Energy System Analysis of the Power Sector Flexibility via Hydrogen Utilisation

According to regulations from the EU Commission, investments in nuclear energy and fossil gas are considered sustainable. These new EU taxonomies, which are intended to provide financial markets with guidance on climate and environmentally friendly investments, actually exclude conventional fossil power- and heat plants. However, the reinterpretation of natural gas as a transitional energy until 2035 allows the construction of new gas-fired power plants. As a limiting factor, an increasing share of low-emission gases have to be used, primarily green hydrogen. In the future, fuel cell power plants could serve as an alternative to such new H₂ready gas power plants. High-temperature solid oxide fuel cells can not only use fossil methane-containing natural gas and/or hydrogen efficiently, but can also be used reversibly for electrolysis and thus provides flexibility to the power grid. This study uses energy system optimization to analyse the behaviour of both technologies, H₂-ready gas turbines and fuel cell power plants. Across three scenarios, fuel cells are used to provide baseload and flexibility especially in periods of low wind and solar irradiation, whereas hydrogen gas turbines appear last in the order of operation. However, short-term flexibility is provided by battery storage, e.g. by using existing battery capacities from electric vehicles. As Germany has a lower potential for local hydrogen production in an international comparison, significant quantities of hydrogen will only be produced in Germany if import possibilities are strongly limited and technology costs decrease at the same time.