German engineering giant Siemens has launched what it calls ‘the world’s largest electrolysis plant’, designed to store excess wind power in hydrogen for use in cars.
The plant in Mainz will capture and store the hydrogen by means of Proton Exchange Membrane (PEM) technology, with the gas later used either as a general fuel or in natural gas pipelines.
The plant, which can process up to six megawatts of electricity, is the largest installation of PEM in the world. Siemens said it could supply up to 2,000 hydrogen-powered cars with fuel and efficiently respond to fluctuations in wind energy generation.
The PEM membrane in the electrolyser is used to separate the two electrodes at which oxygen and hydrogen are formed. On the front and back of the membrane are precious-metal electrodes that are connected to the positive and negative poles of the voltage source, splitting the water by using the surplus energy.
Siemens said the system ‘has a capacity relevant for bottlenecks in the grid and small wind farms’.
The project is a partnership between Siemens, the Mainz energy utility, industrial gases company Linde and the Rhein-Main University of Applied Sciences.
Linde will be responsible for cleaning, compressing, storing and dispensing the hydrogen, which can be fed to industrial systems, or used to fill tanker lorries to go to hydrogen-based car filling stations, or into the gas pipeline network.
Siemens previously tested the technology in cooperation with RWE and confirmed it can respond to fluctuations in energy generation within milliseconds.
With the pending closure of its nuclear reactors and the continuing increase of its renewable energy capacity, Germany will have to focus on deployment of storage technologies to make up for the intermittency of renewable resources.
The development of the Mainz plant was supported by the German Federal Ministry of Economics and Technology as part of the country’s Energy Storage Funding Initiative.