Puerto Rico is an island that lacks any indigenous gas reserves. As a result it is entirely dependent on LNG imports for its gas supply. Imports commenced in July 2000 with the commissioning of the country's first LNG regas facility Penuelas on the southern coast. Puerto Rico has over 5 000 MW of installed power capacity the majority of which is oil fired. The long term potential market for gas relies almost entirely on the power sector. Currently Aguirre 1&2 steam turbines (ST) Costa Sur 3&4 and Palo Seco power plants which runs on no. 6 fuel oil do not comply with MATS. Consequently PREPA should convert these units to natural gas to continue its regular operations or alternatively retire or declare them as limited use. Due to the low reserve margin required to supply Puerto Rican electricity demand PREPA is switching to gas at its power plants.