District heating has a long history in Hungary. Indeed, the very first district heating network in the country was installed in 1889 to heat the parliament buildings in Budapest. A fitting finding as Hungary currently holds the Presidency of the Council of the EU and is seeking to transform its district heating sector into a modern, low-carbon, and energy-efficient heating solution for urbanized areas.
Although district heating has a long history in Hungary, it has yet to realize its full potential.
According to the Association of Hungarian District Heating Enterprises (MaTáSzSz), the representative body of the Hungarian district heating sector whose members provide district heating services to approximately 98 percent of the market, the expansion of district heating in Hungary occurred with the economic and energy policies of the 50’s, 60’s, 70’s and 80’s of the last century.
However, the said policies had no focus whatsoever on fuel or energy efficiency for either heat producers or consumers resulting in non-metered, heat-only hot-water boilers fi red on, the then cheap, oil and later natural gas.
Increasing renewables- and efficiency in heating
Addressing these inefficiencies, a heat metering act was introduced in 1991 and has since been followed by numerous pieces of legislation after Hungary joined the European Union in 2004.
Currently, there are 213 district heating systems operational in Hungary, a decrease compared to 2003 when there were 242 networks in operation yet the total number of heat off-takers has increased suggesting a result of the ongoing modernization and efficiency efforts.
While fossil natural gas is still the dominant fuel (70 percent in 2022), bioenergy with 12 percent has become the largest renewable closely followed by geothermal (11 percent) – Hungary is renowned for its geothermal baths and spas.
The 2030 target is that renewable energy sources increase their share in district heating to at least 50 percent.
Revamping a complex heating system
Commissioned in 2023, the biomass-fired 15 MWth hot-water heating plant in Kaposvár, a town of around 70,000 inhabitants in southwest Hungary, is one of the most modern plants in the country.
Delivered by Austrian biomass combustion specialists Polytechnik, the new bioheat plant reduces the need for natural gas in the network.
This project for Polytechnik originated through our participation in a public tender, which we successfully won. This competitive process allowed us to showcase our expertise and commitment to providing innovative biomass solutions, revealed Thomas Hofmann, Sales Department at Polytechnik.
Polytechnik was responsible for the comprehensive planning, manufacturing, delivery, and installation of the entire system up to the connection with the district heating network which was extended by almost 2 km to integrate the new bioheat plant and additional households into the network.
The total investment for the entire project, including the boiler house, the fuel store, and the woodchip feeding system amounted to EUR 12 million.
This comprehensive funding reflects our commitment to delivering a state-of-the-art biomass heating solution, Thomas Hofmann said.
The new bioheat plant generates about 85 percent of the town’s heating needs during the heating season.
It supplies 7,000 households and 288 additional buildings with renewable heat via Kaposvár’s district heating network enabling significant fossil carbon dioxide (CO2) emission reductions and heating cost savings.
Two boiler units
Comprising two 7.5 MWth units, the plant is among the first in Hungary to follow the national strategy of replacing fossil-fuel-based district heating sources with renewable energy, enhancing sustainability and reducing the overall carbon footprint.
Kaposvár has a complex heating system that is undergoing long-term renovation, and the Polytechnik plant is the first step in that process, serving as the newest energy supplier integrated into this system. The choice of two 7.5 MW units allows fully efficient performance. When full demand is reached through the first unit, the second unit starts up. It provides better operational flexibility compared to a single larger unit. This modular setup is more efficient, as it helps meet the varying heating needs of the city of Kaposvár, explained Thomas Hofmann adding that there is no heat storage, such as a hot water buffer tank, installed at this stage of the network renovation as it is not needed.
Local forestry- and wood processing residues
The fuel mix consists of woodchips and bark supplied by Hungarian state-owned forestry companies as well as SEFAG Erdészeti és Faipari Zrt (SEFAG), a private company specializing in forest management and wood processing.
SEFAG operates a hardwood sawmill and one of the largest parquet flooring manufacturing facilities in the country.
The woodchips are semi-wet, with a moisture content of around 35 percent. The plant is designed to burn this biomass directly. The ash content is kept at a maximum of 5 percent, with a fine fraction limit of up to 6 percent. The system is specifically optimized to deliver maximum performance based on the characteristics of this type of biomass and without a flue gas condenser, said Thomas Hofmann.
The plant uses a water and smoke tube boiler specifically designed for poly-combustion plants.
The biomass burns and releases flue gas at a temperature of up to 950°C before entering the boiler (at maximum output), and around 800°C after passing through the boiler. The water is heated as it flows through spiral tubes, where it is warmed by the flue gases. This is a standard system, without any special features, as it has been optimized to handle the specific characteristics of the fuel used in this plant efficiently, Thomas Hofmann explained.
Expanding the technology reference portfolio
With the Kaposvár bioheat plant firmly up and running, Polytechnik sees opportunities for similar-sized heating plants, not just in Hungary.
We are actively working on other heating plant projects, similar to the one in Kaposvár. In fact, we also see potential opportunities beyond Hungary, as there is a growing demand for sustainable biomass heating solutions in various markets, Thomas Hofmann said without going into more details.
No matter – with a portfolio reference of over 3,000 bioenergy installations worldwide, Polytechnik is a leading global provider of biomass combustion, wood gasification, torrefaction, and carbonization plants.
The company has a firm project pipeline in various stages of development, not least in the latter technology fields.
For instance, the company has just completed its largest wood gasifi cation furnace for the district heating network of the town of Obenpullendorf in Austria.
The 2 MWth POLY HELD gasification furnace eliminates the need for an electrostatic filter and has significantly lower NOx emissions than conventional combustion systems.
In Finland, Polytechnik has begun the commissioning of an industrial-scale torrefaction plant which once fully operational will produce up to 60,000 tonnes per annum of ‘green carbon’.
With its sixtieth anniversary coming up next year, these are just two stories that one can expect to be covered in more detail in 2025.
