Comparative Life-Cycle Assessment Analysis of Power-to-Methane Plants Including Different Water Electrolysis Technologies and CO2 Sources While Applying Various Energy Scenarios

Germany's energy system is transitioning to a more renewable one, leading to new challenges, such as in the wintertime, when solar and wind energy are less accessible. Power to methane (PtM) can, thusly, serve as a long-term storage solution, as the natural gas grid already exists, therefore reducing costs. The study aims for analysis of potential environmental impacts of synthetic natural gas (SNG) production in different PtM plants.including the electrolysis technologies such as alkaline electrolysis (AEL), polymer electrolysis membrane (PEM), and solid oxide electrolysis cell (SOEC).applying various energy scenarios.2019, 2030, 2050, and renewable energy (RE).to show which technology accounts for the lowest CO2 equiv and is potentially the most environmentally friendly, and to compare results to the potential environmental impacts of conventional natural gas production and CO2 emissions of conventional alternatives. The PtM-SOEC shows the lowest CO2 equiv for the scenarios in 2019, 2030, and 2050.PtM-AEL for RE.and is potentially the most environmentally friendly technology regarding 2019's and 2030's scenarios. This applies to PtM-PEM for 2050's scenario as well as RE's. The conventional natural gas production accounts for less potential environmental impacts than SNG. Only the RE scenario results are lower or within the range of CO2 emissions of considered conventional alternatives.