Swiss researchers have improved the process for electricity to natural gas conversion, making another step towards integrating the technology into a future renewable-energy-based power grid.
Based on the so called Sabatier reaction, excess electricity from photovoltaic and wind power plants could be converted into hydrogen, as a part of a well known process. This hydrogen further reacts with CO2 to produce methane, which can then be stored for longer periods of time and distributed in the natural gas network to be used later when energy is needed.
In the latest laboratory experiment, researchers from the Swiss Federal Laboratories for Materials Science and Technology (EMPA) have tested more efficient catalysts to facilitate the electricity-to-gas conversion. Combining a nanoscale nickel with zeolite, the researchers achieved a higher yield of pure methane that forms the basis of natural gas.
EMPA researcher Andreas Borgschulte explains that methane is produced together with water during the reaction of hydrogen and CO2. Water-binding capabilities of zeolites are then employed to remove water from the reaction mixture to swing the equilibrium towards methane.
The team now seeks commercial partners to help them prove the concept on a larger scale and build a pilot plant.
In the meantime, the researchers will work towards optimising the process, increasing the number of sorption catalysts used to provide a smoother process and looking for more efficient materials to replace nickel.
One of the challenges includes removing sulphur, which is produced in biogas plants together with methane. This unwanted sulphur hinders the reaction and damages the zeolite. However, Borgschulte believes it could be possible to remove the sulphur from the crude biogas to protect the zeolite.