Energy transition and sustainable mobility

We have already implemented the efficient production of biogas from sewage sludge using our high-load digestion process at various municipal sewage treatment plants. Through high-load digestion, the sewage sludge is stabilized with net energy gain, can be optimally dewatered and thermally disposed of at the lowest possible cost. The regenerative energy source biogas is produced as a product. With the biogas obtained, the energy requirement of the sewage plant can be covered and thus further costs can be saved. High load digestion is therefore also an intelligent alternative from an economic point of view and significantly improves the energy efficiency of municipal sewage treatment plants.

Bioenergy is becoming increasingly important as a pillar of renewable energy production, because biogas can be stored for a certain period of time and electricity generation can be adapted to demand. On the other hand, the "cornification" of our farmland has come under criticism, as monocultures are detrimental to the diversity of the plant world and energy crops compete for arable land. This is reason enough to take a close look at the processes in agricultural biogas plants and to optimize their efficiency in terms of process engineering.

We also apply our know-how for the efficient fermentation of organic substances to the use of residual materials from the food industry and agriculture and develop specific solutions, from fermentation tests on a laboratory scale to the design of plants on a technical scale. In the course of the decentralization of the energy industry, low mass flows are becoming increasingly interesting.

"Green" hydrogen (H₂), produced by electrolysis of water with renewable energies, is considered a key element of the energy transition. The demand for renewably produced hydrogen for a climate-friendly economy in industry, transport and heat supply is enormous. Germany and Europe are therefore relying primarily on hydrogen imports from southern countries with sufficient solar radiation all year round.

In two current projects, Fraunhofer IGB is taking a new approach to producing the climate-neutral energy carrier and industrial raw material: Using biotechnological processes, for example microorganisms (purple bacteria) or microalgae, biohydrogen is to be produced from residual material streams such as waste wood or rinse water.

Membranes are expected to play an important role at many points in the production and use of green hydrogen. This starts with the provision of clean water for electrolysis, to the electrochemical splitting of water in polymer electrolyte membrane (PEM) electrolyzers, to the reconversion to electricity using PEM fuel cells.

Membrane humidifiers, which we are developing at the IGB and testing in automated test rigs, can also be used for water management in fuel cells.

Other possible applications for membranes are the separation of H₂-containing gas mixtures by means of membranes, such as palladium membranes or the production of hydrogen in so-called membrane reactors by direct splitting of water.