Globe and Mail: Alberta’s oil sands are taking a hit from new U.S. energy legislation passed last month that has an unusual wrinkle suggesting that Canadian crude might be too dirty for the U.S. government. The legislation won’t allow any U.S. federal agencies to buy vehicle fuel derived from non-conventional sources unless the life cycle of its greenhouse-gas emissions is the same or less than that of conventional petroleum. The sticky bitumen in Alberta’s tar sands is considered one of the …