National Grid plc is an energy company operating in the United Kingdom and the United States. The Company's businesses supply gas and electricity to various customers and communities. Its segments include UK Electricity Transmission, UK Electricity Distribution, UK Electricity System Operator (ESO), New England and New York. UK Electricity Transmission segment includes the high-voltage electricity transmission networks in England and Wales. Its networks comprise approximately 7,216 kilometers (km) of overhead line, 2,551 km of underground cable and 347 substations. The UK Electricity Distribution segment includes the electricity distribution networks of Western Power Distribution in East Midlands, West Midlands and Southwest of England and South Wales. The Company operates as the electricity system operator (ESO) across Great Britain. It also has gas distribution networks, electricity distribution networks, and high-voltage electricity transmission networks in New England and New York.