Power-to-gas, i.e. the conversion of surplus electricity into hydrogen, is currently being discussed as a way for the gas industry to contribute to the increasing integration of renewable energies like wind and solar power into the existing energy infrastructures. The produced hydrogen could either be stored and used directly, or it could be injected into the natural gas grid. A third option would be to combine the electrolysis with a subsequent methanation process to convert hydrogen into methane which then could again be injected into the grid. The two latter options would turn the gas grids into huge energy storage devices.
A direct injection of hydrogen into the existing gas grids would offer a number of advantages but there are concerns how end-use applications of natural gas across different sectors might respond to the changing fuel characteristics. Manufacturing processes in thermal processing industries are considered particularly critical in this context. In the course of a publicly funded German research project, GWI investigated the impact of significant concentrations of hydrogen in natural gas (up to 50 vol.-%) on some industrial firing systems in terms of efficiency, heat transfer and pollutant formation. The results of both experiments on a semi-industrial scale as well as CFD simulations indicate that the effects of the presence of hydrogen in natural gas can be managed in gas-fired thermal processing applications if appropriate measurement and control systems are used.
The main results of this investigation will be presented in this contribution.