Canada's National Energy Board granted approval in December to the proposed Mackenzie Gas Project, which would string a natural gas pipeline from the upper-reaches of the Northwest Territories, Canada, 745 miles south into Northern Alberta. Before the $16.2-billion project can proceed, backers must put in place a funding framework. Image: Walter Konefal for ENR "Mackenzie needs to compete on a supply-cost basis with other sources of supply," says Pius Rolheiser, Calgary-based Mackenzie project spokesperson." It remains the critical challenge today to be cost- competitive with shale gas, liquefied natural gas and potential Alaska projects." While Mackenzie runs primarily south, staying
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.