Green hydrogen has a pivotal place in the energy transition, addressing carbon emissions in hard-to-abate sectors. As global hydrogen demand rises, decarbonizing green production becomes vital. This study explores the influence of design choices and local weather patterns on the Carbon Footprint (CF) and Levelised Cost of Hydrogen (LCOH) for green hydrogen production.

An optimisation model is developed, simulating the production chain (cradle-to-gate) and optimising it for low CF and LCOH based on location-specific wind and solar data. Three locations (Duqm, Groningen, Dakhla) and three design choices (electrolyser, PV type and wind-solar ratio) are assessed.

Results indicate that local weather patterns significantly affect system performance. Dakhla boasts low production costs due to consistent solar and wind energy. Groningen has a low CF but high LCOH due to ample offshore wind but inconsistent sun. Duqm has a low LCOH but high CF due to abundant sun but inconsistent wind.

Design choices, particularly the solar-wind energy ratio, strongly impact both LCOH and CF. PV technology selection also matters, with CI(G)S performing well overall. Alkaline electrolysis is preferred over PEM.

The research demonstrates that design choices can substantially influence the CF, resulting in serious CF reduction at prices comparable to blue hydrogen.

Future research should include storage, transportation, and off-taker aspects and expand impact categories, including social and critical raw material depletion impact categories.

Power-to-methanol (PtM) technologies have a potential to store excess renewable energy in methanol molecules. However, there is a lack of understanding about the role of these technologies in the course of energy transition. In this research, the influence of PtM technologies on power grid’s reliability and CO2 reduction are studied. An agent-based model is developed in order to explore possible future scenarios created by deployment of PtM technologies, in case green methanol is primarily supplied to the shipping sector as an alternative low-carbon fuel. The model outcomes are explored using two sets of experiments representing two hypothetical cases: "flexible grid" experiments in which the power grid is assumed to have several flexibility options, and "low flexibility" grid that the grid cannot easily adapt to high levels of renewable power production. The results show that deployment of PtM technologies can help with absorbing excess renewable energy and improving the reliability of the power grid. However, PtM alone is not sufficient to keep the grid reliable. PtM is shown to be successful in enabling high levels of CO2 reduction. The results obtained in this research can be used as the starting point to open up a discussion between system operator and policy makers in order to define a proper support plan for PtM or other Power-to-X (PtX) options.