Curtailment and transmission congestion are increasingly limiting the integration of renewable energy sources, resulting in significant volumes of surplus renewable electricity. Sector coupling can unlock additional flexibility by redirecting this surplus toward alternative energy carriers. One practical route is hydrogen blending into existing natural gas transmission networks, which can accommodate excess renewable electricity at scale in the near term by leveraging existing infrastructure. This study develops a regional-level electricity–gas co-simulation framework to examine hydrogen blending into a major transmission pipeline as a scale-up route for early hydrogen deployment. By converting surplus renewable electricity into hydrogen and using the existing gas backbone as an immediate outlet and intrinsic buffer, the analysis quantifies both system-level performance and infrastructure-level implications over a year-long horizon, without relying on dedicated hydrogen storage. The framework combines quasi-dynamic alternating current power flow with transient gas network modeling and hydrogen compositional tracking. Hydrogen blending levels between 2% and 10% vol are assessed. Results show that redirecting otherwise curtailed renewable generation toward hydrogen production lowers curtailment by 32.5% to 68.4% and supports the rapid deployment of electrolysis capacity, on the order of 40 MW el per percentage point of hydrogen volumetric content. The Levelized Cost of Blended Hydrogen reaches competitive values down to 4.2 €/kg under curtailment-driven operation. Gas transmission infrastructure impacts remain marginal across all scenarios, whereas concentrated electrolyzer siting can induce localized stress on the power grid. Overall, hydrogen blending emerges as an effective component of large-scale sector coupling initiatives, provided that coordinated siting and electric grid-aware integration strategies are adopted. • Blending reduces curtailment and supports gas–power coordination. • Pipelines enable multi-MW hydrogen uptake from surplus electricity. • Large electrolyzer fleets can more than double grid overload hours. • Blending enables fast electrolyzer scale-up: 100 MW e l per 2.41% v o l H 2 . • Existing gas networks and surplus renewable energy enable hydrogen cost of 4.2 €/kg.
Francesconi et al. (Tue,) studied this question.