Storing hydrogen in salt caverns: safe, efficient and affordable
Storing hydrogen in salt caverns is an important step in the energy transition. Salt caverns are underground spaces that are well suited to the storage of hydrogen. For over ten years now, Gasunie subsidiary EnergyStock has been safely storing natural gas in these caverns. Thanks to their proven safety, salt caverns make for a promising option for the storage of hydrogen as an energy carrier for the future.
In a nutshell
- Hydrogen is seen as a key energy carrier for the future.
- Salt caverns are a highly promising prospect for hydrogen storage thanks to their storage capacity, safety and low costs.
- Gasunie subsidiary HyStock has successfully completed a hydrogen storage pilot together with research institute TNO.
- Hydrogen can be stored in virtually the same way as natural gas.
- Hydrogen can be transported safely.
Hydrogen as a key energy carrier in the future
Hydrogen is increasingly seen as a key energy carrier for the future. When generated using green energy, hydrogen is a clean energy carrier that can help reduce fossil fuel dependence. And that is how we fight climate change. Hydrogen is the solution to one of the biggest challenges of power generated from renewable sources: storing it for later use.
Hydrogen storage needed for stable supply of energy
An effective energy market cannot exist without good storage facilities, simply because supply and demand are not always synchronised. Hydrogen offers a good way to balance energy demand and energy supply. Storing energy in hydrogen can be a way to ensure that energy will still be available (quickly) during times of low energy production from solar and wind.
Storing hydrogen in salt caverns is a practical solution
A highly promising method is to store hydrogen in salt caverns. Salt caverns are artificial underground cavities in rock salt formations. Their storage capacity, safety and low costs make salt caverns ideally suited as a storage facility for hydrogen. They offer the benefit of a buffer: large volumes of hydrogen can be stored quickly and extracted equally quickly.
Positive experiences with hydrogen in salt caverns
EnergyStock, a subsidiary of Gasunie, has been safely storing natural gas in salt caverns at Zuidwending for more than ten years. These caverns are also ideally suited to the storage of hydrogen, as shown by a demonstration project run by another Gasunie subsidiary, HyStock and research institute TNO at Zuidwending since 2021 to gain experience with hydrogen storage. This trial period ended in 2022. Thus far, the main conclusions drawn from this demonstration project are the following:
- The current way of working when it comes to storing natural gas safely is also suitable for hydrogen storage.
- Hydrogen can be stored in salt caverns in a controlled manner in terms of technical integrity, geological containment, stability and safety.
HyStock’s demonstration project was partly funded through a grant under the Energy and Climate Innovation Demonstration (DEI+) scheme.
Four salt caverns under development
At the Zuidwending site, work is currently ongoing on plans for the creation of four new salt caverns for hydrogen storage. There is a rock salt formation deep underground below this site. Dissolving the salt in this rock salt formation with water, and pumping the resulting brine to the surface will create caverns, i.e. underground cavities.
Six salt caverns for future use
Work has also started on an above-ground hydrogen injection and extraction plant on the Zuidwending site. The six salt caverns that are currently still used as natural gas storage facilities can in the future be repurposed for hydrogen storage.
The benefits of storing hydrogen in salt caverns
- Underground rock salt formations are impermeable, meaning that the gas cannot escape and is not exposed to external influences that could contaminate it either.
- Salt caverns offer great storage capacity and are relatively economical.
- Rock salt is a somewhat malleable and very stable material.
- Caverns are an ideal buffer: hydrogen can be inserted quickly and extracted equally quickly.
Storing hydrogen in salt caverns is comparable to storing natural gas in salt caverns
There are many similarities between storing natural gas and storing hydrogen. So much so, in fact, that it only takes a few minor adjustments to be able store hydrogen in the same way as natural gas. At Zuidwending, measures are taken, just like with natural gas storage, to rule out any possible risk of hydrogen leaking from the cavern. High-quality shut-off valves, seals and a system with pipelines inside pipelines prevent any risk of possible leaks.
Hydrogen transport also safe
Not only is large-scale (underground) storage of hydrogen essential for the development of a hydrogen market, so is good infrastructure. An efficient and reliable transport network is needed to transport hydrogen from storage facilities to where it will be used. This network will be based on the current natural gas network comprising 12,000 kilometres of pipelines. By using the existing network, natural gas pipelines will be reused effectively.
Hydrogen is a highly promising prospect in the energy transition
All in all, storing hydrogen in salt caverns offers a highly promising solution for the storage of large volumes of renewable energy. It is safe, efficient and affordable, and it can help reduce dependence on fossil fuels such as natural gas. And that is the way to fight climate change. Here at Gasunie, we firmly believe that hydrogen will play an important role in the energy transition as an energy carrier. This is why Gasunie is putting its full weight behind supporting hydrogen on a broad scale, including by building hydrogen import, storage and transport infrastructure.
