Techno-economics of green hydrogen compression

The potential of green hydrogen in the realization of sustainable energy transition is significant. Itcan store substantial amounts of renewable energy for extended durations and plays a crucial rolein sector coupling (connecting the energy sector with various industries such as transportation,industry, and building) [1–3]. This includes its application in Power-to-X (PtX) processes, whichinvolve the production of fuels and chemicals such as kerosene, diesel, petrol, ammonia, methane,dimethyl ether, and can be used in industries as a source for high-temperature process heat [4–6].However, due to hydrogen's low density, it must be compressed for effective transportation andstorage for these applications. Hydrogen compression is an energy-intensive process, and differentapplications require hydrogen to be delivered at varying pressures for their operations [7].Understanding hydrogen compression is one of the important aspects in the hydrogen supply chain.A techno-economic analysis of hydrogen compression has been conducted in this thesis, with afocus on evaluating different compressor types and configurations across the three most commonuse cases where hydrogen will be used, they include hydrogen refueling stations (HRS),compressed hydrogen storage in above-ground buffer tanks, and geological storage like saltcaverns. A Python model has been developed to assess the energy consumption and associated costsof hydrogen compression for these three scenarios, along with optimization of these compressorconfigurations to identify the energy and cost-efficient compressor configuration. Additionally, asensitivity analysis has been carried out to examine the impact of suction pressure, design capacity,and isentropic efficiency on the levelized cost of hydrogen compression (LCOHC).The results indicate that for the HRS use case, both for 350bar and 700bar configurationsdiaphragm compressors were found to be efficient because of their high efficiency and pure gascompression characteristic, with an LCOHC of 0.54 USD/kg and 1.11 USD/kg. For the large-scalehydrogen buffer storage (above ground) and underground storage in the salt cavern, heavy-dutyreciprocating compressors were found to be only suitable candidates because of their ability tohandle high mass flow rates and discharge pressures. The LCOHC was found to be 0.72 USD/kgfor a 100 MW electrolyzer system, 0.29 USD/kg for a 1.2 GW electrolyzer system (a modularcompressor system), 0.23 USD/kg for a TWh storage scale salt cavern, and 0.18 USD/kg for a GWhstorage scale salt cavern.