The British power-to-gas energy company ITM Power announced in a press release on 11th February 2015, that its proton exchange membrane (PEM) electrolyser had performed well in tests conducted for the Thüga Group in Germany.(1.) The electrolyser which has been in operation at Frankfurt-am-Main in Germany since 2013 converts electrical energy into hydrogen gas, which is then injected into the gas distribution network.
During initial tests the electrolyser recorded an efficiency of up to 77% when operating between 50 and 325 kilowatts. Stress tests on the equipment have been carried out jointly by the European Institute for Energy Research and DVGW Research at the Engler-Bunte-Institut. As part of these tests the variables of efficiency, control speed, load behaviour, and gas quality are being analysed.
A piece of plant equipment such as the PEM electrolyser in effect connects an electricity grid to a gas network, while at the same time making renewable systems of electricity generation such as solar panels, wind turbines, and tidal water turbines more efficient. Power-to-gas technology tackles the problem that renewable sources of energy are unreliable. Wind turbines only produce electricity when the wind is blowing, and solar panels only produce electricity when the sun is shining. However, with power-to-gas electrolysers, electrical energy can be stored in the form of hydrogen gas, when wind turbines or solar panels are producing electricity at their full capacity.
At the moment the Thüga Group’s power-to-gas plant at Frankfurt is operating on a very small scale, so its energy storage potential is limited. However, the press release from ITM Power said: “According to a Thüga analysis, energy storage requirements could reach 17 Terawatt hours (TWh) by 2020 and could be as high as 50 TWh by 2050.”
In future the electricity grid will be balanced, as excess electricity is turned into gas and injected into the gas network, when there is more electricity than demand. Likewise the gas that has been stored in the gas network will be used by gas power stations, when there is more demand on the grid such as in the evenings, but less power generation from renewable sources. The combination of the electricity grid and gas network in this way will create an intelligent energy system.
©Jolyon Gumbrell 2015