Hydrogen – a long-term storage medium for renewable energies

Electricity from renewable energies abounds in the EWE network area. At times, there is actually more power than people and companies in the region are able to consume. Hydrogen technology offers promising approaches to fully exploit this surplus, integrating it seamlessly into the energy supply system.

Excess electricity can be used to produce hydrogen in a climate-friendly way. This hydrogen can then be stored, transported via the existing natural gas network and reused for an extensive range of purposes exactly when required without emitting harmful greenhouse gases.

The EWE regions provide the perfect environment for establishing this new technology because they offer all the necessary expertise, infrastructure and power from renewable energies, as well as partners seeking to build a successful, climate-friendly hydrogen economy.

The first element in the periodic table: hydrogen

Wasserstoff Foto: Adobe Stock |

To understand why hydrogen can be such a valuable building block for the energy revolution, it helps to zero in on its molecules. H is the chemical symbol for hydrogen, the word derived from the Latin hydrogenium. Hydrogen is the first element in the periodic table and a constituent part of almost all organic compounds.

Two hydrogen atoms and an oxygen atom form the basis for all life on Earth: water or, expressed as a chemical formula, H2O. Electrical energy can be used to produce hydrogen and oxygen from water during electrolysis.

Hydrogen is combustible and can be used as an energy carrier in a similar way to fossil natural gas. Unlike fossil fuel combustion, however, the hydrogen combustion process merely produces water vapour instead of environmentally harmful waste products such as sulphur oxides, carbon monoxide or extremely climate-damaging carbon dioxide.

From wind and sun to green hydrogen


There are different methods available to generate hydrogen. One is electrolysis, which produces climate-friendly, “green” hydrogen.

During electrolysis, electricity is used to split water into hydrogen and oxygen. While electrolysis is more complex than other industrial processes used to produce hydrogen from fossil fuels, electrolysis is a climate-neutral production process if the electricity used comes from renewable sources.

Electrolysis also helps to overcome another challenge in the renewable energy industry since it allows weather-dependent electricity produced from the sun and wind to be converted into the storable energy carrier hydrogen. This hydrogen can then be used for a wide range of applications ranging from mobility to heating.

Over 90 per cent of the electricity flowing through the networks in the EWE region in northwest Germany already comes from renewable energy sources. The flat terrain and the coastal regions offer optimum conditions to exploit wind power extensively on land. Large offshore wind farms also supply substantial electricity from the sea to the mainland.

The region frequently produces more energy than people and companies could ever use. As flexible consumers, hydrogen electrolyzers can help absorb production peaks when this happens; if there is too much electricity from the sun and wind in the network, the electrolyzers run at full speed, while in slack periods, they switch off.

From theory to practical everyday use – the electrolyzer in Huntdorf and Hyways for Future


At its Huntdorf site in Lower Saxony, EWE is conducting a trial to see how a hydrogen economy might work on a small scale. EWE maintains a number of caverns on this site, consisting of giant underground hollows in natural salt domes, where natural gas is stored. It also operates an electrolyzer with a power output of 25 kilowatts (kW) on the same premises.

A 100 kW photovoltaic power plant will cover the cavern facility’s basic requirements initially. The electrolyzer is powered by surplus electricity.

The green hydrogen produced is currently still stored in above-ground storage tanks, but in the future it may also be stored in the caverns on site. The hydrogen produced is currently used to refuel EWE’s own small fleet of fuel cell vehicles at a hydrogen filling station on the Huntdorf site.

EWE has a broader ambition to establish a domestic hydrogen market in cooperation with partners, and intends to invest around 90 million euros in its Hyways for Future project.

What hydrogen can do for the climate – we call it sector coupling

When electrical power is used to generate hydrogen, it produces an energy carrier which can be used for transport, industry, as heating energy or in power plants. This means that different areas in the energy economy unexpectedly become interlinked. The technical term for this interconnection is sector coupling.

Thanks to sector coupling, energy from renewable sources also comes into use in areas such as transport and industry, which are currently still heavily dominated by fossil fuels. However, global climate protection goals can only be achieved if the sectors which currently do too little towards climate protection are also gradually made greener.

EWE believes hydrogen can be used effectively in industry and for long-distance and heavy-duty transport. The transport sector is thus precisely one area where hydrogen fills a gap with comparatively climate-friendly electric mobility, which is particularly suitable for short and medium distances in passenger transport.

Find out more here: Energy revolution on roads with electric mobility

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