A non-profit making European association established to facilitate and enhance co-operation between national gas transmission system operators (TSOs) across Europe to ensure the development of a pan-European transmission system in line with European Union energy goals. ENTSOG's tasks are set out in Regulation 715/2009 on conditions for access to the natural gas transmission networks, which forms part of the Third Energy Package. These include the development of European network codes (following the issue of framework guidelines by ACER), publishing a ten year network development plan and annual winter and summer supply outlooks. For more information on ENTSOG, see its website, ENTSOG, and Practice note, EU network codes for gas: overview. For a list of ENTSOG members, see ENTSOG: Members. For more information on the Third Energy Package, see Practice note, EU energy regulation: Third energy liberalisation reform, as amended by the Clean energy package.