Existing natural gas infrastructure
In the Netherlands the transmission system operator Gas Transport Services B.V. (GTS) from July 2004 is responsible for operating the transport system . The previous operator Gasunie  passed legal tasks of the national transmission system operator to GTS, however retained ownership of the main transport network. The Gasunie business unit Technology & Assets (GTA) will perform works on the system, is responsible for the technical maintenance including construction. Gasunie also offers engineering and consultancy services (Gasunie Engineering, GE), takes part in research and development activities (Gasunie Research, GR). GasTerra buys, sells and exports natural gas. Gasunie is since July 2005 fully state owned, GasTerra is a joint venture with state, Shell and Exxon. The main supplier is NAM (Nederlandse Aardolie Maatschappij), the company that operates the well clusters on the Groningen field. Additionally, a small volume of gas is imported from Norway and Russia.