| dc.description.abstract | The Dutch energy transition faces multiple challenges and opportunities with the development of green hydrogen and offshore wind. The intermittency of offshore wind energy and the economic challenges of transporting electricity over long distances require novel solutions. One promising solution is the offshore production and storage of green hydrogen by electrolysis on platforms powered by wind farms. One possibility is the system studied in this thesis, which uses power-to-gas (P2G) technology to convert electricity into hydrogen, which is then transported via existing or new pipelines, with the excess stored in salt caverns under the North Sea. Ongoing technical and economic research highlights the P2G potential. However, it also raises environmental concerns that must be addressed before this offshore energy system can be developed.
The objective of this thesis is to conduct technical-environmental research on the environmental impact of the P2G energy system, with particular emphasis on brine production and its use of seawater. To address this, the following research question was defined:
"What is the projected seawater intake requirement for offshore green hydrogen production and storage by 2050, and what strategies could effectively mitigate the ecological impacts of waste streams like brine and cooling water in the Dutch North Sea?"
To address this question, a literature review was conducted on the environmental impacts of offshore green hydrogen production and storage, focusing on brine disposal, cooling water management, and emissions of hazardous substances. The impact of these processes on the marine ecosystem was investigated. A case study modeled the impact of brine discharges from offshore salt cavern construction, while a scenario analysis projected the future demand for salt caverns and seawater for electrolysis and cooling, with hydrogen production and associated storage projected for a 1 GW, 8 GW, and 20 GW scenario in 2050.
This study concluded that while no negative environmental impacts were identified that would preclude the implementation of a comprehensive green hydrogen production and storage system, a definitive assessment of the environmental impacts is not possible without more in- depth research into the combined effects and as yet unexplored influencing factors. This study predicts that by 2050, hydrogen production and storage will require up to 100 m3/s of seawater, primarily for electrolyser cooling, with a minimal amount for salt cavern construction. Brine production could reach 2.3 m3/s during cavern construction, but environmental impacts are expected to be limited to a zone of 900 meters maximum.
Overall, this study demonstrates that brine discharge is likely to have manageable environmental and ecological impacts, but emphasizes the need for additional research to develop detailed plans for a complete P2G system, with a focus on modeling cooling water impacts and monitoring the effects of cooling water use in offshore hydrogen production pilots. | |
