Driving Hybrids – Cost Evaluation vs. Conventional Cars

Introduction

In my earlier posts [1][2], I have shown you the energy consumption as well as the environmental impact caused by automobiles, where hybrids come handy in both energy saving as well as being environmental friendly. However, exactly how to evaluate the cost of driving hybrids as compared to driving just conventional internal combustion engine cars? What are the factors involved in deducing the costs for driving hybrids and conventional cars that will be meaningful for both end consumers and policy makers for a more sustainable future society? As ho as the term “hybrid” may seem to be, it seems a little bit too demanding for switching over to the hybrid life style, to all hail “hybrids”. In this article, I hope to further elaborate on analytical details of the economic and environmental benefits from hybrids, as compared against their existing dominant internal combustion engine counterparts.

Market Trend

Before we dive into the technical data, allow me to first present some interesting marketing and sales trend information on hybrid cars. Some earlier research work are pretty pessimistic about the actual deployment of hybrid cars in real markets. There are doubts about whether hybrids could be really meaningful in changing the way people drive for saving energy and improving environment [3]. One such study [4], published back in 2002, claims that hybrids would not “have significant sales unless fuel prices rise several-fold or regulators mandate them”.

Figure 1: US Hybrid-Electric Vehicle Sales [7]

However, the sales of hybrids in US have been steadily increasing since early 2002 [5][6], as evidenced by the latest data from the Alternative Fuels & Advanced Vehicles Data Center of US Department of Energy, the sales of hybrid cars have been increasing steadily every year in US since 2000 [7], as shown in the following Figure 1. As pointed by [10], with their superior fuel economy and performance, hybrid vehicles will likely increase in popularity in coming years. The drop in 2008 was most likely caused by the economy downturn that has brought almost all industries to a stall. However, as the economy slowly recovers from the recession, we can see from 2009's figure, the sale is climbing back up.

Hybrids vs. Conventional

In most research literature on evaluating the cost of automobile, researchers tend to consider costs involved in all stages of the vehicle for an objective view on the impact on energy consumption and environment damage [8][9][10][13], In [8], the societal lifecycle cost (LCC) is used for such evaluation purpose, which includes “vehicle first cost, fuel costs, external costs for oil supply security, and damage costs for emissions of air pollutants and greenhouse gases calculated over the full fuel cycle.” In [9], authors have used actual data to perform economic and environmental comparisons for four types of vehicles, conventional, hybrid, electric, and hydrogen fuel cell. To understand the overall cost difference, the comparison needs to be based on a calculation of costs in both production and utilization stages of the vehicles, normalized with prices of vehicles and fuels during the vehicle life and driving and greenhouse gas and air pollution emissions, to evaluate both the economical and environmental indication of the compared vehicle types. On the economic side, we should consider price, fuel costs and driving range consumption [9] as indicated in Table 1. Note that for electric car, battery changing must be included to reflect its associated additional cost due to the dependency on the battery.

Table 1: Vehicle economic characteristics [7][9][11]

On the environmental side, cost caused by damage to air includes air pollution (AP) and greenhouse gas (GHG) [9], where typical emission data is given by Table [2].

Table 2: Vehicle gas emission in all stages [9][13][15]

Table 3: Vehicle environmental characteristics [9][14][15]

Furthermore, there will be variations on the environmental impacts due to different battery technologies used in hybrids. Another important fact that must be taken into consideration is the energy source because different energy sources, e.g., electricity from renewable energy like nuclear power plant or just natural gas, will have different greenhouse gas emission and air pollutions. Combining all these factors, as indicated in [9], hybrid cars have obvious advantages over conventional internal combustion engine vehicles. It must be noted that the economics and environmental impact associated with hybrids and electric cars depends substantially on the source of the electricity.

