A couple of months ago somebody gently criticised the choice of picture in the banner on the Terra Infirma website [update: long gone!] – saying that these ‘dark satanic mills’ were the wrong message for our company. But we’ve stuck with them as these aren’t just any dark satanic mills, these dark satanic mills are in Kalundborg, Denmark and they aren’t nearly as dark or satanic as you might expect.

Kalundborg is a sleepy little port of 20 000 people on the western coast of the Danish island of Zealand, famous for its remarkable five towered red brick medieval church which looms over the cobbled streets and red and yellow rendered houses of the old town. According to the tourist guides, that is pretty much all the town has to offer. But down at the waters’ edge the view is dominated by two monolithic blocks of a huge coal fired power station across the fjord. Just to the left and beyond the older block of this plant, the flickering flames of two flare stacks mark the location of an oil refinery. Further left again is one of the world’s biggest pharmaceutical plants. It is the story of these three industrial complexes, a number of smaller plants, the town itself, and their unique symbiotic relationship that brings environmentalists on pilgrimages from all over the world. Our party was predominantly from UK academia, but two Koreans had flown halfway around the world to hear the story of the Kalundborg Industrial Symbiosis.

In a meeting room in the swish Youth Hostel where we were staying, Noel Brings Jacobsen, CEO of the Kalundborg Symbiosis Institute, told us how it all began. In the sixties, the Government decided to attract some big dirty industries to Kalundborg as it had become an unemployment blackspot. Planning regulations were relaxed and land was provided practically free of charge. The only problem being that there was no source of fresh water needed for all three plants except for Lake Tisso, over 25km away. So the plant managers worked together to cascade wastewater from one process to another, starting where it had to be cleanest and working its way down through the less fussy processes, and recycling it wherever possible. The power station produced an excess of steam so it was piped the short distance to the other plants and then around the fjord to the town where it heats all the buildings. More companies turned up to take advantage of other opportunities: a plasterboard company which takes the gypsum from the pollution control to build into its products and a fish farm which uses (and cools) some of the warm wastewater.

On Earth Day 1989 a number of students were asked to study the environmental impact of the town’s industries and they started to trace these connections. Using a pinboard and coloured string, they presented the findings to the companies’ management teams. The industrialists hadn’t realised just how integrated and interdependent their plants had become, so they set up a small Institute to co-ordinate the relationships and started investing heavily in further synergies. Links have come and gone, but with the habit ingrained and the benefits proven, the infrastructure has simply been adapted to exploit new opportunities.

Noel took us around the plants, showing us the relatively minor adjustments required to make the processes compatible. The steam and water pipes run alongside each road, painted green and surrounded by vegetation. On top of the power station we got to see just how close the plants are physically, looking almost vertically down on the fish farm below. At the pharma plant, Claus the public relations/security man showed us the fertiliser product made from the process substrate. It is trademarked, but given away free to local farmers. If the company had to pay for disposal to landfill, the plant would go bust and 2700 local people would be on the dole.

Of course this is not eco-nirvana, explained Noel. The power plant burns coal, the oil refinery provides fuel for planes, trains and automobiles, and fish farming is rarely seen as ‘green’. But, given these processes are a fact of modern life, the environmental impacts have been minimised. Almost every last scrap of energy and water is used and waste arisings minimised. None of the individual links are unique to Kalundborg, in fact most are found somewhere in the UK with the notable exception of large scale district heating. It is simply that nowhere else in the world can you find such a compact example of the benefits of Industrial Symbiosis.