Each year public authorities spend approximately 2 trillion euros (17% of the EU's Gross Domestic Product) on purchasing a variety of goods, services and works. If they can be encouraged to purchase environmentally friendly products and services instead of conventional ones with the same functions, they can save energy, natural resources and water, reduce harmful emissions and hazardous substances, generate less waste, improve health and stimulate behavioural change towards sustainable consumption and production. In this way, public authorities will be promoting modes of production that are more environmentally friendly and stimulate the supply of green goods and services. Politically GPP has been widely recognised as a powerful voluntary instrument in most of the Member States. At EU level European Commission sets a target that, by 2010, 50% of all tendering procedures should be green, where green means compliant with endorsed common core GPP criteria. Also, GPP guidance tools have been developed, together with common criteria for 10 priority product groups, and translated into all EU languages. However, in order to make GPP a standard practice of procurement procedure, more needs to be done to develop further common GPP criteria, and to train procurement officials, and possibly to establish a product database at EU level.