December 2, 2009
Analysis of the emissions of different types of vehicles based on fuel consumption and life cycle
In the majority of cases, the use of bioethanol in existing vehicles with internal combustion engines produces fewer emissions than the use of electric vehicles.
This fact is easily proven by making a comparative analysis between different types of vehicles with similar performance: conventional vehicles with piston engines, hybrids, electric vehicles and flex-fuel hybrids. It is worth noting that a conventional gasoline engine was used as the reference for the analysis. The fuels used in the study were gasoline and e85 (85% bioethanol and 15% gasoline).
The bioethanol used to produce the e85 fuel can be obtained from different raw materials and processes. These processes provide different levels of emissions for the fuel’s lifecycle. Therefore the use of e85 leads to different levels of emission savings depending on the process used to obtain the bioethanol. The bioethanol used in the analysis was low environmental quality with 35% emissions savings in its lifecycle compared to gasoline with the same energy value. Medium environmental quality bioethanol has a 50% emissions savings in its lifecycle, and very high environmental quality bioethanol achieves 90% emissions savings in its lifecycle.
The main results of the emissions comparison between different types of vehicles based on the consumption and life cycle of the fuel (see image) shows that, firstly, a hybrid vehicle reduces emissions of greenhouse gases by 32% compared to a conventional gasoline vehicle. The reduction in emissions from an electric vehicle that uses the European electric mix has also been calculated. This generates savings of 46%, although this would be less (38%) if it used the Spanish electric mix.
Nevertheless, the most interesting results of the analysis are for vehicles that run on e85, which achieve reductions that are clearly superior to those achieved by the electric vehicle. This leads to the conclusion that a conventional flex-fuel vehicle that uses e85 could reduce its emissions to a level that is better than an electric vehicle, provided that the environmental quality of the bioethanol generates an emissions reduction of at least 58% for the case of the European electric mix and 49% for the Spanish electric mix.
A hybrid flex-fuel vehicle running on e85 therefore reduces its emissions to a greater extent. This type of vehicle has lower emissions compared to an electric vehicle provided that the bioethanol contains reductions during its lifecycle of more than 29%. For example, a flex-fuel hybrid running on e85 obtained from bioethanol with a lifecycle with a 50% reduction reduces emissions by 59% compared to a conventional gasoline vehicle, and by 23% compared to an electric vehicle. If it used a bioethanol that had a 90% reduction during its lifecycle, it would reduce its emissions by 80% compared to the conventional car and by much more than the reductions achieved by the electric vehicle.
In short, the use of bioethanol in existing hybrid vehicles, with a simple adaptation to flex-fuel, represents a greater decrease in emissions than those generated by electric vehicles.
Furthermore, it should be taken into account that the use of electric vehicles on a large scale would lead to a significant rise in the price of electricity. Considering the fact that the current price is loss-making, each kilometer driven by an electric vehicle would be subsidised, the opposite situation to liquid fuels that represent an important source of tax income for the government. Therefore it would be misleading to think that a move towards electric vehicles could happen without a significant increase in the price of the “new fuel”.
In light of the results of the study and the current energy situation, we can say that biofueled vehicles are already a more appropriate and sustainable alternative for the world.
Aware of this fact, Abengoa already produces bioethanol at its European plants with an emissions reduction in the lifecycle of between 35% and 60% compared to gasoline. In the near future, Abengoa will produce bioethanol with reduction levels between 60% and 80% in hybrid plants with cellulose bioethanol or from cogeneration plants that use biomass. It is undoubtedly a clear commitment to a sustainable future that will benefit the end consumer.
© 2009 Abengoa. All rights reserved
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