The Guarantee of Origin (GO) is a crucial instrument for the widening business strategy for clean power. The Association of Issuing Bodies (AIB) has created and operates the European Energy Certificate System (EECS) to harmonise the functioning of the GO-systems. The AIB is a ‘not for profit’ membership organisation consisting of national GO issuing bodies. We have also established an electronic Hub for efficiently transferring GOs across the European market. The Hub enables full traceability and transparency and ensures in a cost-effective way, ensuring that there will never be double-selling or double-counting of renewable GOs within this system. There are now already 20 active AIB member countries – all of which are fully EECS compliant.