Global Warming Cool It – Lighting: “Low voltage halogen lamps are not low energy lamps: each one generates a kilogram of greenhouse gas every 15 hours—about the same as an ordinary 60 watt globe, although it does produce a little more light. Halogens are not easily replaced by more efficient alternatives, so installing them locks you in to high lighting bills.”
The Government Greenhouse site has plenty of information and practical ideas about saving energy and costs. It also gives links to the documents relating to our greenhouse protocols, targets and procedures. The Cool It part of the site really is a handy link.