Megawatt scale on the Upper Rhine works reliably to generate green hydrogen more economically for mobility. Renewable hydrogen can make mobility greener. However, the costs have to be reduced.

How this works is currently being tested by the energy industry and research in an industrial power-to-gas plant in Grenzach-Wyhlen in southern Germany. The megawatt system has been in operation for four months and up until now, April 2020 all signs are that it works reliably. A research electrolyser connected to it is also running very successfully. The Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) coordinates the project.

The power-to-gas plant with an electrical connected load of one megawatt generates renewable hydrogen using the electricity from the Rhine hydropower plant in Wyhlen. Since it is not necessary to use the public power grid, network charges and the EEG surcharge are not applicable. Compared to power-to-gas plants that are based on wind or solar energy, they achieve high full-load hours because hydropower is available practically around the clock. This further improves economy and quickly enables extensive operating experience.

Over 1,800 operating hours in four months, more than 60 trailers filled since the beginning of December 2019, the system has been running regularly and has already had 1,850 operating hours.

The monitoring system set up by the ZSW, which measures all essential components and subsystems, works perfectly. The system works fully automatically in 24-hour operation both at full load and in various partial load states. ZSW is monitoring the plant, with the help of a remote data transmission and automated data evaluation.

The scientists are investigating among other things, the efficiency of the entire system including all Subsystems. The overall efficiency from electricity to high purity, on 300 bar compressed hydrogen is currently up to 66 percent based on the calorific value of the gas.

Hydrogen

Each of these transportable containers holds around 300 kilograms. The plant can produce up to 500 kg of hydrogen per day. That is enough for an average daily mileage of more than 1,000 fuel cell cars.

Reduce the cost of electrolysers for industry

The research project connected to the commercial facility is also proceeding successfully. In a research facility, the scientists are testing improved electrolysis blocks with a maximum output of 300 kilowatts in parallel operation with the commercial facility. They should lower the price of hydrogen further. But companies can also test and optimize components there so that they can later be transferred to their products. The project thus supports technology transfer to the economy. Last year, the ZSW and its research partners achieved their first success during the test operation of the plant: with new electrode coatings, the researchers achieved 20 percent more power density compared to the electrolysis blocks of the industrial part of the plant. This means: less space and material are required for the same performance.

Long-term

The goal of the ZSW researchers and energy service engineers is to roughly halve the current production costs of electricity-based hydrogen.

The state of Baden-Württemberg is funding the lighthouse project with a total of 4.5 million euros. In 2019, a project based on this was selected as one of the winners of the first round of tenders by the Federal Ministry of Economics as part of the ideas competition “Reallabors of the

Source: BW