Conclusion

Nowadays, these findings are becoming more acceptable facts to general public as well as main stream policy makers, where both energy consumption and environmental impact must be put into serious consideration. Advantages of hybrids over conventional cars are no longer surprising news, rather established truth supported by field data from different sources.   However, it does require special attention that, as indicated by the cost evaluation model described in previous section, we have to evaluate all related costs based on the whole lifecycle of the vehicle. Hybrid technology is advancing fast and steady, with their sales catching up fast with the mainstream conventional cars. Furthermore, hybrid cars have the unique advantage of evolving along with the nation-wide long term policy on renewable energy. This is particularly important to local policy makers looking for ways to provide more sustainability, since hybrid cars already have all the industrial and governmental support plus public acceptance to be a successful solution.

By Can Mao

References

[1] Can Mao, “Driving Hybrids – The Energy Consumption Background,” August 2010, EcoPol Project http://ecopolproject.blogspot.com, accessed on August 8, 2010.

[2] Can Mao, “Driving Hybrids – A Scientific Justification,” July 2010, EcoPol Project http://ecopolproject.blogspot.com, accessed on August 8, 2010.

[3] “Dust in the Wind: Hybrids' Total Energy Cost,” hybridCARS, September 28, 2006, http://www.hybridcars.com, accessed on August 8, 2010.

[4] L. B. Lave and H. L. MacLean, "An environmental-economic evaluation of hybrid electric vehicles: Toyota's Prius vs. its conventional internal combustion engine Corolla". Transportation Research Part D: Transport and Environment (1361-9209), vol. 7 (2), pp. 155, 2002.

[5] US Hybrid Car Sales Figures For 2007 Continue Upward Trend, hybridcar.com, Jan 14, 2008, http://www.hybridcar.com, accessed on August 8, 2010.

[6] Reported US Sales of Hybrids Up 27.3% In January, Green Car Congress, Feburary 7, 2008, http://www.greencarcongress.com, accessed on August 8, 2010.

[7] US Hybrid-Electric Vehicle Sales, Alternative Fuels & Advanced Vehicles Data Center, US Department of Energy, accessed on August 8, 2010.

[8] Joan M.Ogden, Robert H.Williams, Eric D.Larson, "Societal lifecycle costs of cars with alternative fuels/engines," Energy Policy vol. 32 7–27, 2004.

[9] Mikhail Granovskii, Ibrahim Dincer, Marc A. Rosen, “Economic and environmental comparison of conventional, hybrid, electric and hydrogen fuel cell vehicles, ” Journal of Power Sources, vol. 159, pp. 1186–1193, 2006.

[10] C. C. Chan, "SPECIAL ISSUE - ELECTRIC, HYBRID & FUEL CELL VEHICLES - The State of the Art of Electric, Hybrid, and Fuel Cell Vehicles - INVITED PAPER - With their superior fuel economy and performance, hybrid". Proceedings of the IEEE (0018-9219), 95 (4), pp. 704, 2007.

[11] Energy Information Administration, Official energy statistics from the U.S. Government, http://tonto.eia.doe.gov, accessed on August 8, 2010.

[12] Malcolm A. Weiss, John B. Heywood, Andreas Schafer, and Vinod K. Natrajan, “Comparative Assessment of Fuel Cell Cars,” Lab. For Energy and the Environment, MIT, LFEE 2003-001 RP, 2003.

[13] R. Dhingra, J. Overly, G. Davis, “Life-Cycle Environmental Evaluation of Aluminum and Composite Intensive Vehicles, ” Report, University of Tennessee, Center for Clean Products and Technologies, 1999.

[14] M. Pehnt, “Life cycle assessment of fuel cell stacks,” Int. J. Hydrogen Energy, vol. 26, pp. 91–101, 2001.

[16] United States Environmental Protection Agency, http://www.epa.gov, accessed on August 8, 2010.

[17] Electric Drive Transportation Association, http://www.electricdrive.org, accessed on August 8, 2010.

[18] The United States Department of Energy, http://www.energy.gov, accessed on August 8, 2010.