Going green doesn’t always mean going high-tech. New Zealand's Rimutaka prison is solving overcrowding with the use of old metal shipping containers. Shipping containers have been used for green design in the past, and they are a cost-effective solution for New Zealand, which is expected to need 5,000 more cells by 2018. The cost of outfitting each container is about $53,000 to $63,000 — about half the cost of a conventional cell, according to Greenbiz.com.