Emissions from petroleum production account for over 27% of Norway's total CO2 emissions, and a resolute decarbonisation of the industry is needed to meet national obligations under the Paris Agreement. Powering offshore platforms by wind power is thus an important goal, however, intermittent renewable energy sources such as wind and solar power require innovative and cost-effective energy storage methods to balance supply and demand mismatches. Hydrogen storage in salt caverns is potentially a cost effective and safe solution to overcome present limitations in long-term (days, weeks) energy storage. For wind powered offshore platforms this mismatch is estimated to be in the range of 10s to -100s GWH. Salt caverns are artificial cavities in rocks consisting of water-soluble salts and can typically store 10 000 to over 1 000 000 m3 of compressed hydrogen. The salt caverns are manufactured by drilling a well into the formation, pump water into the deep underground and dissolve the salt. Thereby a large cavity deep down in the underground is formed. However, the salt in the underground must be thick and stable to guarantee a smooth construction of the caverns. Preliminary geological mapping indicated that suitable formations are present on Norwegian continental shelf. The present project will evaluate the economic potential, technical feasibility and safety aspects of large-scale offshore hydrogen production and storage in salt caverns, integrated with renewable power generation. Geological material and data collected through 50 years of oil and gas exploration will be used to map the most suitable locations for salt cavern manufacturing and hydrogen storage. Flexible energy storage is a corner stone to fulfil the Ministery of Petroleum and Energy vision of the North Sea as a platform for the Clean Energy Transition. This project will aid to reach this goal by evaluating a crucial component of a diversified offshore energy system along the Norwegian continental shelf.
Developing diversified offshore energy system(s) which can remain in operation and serve a profitable role after oil and gas production has ceased can potentially lead to needed decarbonisation of current oil and gas production. The energy transition creates job opportunities and value creation based on top-level research in the Norwegian energy sector. The diversified offshore energy system(s) addressed in the project includes large-scale hydrogen production and storage in salt caverns. Hydrogen storage in salt caverns is a viable solution to overcome present limitations in long-term (days, weeks) energy storage required by fluctuating renewable energy sources, estimated to be in the range from 10s to -100s GWh for offshore platforms. Gas storage in salt caverns is well established onshore NW Europe and, in this project, suitable locations to manufacture offshore salt caverns on the NCS will mapped and characterised. The safety-related properties of hydrogen imply that the overall risk in many cases will be significantly higher for hydrogen compared to that of ‘conventional’ energy carriers. The current methods for offshore risk assessment to hydrogen installations, including quantification of the inherent uncertainties in probabilistic explosion studies lack predictive capabilities, which will be addressed in the project.
The most critical R&D challenges to be addressed are:
• Determine potential locations on the NCS for hydrogen storage in salt caverns based on available geological material and data.
• Provide recommendations for future development of storage sites and needed data collection.
• Ensure sufficient knowledge in risk assessments for offshore hydrogen installations.
• Adapt modelling tools and design relevant user cases to assess the economic potential and feasibility.