Solar Hydrogen Bavaria - Entry into H2 Technology

Author: Dr. Klaus Hassmann, Cluster Energietechnik (As of: July 2017) In 1986, the Solar-Wasserstoff-Bayern GmbH (SWB) was founded ¹. The shareholders were the then Bayernwerk with 60% and the companies BMW, Linde, Messerschmitt-Bölkow-Blohm (MBB) and Siemens with 10% each. The goal was the large-scale testing of important system components and their technological linkage for a later hydrogen economy. The project was implemented at the Neunburg vorm Wald site in the Upper Palatinate. The project was launched in 1987 and completed in 1999. In 2000, the site was handed over to the town of Neunburg. A total of DM 145 million was spent over two project phases. The project was subsidized by 35% from the federal government and 15% from the state of Bavaria. The author was a member of the shareholders' meeting for one of the minority shareholders; in this capacity he was able to influence the project content.

Facility structure/results (see functional diagram at end of report)

1. Power generation

Construction: Installed were 372 kW of photovoltaic (PV) modules in conventional and advanced technology supplied by German manufacturers; monocrystalline and polycrystalline thick film technology were used, as well as some modules in amorphous thin film. The modules were mounted on racks that tracked the sun. None of the then established German suppliers/developers is in business today.

Result: As far as the author still remembers, delamination as well as discoloration occurred sporadically in the PV, and defects in the current collectors of the PV module occurred in one PV type. The causes were identified and eliminated in cooperation with the suppliers; the defective modules were replaced. Recommendations for improved assembly were developed for some types. After the modifications, the affected solar cells/modules operated reliably.

2. H2 generation

Construction: For H2 generation, 3 electrolysers were tested, each with about 100 kWel, two at 1.5 bar  and one under pressure (32 bar).

Result: About 25 Nm3 of H2 was generated per hour with each of the 3 electrolysers. The pressure system did not run satisfactorily at first; however, after modification, it ran well. The two low-pressure systems also required some modifications; after that, long-term operation ran smoothly.

3. Storage

Structure: The product gases H2 and O2  from the electrolysers were purified and compressed with compressors up to 30 bar; H2 was collected in two pressurized storage tanks (30 bar) with a total capacity of 5000 Nm3, O2 in a 50 Nm3 storage tank (also 30 bar). In addition, one storage tank for liquid gas and one metal-hydride storage tank were tested.

Result: In the processing and gas storage systems, some problems sporadically occurred in the compressors and in components of the decentralized process control system, which could be eliminated.

4. H2 utilization

Regenerative power generation 

Construction: An 80 kW fuel cell plant (PAFC: Phosphoric Acid Fuel Cell) was procured and operated from a Japanese supplier for operation with H2 or natural gas; heat extraction at 160°C was possible.

Result: The operating results of the PAFC were in line with expectations after some rework.

Heating and cooling

Construction: Two 20 kWth gas boilers each were installed, one operated with air, the other with oxygen. One is a modified standard boiler that has been expanded to include premixing of fuel gas and air and a catalytic burner with 10 kW of thermal capacity. With the catalytic technology, only a small amount of nitrogen oxides is produced and released into the environment due to the relatively low combustion temperature of less than 900°C. A 17 kWth catalytically heated absorption refrigeration system was installed to generate cooling.

Result: The experience gained from operating the systems proved promising.

Mobility Propulsion

Construction: The mobile fuel cell application was tested using a forklift truck powered by a prototype polymer electrolyte membrane (PEM) cell with a nominal electrical power of 10 kW. A UBoot cell converted from hydrogen/oxygen to hydrogen/air was used for this purpose. For about 8 hours of operation, the PEM hydrogen was supplied via a 26 Nm3 hydride storage tank before the storage tank had to be recharged.

Result: The forklift truck with the PEM fuel cell was successfully used as an experimental vehicle, but also as a work tool.

Mobility refueling

Setup: An automatic 3000 liter liquid H2 refueling system was used to practice and optimize the refueling process on a passenger car.

Result: Vehicle refueling required the highest precision in process engineering; it must cope with the large temperature differences from the inside (liquid hydrogen) to the outside (ambient temperature). Initially, the refueling process took far too long and losses were far too high. After some improvements in process engineering and handling, a refueling operation eventually took only 6 minutes with gas losses in the single-digit percentage range.