Since 2022, Sønderborg has held the title of the Global Capital of Energy Efficiency. This honour, announced during the International Energy Agency’s (IEA) annual conference, recognises the town as a pioneer in energy-efficient innovation and technology. As Denmark’s 24th largest town, with approximately 30,000 residents, this achievement is nothing short of remarkable.
But how did this town become such a global leader in the journey towards Net Zero?
For over a decade, energy efficiency and decarbonisation have been at the heart of Sønderborg’s urban planning decisions. With a pledge to reach carbon neutrality by 2029, Sønderborg has long been a trendsetter in climate action. This leadership is most clearly demonstrated through ProjectZero.
Energy efficiency is a critical solution to so many of the world’s most urgent challenges – it can simultaneously make our energy supplies more affordable, more secure and more sustainable.”
Dr. Fatih Birol, Executive Director of the International Energy Agency (IEA)
Project Zero
Launched in 2007 by the Bitten & Mads Clausen Foundation, ProjectZero is a public-private partnership that brings together companies like Danfoss (headquartered in Sønderborg), the Sønderborg Municipality, the University of Southern Denmark, and other local organizations to achieve decarbonization goals. Thanks to ProjectZero, the municipality has already reduced carbon emissions by nearly 60%, placing them on track to meet their 2029 target.
ProjectZero has proven that a systematic approach to decarbonisation can deliver both environmental and economic gains. Since its launch, the initiative has driven significant emissions reductions across the municipality, with energy efficiency alone contributing to 27% of total CO2 reductions from 2007 to 2029. Sønderborg’s integrated energy system facilitates the efficient reuse of waste heat and its connection to renewable electricity sources through district heating networks. By 2029, this district heating network is expected to source 40% of its heat from surplus energy, minimising waste and securing a stable supply of clean energy from local wind and solar resources to meet rising demand.
ProjectZero in Sønderborg has implemented a comprehensive strategy to achieve climate neutrality by 2029, focusing on energy efficiency, renewable energy, and community engagement.
Key initiatives include:
- Energy Efficiency in Buildings: Retrofitting existing structures to enhance energy performance; Implementing strict energy standards for new constructions.
- Promotion of Renewable Energy: Expanding district heating systems utilizing renewable sources; Installing solar panels and wind turbines to increase local green energy production.
- Sustainable Transportation: Developing infrastructure to support electric vehicles, including charging stations; Encouraging cycling and public transport to reduce reliance on fossil fuels.
- Industrial Energy Optimization: Collaborating with local industries to improve energy efficiency and reduce emissions; Supporting the transition to renewable energy sources in industrial processes.
- Educational and Community Engagement: Launching campaigns to raise awareness about energy conservation and sustainability; Involving citizens in climate action plans through workshops and local initiatives.
- Smart Grid Development: Implementing intelligent energy management systems to optimize consumption and distribution; Facilitating the integration of renewable energy into the local grid.
- Green Business Initiatives: Supporting startups and companies that focus on sustainable technologies and services; Providing incentives for businesses to adopt eco-friendly practices.
Sønderborg: The Living Lab
At the core of Sønderborg’s energy efficiency success is its integrated energy system, often referred to as a “living lab”. District heating networks play a central role, integrating various energy sources, including renewables, and reusing excess heat to provide efficient energy to the town.
The district heating network, managed by by the heat utility company Sønderborg Varme, is one of the most expansive and affordable in Denmark, offering an average household heating cost of just £1,575 a year. Established in 1963, the network now supplies over 16,000 consumers with reliable and renewable heating.
One reason for these consistently low heating costs is the diversity of heat sources connected to the network. With eight different suppliers, Sønderborg Varme is insulated from the price volatility often seen in energy markets. This insulation has proven especially valuable in the wake of geopolitical tensions, such as Russia’s invasion of Ukraine and conflicts in the Middle East. By relying on diverse, local energy sources, the system also eliminates the need for imported energy, keeping money within the local economy.
