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Abstract Background To limit climate change and reduce further harmful environmental impacts the reduction and substitution of fossil energy carriers is a main challenge for the next decades. Recently, during the United Nations Climate Change Conference COP28, the participants agreed on the beginning of the end of the fossil fuel era. Hydrogen, when produced using renewable energy, can be a substitute for fossil fuel carriers and enables the storage of the renewable energy, leading into a post-fossil age. This paper presents environmental impacts as well as levelized costs along the life cycle of water electrolysis technologies for hydrogen production. Methods The applied methodological approaches are Life Cycle Assessment (LCA) and Life Cycle Costing (LCC), both life cycle-oriented and based on consistent data sources and detailed assessments of prospective technological developments and their effects on environmental and economic indicators. The considered technological developments include electricity and critical raw material demand decreases on the one hand and lifetime as well as electrolysis capacity increases on the other hand. The objectives of the investigations are AEC, PEMEC, and SOEC as the currently most mature water electrolysis technologies for hydrogen production. Results The environmental impacts and life cycle costs provoked by the hydrogen production will significantly decrease in the long term (up to 2045). For the case of Germany, worst-case climate change results for 2022 are 27.5 kg CO 2eq. /kg H 2 . Considering technological improvements, electrolysis operation with wind power and a clean heat source, a reduction to 1.33 kg CO 2eq. /kg H 2 can be achieved by 2045 in the best-case. The electricity demand of the electrolysis technologies is the main contributor to environmental impacts and levelized costs in most considered cases. Conclusions A unique combination of possible technological, environmental, and economic developments in the production of green hydrogen up to the year 2045 is presented. Based on a comprehensive literature research, several research gaps, like a combined comparison of all three technologies by LCA and LCC, were identified and research questions were posed and answered. Consequently, prospective research should not be limited to one water electrolysis but should be carried out with an openness to all three technologies. Furthermore, it is shown that data from the literature for the LCA and LCC of water electrolysis technologies differ considerably in some cases. Therefore, extensive research into the material inventories for plant construction is needed, but also into the energy and mass balances of plant operation, for a corresponding analysis. Even for today’s plants, the availability and transparency of literature data is still low and must be expanded.
Koj et al. (Mon,) studied this question.