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Written by Alejandra Leon, Project Officer at WBA 

In mid-September, I travelled to Linz, Austria, to attend the International Training Seminar on Sustainable Bioenergy Heating, organised by the Energy Academy of the OÖ Energiesparverband, the regional energy agency of Upper Austria. Over four days, and together with other 15 participants from 10 countries, we followed a full program covering the sustainability of bioenergy, market development, and bioenergy technology within the bioheat sector in the region, with expert presentations and site visits across the value chain. 

The seminar had a specific focus on small- and mid-scale heating systems with wood pellets and wood chips as the main fuels, within systems in homes, commercial/public buildings, and district heating networks. This is usually not the most visible part of the energy transition, but certainly one of the most practical ones for many regions, especially for Upper Austria. 

Why Upper Austria? 

Besides the breathtaking nature scenery, Upper Austria is a useful place to study bioheat because it is the leading region in biomass heating, as it supplies around 17% of the region’s primary energy, around a third of homes are heated with modern bioenergy systems, and the bioheat sector employs more than 6,000 people. The region is also a manufacturing hub, producing over a quarter of the modern small-scale biomass boilers installed and sold in the EU. 

During the training, it was shared that this was the result of a deliberate policy mix, maintained for nearly three decades. Subsidies for replacing fossil heating were combined with a program on phasing out oil and gas boilers in new buildings, around 10,000 free energy advice sessions a year, training programs, and awareness campaigns, all part of the joint effort to put Upper Austria in a leading position on prioritized energy efficiency and renewable energy.  

A recurring message during the week was that bioheat markets are built on three pillars that must develop together: sustainable forest management, high-quality fuel production and effective distribution, and efficient, low-emission heating equipment. If one of them is weak, public trust in the whole system suffers.  

Day 1: From policy to practice 

After a welcome from Christiane Egger of OÖ Energiesparverband on Monday evening, Tuesday opened with a session on how Upper Austria's policies and programmes shaped its bioheat market. We then headed out to see the results. 

Our first stop was the RURU Donausäge Rumplmayr pellet plant in Enns, commissioned in 2022, producing around 75,000 tonnes of pellets per year. The plant is fully integrated into sawmill operations, so the sawdust and shavings that become pellets never travel far, and the energy needed to dry and press them is generated on site. 

Photo: RURU Donausäge Rumplmayr pellet plant and pellets, Photo credits: WBA 

Next was the district heating system in Sattledt, which combines two biomass boilers with two wood gasifiers that also generate electricity. Its 6-km network supplies around 120 customers, including the municipality's public buildings, local businesses and homes. 

The day ended in Traunkirchen with a session on energy contracting, with a presentation from Siegfried Aigner of Aigner Energie Contracting, followed by a visit to a plant that shows the model in action. Aigner Energie Contracting designed, financed, built, and operates the biomass heating system that has a 20-year contract and supplies a forestry education centre and nearby homes since 2018. Under this ESCO model, the customer pays for the heat through a fixed monthly fee plus a charge per kilowatt-hour used, which removes one of the biggest barriers to switching, the upfront investment. 

Photo: Traunkirchen, Photo credits: WBA 

Day 2: Technology, emissions and new uses 

Wednesday began back in the classroom with Elisabeth Wopienka of BEST-Bioenergy and Sustainable Technologies, providing useful context for the rest of the day and covering combustion technologies, emissions and efficiency. Elisabeth shared test data from Austria that showed how much pellet boilers have improved since the late 1990s. Efficiency has risen from about 55% to over 90%, and carbon monoxide emissions have fallen by more than 99%. Newer developments include integrated dust filters and hybrid systems that combine biomass with solar or heat pumps. 

To see the boiler technologies we discussed, we visited Hargassner in Weng, a family-owned manufacturer that has produced automatic wood heating systems since 1984 and now exports to more than 40 countries. Producing over 25,000 boilers a year, Hargassner is one of the key players in the boiler manufacturing industry in the region. Alongside the factory tour, we heard examples of how systems are designed for different buildings and needs, including public buildings and industrial cases. 

Photo: Hargassner, Photo credits: WBA 

The afternoon turned into a weather nightmare, with heavy rain trying to hinder our tour. However, we managed to visit a small, combined heat and power plant in Antiesenhofen, where wood gasifiers supplied by Fröling produce both heat and electricity for a local heating network, with an integrated dryer for the wood chips. The last stop was an organic farm in Puchenau, where a GUNTAMATIC unit produces heat and biochar from wood chips at the same time. The farm uses the biochar as animal bedding and feed supplement, after which it ends up in the manure and eventually in the fields to improve soil quality. It was a good reminder that bioenergy systems can deliver more than one product and that a circular model is possible and efficient. 

Photo: Guntamatic visit, Photo credits: OÖ Energiesparverband

Day 3: Fuel delivery and the end user 

Thursday was about logistics and the customer's perspective. At the Genol logistics centre in Eferding, which handled around 17,000 tonnes of pellets last year, we learned why fuel quality matters as much as boiler quality. As part of the visit, we followed a truck being filled for bulk pellet delivery and then being delivered to a single-family home, where we saw the pellet storage room being filled and the boiler room in operation. Seeing this made it clear why reliable fuel delivery matters; for households, heating with pellets should be as convenient as heating with other fuels. 

Photo: Pellet truck delivery, Photo credits: OÖ Energiesparverband 

Our technical site visits ended at ÖkoFEN's production facilities in Niederkappel, with a presentation given by Michael Scharinger, describing how quickly markets have shifted since the 2022 energy crisis, from a boom in demand to a sharp correction when subsidies changed. Customer priorities have shifted too, from environmental values towards reliability, comfortand running costs. Many customers now want pellet boilers that work alongside solar panels, heat pumps and batteries. As he put it, the right question is not which technology is best, but which is best suited to a given building. 

Why this matters 

For anyone working on the energy transition, the most valuable lesson from Linz was that technology alone does not create a market. Upper Austria's boilers are among the best in the world, but they work because of everything around them, including fuel standards that ensure consistent quality, delivery networks that make pellets convenient, financing models that lower the barrier to entry, and decades of consistent policy efforts. 

This is especially relevant for countries where automatic bioenergy heating is still at an early stage, which is exactly who the seminar was designed for. Heat accounts for a large share of global energy demand, and much of it is still supplied by fossil fuels. Local, sustainably sourced biomass can provide affordable heat, strengthen energy security and create jobs, but only if the whole value chain is developed carefully. 

Seeing that chain in operation and discussing it with participants from very different national contexts was a practical way to understand both the potential and the conditions needed for bioheat to succeed. 

Our thanks to OÖ Energiesparverband and all the hosts for opening their facilities and sharing their experience with the group. 

Photo: Group photo, Photo credits: OÖ Energiesparverband