A stable energy mix with a green focus

The future belongs to renewable energy. It currently covers around 35% of Germany’s needs, a figure expected to rise to 80% by 2050 and therefore supplying most of the energy required. Wind power and photovoltaics in particular play an important role here. But sometimes the wind doesn’t blow and the sun doesn’t shine – for times like that we need new, environmentally-friendly technologies that store electricity from renewable sources and then make it available when it’s needed. It means that renewable energies can be used with 100% flexibility and provide a stable energy mix with a green focus. That’s what we’re working hard to achieve!


Efficient storage

In order to store large quantities of wind and solar electricity, it needs to be converted. An important element in this is known as the power-to-gas process, which stores energy in the form of hydrogen or methane. Hydrogen (H2) can be produced via electrolysis wherever electricity and water (H2O) are available. The gas generated can then be converted directly and very efficiently into electricity later in a fuel cell or converted back in gas turbine power plants. Carbon dioxide is also required (CO2) to produce methane (CH4) and can be taken from circulating air or upstream industrial processes. Methane can be fed into the natural gas network or used to power cars and ships. It will also make Germany less dependent on imported natural gas.

Electrolysis, methanation  and application

Energiepark Mainz

Power-to-gas already a reality

Since 2012 our parent company, Mainzer Stadtwerke AG, has been working with the Linde Group, Siemens AG and RheinMain University on storing wind and solar energy using power-to-gas. Energiepark Mainz has been producing hydrogen through electrolysis using surplus electricity from nearby wind farms since 2015. The installation has been in regular commercial operation since 2018 and attracts considerable interest both nationally and internationally as a viable long-term project.


Looking to the future

The term power-to-X covers various different technologies. Their common goal is to store surplus electricity from renewable energies or make it accessible for other uses. Using renewable energies, different fuels and basic chemical substances emerge in the process that can then be reused in various ways. This will enable the electricity, heating and mobility sectors to become better connected in future. Some power-to-X technologies are only used for the temporary storage of renewable energy while others are replacing fossil fuels and so reducing greenhouse gas emissions, e.g. in the operation of heat pump systems.

Basic materials, processes and products of power-to-X

Interested in finding out more?


Marco Eggensperger

Authorised officer
Email: m.eggensperger@altus-ag.de