Natural gas transportation and supply in Thailand is undertaken by the Petroleum Authority of Thailand (PTT), which was a state enterprise at the time of its establishment in 1978 but upon corporatization in 2001, it has now become a listed public company. PTT sells gas to power sector at a price comprising of the following elements: gas pool price, PTT's marketing margin charge, and pipeline tariff (PTT public company (PTT), 2005). Each of these elements is discussed below.