Integrating solid direct air capture systems with green hydrogen production: Economic benefits and curtailment reduction

Abstract

The transition to a low-carbon energy system has positioned green hydrogen as a key clean energy carrier. However, the intermittent nature of renewable energy sources introduces significant challenges, such as substantial electricity curtailment, which affects both the economic feasibility and grid stability. Solid sorbent-based direct air capture systems, known for their high operational flexibility, offer a promising complementary solution to effectively utilize curtailed renewable power from green hydrogen production. This study examines the economic viability of integrating green hydrogen systems with solid direct air capture technology. The findings indicate that the integration can reduce curtailed renewable energy by up to 40 %, subsequently decreasing total annualized costs by approximately 6 % compared to operating these systems independently. Further economic improvements could be realized by optimizing the CO₂ capture-to-H₂ production ratio, capitalizing on anticipated cost reductions in direct air capture technology, and enhancing heat pump flexibility. With these improvements—including a 50 % reduction in direct air capture costs, an optimized CO₂-to-H₂ ratio, and enhanced heat pump flexibility—the economic benefits could increase from 6 % to 12 %. These results underscore the transformative potential of sector coupling in addressing the scalability challenges of green hydrogen, reducing renewable energy curtailment, and accelerating progress towards achieving net-zero and net-negative emissions goals.