Glimpsing a green, profitable future at an industrial park in Denmark

The Kalundborg Symbiosis is a set of factories and municipal water treatment facilities that recycle one another’s water, energy, and waste. They also sell byproducts such as fly ash, a coal-burning residue, to other companies. The system grew gradually through intercompany agreements starting in the 1970s, when a local oil refinery started piping excess gas to a nearby factory that manufactured sheetrock. The recycling not only has environmental benefits but also helps companies lower costs. “If there wasn’t a good business case, we wouldn’t be doing it,” says Michael Hallgren, senior vice president of member Novo Nordisk.