Private customers will be able to generate hydrogen using small wind turbines in the future, according to the plan.
The main technologies needed are small, powerful rotors and safe tanks, which are currently being developed by experts at the Fraunhofer Institute for Applied Polymer Research IAP, BTU Cottbus, and an industrial partner.
Private households account for roughly a quarter of Germany’s overall energy consumption, according to data from the German Environment Agency. Natural gas and crude oil provide about half of this energy. This figure is sobering in light of the increasing severity of climate change.
Prof. Holger Seidlitz, head of the “Polymer Materials and Composite PYCO” research, says, “Hydrogen derived from renewable energies has so much more potential as an energy carrier for the future.”
He’s taking a two-pronged approach to the future of hydrogen with his team and a medium-sized business: First and foremost, he is concentrating on obtaining the energy required for hydrogen production. To accomplish this, the collaboration partners are currently building a small and powerful wind power plant. Second, the team is working on a solution for storing this vital gas. To this end, they are developing new forms of fiber-reinforced composite hydrogen tanks.
Hydrogen for cars and fuel cells
Holger Seidlitz says, “The aim is to build the wind turbine small enough to allow private individuals to have a device like this in their backyard.” “Hydrogen will be generated on-site in a small electrolyzer and stored in a tank. It can then, for example, power a fuel cell inside the home, which generates both heat and electricity. Drivers of hydrogen-powered cars will be able to refuel their vehicles at home in the future. The concept’s real strength is that the entire system is built to be small but incredibly efficient,” Seidlitz emphasizes. Let’s start with a wind turbine. Experts in lightweight construction have developed a new propeller that can start spinning even in a light breeze. “The wind here in Lusatia is much weaker than it is in Northern Germany,” says Marcello Ambrosio, the Fraunhofer IAP mechanical engineer in charge of the project. “In comparison to traditional small wind turbines, we engineered the rotor blades to accommodate these wind conditions and reduced their dimensions by about 30%.” Fraunhofer IAP recently purchased an industrial 3D printer that can create items up to two meters by two meters in size. Marcello Ambrosio and his colleagues recently used the technique to create a plastic mold for making fiber composite rotors for poor winds. EAB Gebäudetechnik Luckau, a company that specializes in lightweight construction, supported them.
Rotors that are light and agile
Fiber-reinforced composites are made by carefully placing fiber strips into a mold and then hardening them with resin or other synthetic materials to form a part. Strips are frequently mounted by hand. A modern automated fiber placement system at Fraunhofer IAP performs this task, precisely positioning the reinforcement fibers in the mold. “The distinction between this method and manual positioning is that there are less overlaps, which helps one to reduce the dimensions significantly,” Ambrosio says.
The rotors are built to be more efficient in weaker winds, but they can also withstand strong winds. In a storm, the rotor blades are built to yield and bend, then rotate away from the wind. “As a result, the turbine slows down its rotation speed on its own, avoiding any damage,” explains Holger Seidlitz. As a result, complex control technology and complicated procedures are no longer needed. In the next few months, the rotors will be put to the test in the open. They’ll have to show that they know how to operate traditional small wind turbines.
Protection sensors installed into the tank
The hydrogen tank in the second project is also made with lightweight construction technology. Hydrogen tanks for industrial use are usually made up of two pressure-resistant steel containers. Lightweight tanks made of carbon fiber composites, on the other hand, would require far less material, be far easier to manage, and offer distinct advantages, especially for mobile applications. Having said that, they must be highly cautious. In the presence of atmospheric oxygen, hydrogen can form an explosive mixture, so it must not be allowed to escape. The Lusatia team is suggesting an intriguing approach here as well. Carbon fiber strips are woven onto a cylindrical body to create the tanks. These strips are impregnated with synthetic resin and then harden to form a tank that can withstand hundreds of pounds of pressure. Sensors are also being integrated into the tanks to detect leakage, according to the experts. Marcello Ambrosio explains, “We’re actually using 3D printers that can process electrically conductive dyes.” “These dyes are infused directly into the fiber composite,” says the researcher. And tiny electronic components can be integrated into the tank wall by the researchers. This early warning system is one of the most important requirements for potential end-user safety.
Importantly, Holger Seidlitz emphasizes that the research collaboration is beneficial to the field. “The institutional change has had a major impact on Lusatia. Coming from this area, I believe it is critical to include small and medium-sized businesses in our research projects in order to build continuous value chains.” He’s now merging two technologies — renewable energy and hydrogen technology — with the wind turbine and the tank, and both will be critical in the coming years.