Abstract The EU Delegated Act establishes criteria for certifying electrolytic hydrogen as renewable. However, adjustments to these criteria are under review to balance hydrogen’s economic viability with its sustainability. This study employs a European integrated electricity and hydrogen system model to evaluate the climate and economic impacts of relaxing additionality and spatiotemporal correlation criteria by 2030. Scenarios range from unrestricted electrolysis flexibly operating at short-run marginal electricity prices to domestic and cross-border Power Purchase Agreements (PPAs) with newly installed renewables, under hourly or annual temporal matching. Two perspectives are explored, both applying a “compete” additionality framework where hydrogen production competes with direct electrification in a co-optimized system. The first analysis constrains the country-specific renewable buildout to National Energy and Climate Plans (NECPs) using Ten-Year Network Development Plan’s (TYNDP 2024) National Trend trajectories. This reflects the practical difficulty of accelerating renewable expansion by 2030, even with green hydrogen mandates. Under this constraint, additionality with spatiotemporal correlation reduces attributional emissions (i.e., emissions from grid electricity use, attributed to hydrogen production) but raises power system emissions by ~1 kgCO2/kgH2 compared to the unrestricted electrolysis scenario, as scarce new renewables are diverted to green hydrogen production, increasing fossil generation in the background electricity system. The second, exploratory perspective allows endogenous expansion beyond NECP targets to simulate policy-driven accelerated deployment, where building out green hydrogen, slightly reduces the additional power system emissions associated with hydrogen integration compared to unrestricted electrolysis. Moreover, although total system cost impacts remain modest, additionality with spatiotemporal criteria raises the levelized cost of hydrogen (LCOH) in both perspectives, with cross-country variation driven by short-run electricity prices. EU-averaged results show unrestricted electrolysis yields lower LCOH of €2–2.5/kgH2 (assuming NECPs are met), while stringent PPA-based scenarios increase it up to €7/kgH2. Easing temporal correlation in PPA-based scenarios slightly raises attributional emissions but lowers LCOH. However, additionality remains the dominant cost driver. Finally, the study underscores the need for tailored exemptions from additionality and spatiotemporal correlation criteria based on factors such as nuclear share, renewable targets, and marginal clean generation frequency to refine these requirements effectively.
Namazifard et al. (Wed,) studied this question.