Denmark: 18 September 2024

Thumbs up for Sorø Bioenergi

We offer a close look into Sorø Fjernvarme’s biomass-fired combined heat and power (CHP) plant to understand its fuel sourcing and operational experiences. The plant is located in the town of Sorø in Denmark, a municipality with around 8,000 residents, and was officially inaugurated on October 14, 2021, following a groundbreaking ceremony in June 2020..

A story brought to you by:

Sorø, a historic town in Region Sjælland, Denmark, is home to a new biomass-fired combined heat and power (CHP) plant, Sorø Bioenergi, which was officially inaugurated on October 14, 2021.

This facility marks a significant step in the town’s transition to renewable energy. The plant not only represents a technical and sustainable achievement but also as a striking architectural feature in the region, fulfilling a key objective set by the local town council.

AffaldPlus and Its Role in Biomass Fuel Supply

The plant’s fuel is sourced and processed by AffaldPlus. AffaldPlus plays a vital role in transforming local green waste into biomass fuel, making the project both sustainable and community-driven.

In fact, the municipality-owned non-profit company operates multiple waste processing facilities, including waste-to-energy (WtE) plants in Næstved and Slagelse, and manages green waste from 13 depots. One of these is Næstved Biobrændsel, the central biomass processing terminal that supplies the fuel to Sorø Bioenergi. Here, garden waste such as hedge trimmings, tree prunings, and other park waste is processed into biomass fuel.

Each year, around 53,000 tonnes of green waste are processed at Næstved Biobrændsel, with 11,000 tonnes becoming biomass fuel. This fuel is then transported to Sorø Bioenergi to generate district heat for Sorø, replacing the natural gas previously used.

Architectural and Environmental Considerations

The CHP plant was designed not just as an industrial facility but as a landmark for Sorø. Its design was influenced by traditional local farmsteads, incorporating sustainable materials such as heat-treated wood for the façade and a green sedum roof to promote biodiversity and manage rainfall. These design choices ensure that the plant contributes positively to the town’s visual and environmental landscape.

Overall, the Sorø Bioenergi project stands as a success, demonstrating how modern technology can be integrated with sustainable construction and community involvement. It offers a model for other regions looking to transition to renewable energy while maintaining strong ties to the local economy and environment.

Find out more on Bioenergy International, and discover their first-hand insights on Denmark’s path to defossilisation.

About the campaign

The European Bioenergy Day campaign is powered by Bioenergy Europe and relayed across Europe by both national and international partners supporting the view that bioenergy is more than a renewable energy source, it is also a reliable path that will lead Europe to achieve its renewable energy transition.

European Bioenergy Day on Social Media

Solid Biomass Conversion Processes

Logging, grinding, screening and drying operations are mechanical processes for enhancing solid biomass fuels. These operations help transform biomass into homogeneous fuel that is easy to handle, with a higher energy recovery (eg. woodchips, wood logs, agrofuel). In general, moisture content in woodchips used for energy generation in municipal or industrial plants ranges between 20-30%.

Densification is another popular way to transform woody material into an advanced fuel with high calorific value. This process involves compressing biomass and lowering moisture levels to a range of 8-10%, allowing for an homogenous fuel – either in the form of pellets or briquettes. The heat during compression fuses the lignin in the biomass, naturally binding the biomass together in a new, enhanced shape. Thanks to densification, the homogenous biomass fuel is easier to transport and can be used in automated biomass installations, such as pellet stoves and boilers.

Thermo-chemical conversions are now used to produce fuel with even higher calorific value, utilising torrefaction or steam explosion technologies. During the torrefaction process, wood is subjected to temperatures of 230°C-300°C at atmospheric pressure without oxygen. Comparable to some extent to coffee torrefaction, this method creates a fuel with unique characteristics. As compared to conventional wood, torrefied wood has very low (>5%) moisture content, is easily grindable and is relatively hydrophobic.

