What would happen to Alaska's natural gas once it reaches the end of the proposed pipeline, 1,700 miles from Prudhoe Bay? The gas would flow into a vast network of Canadian and U.S. pipelines assembled over the past 60 years. Some key components of that network were built or expanded in the early 1980s in anticipation of Alaska gas starting to flow back then. Those components went into service without Alaska gas and helped Canada double its natural gas exports to the United States in the 1980s, then double them again in the 1990s. In all, the entire network today can move 15 billion to 20 billion cubic feet a day of natural gas, roughly three to four times the volume the Alaska pipeline would deliver to the British Columbia-Alberta border northwest of Edmonton. Of course, the network still moves billions of cubic feet of gas daily. But the volume it handles has been declining, leaving room for Alaska gas, and even if the flow is relatively flush when the Alaska pipeline is finished, the network's capacity could be expanded. No longer is there serious talk of needing a pipeline stretching all the way from Prudhoe Bay to Chicago. But why end the Alaska pipeline near the B.C.-Alberta border as opposed to somewhere else? The answer is simple: Three major North American gas pipeline systems converge there, in the heart of some of Canada's hottest natural gas plays.