The government as an entity is quite often the largest, single consumer of goods and services in developed as well as developing countries. Government procurement can be a powerful tool for positive environmental change by creating a market for environmental goods and services. At the same time, procurement policies will need to be designed and implemented in a manner that does not discriminate against trading partners. What sort of space is available in the context of existing trade-rules for governments to pursue proactive procurement policies for sustainable energy goods and services? Is there a need to review existing rules so as to enhance their effectiveness with regards to the objectives of strengthening markets for renewable energy? This paper, by Alan Herve and David Luff, sheds light on these questions and also explains how a possible Sustainable Energy Trade Agreement could spur reform while ensuring a level playing field in procurement markets for producers of sustainable energy goods and services worldwide.