Energy transportation is an increasingly critical component of energy markets and energy security. As the market becomes ever more global and interdependent, the role of logistics will be of key importance. Transportation does not, however, occur in a vacuum, but amid ever-changing market conditions. The market's moving parts include, among others, supply sources, the regional allocation of demand, and the quality make-up of the demand barrel - i.e., the type and quality of products that are most in demand at any given time, and thus of the crude grades offering maximum yields of those products. The price impact of changes in transportation infrastructure will therefore vary over time based on the availability of alternate supply and changes in demand patterns.