The Kalundborg Industrial Symbiosis is one of the best-known examples of urban circularity, showing how collaboration between public and private sectors can create economic, social, and environmental benefits for the entire community.
Structure and Functioning of the Symbiosis
In Kalundborg, nine legal entities—private and public companies—are interconnected through a resource exchange network, where waste from one company becomes an input for another. Notable examples include the Asnæs power plant, which supplies steam and ash to other companies, and by-products from insulin production being transformed into agricultural fertilizers. These exchanges are not just economic; they create interdependence, enhancing local resilience and reducing reliance on external resources.
Economic Benefits
- Companies benefit from local resources at lower costs, increasing competitiveness and reducing production costs.
- The municipality saves significantly on waste management and treatment, while business taxation ensures a stable revenue stream.
- The symbiosis has generated total savings of over $28 million, with estimated socio-economic effects of $16.5 million.
Social and Urban Impact
- Jobs are created and maintained locally, supporting community development and a higher standard of living.
- Citizens benefit from a healthier environment due to reduced pollution and waste, improving quality of life.
- Engagement of local actors and social institutions strengthens public services and promotes sustainable practices among residents.
Environmental Benefits
- By recycling resources and transforming waste into raw materials, CO₂ emissions have been reduced by 635,000 tons, and water and energy consumption have decreased significantly.
- Reducing the amount of waste deposited and greenhouse gas emissions contributes to local and global climate goals.
- The model demonstrates how a circular economy can be an effective solution for sustainable urban development and green transition.
Replicability and Innovation
Kalundborg’s industrial symbiosis has become a replicable model for other cities and industrial parks, inspiring circular practices and cross-sector collaboration. Through innovation and cooperation, the Danish city shows how transitioning to a circular economy can turn waste into opportunities and communities into active agents of change.
This model highlights the importance of public-private partnerships, citizen involvement, and efficient resource management for developing more resilient, inclusive, and sustainable cities.


