http://www.energybulletin.net/22358.html
"Production of "oil" from the tar sands is a very energy-intensive process. Production estimates for 2025 are that the energy input will require between 1.6-2.3 billion cubic feet (bcf) of natural gas per day, approximately equal to the planned maximum capacity of the proposed Mackenzie Valley gas pipeline (1.9 bcf/d) out of northern Canada, or about one-fifth of anticipated daily Canadian gas production."