One of the big problems of renewable energies is that they are difficult to store without high losses. Power-to-gas industrial plants make it possible to convert electricity into methane. Using conventional technology to do so has, so far, achieved an efficiency rate of only 54%. A team of researchers led by the Karlsruhe Institute of Technology (KIT) has now succeeded in increasing efficiency by more than 20%.
Power-to-gas plants use an electrolysis process that breaks water down into hydrogen and oxygen using an electric current. The hydrogen then reacts with carbon dioxide or carbon monoxide to form methane, the main constituent of natural gas. Unlike electricity, methane is easy to store. The natural gas substitute generated as part of the KIT project even meets all requirements for being fed directly into the German natural gas grid.
To increase the efficiency, the KIT team led by Dimosthenis Trimis consistently exploited the synergies between electrolysis and methanation and leveraged the process heat resulting from methanation to support the high-temperature electrolysis used. The process was developed within the framework of the EU project HELMETH (Integrated High-Temperature ELectrolysis and METHanation for Effective Power to Gas Conversion) and received funding to the tune of 2.5 million euros from the "European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology" initiative. In addition to KIT, project partners included the University of Turin and the TU Athens, the companies Sunfire and EthosEnergy Italia, as well as the European Research Institute of Catalysis ERIC and the German Gas and Water Association (DVGW).