Photographer: Unsplash/Christian Löwhagen/Chalmers University of Technology

In an article published in Nature Energy, researchers from Chalmers University of Technology, Rise Research Institutes of Sweden, and Technische Universität Berlin have conducted a comprehensive analysis and presented what Europe's future energy system could look like—including electricity, heating, industry, and transportation.

The researchers looked at two emission targets for energy production: one with zero carbon dioxide emissions and the other with negative emissions (minus 110 percent compared to 1990). The biomass in the system consists mainly of forestry and agricultural waste from Europe, with a more expensive portion imported.

Lead author Markus Millinger, who was a researcher at Chalmers during the study and is now a researcher at the Rise research institute, notes that biomass plays a surprisingly important role in the energy transition.

"One thing that surprised us was how quickly costs rise if the availability of biomass for energy production decreases, because the costs of alternatives are high. If biomass were completely phased out, the costs of negative emissions energy production would increase by €169 billion per year compared to the same system where biomass use would be cost-optimal. This is a 20% increase, which roughly corresponds to the cost of phasing out wind power."

If the availability of biomass is limited to the current level of European energy production, the additional costs would be 5% compared to the cost-optimal level.

Markus Millinger, Senior Researcher, Rise Research Institutes of Swede Photographer: Christian Löwhagen/Chalmers University of Technology

"However, the economic aspect is perhaps not the biggest problem," says Millinger. "The biggest difficulty may be expanding the range of options. Even with biomass in the system, it is a real challenge to expand the use of fossil-free energy to the required level. Further restrictions on biomass supply would make the energy transition much more difficult, as even larger amounts of other fossil-free energy sources would be needed."

"In addition, we would lose the opportunity to achieve negative emissions offered by biomass utilization. To achieve negative emissions in the energy sector, carbon capture directly from the air would have to be expanded significantly. This is a much more expensive technology that requires energy input rather than producing net energy."

Carbon capture is most important

The key conclusion of the study is that the value of biomass in the energy system is primarily linked to its carbon content. Biomass is less important as an energy source.

Current large-scale technologies for utilizing the energy content of biomass, such as burning it in power plants, can be combined with technologies that capture carbon dioxide from waste gases. The carbon dioxide can then be either stored permanently in the ground or reused as a building material, for example in fuels and chemicals.

Biomass can thus produce energy while enabling negative emissions or replacing fossil raw materials. It is precisely the latter possibilities that have now proven to be the most important for the climate transition. It is therefore crucial that carbon atoms are captured for storage or reuse in an efficient manner, but the intended use of the energy content of biomass is less important.

"As long as carbon atoms are utilized, it is not decisive in which sector biomass is used, except that it is advantageous to use a small portion of biomass as a flexible reserve for electricity generation to strengthen security of supply," says Millinger.

"Therefore, factors such as regional conditions and existing technical infrastructure are important in determining what is most advantageous. This means that countries can choose different paths if they want to use biomass to achieve negative emissions – for example, through the production of electricity, heat or biofuels."

Expanding the knowledge base for policy development

The researchers used an advanced model that includes more technologies and is more detailed than previous studies. The model also shows how all sectors of society influence each other in the energy system. The new study thus provides a broader knowledge base for policy development, particularly with regard to biomass and negative emission technologies.

"Carbon capture and storage or reuse, for example in the production of advanced fuels, requires large initial investments and the establishment of long-term, sustainable, and reliable value chains. A market for fossil-free carbon dioxide would significantly strengthen the potential for such investments compared to the current situation, where energy is the primary value. However, this requires policymakers to create stable policy instruments to capture the high value of fossil-free carbon atoms in the climate transition," says Millinger.

Technological developments and policy have promoted the increased use of bioenergy in the EU. However, there are also policy instruments that restrict its use in various ways because of potential negative impacts such as rising food prices, deforestation, and biodiversity loss.

Göran Berndes, Professor, Department of Space, Earth and Environment, Chalmers University of Technology Photographer: Anna-Lena Lundqvist/Chalmers University of Technology

"The bioenergy sector is developing in a situation where agriculture and forestry are facing increasingly stringent sustainability requirements," says Göran Berndes, professor of biomass and land use at Chalmers and co-author of the study. "As the climate transition is expected to increase pressure on forests and agricultural land, it is important that there are regulatory systems in place to steer development in a positive direction."

"At the same time, bioenergy systems can be designed to promote more efficient use of resources and mitigate the negative environmental impacts of current land use. If policy instruments are designed to reward landowners and other actors for 'doing the right thing', this in itself can steer development away from environmentally harmful activities," says Berndes.