Having a chemical plant sited next door to your plantation isn't what the average farmer might want for his crop. Jan van Duijn, however, walks proudly through his greenhouse, a vast glass and metal structure spread out over five hectares (12.3 acres) where millions of aubergines are doing very nicely thank you. He's happy because thanks to a deal with a supplier, he's getting hot water piped in from the factory, which produces ammonia, to maintain the temperature at a constant 68 degrees F (20C). The chemical site, five kilometres (three miles away), also supplies carbon dioxide which helps his...