BionicHydrogenBattery

Storing and transporting hydrogen with the help of bacteria
With the biotechnological BionicHydrogenBattery system, Festo is presenting a completely new, fully automated solution for the energy-efficient storage and low-risk transport of one of the energy sources of the future: hydrogen. It is converted into formic acid with the help of bacteria – and, compared to previous processes, at mild temperatures and low pressure.

The core of the biological process is the bacterium Thermoanaerobacter kivui (T. kivui). The bacterium lives in Central Africa, deep in the mud of Lake Kivu, far away from light and oxygen. Nature has endowed it with a special enzyme that enables it to convert hydrogen (H2) and carbon dioxide (CO2) into formic acid (CH2O2) and vice versa.

This property was researched in-depth by the team led by Prof Dr Volker Müller, Head of the "Molecular Microbiology and Bioenergetics" department at Goethe University Frankfurt, with whom Festo is working closely on the project.

Please have a look at how it works in this movie.

Efficient storage
Storing and transporting hydrogen remain a challenge to this day. Common methods compress hydrogen under high pressure, liquefy it at extremely low temperatures or convert it chemically. All these processes are energy-intensive and complicated.

Using the bacteria T. kivui, hydrogen can be converted into formic acid at temperatures of around 65 °C and a low pressure of 1.5 bar, which can be stored and transported with relatively little effort.

Although it is a biological process, this reaction takes place quickly because it is not linked to cell growth. Instead, the bacteria are used like catalysts: they are not used up and the process can be repeated as often as required with sufficient regeneration phases – just like in a cycle.

Automating complex sequences
What was previously only possible in a laboratory can now be achieved on an industrial scale with the BionicHydrogenBattery. Many products from the Festo portfolio are used to automate the highly complex biotechnological processes.

A total of 117 different Festo product types (corresponding to 1,089 parts) are installed in the exhibit. For example, the new modular valve terminal VTUX in combination with the automation system CPX-E controls a large number of valves with a small footprint. The media valves VYKC from our Lifetech portfolio ensure the smooth transport of the viscous biomass solution into and out of the bioreactors. The flow through the filters is regulated by pinch valves VZQA. For precisely dispensing the minutest volumes of liquid into the reactors, the stepper motors EMMS-ST work in combination with pump heads as peristaltic pumps. A colour sensor SOEC detects even the smallest amounts of hydrogen in combination with supraparticles.

Reliable processes
Bacteria T. kivui are anaerobic, meaning they thrive exclusively in the absence of oxygen. The bacteria would die immediately if there was a leak in the system, and therefore pose no risk to people. At the same time, the absence of oxygen makes it impossible for the hydrogen to form an ignitable mixture. In addition, the system only contains very small quantities of it at any one time.

From hydrogen to formic acid and back again
Bacteria have optimised their metabolic processes over millions of years evolution. We can make the most of their capabilities by combining them with technology. The BionicHydrogenBattery is our replication of the biological process on a small scale; thanks to our automation technology we can now scale it up as required.

1: Propagate T. kivui bacteria under optimised conditions in a bioreactor.
2: Hydrogen is produced from water by electrolysis.
3: Bacteria convert CO2 and hydrogen into formic acid.
4: The acid is extracted and poured into a container.
5: Safely transporting the formic acid to where it is reconverted.
6: The same bacteria break down the formic acid back into its components hydrogen and CO2.
7: The hydrogen is converted back into electrical energy in a fuel cell.