With the inauguration of the plant, a big hurdle to the marketability of power to gas technology has been overcome. The researchers in Stuttgart are now close to achieving the industrial scale application of this alternative storage solution for renewable power.
ZSW has been working together with Fraunhofer IWES and SolarFuel GmbH to optimise the technology and develop an efficient industrial scale solution. With the 250 kW research plant going into operation successfully, the scale up to 1-20 MW range relevant for the industry has become easier.
"Our research plant works dynamically and intermittently. In contrast to the first plant, it can respond flexibly to fluctuating energy supplies from the wind and sun and can also respond to sudden interruptions," explains Michael Specht, head of ZSW’s Renewable Fuels and Processes research department. "That is a requirement for future energy systems with a high proportion of renewable electricity."
Another advantage for its application is that the control and regulation technology corresponds to the technology used by future large-scale industrial plants.
The gas grid offers ample storage opportunities for solar and wind power. Solar and wind generated power is channelled into electrolysis which produces hydrogen. A further step in the methanisation chamber can additionally convert hydrogen, with the input of carbon dioxide, into methane gas. This can then be fed into the gas grid. The gas can be stored in natural gas storage caverns or chambers or used for tanking of vehicles or industries. Alternatively the gas can also be converted back into electricity when needed.
Baden-Württemberg’s Environment Minister Franz Untersteller praised the progress made with the Power-to-Gas technology. "In order to master the challenges posed by the energy revolution, we need innovation and new technologies. With a continually growing proportion of renewable electricity, this also includes the research and use of storage gas. The 250-kilowatt research plant is a successful step in establishing the new technology," he said.
SolarFuel is also constructing a 6 MW power to gas plant for Audi AG in Werlte, Lower Saxony. The experience gained from the ZSW’s 250-kilowatt research plant will also be incorporated into the Ingolstadt-based company’s "e-gas" project.
The proportion of green electricity in the German grid is growing enormously. That is presenting the energy system with new tasks: with a high proportion of wind and solar energy, the electricity volume fluctuates considerably in accordance with the weather conditions. In some regions it is already no longer possible to feed surplus green electricity into the grid. Between 2020 and 2030, surplus electric power in the gigawatt range can be expected throughout Germany during specific seasons.