricity TSO and hydrogen TSO.
AquaVentus calls on the BNetzA, in its recommendations to the legislature, to treat the WindSeeG amendment as a prerequisite for legally secure grid planning that incorporates an offshore sector-coupling component, and to continue developing the NEP Strom accordingly.
Summary of the AquaVentus Statement
1. Sensitivity analysis of ONAS demand vs. offshore electrolysis share in Zone 4 before final confirmation of the five ONAS (NOR-14/NOR-16) – macroeconomic savings are in the billions. 2. Add an offshore sector-coupling pathway to the NEP 2027 scenario framework. 3. Treat offshore electrolysers methodologically on a par with onshore flexibility. 4. Transparency on the impact of market survey data (SEN-1, SEN-X) in NEP 2027. 5. Prioritise the WindSeeG amendment as a prerequisite for NEP-compliant offshore sector coupling.