Hybrid cars now, fuel cell cars later

Science

Volumn 305, Issue 5686, 2004, Pages 974-976

  Demirdöven, Nurettin ^a   Deutch, John ^a  

^a MASSACHUSETTS INSTITUTE OF TECHNOLOGY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ENERGY EFFICIENCY; FOSSIL FUELS; FUEL CELLS; INTERNAL COMBUSTION ENGINES;

FUEL CELL VEHICLES; HYBRID VEHICLES;

RAILROAD CARS;

FOSSIL FUEL; FUEL;

ENERGY RESOURCE; HYDROGEN; TECHNOLOGICAL DEVELOPMENT;

AUTOMOBILE INDUSTRY; CAR; COMBUSTION; ENERGY TRANSFER; ENERGY YIELD; GOVERNMENT; PRIORITY JOURNAL; REVIEW;

EID: 4043093570     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.1093965     Document Type: Review

References (22)

1. Calculated from weekly data of supplied gasoline products published by DOE, Energy Information Agency; see www.eia.doe.gov/oil_gas/petroleum/ info_glance/gasoline.html.
2. "National transportation statistics 2002," U.S. Department of Transportation, Bureau of Transportation Statistics (BTSO2-08, Washington, DC, 2002), table 4-1.
3. "Inventory of U.S. greenhouse gas emissions and sinks: 1990-2001," final version, U.S. Environmental Protection Agency (EPA 430-R-03-004, Washington, DC, 2003), table A-1.
4. Only gasotine and natural gas are widely available as a transportation fuel today; a hydrogen or methanol fueled transportation system would take decades to deploy, at significant cost.
5. rb for fuel processing, engine or fuel cell, drive train, and regenerative braking, respectively. We focus on efficiency rather than the more common fuel economy because the efficiency is less sensitive to vehicle weight than fuel economy.
6. In 2001, General Motors (GM) collaborated with Argonne National Laboratories (ANL) to use ANL's Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. The report, "GM study: Well-to-wheel energy use and greenhouse gas emissions of advanced fuel/vehicle system, North American analysis," is referred to as the ANL/ GM study and is available online at http://greet. anl.gov/publications.html.
7. M. A. Weiss, J. B. Heywood, E. M. Drake, A. Schafer, F. AuYeung, "On the road in 2020: A life cycle analysis of new automobile technologies," (MIT Energy Laboratory Report No. MIT EL 00-003, Cambridge, MA, 2000). We thank M. Weiss for helpful discussions about this work.
8. M. A. Weiss, J. B. Heywood, A. Schafer, V. K. Natarajan, "Comparative assessment of fuel cell cars" (MIT Laboratory for Energy and Environment Report No. 2003-001 RP, Cambridge, MA, 2003).
9. P. Ahlvi, A. Brandberg, Ecotraffic Research and Development, "Well to wheel efficiency for alternative fuels from natural gas to biomass," Vagverket (Swedish National Road Administration), Publication 2001: 85 (2001), appendix 1.8.
10. F. An, D. Santini, SAE Tech. Pap. 2003, no. 2003-01-0412 (2003).
11. B. Hohlein, G. Isenber, R. Edinger, T. Grube, Handbook of Fuel Cells, W. Vielstich, A. Gasteiger, A. Lamm, Ed. (Wiley, New York, 2003), vol. 3, chap. 21, p. 245.
12. More information is available at the DOE Web site: www.fueleconomy.gov/ feg/atv.shtml.
13. We wish to keep the presentation of our model simple. The assumption of complete regenerative braking and reduction in idling losses is not realistic. However, improvement in ICE engine efficiency is also possible (7). The current performance of hybrid ICE passenger vehicles such as the Toyota Prius is impressive. Toyota reports TTW efficiency of the Prius as 32%, compared to 16% for a conventional ICE: www.toyota.cojp/en/tech/environment/fchv/fchv12.html. Prius regenerative braking reportedly recaptures 30%; see www.ott. doe.gov/hev/regenerative.html.
14. For this case, there is no processor loss, and the FC stack efficiency improves to 55% because the FC functions better on pure hydrogen than reformate.
15. The NREL ADVISOR simulator is described online at www.ctts.nrel.gov/ analysis. Use of the model is described in several publications at www.ctts.nrel.gov/ analysis/reading_room.html; see, for example, (20, 21).
16. GM quotes 15 to 20% fuel economy improvements in 2007 for hybrid Tahoe and Yukon sport utility vehicles. Not surprisingly, Toyota seems more optimistic about hybrids than GM.
17. In Europe, where fuel prices are much higher than in the United States, the advantage of hybrids over conventional ICEs is significantly greater.
18. The 2003 Energy Act, currently under consideration by Congress, would extend the time period for the hybrid car tax credit.
19. Quote taken from www.eere.energy.gov/vehiclesandfuels/.
20. T. Markel et al., J. Power Sources 110, 225 (2002).
21. M. R. Cuddy, K. G. Wipke, SAE Tech. Pap. 1997, no. 970289 (1997).
22. This work was supported by the Alfred P. Sloan Foundation.