Environmental emissions from transports need to be reduced in order to construct a sustainable society. Nowadays, gasoline and diesel account for 21% of the total carbon emissions in the world. In the Netherlands, important projects are present to develop a hydrogen economy by 2050. Hydrogen can be used as a sustainable fuel alternative for transports as its consumption produces only water. However, the current technologies for hydrogen production possess environmental emissions such as CO2, based on steam reforming and coal gasification. If hydrogen is to be used massively as an energy carrier, a shift in its production paradigm is necessary.
The thesis compares the environmental performances of the two strongest potentials for green hydrogen (without harmful emissions) production: the alkaline and PEM electrolysers. Both of these technologies are based on the same principle: water is split with electricity into oxygen and hydrogen. To produce green hydrogen, the electricity comes from the wind energy, the largest renewable energy source potential in the NL. Both electrolysers are used at a pilot-scale currently. The main question studied in the thesis is to see how the environmental profiles of these two alternatives may evolve when a shift is operated pilot-scale to large-scale implementation. The Life Cycle Assessment tool is used to achieve the assessment and to put the focus on environmental emissions. LCAs at a pilot-scale were constructed based on a literature review. Analyses of the environmental performances from alkaline and PEM electrolysers enabled to settle a list of potentially relevant parameters to consider during upscaling process.
Several technology analyses were conducted (workshop, interviews, collaboration with a company) and combined with the General Morphological Approach (GMA) to create scenarios for 2050. By combining the scenarios constructed with the GMA approach and the pilot-scale LCA models, prospective LCA models were created for potential future electrolyser’s plants. A special focus was made on electrolysers’ parameters to understand clearer their potential influences.
Analyses of the prospective (named “ex-ante”) LCA models and comparisons were made between alkaline and PEM electrolysers. The alkaline electrolyser performs slightly better than PEM, even though the two alternatives possess virtually the same environmental performances. The differences in environmental performances between alkaline and PEM electrolysers are most of the time non-significant. The largest contributor in environmental emissions remains the electricity production (from Dutch wind turbines). That said, other perspective, such as geopolitical ones, may favour more one technology than the other (e.g. the PEM electrolyser consumes noble metals).
Overall, a combination of LCA and GMA methodologies has been applied in the thesis to assess the environmental performances for two electrolysers in 2050, for green hydrogen production. Using renewable energy source decreases significantly the environmental impacts but the electricity production will likely remain the biggest contributor. The electrolysers are unlikely to influence significantly the environmental profile of green hydrogen production. A focus should be made on the electricity’s production.