The Kalundborg area was first settled in 1170 at a natural harbour at the head of the narrow bay today known as Kalundborg Fjord. It became more urbanized during the nineteenth century and had grown into a major industrial centre by the mid-twentieth century.
Kalundborg Municipality has approximately 20,000 inhabitants, and its network is the most published example of Industrial Symbiosis. The history of Kalundborg Industrial Symbiosis activities began in 1961 when a project was developed and implemented to use surface water from Lake Tisso for a new oil refinery, to save the limited supplies of ground water. The City of Kalundborg took the responsibility for building the pipeline while the refinery financed it. Starting from this initial collaboration, a number of other collaborative projects were subsequently introduced and the number of partners gradually increased.
By the end of the 1980s, the partners realised that they had effectively "self-organised" into what is probably the best-known example of Industrial Symbiosis. The material exchanges in the Kalundborg region include: conservation of natural and financial resources; reduction in production, material, energy, insurance and treatment costs and liabilities; improved operating efficiency; quality control; improved health of the local population and public image; and realisation of potential income through the sale of by-products and waste materials
