Generation and distribution of hydrogen for industry electrification in urban energy systems

Licentiatavhandling, 2025

This thesis investigates how hydrogen from electrolysis for industry electrification can be produced and distributed in future urban energy systems. Three municipalities on the Swedish west coast with hydrogen-intensive industries are used as a case study. The industries can be connected by investments in pipelines in order to transport hydrogen between them. Three different ways to include gas dynamics when transporting hydrogen through pipelines in energy system optimisation models are evaluated in this thesis.

Including a greater level of detail of gas dynamics into the energy system models results in a more constrained flow of hydrogen as compared to not including it. A more constrained flow of hydrogen makes the pipelines less flexible in terms of how fast the flow can be changed, affecting investments in pipelines but also hydrogen storage units and electricity production technologies. In the municipality with large availability of off-shore wind power but poor power transmission capacity (Lysekil), the hydrogen storage units and electrolyser capacity increase with a more detailed representation of gas dynamics, while they decrease in the municipality with larger power transmission capacity (Stenungsund). This means that the municipalities need to be more self-sufficient than relying on flexible import of hydrogen.

In the system studied, it is cost-efficient for the three municipalities to collaborate using hydrogen pipelines to supply hydrogen under a wide range of assumptions. Even with a relatively low demand for hydrogen (4.9 TWh compared to 14 TWh annually for the whole system) investments are made in pipeline infrastructure. For the whole system, it is cost-optimal with investments in approximately 40-50% over-capacity in electrolysers. With over-capacity of electrolysers and together with storage alternatives, the electrolyser can adjust its load depending on availability of electricity.

The demand for electricity includes, apart from the industry sector, the residential, commercial and road transportation sectors and it becomes cost-optimal to primarily meet this demand with off-shore wind power and imported electricity. With good connection to the transmission grid and available site for off-shore wind power, Stenungsund becomes a net exporter of hydrogen, while Lysekil and Gothenburg end up as net importers of hydrogen. If the industrial loads in terms of hydrogen increase before the power transmission grid has been reinforced, or off-shore wind power can be invested in, investments are made in combined cycle gas turbines using biogas. With a biogas consumption of 19 TWh (as compared to the total production of biogas in Sweden of 2.3 TWh) and an increase in total system cost of 17% compared to having access to both off-shore wind and power grid reinforcements, indicates that access to either off-shore wind or electricity grid reinforcement is crucial to meeting a high demand for hydrogen through electrolysis from industries in a cost-efficient manner.