across the province. However, the Saint John, New Brunswick area accounts for nearly half of the total NB Power-owned generation capacity, with the Coleson Cove (972 MW), the Point Lepreau Nuclear Generating Station (660 MW), and Bayside Generating Station (277 MW). Saint John is home to energy-intensive industries such as the Irving Oil Refinery, JD Irving pulp and paper mills, and the Canaport liquefied natural gas terminal. Thermal Generation NB Power operates two thermal and three combustion turbine facilities with a combined generating capacity of 1,964 MW. Nuclear Generation NB Power operates the Point Lepreau Nuclear Generating Station which is the only active nuclear generating station in Canada outside of Ontario. It has a generation capacity of 660 MW. Hydroelectric Generation NB Power operates seven hydroelectric dams in the province with a combined generating capacity of 889 MW. The main hydroelectric facilities are located on the Saint John River. The province's largest, the Mactaquac generating station (668 MW), stands some upstream of the capital city, Fredericton. It was built between 1965 and 1968 at a cost of C$128 million. The plant has been a concern for some time due to a phenomenon called alkali-aggregate reaction, causing the dam to expand and crack. The problem has been known since the 1970s and could reduce the dam's life by half, according to a 2000 report by a panel of international engineering experts commissioned by the Crown corporation. Electric transmission NB Power's transmission grid includes over of high voltage transmission lines ranging from 69 kV AC to 345 kV AC. The company operates interconnections with Hydro-Québec, Nova Scotia Power, Maritime Electric in Prince Edward Island and the ISO New England network in the United States. The network is operated by the Transmission & System Operator division of NB Power. The main power grid forms an "O"-shaped loop with 345 kV lines. This power line runs through substations at Keswick, Saint-André, Eel River, Belledune, Bathurst, Salisbury, Norton, Coleson Cove, Point Lepreau, and back to Keswick. There is also a direct connection of a parallel 345 kV line between Coleson Cove and Keswick. NB Power supplies electricity to Maritime Electric in Prince Edward Island through a sub-sea interconnection cable on the floor of the Northumberland Strait, and imports/exports from/to Nova Scotia via Canada's first electrical interconnection between two provinces. NB Power also has interconnections to Maine. Because of the asynchronous nature of Hydro-Québec's electricity transmission