Many cities throughout the world are looking for ways in which to cope with population growth, whilst curbing energy consumption and environmental impact. And the unlikely focus of international interest currently is the historic city of Heidelberg, in south-west Germany. Residentially it is very popular and commercially it is very successful, but Heidelberg has an expansion problem. There is barely any property to be had in the city’s picturesque old town, or along the banks of the River Neckar, and if anything does become available, the prices are on a par with those of Munich, in the region of €5,000 or more per square metre.
The spectacular solution is to build a completely new district – the Bahnstadt – on a 286 acre area that was once home to Heidelberg’s now defunct rail freight and marshalling yards. The €2 billion initiative is claimed to be the largest single passivhaus development…