Fraunhofer IGB: From Wood Waste to Biohydrogen

H2Wood – BlackForest, that's the name of a joint project subsidized with twelve million euros by the BMBF, aiming for a climate-neutral circular economy based on wood. Within this framework, the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB is to develop a biotechnological process that generates hydrogen and bio-based coproducts from wood waste.

Also involved as a project partner is the Campus Schwarzwald in Freudenstadt, where the process will be demonstrated in a specially designed facility. Together with the University of Stuttgart, the Fraunhofer Institute for Manufacturing Engineering and Automation IPA also aims to demonstrate how this energy carrier can be used by both energy suppliers and local businesses.

Since August 2021, the Black Forest region has been working towards the goal of energetically utilizing regional wood waste, which arises from furniture and building materials processing and the demolition of buildings, to produce renewable hydrogen instead of partially incurring high disposal costs for the waste.

"Following the approach of the bioeconomy, we aim to produce climate-neutral biohydrogen as well as additionally usable substances such as carotenoids or proteins from old wood and wood waste using biotechnological processes," explains Dr. Ursula Schließmann from Fraunhofer IGB, who coordinates the H2Wood project.

Partners in the research consortium, besides Fraunhofer IGB, include the Fraunhofer Institute for Manufacturing Engineering and Automation IPA, the Institute for Industrial Manufacturing and Management IFF of the University of Stuttgart, and the Center for Digitalization, Leadership, and Sustainability Schwarzwald gGmbH (Campus Schwarzwald).

"The initiative's objective is to save CO2 emissions and support the region in achieving its climate goals with the help of a comprehensive concept for a sustainable and innovative biohydrogen supply for the Black Forest," says Stefan Bogenrieder, Managing Director of Campus Schwarzwald.

Carbon dioxide is to be saved in two ways: On one hand, the renewable biohydrogen is to replace fossil energy carriers, and on the other hand, the residual and old wood provides not only hydrogen but also carbon-based coproducts.

"The CO2 released from the wood is bound in the form of carbon-based coproducts and thus returned to the natural carbon cycle," explains Schließmann.

A research team is also addressing the question of what quantities of residual and old wood are generated in the woodworking trade and municipalities, how much hydrogen could be generated from it, and what the potential savings in CO2 emissions would be. Additionally, the team is investigating how the generated hydrogen can be best stored, transported, and used - as fuel for vehicles, fuel for blast furnaces and fuel cells, as well as raw material for industrial processes and chemical byproducts.

According to Dr. Erwin Groß from Fraunhofer IPA, the energy consumption of industry, households, and local and long-distance transport is analyzed and evaluated to derive potentials for decentralized hydrogen production and use within the Black Forest region. The results of the surveys and calculations will then be summarized in a hydrogen roadmap for the Black Forest region.

Since no facility currently exists that produces biohydrogen on a larger scale, Fraunhofer IGB is developing and researching the necessary processes. Subsequently, this is to be implemented in an integrated facility at Campus Schwarzwald in Freudenstadt.

A prerequisite for the biotechnological conversion is the pretreatment of old and residual wood. According to Schließmann, all chemical components of wood waste from house demolition, furniture construction, and building material production, such as adhesives like resins and phenols or paints, must first be removed so that the bacteria and microalgae can do their job.

Additionally, the wood has to be broken down into its components, and the obtained cellulose has to be split into individual sugar molecules, which serve as feed for the hydrogen-producing microorganisms.

The H2Wood – BlackForest project is funded until July 31, 2024, with a total amount of 12 million euros by the Federal Ministry of Education and Research (BMBF) within the framework of the idea competition "Hydrogen Republic Germany."

What does that mean?

Residual and old wood is definitely a valuable raw material - the more efficiently and diversely it can be utilized, the better.