The Western States Petroleum Association (WSPA) retained MathPro Inc. to assess its proposal for a voluntary program, starting not later than 2003, to supply ultra-low-sulfur diesel (ULSD) to vehicle fleets in the Maricopa County, AZ area. In this quick-response engagement, we assessed the potential supply of ULSD under the WSPA proposal, the potential demand for ULSD (in terms of number of vehicles and vehicle miles traveled), and the total refining cost of the WSPA proposal. (Another consulting firm estimated the reduction in area emission inventories that the estimated volumes of ULSD would produce and the total annual cost (including vehicle retro-fit costs) of the WSPA proposal.)

We estimated the potential supply of ULSD in terms of the refineries likely to participate in the program, the maximum prospective ULSD volume that each refinery would supply, and the average incremental refining and supply cost, relative to EPA diesel, incurred by each refinery.

We developed this information on the basis of direct contacts with each refinery and the results of prior analyses of Maricopa County’s fuel supply.

WSPA applied the results of the analysis in framing its proposal state officials and in answering questions posed by state officials and interested parties.