A hydrogen backbone needs storage. In the Netherlands, four to five salt caverns are being planned to store hydrogen. These should be ready in eight years. Nine years later, in 2040, the equivalent of ~50 salt caverns are needed. And then there’s only enough storage for normal weather conditions. Taking into account extreme conditions, requirements could double. Europe can make use of Dutch storage. To ensure enough volume is available, we need a sharp acceleration in development.
Great need for hydrogen storage for industry and dispatchable electricity production
With the rapid expansion of renewable energy sources and the variability of their production, the need for storage in the energy system is growing. For long-term storage (days to seasons), energy is best stored as molecules as it is low cost and easy to store, just like oil and gas in the current fossil energy system.1
In a renewable energy system, underground storage of renewable hydrogen is the preferred storage medium for long-term storage. Peaks in renewable electricity production such as from solar PV in summer can be used to produce hydrogen for immediate consumption and to store hydrogen when supply exceeds demand. Stored hydrogen could, for example, be used to meet the expected baseload demand for green hydrogen from industry, and for green dispatchable electricity production during windless winter weeks (with little solar and wind production but high demand for electricity and heat).
Dozens of salt caverns needed for storage in 2040
According to recent scenarios from the Dutch association of grid operators (Netbeheer Nederland's Integrale Infrastructuur-verkenning 2030-2050, hereafter II3050),2 the equivalent of some 50 salt caverns with working volumes of 0.2 TWh per cavern will be needed for hydrogen storage in 2040. This is about 10 TWh, which is roughly equivalent to the estimated hydrogen demand of Tata Steel in the Netherlands from 2040 onwards.3
This is the demand for storage in an average weather year. If we want to ensure security of supply for extreme weather years with cold winters and/or little renewable electricity, we need roughly twice as much. This is visualised in the figure, where 2016 represents hydrogen storage in an average weather year and 2010 an extreme weather year.
Source: II3050.2 Hydrogen storage needs for 2050, calculated with different weather years for the National leadership 2050 scenario.
Europe can make use of Dutch storage
The need for hydrogen storage volume will become much greater when it’s put to use for the European energy system. The Netherlands, together with Germany and Poland, are likely to play a pivotal role for in Europe because the largest potential for salt caverns lie here, and because most of the depleted gas fields are under the Netherlands and the North Sea. With such a key international role, the needs in the Netherlands become far greater. Hydrogen storage could become a Dutch export product.
Next to salt caverns, gas fields can play an important role for hydrogen storage
From the analysis in II3050 by the Dutch grid operators, the usefulness of hydrogen storage in gas fields alongside salt caverns becomes clear; In 2050, using gas fields next to salt caverns means that roughly four times fewer salt caverns are needed. This is mainly due to the large volumes of gas fields (up to tens of TWh), which fit well with seasonal storage. On the other hand, salt caverns are small and modular (~0.25 TWh), with higher injection and discharge capacities. They can therefore be used well for shorter-term storage and to grow simultaneously with hydrogen demand and supply.4
...but more research and development is needed for all types of storage
Research from the Dutch state-owned manager of underground energy (EBN) and the organisation for applied scientific research (TNO) shows that the potential for storage in salt caverns under land is tens of TWh and in gas fields hundreds of TWh.5 Under sea, the potential for both storage types is also hundreds of TWh.6 To summarise: there is plenty of potential, but apart from salt caverns under land, none of the options are fully proven, and so research and development is needed.
Sharp acceleration in hydrogen storage development needed now
In the Netherlands, one salt cavern of ~0.2 TWh is expected to be in operation by 2028,7 as well as a pilot for storage in a gas field. By 2031, an additional 3 or 4 salt caverns are planned for completion according to the Energy Storage Roadmap.8 This means we will have ~1 TWh of hydrogen storage at most by 2031. Demand for storage will also increase sharply in the years thereafter, due to sharply rising demand for green hydrogen in industry and growing electrolysis capacity.
To have a functioning Dutch hydrogen economy in 2040, an additional 9 TWh of storage is needed, and in extreme weather years even 20-35 TWh more. In other words, we need major acceleration; building the equivalent of around 5 salt caverns per year between 2032 and 2040. Gas fields could contribute significantly, but there is currently no plan to reach these storage volumes. Given the long lead times, it becomes apparent that we cannot rely solely on private sector investments. If volumes were going to be achieved, we would already need to be seeing much more activity.
With insufficient hydrogen storage, we risk not capturing our renewable electricity, not greening industries dependent on hydrogen, not having enough power during scarcity, and ultimately failing to meet our climate targets. At the same time, Europe can make use of Dutch storage. Therefore, the Netherlands needs an approach to realise large-scale hydrogen storage in salt caverns and empty gas fields under sea and land as soon as possible.
1 Which storage technology is most cost-effective depends on the frequency and volume of storage required. Batteries, for example, are very effective at storing electricity at scales from seconds to hours and sometimes days.
4 Besides salt caverns, pipelines and steel tanks also have an important yet limited role in short-term hydrogen storage, as previously analysed by Common Futures.