As with any controversial, large-scale energy project, long-term economic analyses stir up discussion. A newly released study (.pdf) of various pipeline scenarios conducted by EnSys Energy and commissioned by the U.S. Department of Energy of TransCanada Corp.'s proposed Keystone XL bitumen line -- and an accompanying DOE greenhouse gas assesment (.pdf) -- are no different. Among many other things, the study found that regardless of whether or not the line is built, the U.S. will still import oil from Western Canada and that any reduction in U.S. crude oil demand would first affect non-Canadian sources. TransCanada says the report confirms the assertion that the proposed line will increase the security of the U.S. energy market, and environmental groups opposing the line say it confirms the assertion that the line would increase dependence on carbon-intensive oilsands crude to the detriment of alternative forms of energy. The Calgary Herald has a long article featuring statements from TransCanada's chief executive Russ Girling, and the Natural Resources Defense Council, opposed to the Keystone line, has posted a somewhat informal, but lengthy, response to the DOE-commissioned report on its staff blog, here.