This hydrogen filling station marks the first time that a steam electrolysis plant in flexible operation is used for the production of hydrogen. It is funded by the state of Baden-Württemberg’s BWPLUS program and administered by the European Institute for Energy Research (EIFER).

Steam electrolyzers (earlier post) are excellent for converting electrical energy into chemical energy. Due to their high operating temperatures of up to 850 °C and the possibility of supplying the required energy in the form of heat, significantly higher electrical efficiencies can be achieved than with low-temperature electrolyzers.

This project allows EIFER to research steam electrolysis technology, which has been tested and evaluated at the cell and stack level in our laboratories for several years now, at the systems level as part of its industrial application.

—Dr. Annabelle Brisse, EIFER project head

The scientific monitoring of the hydrogen filling station will involve testing the electrolyzer’s load-sequence operating capability of more than 5,000 hours. Using a monitoring system, all of the facility’s system parameters will be recorded, and then evaluated and analysed by EIFER.

The electrolysis system is supplied by Dresden company Sunfire. In June 2017, Sunfire delivered the world’s most efficient steam electrolysis module (SOEC) in the context of the Horizon 2020 project ‘Green Industrial Hydrogen via reversible high-temperature electrolysis’ (GrInHy) at Salzgitter Flachstahl GmbH. With an input power of 150 kW_el the module produces 40 Nm³ per hour of hydrogen. It can also be reversed into fuel cell mode with an output power of 30 kW_el.

A particular feature of Sunfire technology is the high electrical efficiency of more than 80% with reference to the lower calorific value of hydrogen as it is not liquid water but gaseous water – i.e. steam – which undergoes the splitting process. The steam required is provided in the form of waste heat from the processes of the smelting plant at Salzgitter Flachstahl GmbH and supplied to the steam electrolysis unit. This is housed in a 20-foot container on the production site. After purification, the crude hydrogen is fed directly into the local H₂ pipeline and recycled. The delivery from Dresden to Salzgitter took place in June 2017. Two smaller modules were put into operation at Boeing back in 2015.

Sunfire is working to bring renewable energies into the mobility sector in an efficient way.

This can happen directly as hydrogen at the filling station, or by supplying green hydrogen, synthesis gas or synthetic crude oil substitute (e-Crude) to refineries for the production of traditional fuels for combustion engines based on water, green electricity and CO₂. The hydrogen filling station in Karlsruhe provides outstanding proof that Sunfire’s electrolysis technology is very versatile.

—Nils Aldag, Chief Commercial Officer at Sunfire

Proponents of fuel-cell vehicles, which use hydrogen to generate the electricity that drives their electric motor, argue that the technology is an important component for future electromobility. Fuel cell vehicles offer long ranges exceeding 400 km (249 miles) and refueling times of less than five minutes. Daimler will soon be unveiling its latest generation of fuel cell vehicles based on the Mercedes-Benz GLC. (Earlier post.)

Through the Clean Energy Partnership (CEP), the public and private sectors are jointly building a network of filling stations in Germany. Daimler is the investor behind the facility in Karlsruhe; the refueling technology comes from Linde. The station will be operated by H2 MOBILITY, a new joint venture formed by the industry partners Daimler, Air Liquide, Linde, Shell, OMV and TOTAL in order to expand the nationwide hydrogen network to as many as 400 stations by 2023. (Earlier post.)

H2 MOBILITY is planning to commission further hydrogen filling stations in the months ahead and recently issued a call for proposals for additional filling-station locations: several stations are to be built in regions with the largest potential hydrogen sales for fuel-cell cars (700 bar).

H2 MOBILITY has been tasked with building and operating a hydrogen infrastructure across Germany. This is unique: nowhere in the world is there a comparable business initiative that solves the chicken-and-egg problem so sustainably. By the end of 2018, 100 hydrogen stations will ensure a basic supply. If the introduction of hydrogen as a fuel is successful and the number of fuel-cell cars continues to grow, we will expand the network to as many as 400 hydrogen stations by 2023.

—Nikolas Iwan, Managing Director of H2 MOBILITY GmbH & Co. KG

Resources

• Annabelle, Brisse & Schefold, Josef (2012) “High Temperature Electrolysis at EIFER, Main Achievements at Cell and Stack Level” Energy Procedia. 29. 53–63. doi: 10.1016/j.egypro.2012.09.008