Diverse heat sources that contribute to Sønderborg Varme’s low-cost and sustainable heating:
- Sønderborg Kraftvarme: The primary contributor to the district heating network, this Combined Heat and Power (CHP) was established in 1993 and became operational in 1996. It’s one of Denmark’s most environmentally friendly and efficient facilities, processing waste from Sønderborg and neighbouring municipalities to produce heat.
- Flisanlæg Vestermark: This wood chip plant, inaugurated in 2013, powers heat pumps with 170-degree hot water from its boilers, raising the temperature of return water from consumers to supply temperature, ensuring efficient heating distribution.
- Central Sønderborg Landevej: This plant combines solar panels, a locally sourced straw biomass boiler, and a wood pellet boiler to provide heat, with the pellet boiler driving a heat pump to enhance efficiency during transitional periods. The plant was commissioned in 2012, with solar capacity expanded in 2017.
- Central Glansager: Commissioned in 2015, this biomass plant uses waste wood chips and park waste to fuel its 9 MW gasification process. It supplies heat in the winter to areas that rely on solar power in the summer.
- Central Solparken: Opened in 2009, the solar park uses solar collectors, solar panels, and bio-oilfired boilers to supply district heating. The site is also home to a Viking Age archaeological find, which has been preserved and showcased for public viewing.
- Kraftvarmeanlægget on Industrivej: This facility uses electrodes to heat water for district heating, with electricity sourced from wind and solar power. A green gas fired CHP plant provides backup during high-demand periods.
- Varmecentralen on Møllegade: This plant serves as a backup, using oil- and gas-fired boilers during operational disruptions or maintenance at the main heating plant.
- Geothermal Energy: Sønderborg has been exploring geothermal energy since 2007, with two boreholes established in 2010. These boreholes contribute to the town’s renewable energy mix.
Sønderborg’s energy system is highly flexible, allowing different sectors to work in harmony. For example, surplus heat from local businesses is used to warm homes, and electric vehicles are charged when energy demand is low. Data is used to optimize energy use, helping reduce the costs of decarbonization by up to 50%.
Without urgent action, energy demand will grow significantly, getting us off track to meet global climate goals. Instead, according to IEA a collective push for energy efficiency can deliver one-third of the total emissions reductions needed to reach net zero.
“The district heating network, managed by Sønderborg Varme, is one of the most expansive and affordable in Denmark, offering an average household heating cost of just £1,575 a year. “
In Sønderborg, they have taken early action on energy efficiency. The effect is clear:
- In the period 2007 2020, energy efficiency has reduced the need for expansion of renewable energy corresponding to 130kton CO2.
- Energy efficiency contributes 27% of the total CO2 reduction in the period 2007-2029.
- The accumulated CO2 emission over the entire period has been reduced by 8mton
- Cheap reduction costs of DKK 170/ton (vs. DKK 390/ton without EE measures).
- Without EE initiatives, CO2 emissions would have increased from 701-760kton due to growth in society.
Through its innovative approach and commitment to sustainability, Sønderborg has become a model for energy efficiency worldwide, proving that our villages, towns and cities play a big role in the fight against climate change. As Sønderborg gets closer to carbon neutrality it is getting increasingly more difficult to reduce the last percentage of carbon emissions. However, their experience and knowledge will serve as a vital leap frog for our urban areas in the UK.
The Energy Efficiency Principle
This principle emphasises not only the need to reduce fossil fuel consumption, but also the importance of reducing energy production. Reducing energy demand can help control the level of investment needed for the transition towards renewables.
While taking full account of security of supply and market integration, the Energy Efficiency First Principle aims to ensure that:
- Only the energy really needed is produced.
- Investments in stranded assets are avoided.
- Demand for energy is reduced and managed in a cost-effective way.
- Ensure that energy needs are considered in policy and investment decisions.
- Increase the resilience of the EU’s energy system.
