Urged by international accords such as the Paris Agreement and the IPCC’s global warming report, the Dutch government is in the process of developing the national industrial hydrogen market across five main industry clusters. In addition, regional hydrogen demand is being explored to complement the national hydrogen backbone by connecting decentralized industrial customers outside the five clusters through regional hydrogen distribution networks. This emerging regional industrial hydrogen market is collectively referred to as Cluster 6.

Hydrogen distribution network operators (HDNOs) are expected to play a key role in this transition as neutral market facilitators at the regional level. However, as heavily regulated entities, HDNOs are dependent on appropriate regulatory frameworks. The EU’s Hydrogen and Gas Decarbonisation Package introduces a legal framework for third-party access (TPA), allowing Member States to adopt regulated (rTPA), negotiated (nTPA), or hybrid (hnTPA) regimes. In the Dutch context, regional TPA regulation remains under development. The implications of these regimes for HDNOs and regional market development are currently unclear.

This research addresses the knowledge gap surrounding the influence of TPA regimes on stakeholder behaviour and hydrogen deployment in Cluster 6. Using a case study approach, the study combines literature review, expert interviews, and agent-based modelling (ABM) to analyse how TPA regimes affect stakeholder decision-making and infrastructure rollout. Interviews were held with system operators, a Cluster 6 representative, local industries, and the municipality. Interviewees highlighted challenges due to unclear stakeholder roles and financial responsibilities. While some industries expressed interest in hydrogen, driven by visionary entrepreneurs, most remained hesitant and dependent on broader commitment. High costs and uncertainty around hydrogen pricing were key concerns. Network operators indicated that key negotiation terms under nTPA could include prioritization based on project characteristics and investment cost division.

These insights informed the agent-based model. Industrial agents in the model decide to transition to hydrogen based on a motivation score derived from peer pressure, cost-benefit analysis (CBA), and waiting list incentives. Scenarios reflect different TPA regimes and associated rules: rTPA with first-come-first-served prioritization, and nTPA and hnTPA with negotiable prioritization and cost division.

The results show that TPA regimes significantly affect the pace and scale of hydrogen deployment. nTPA yields the most favourable outcomes for hydrogen off-take and CO₂ reduction, due to prioritization mechanisms that reward large, efficient projects. However, prioritization alone does not accelerate the timing of transition unless economic conditions are also supportive.

The investment cost division plays a stronger role in influencing the pace of transition. When industries are partially relieved of investment costs (under nTPA and hnTPA), the model shows shorter average waiting times and an earlier final transition year. Even when hnTPA switches to rTPA, results remain favourable due to early negotiation-phase decisions. Together, the negotiation terms support more ambitious transitions and earlier uptake.

Based on these findings, the study recommends clarifying stakeholder roles and financial responsibilities, assigning an HDNO, and considering scenario-based price guarantees. HDNOs could use negotiation terms to incentivize cost-efficient projects and introduce cost-sharing mechanisms to reduce risk. Both actors should promote visibility and flexibility in early-phase TPA design to increase motivation for hydrogen adoption.

In conclusion, third-party access regimes play a crucial role in shaping the regional hydrogen transition. While regulated TPA delays progress, negotiated TPA supports more ambitious and timely outcomes. Hybrid regimes offer a partial solution but depend on economic conditions and timing.