Deutsche Version  ACT
Physical Storage
Power-to-Gas 12.4.2017

At the Energiepark Mainz, compressed hydrogen tanks are used for temporarily storing the generated hydrogen. The storage capacity will amount to approximately 1000 kg, which corresponds to about 33 MWh of energy. In contrast to the image, the tanks in Mainz will be installed on their sides.
© Linde AG

Gas and fuel from wind

Can wind be stored? Siemens, Linde, RheinMain University of Applied Sciences and the Mainz municipal utility company want to enable that during periods with no wind at “Energiepark Mainz” (Mainz Energy Park). For this purpose the researchers are producing hydrogen from wind energy. From 2015, it is intended to produce hydrogen using a Power-to-Gas plant at the newly developed Mainz Energy Park.

Project status Scientifitic monitoring
Project duration Ocotber 2012 until December 2017

The constantly growing use of renewable electricity generation is placing increasing strain on the German power grid. More and more frequently, solar and wind energy in particular will deliver power at times when it cannot be used. Four prominent partners from the fields of industry, technology and research are planning to collaborate on an innovative solution to this core challenge in German energy policy: over the last one and a half years, Siemens, the Linde Group, the RheinMain University of Applied Sciences and Stadtwerke Mainz have been developing a project funded by the German Ministry of Economics and Technology – from 2015 on, the new "Energiepark Mainz" will produce hydrogen with the help of electricity which has been ecologically generated from wind energy.

  • Two engineers are visually inspecting one of the hydrogen tanks. In addition to the visual inspection, the tanks being operated regularly undergo ultrasound and acoustic emission tests in order to reliably identify any possible signs of damage and material fatigue at an early stage. © Linde AG
  • The pressurised gas tubes are fixed on the lorry trailer. The trailer is used to transport medium-sized volumes of hydrogen from the production site to consumers. Here the hydrogen can either be pumped from the trailer to a stationary tank at the consumer (as in the image) or the trailer can be swapped for an empty one. © Linde AG
  • The control room supplies the control signal which, in the event of high grid loads caused by, for example, the injection of renewable energy, enables the plant to relieve the electricity grid by increasing or throttling the reference power. © Stadtwerke Mainz AG
  • The technician is conducting maintenance work on a control system. A similar control system is being installed at Energiepark Mainz in order to be able to automatically operate all components for the overall system. © Stadtwerke Mainz AG
  • The technician disconnects a cable connected to the control system. A comparable control system is also being installed in the Energy Park. This supplies the entire technical equipment for the Energy Park with electricity. © Stadtwerke Mainz AG
  • The wind turbines currently near the Energy Park are from Enercon. It is planned to install further wind turbines at this site. The operator of the wind turbines connected to Energiepark Mainz is Rio Energie GmbH, a subsidiary of Stadtwerke Mainz AG. © Stadtwerke Mainz AG

Hydrogen can be easily stored and used as an energy carrier in a wide variety of ways. For example, the gas produced in Mainz is to be delivered by tanker to special hydrogen filling stations and used as environmentally–friendly fuel for emission-free fuel-cell vehicles. It is also planned to feed hydrogen into the natural gas grid, where it will be available for gas heating or modern gas and combined heat and power plants. The research project will also examine whether the hydrogen produced in Hechtsheim can be utilized as a fuel for energy recirculation at Kraftwerke Mainz-Wiesbaden AG's Ingelheimer Aue combined cycle power plant to ensure the supply of renewable electricity when no wind is blowing. Aim of the project is the development of a storage plant with the scale to manage bottlenecks in the distribution network (peak-shaving, avoided grid expansion) on one hand, and to function as link between today's small scale (100 kW) and tomorrow's large scale (100 MW) electrolysis plants on the other hand.

The "Energiepark Mainz" will be built in the Mainz-Hechtsheim business park. The electrolysis hall will form the heart of the research plant and will feature a hydrogen electrolysis system developed by Siemens in which water will be broken down into its constituents of hydrogen and oxygen. All the basic components of energy storage (wind power, electrolysis, gas line feed-in, hydrogen compressor, pressurized tank, trailer filling) will be tested at the energy park and explained to further potential users and other interested parties. At an info center on the site, visitors will be able to see how hydrogen electrolysis works and learn about the place of storage technologies in the energy system of the future.

Research focus

Central aim of the project is the development, testing and operation of innovative technologies for the production of hydrogen via water electrolysis using renewable energies. Even today there are times when wind power plants have to be cut from the power grid, due to lacking capacities. In the following years renewable energies will deliver more power than demanded. The “Energiepark Mainz” can be one part of the solution: it can store this surplus environmentally-friendly energy through the decomposition of water into hydrogen and oxygen and therefore provide energy time independent. Thus, renewable energies will become 100% flexible and are available when they are needed.

Supported by: The Federal Government on the basis of a decision by the German Bundestag


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Research funding

The information system EnArgus provides information on research funding, including on this project (German only).