On January 17, 1961, Canadian Prime Minister John Diefenbaker and United States President Dwight Eisenhower signed the Columbia River Treaty. It was a landmark agreement that required Canada to build three dams to aid in U.S. flood protection and power generation. In exchange for taking on the impacts of these water storage projects, Canada was paid $64 million for 60 years of flood control benefits. 
Canada also received an entitlement to one-half of the estimated additional hydroelectric generation capability at power plants on the Columbia River in the United States made possible by the operation of the dams in Canada. The power is referred to as the "Canadian Entitlement" and since 2003 it has amounted to at least 1,176 megawatts of capacity and 4,073 gigawatt hours of energy per year.
That is nearly identical to the amount of electricity B.C. would get from Site C. 
http://www.desmog.ca/2015/05/28/forgotten-electricity-could-delay-need-site-c-dam
Why have we been kept in the dar