A Techno-economic Analysis of Future Hydrogen Reconversion Technologies

The transformation of fossil fuel-based power generation systems towards greenhouse gas-neutral ones based on renewable energy sources is one of the key challenges facing contemporary society. The temporal volatility that accompanies the integration of renewable energy (e.g. solar radiation and wind) must be compensated to ensure that at any given time, a sufficient supply of electrical energy for the demands of different sectors is available. Green hydrogen, which is produced using renewable energy sources via electrolysis, can be used to chemically store electrical energy on a seasonal basis. Reconversion technologies are needed to generate electricity from stored hydrogen during periods of low renewable electricity generation. This study presents a detailed technoeconomic assessment of hydrogen gas turbines. These technologies are also superior to fuel cells due to their comparatively low investment costs, especially when it comes to covering the residual loads. As of today, hydrogen gas turbines are only available in laboratory or small-scale settings and have no market penetration or high technology readiness level. The primary focus of this study is to analyze the effects on gas turbine component costs when hydrogen is used instead of natural gas. Based on these findings, an economic analysis addressing the current state of these turbine components is conducted. A literature review on the subsystems is performed, considering statements from leading manufactures and researchers to derive the cost deviations and total cost per installed capacity (€/kWel). The results reveal that a hydrogen gas turbine power plant has an expected cost increase of 8.5% compared to a conventional gas turbine one. This leads to an average cost of 542.5 €/kWel for hydrogen gas turbines. For hydrogen combined cycle power plants, the expected cost increase corresponds to the cost of the gas turbine system, as the steam turbine subsystem remains unaffected by fuel switching. Additionally, power plant retrofit potentials were calculated and the respective costs in the case of an upgrade were estimated. For Germany as a case study for an industrialized country, the potential of a possible retrofit is between 2.7 and 11.4 GW resulting to a total investment between 0.3 and 1.1 billion €.