Kortrijk’s Fossil-Free Future

District heating plays a crucial role in Kortrijk’s climate strategy. The city has committed itself through the EU Covenant of Mayors and the Kortrijk Green Deal to reduce carbon emissions and transition away from fossil fuels. EU legislation also sets clear milestones. District heating has the potential to deliver major CO₂ reductions, substantially contributing to the European targets.

A fair and liveable heat transition in Kortrijk

Beyond climate targets, heat detox is also a matter of social justice and urban quality of life. Collective systems allow households with limited financial means to access clean and affordable heating without making heavy individual investments. District heating also helps avoid noise pollution and reduces the urban heat island effect in dense areas, while increasing local energy independence by tapping into local resources. 

The River Leie adds a unique dimension to Kortrijk’s heat transition. Throughout history, the river has shaped the city’s identity, from its Roman origins to its flourishing flax industry that made Kortrijk one of the wealthiest cities in Flanders. Today, the Leie once again offers an opportunity for progress: aquathermy. At Kaai City, aquathermy is combined with a large borehole thermal energy storage field with more than 300 boreholes up to 200 metres deep. On Buda Island, an innovative project will use a pumping station to extract sustainable heat from the river to supply the island. In the future, the Kortrijk Weide district heating network will also switch to a combination Lys water and geothermal as its energy source. In this way, the river continues to fuel the city’s development, this time driving a sustainable and climate-friendly future.

^{Preferred locations for aquathermy from the River Lys.}

^{Impact of the coming aquathermy projects in Kortrijk Weide & Buda Island.}

From mapping to strategy 

Kortrijk developed a heat zoning map, which is being refined into a heat zoning strategy. This tool highlights where district heating is most viable and helps prioritise investments. The process showed both opportunities and challenges. For example, unexpected industrial waste heat improved the business case for a project, while elsewhere outdated sewer infrastructure made another project unfeasible. 

These examples demonstrate that each project requires tailored, local solutions, influenced by technical, spatial, and financial factors. District heating is therefore both a technical and strategic challenge, but also an opportunity to unlock hidden local resources.

^{The city's heat map}

District heating as a strategy pillar

District heating is a cornerstone of Kortrijk’s strategic ambitions: 

• Heat transition and networks
• Energy generation and sharing
• Energy and mobility
• Energy and entrepreneurship
• Social energy policy and renovation

In the city, a district heating network is already operational at Havenkaai, connecting 107 apartments, 202 student housing units, a school building and 10 retail spaces. This network makes use of a combination of aquathermy from the River Lys and geothermal energy.

Kortrijk Weide hosts a fully operational district heating network which, although currently still fossil-based, provides an ideal environment to serve as a test, demonstration, and pilot site for innovative energy solutions. Thanks to the close involvement of the educational partners Howest, UGent Campus Kortrijk and the province of West-Flanders, the site also offers a strong platform for dissemination, training, and knowledge transfer activities linked to research and innovation projects. A dedicated cooperative company has been established to own and manage the network, bringing together the various end users and enabling real-life experimentation with new technologies and system concepts in both heat and electricity. Ongoing studies are currently exploring the most effective pathways to transition the network towards a fully fossil-free system.

^{Overview of the buildings connected to the Kortrijk Weide district heating network.}

In addition, new heat networks are planned for Hoog-Kortrijk, Buda Island and the Psilon–Kulak area.

While Kortrijk is still largely in the planning phase, the city aims to gradually expand and interconnect these individual “heat clusters” into a large-scale, resilient heat system powered by a diverse mix of renewable energy sources. 

^{Aerial view of Kortrijk Weide and Hoog-Kortrijk.}

Main challenges to detoxify heat and next steps

• From Ad-hoc to Structured Planning

Kortrijk’s heat transition requires moving from isolated, project-based initiatives towards a phased, long-term and integrated strategy.

• Dependence on Fossil Gas

The city still has over 30,000 active gas connections, with a total annual consumption of nearly 378,000 MWh. At present, installing a new gas boiler remains cheaper than a heat pump. This economic reality makes it difficult to convince individual households to switch away from fossil heating.

• High Upfront Costs for District Heating

While district heating with sustainable heat (and cooling) sources offers significant long-term benefits, projects face high capital requirements and complex business cases. This slows down large-scale deployment.

• Insufficient Renovation Rate

The average energy score of residential buildings in Kortrijk is still 322, far from the 2050 targets. Although many homes are being renovated, the overall renovation rate remains too low to meet the climate goals. The city has its own renovation team and additional municipal renovation grants to accelerate progress and support households willing to renovate. 

The city's next steps

• Refinement of the heat zoning map and development of a citywide heat zoning strategy (currently in preparation).
• Establishment of a municipal energy company to coordinate and drive projects.
• Launch of the most urgent and promising “heat clusters”.
• Development of a step-by-step action plan to connect these heat clusters over time, building towards a large-scale district heating network with multiple renewable sources that can complement each other and provide backup.

