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NKA: Niska Gas Storage Partners LLC owns and operates natural gas storage assets in North America. It owns or contracts for approximately 185.5 billion cubic feet of total gas storage capacity. The company owns and operates gas storage facilities in Alberta, Canada, as well as in northern California and Oklahoma, the United States. Its gas storage customers include financial institutions, producers, marketers, power generators, pipelines, and municipalities. The company was founded in 2006 and is headquartered in Houston, Texas.

NRGY: Inergy, L.P. engages in the retail marketing, sale, and distribution of propane to residential, commercial, industrial, and agricultural customers in the United States. The company owns and operates four natural gas storage facilities (Stagecoach, Steuben, Thomas Corners, and Tres Palacios); a liquefied petroleum gas storage facility (Finger Lakes LPG); a natural gas liquids business; and solution-mining and salt production company (US Salt). As of October 29, 2010, it served approximately 700,000 retail customers in 33 states from 356 customer service centers. Inergy, L.P. is headquartered in Kansas City, Missouri.

NGG: National Grid plc owns and operates regulated electricity and gas infrastructure networks in the United Kingdom and northeastern United States. The company operates high voltage electricity transmission networks and gas distribution systems in the Great Britain, New York, and New England; gas transmission networks in the Great Britain; electricity distribution networks in New York and New England; and electricity generation facilities in New York. It also owns and operates electricity interconnector between England and France; and a 224 kilometer transmission interconnector between England and Canada; and 3 liquefied natural gas storage activities in the Great Britain. The company serves residential and commercial consumers. It delivers gas through its approximately 132,000 kilometers gas distribution pipeline network to approximately 10.8 million customers in the United Kingdom; distributes electricity to approximately 3.4 million customers in New England and upstate New York; and distributes gas through its approximately 58,000 kilometers gas pipeline network to approximately 3.5 million consumers. The company also owns 57 electricity generation units on Long Island that provide approximately 4.1 gigawatt of power. Its electricity generation units generate power from oil, gas, and diesel fuel sources. National Grid plc was founded in 1990 and is based in London, the United Kingdom.