This primer (download PDF version) accompanies the EPRINC report examining the value of the Keystone XL Gulf Coast pipeline expansion to the United States. It is posted at www.eprinc.org/pdf/oilsandsvalue.pdf
U.S. federal law has encouraged the use the renewable fuels in the U.S. transportation sector since the 1970′s. Under President Carter, Congress enacted several renewable-energy programs, including targeted subsidies to promote the use of ethanol in transportations fuels.
Refineries produce a more expensive fuel blend during the summer to cut down on smog during hot months. Stations nationwide will start selling a less-expensive winter fuel usually by mid September, which on average means that winter gasoline is less expensive than summer gasoline.