Where Kortrijk is in its heat strategy

[2] Heat Planning: Hoog-Kortrijk, Buda Island

[1] Beginning Implementation: Psilon-Kulak

[1] Partially Implemented: Kortrijk Weide – network is in place but still supplied by fossil heat; a switch to a mix of (deep) geothermal energy and aquathermy from the River Lys is planned.

[2] Implemented: Havenkaai & De Venning

Kortrijk's Heat Detox

Methods:

• [3] District Heating
• [1] District Cooling
• [807] Heat Pumps (based on subsidy applications + new-build homes with heat pumps; this is an underestimate of the actual number)

Clean sources of heat

• Geothermal

Sporadic use of geothermal energy, not yet common practice (e.g. individual households, AZ Groeninghe, Loof project, Kaai City…). Exact figures are not available. There are 124 known geothermal heat sources but many are unknown. 

• Waste Heat from: 

The following sources of residual heat are not yet in use, but there are concrete plans to move forward with them in the near future:

• The residual heat from the Psilon crematorium will be captured to provide sustainable warmth to the KU Leuven Kulak campus.
• Residual heat provides a viable business case for a district heating network in Hoog-Kortrijk.
• Potential to use residual heat from waste incinerator Imog in Harelbeke for a district heating network in Kortrijk (already used in Harelbeke and Kuurne, with surplus heat available to supply part of Kortrijk).

• Solar thermal

(based on subsidy applications, this is likely an underestimate of the actual number.) Currently limited use, but significant potential.

• Water-Source

River Lys: up to 87% of the heating demand of Buda Island can be met through aquathermal energy from the river Lys, complemented during the coldest weeks of winter by geothermal (primarily covering cooling demand). Aerothermal systems would act as a back-up on days when water temperature is too low.

The Kortrijk Weide district heating network will probably also eventually switch to fossil-free heat from geothermy and aquathermy from the Lys.

Further potential sources:

• Kortrijk-Bossuit canal
• Wastewater treatment plants 
• Sewer pipelines with high potential
• Drinking water pipelines with sufficient flow showing potential
• Deep geothermal

• Air-Source

There are a significant number of aerothermal installations, but numbers are not available. 

• Biomass

Since 2015, the social housing district De Venning in Kortrijk has been heated by a district heating network powered by biomass, that was considered highly innovative at the time.

• Biogas: 

A brewery converts its organic residues into biogas and then uses it internally to make its production processes more sustainable.

Key Heat Figures

Emissions related to heating: 

• City’s own building stock: 4,839.01 tons CO₂ in 2021 (heating).
• Households: 24.3% of total CO₂ emissions in Kortrijk (2023). There is a decline from 136,721 tons (2011) to 93,468 tons (2023) of CO₂-emissions. The reduction is mainly due to lower energy consumption (renovations, energy-efficient new builds) and increased local renewable production. Despite a +4.8% growth in households (2011–2022), household energy use fell by -23.2% and CO₂ emissions by -28.7%. The average household emissions in 2023: 2.70 tons CO₂

District heating and cooling:

• Km of DHC currently: 2,483 m (Venning 1,283 m & Kortrijk Weide ~1,200 m & Kaai city).
• Km of DHC planned: 3.335m (Psilon-Kulak: ±435 m / On the Buda island, a total of 600 m of district heating is planned, to be rolled out in phases / Hoog Kortrijk: ÷2,300 m)

Renewables in heating system:

• An estimated 1.11 MWh of renewable heat per household in 2023.
• The total known renewable energy production in Kortrijk is 33.426,717 MWh (2024). 

Other interesting figures:

• A reduction of 11.4% in energy consumption between 2005–2017 in Kortrijk.
• Ranked 2^nd among 13 Flemish central cities (2011–2018) in energy reduction 

Covenant Figures 

• Signatory to the Covenant of Mayors since: 2013

Overall CO2 emission reduction target: -90% CO2 emission reduction by 2029 compared to year 1990, climate-positive from then onwards. -63% CO2 achieved in 2023.

• % GHG emissions reductions by 2030: at least 55% compared to 2015
• % GHG emissions reductions by 2050: climate neutrality (ambition)

In the cities own building stock : yearly 3% energy savings and fossil-free heating by 2040. The city has the ambition to increase our share of renewable energy to 15% by 2030.

City Awards

• Nominee for European Green Cities Award 2021 

Related links 

• Klimaatplan | Kortrijk
• About us WaterWarmth | Interreg North Sea
• WaterWarmth: duurzame energie uit de Leie | Kortrijk
• Wijkrenovatie Stade | Kortrijk
• Kaai City in Kortrijk: largest aquathermal project