Process Economics Program Report 243A
Direct Methanol Fuel Cells
Published: November 2004
With crude oil prices rising above $50/b, natural gas prices at the U.S. Gulf Coast appear to have risen to a new floor of just under $5/MM Btu. The demand for electric power generation appears to be driving the demand for natural gas, with environmental concerns discouraging the use of coal as a conventional boiler fuel. In certain regions, such concerns even appear to be hampering the construction of long distance electrical transmission and natural gas pipeline facilities required by large centralized power plants. This is one factor behind the growing interest in fuel cells as an efficient, reliable and environmentally acceptable means to small scale "distributed" power generation.
Proven world natural gas reserves, which currently represent about 83% of the energy equivalence of proven oil reserves, have been growing at a faster rate. In some remote locations, wellhead costs of "stranded" natural gas have been estimated to be below $0.25/MMBtu. New world scale methanol production technologies using stranded natural gas as feedstock may result in the availability of a fuel grade methanol importable to the U.S. Gulf Coast and other major consuming regions at a price which would be competitive with that for natural gas. This is a factor behind growing interest in methanol based fuel cell technologies for various new small-scale mass-market transportation, portable power, and stationary power applications.
Recent advances in liquid feed direct methanol fuel cells (DMFCs), which eliminate the need for bulky reformer based fuel processors, may soon represent a practical alternative to conventional batteries for laptop computers and other portable power applications. Aside from promising considerably longer operating times than similarly sized conventional batteries via "hot swappable" disposable methanol fuel cartridges, DMFCs may also prove to be more economical. The scope of this report includes a comparative evaluation of the technology, energy efficiencies and estimated costs of DMFC concepts applied to microelectronic, portable electric power generation, and onboard automotive electric propulsion systems. The scope of our review also includes a rundown on the status of polymer electrolyte membrane (PEM) development for DMFCs, including promising new membranes under development by Polyfuel and Giner which appear to be nearing commercialization for such mass market "personal" power applications. We also include a discussion of a promising new sputter deposition (SD) technique which may dramatically further reduce costly platinum electrocatalyst requirements, a major drawback of earlier DMFC prototypes.