Thanks to advanced technologies, woody biomass can also produce liquid and gaseous fuels. Pyrolysis, for instance, is a thermal-chemical conversion that requires a high temperature (>400°C) and little oxygen to convert solid biomass into gas, liquid fuels (pyrolysis oil) and/or biochar. Gasification is another thermo-chemical conversion that takes place at high temperatures (>800°C), with limited oxygen and/or steam, and converts solid biomass into synthesis gas, known as syngas – which contains carbon and hydrogen and can be used to produce liquid fuels such as biodiesel.

Wet Biomass Conversion Processes

Wet biomass is present in high volume across Europe (manure, agricultural waste and by-products). As it contains too much moisture to be converted efficiently into energy via a direct combustion process, other conversion pathways and energy outputs have been developed by the biogas (eg. anaerobic digestion) and biofuel sectors (eg. fermentation). Anaerobic digestion and fermentation are the two main conversion pathways used for converting wet biomass feedstock into advanced fuel.

Anaerobic digestion is the microbiological process of decomposition of organic matter, in the absence of oxygen, and is common to many natural environments; it is largely applied today in order to produce biogas in airproof reactor tanks, commonly referred to as digesters. A wide range of micro-organisms are involved in the anaerobic process which has two main end products: biogas and digestate. Biogas is a combustible gas consisting of methane, carbon dioxide and small amounts of other gases and trace elements. Biogas can be used in direct combustion to produce heat, but also power if converted within a cogeneration plant or in adapted gas motors. Biogas can also be upgraded via purification processes to a biomethane that can be injected into the existing natural gas networks, used as a chemical product and/or vehicle fuel. Digestate is the decomposed substrate, rich in macro- and micro-nutrients and therefore suitable for use as plant fertiliser.

Fermentation is a biochemical conversion whereby microorganisms, including yeast and bacteria, convert matter into products such as ethanol and liquid transport fuel (biodiesel). This process is done in several stages. First, sugary and starchy feedstock such as corn must be crushed and combined with water, allowing enzymes to convert this starch into sugar. This ferments along with the addition of yeast and is distilled into bioethanol. Bioethanol can also be produced from cellulosic biomass, such as grass, wood and stalks, via fermentation; however, this process is more complex and involves a mechanical pre-treatment and the addition of enzymes, or the breakdown of the lignocellulose into sugar through hydrolysis, followed by the same procedure.

Solid bioenergy feedstock

Renewables represent 8,0% of EU-27 total energy consumption (22.473 kilotonnes of oil equivalent) in transportation, of which 68% is provided by biofuels in 2018. It is rather challenging to foresee how biofuels (in particular first-generation biofuels) will continue to develop, since recent EU legislation established a quota for these biofuels. EU statistics on renewables in transportation can also be misleading regarding the actual level of production, because multiple counting rules are applied in accordance with the EU renewable energy directive. Looking at it in more detail, the biofuel market is driven by biodiesel and bioethanol. Biodiesel was the first biofuel developed and used in the EU in the transport sector in the 1990s. EU-27 remains the world’s largest biodiesel producer and it consumed 13,303 Ktoe in 2018. By comparison, bioethanol consumption in 2018 reached 2,620 Ktoe for an actual production of 2,365 Ktoe (Biofuels Report, 2020).

Bioenergy comes in all shapes and sizes

Within our close environment, a great source of organic materials such as plants, algae, or organic wastes, can be valuable fuels as soon as a technology makes it possible to efficiently extract all of its energy potential. Bioenergy players traditionally refer to biomass to describe those usable feedstocks. Biomass currently used in Europe includes wood from forests, agricultural crops and residues, by-products from the wood and agricultural industry, herbaceous and woody energy crops, municipal organic wastes and manure, and could potentially integrate algae and marine biomass in the future.

Cookie	Duration	Description
cookielawinfo-checkbox-analytics	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
cookielawinfo-checkbox-functional	11 months	The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
cookielawinfo-checkbox-necessary	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
cookielawinfo-checkbox-others	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
cookielawinfo-checkbox-performance	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
viewed_cookie_policy	11 months	The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.