Wind energy will become a primary energy source of the future. But the wind is not really reliable. Sometimes it produces more power than is needed and wind turbines need to be shut down. Sometimes it's the other way round. Converting electricity into hydrogen is an optimal way to store and harness excess wind energy.
The challenge: using energy instead of switching off wind power plants
There are times when wind turbines have to be shut down because the electricity produced exceeds current demand. On the other hand, there are phases in which it is the other way round. A low power production is not really a problem, because somewhere in the European grid there is always sufficient wind. But it makes sense to use current overproduction instead of switching off wind power plants.
A path to this goal is called sector coupling, meaning the conversion of electrical energy into other energy sources and vice versa.
The solution: turning unused electricity into hydrogen
Wind to Gas Energy GmbH & Co. KG was founded by 15 wind farm operators in the Schleswig-Holstein region of Germany. The aim of the company is to avoid the curtailment of wind energy production by converting excess wind energy into hydrogen.
Hydrogen can be used in many ways – as a chemical raw material in industry, in conjunction with natural gas for heating buildings and for driving fuel cell vehicles. A key advantage is that the use of hydrogen does not require any new infrastructure. Instead, the existing natural gas network can be used. Hydrogen produced from wind energy can be mixed with natural gas and thus contributes to a certain extent to the independence of external energy suppliers.
With an electrolysis test facility in Brunsbüttel, Wind to Gas Energy wants to demonstrate that such a sector coupling works and is economically feasible. The plant is a project within the framework of the initiative North German Energy Transition 4.0 (NEW 4.0), which will be completed by the end of 2020. The project is being funded within the framework of the program »Schaufenster Intelligente Energie – Digital Agenda for the Energy Transition« (SINTEG) of the Federal Ministry of Economics and Innovation (BMWI). The project partners in the field of science include Schleswig-Holstein Netz AG and the Fraunhofer Institute for Silicon Technology (ISIT) in Itzehoe.
The compact electrolysis plant is housed in two containers and has a capacity of 2.4 MW. It serves to split distilled water into hydrogen and oxygen with the help of wind power. The electricity comes from five wind turbines in the region with a total output of 15 MW. At peak times, the plant is able to produce up to 450 cbm (or 40 kg) of hydrogen per hour. This could easily provide sufficient energy for 1740 cars powered by fuel cells.
The hydrogen from the pilot plant is primarily fed into the public grid, for which purpose a new compaction and feed station was created. In addition, a hydrogen filling station for cars will be built at the site.
Potential: Energy in the form of electricity or hydrogen, electrons or molecules
The vision of the wind2gas project is the close interaction of wind energy and hydrogen gas. Both are CO2-free energy sources that are easy to transport. A possible future scenario is the conversion of excess wind energy into gas and the re-conversion of this gas-bound energy in situations of increased electricity demand. This makes it possible to realize a regionally focused energy supply that can respond flexibly to supply and demand.
Presently, Wind to Gas Energy sees the current legal situation as an obstacle to economic sector coupling. For example, the company has to pay an EG levy on the electricity generated in its own wind farm, which does not allow attractive price structures. After completion of the project, proof will be provided that sector coupling is a sensible way of storing energy. The breakthrough of technology then depends on politics.