It can be remembered that last week, a study conducted by CNW Marketing Research reported that hybrid cars are not as green as they appear to be. The study focused on the amount of energy a vehicle would need in its lifetime. The result of the study conducted over two years shows that hybrid cars uses up more energy than conventional gasoline engined vehicles. In fact, the study claims that compact and midsized SUVs consume less energy than hybrid vehicles. More interestingly, the Hummer is considered ‘greener' than hybrid cars. When the eco-friendliness of cars is concerned, environmentalists and points to the gas-guzzling capability of the Hummer. But with the result of the study conducted by CNW gives Hummer lovers an argument in the ongoing battle of words. Environmentalists though have found an ally in Dr. Peter H. Gleick of the Pacific Institute. Dr. Gleick recently published his study entitled "Hummer versus Prius: ‘Dust to Dust' Report Misleads the Media and Public with Bad Science". The said paper refuted the study published by CNW Marketing Research. According to the result of Dr. Gleick's study, the ‘Dust to Dust: The Energy Cost of New Vehicles From Concept to Disposal' uses poor assumptions. The data pointed out by Dr. Gleick, which shows that the study conducted by CNW Marketing is erroneous, is the usable life of a Prius and the Hummer. According to the expert, the original study put the usable lifespan of a Prius at only 11 years while the Hummer's lifespan was placed at 35 years. This disparity in lifespan is also being argued by Prius owners. With the reliability that Japanese automakers are known for, it is indeed surprising that the Toyota Prius was given an expectancy of only 11 years while the Hummer H1 was given an expectancy as high as 35 years. Another figure being questioned by Dr. Gleick's study reflects the seemingly erroneous lifespan of the vehicles in question. The original study released by CNW Marketing shows that in its lifetime, the Prius covers about 109,000 miles while for the Hummer H1, it was placed at 379,000 miles. The disparity is being questioned especially by Prius owners who have already covered more than the 109,000 miles assumed by CNW Marketing. The paper released recently by Dr. Gleick does not necessarily show that the Prius uses less energy than conventional vehicles but it points out that the public should be aware of the fact that the study conducted by CNW Marketing may have some erroneous data. According to CNW, the reason why hybrid vehicles such as the Toyota Prius use more energy in their lifetime is that they are more complex than conventional vehicles. A hybrid uses a powertrain that includes an internal combustion engine and an electric motor powered by a battery pack. The presence of the electric motor alone means that it has more parts thus more energy is being used up in the production of these auto parts. Another concern is the material used in the manufacturing of hybrid car batteries. Nickel, a major component of the Prius' battery pack, is mined in Canada and shipped to China than to Japan. During the transportation of the said material, petroleum fuels are used by cargo ships and trucks. The study conducted by CNW took this into consideration. Meanwhile, Hummer H1s even with Hummer car covers uses considerably fewer auto parts than advanced hybrids. This debate though is far from being over even with the ‘dust to dust' study being refuted.