A critique of Plug-in Hybrid cars as Clean Technology

G. Hernandez





 This paper provides a critique in the promotion and use of plug-in hybrid cars. The promotion of this technology as a replacement for the combustion engines do not necessarily lead to improvements in the environment, reductions in electricity use, GHG emissions or pollution. The technical development of this technology as a replacement for the classic technology is negligible, and its use could produce more contamination than the classic technology. This paper presents different points of view that are commonly overlooked in the global analysis of this technology. The analysis also shows outcomes in different jurisdictions across Canada.


Keywords: hybrid car, plug-in car, greenhouse gas (GHG), electricity, contamination, battery


1        Introduction


The urgent need to reverse the business-as-usual growth path in pollution in the next two decades to avoid serious environmental impacts necessitates action to make our vehicles far less polluting.

In the near-term, the most cost-effective strategy for reducing emissions and fuel use is efficiency. Several authors and scientists have come to the conclusion that the car of the future is the hybrid gasoline–electric vehicle. The thinking is that this vehicle can reduce gasoline consumption and greenhouse gas emissions (GHG) by 30 to 50% with no change in vehicle class and hence no loss of jobs, compromise on safety or performance. The researchers contend that it will likely become the dominant vehicle platform by the year 2020 [1].

The general thinking is that gasoline will be replaced with a zero-carbon fuel. All alternative fuel vehicles (AFV) have captured the attention of people, media and governments because the pathways require technological advances and strong government action to succeed. Hydrogen is the most challenging of all alternative fuels, mainly because the technology does not require the use of fossil fuel, as it is the more common way to feed a huge hydrogen demand.

Another important consideration for pollution and GHG emission abatement is to develop a relationship with hydrogen vehicles. In this case, the most important gas in the GHG is the water vapor, the exhaust gas for hydrogen vehicles. Also, to obtain the hydrogen for renewable source, the requirement of water will be a serious problem to supply all the hydrogen demand that the car industry would require. The hydrogen car is visibly not a complete solution to the problem of the next generation of cars keeping in mind the pollution, resources and contamination.

Electric hybrid cars appear as interesting solution as replacement for the actual car infrastructure, but not all the promoted solutions of this kind of technology are seriously analysed and shared with the people. The people don't have enough information about all the implications of this technology; therefore, the judgement is not fair.

New discussions and policies supporting are necessaries to address the car emission and efficiency problem. The solution is not unique, and a lot of things need at be considered to reach the best solution for each jurisdiction.

This paper is organized as follows. In Section II we analyze the different points of view to address the plug-in hybrid car problem. In Section III we present different remarks around the hybrid cars and contamination. In Section IV we show examples of the use of plug-in hybrid cars in different jurisdictions. Finally, concluding remarks are drawn in Section V.


2        plug-in hybrid cars


 Hybrid cars, as alternative fuel vehicles and their fuels, face several central problems. First, they typically suffer from several marketplace disadvantages compared to conventional vehicles running on conventional fuels. Hence, they inevitably require government incentives or mandates to succeed, but not all governments are disposed to this. Second, they typically do not provide cost-effective solutions to major energy and environmental problems, which undermine the policy case for having government intervention in the marketplace to support them. Third, the main goals that the hybrid cars try to overcome about energy efficiency, contamination and environmental protection are not commonly reached in most of jurisdictions.

Considering the marketplace disadvantages, if the market is regulated as in the most important countries with high car use density, the hybrid cars are not cost competitive. This leads the car manufacturers to develop an aggressive media campaign promoting the hybrid car. The complete information is not addressed about the contamination and energy efficiency problems. Instead of this huge media campaign, the Canadian Federal Government cut in its Federal Budget 2008 the discount for green vehicles. The car manufacturer’s approach has several shortcomings showing that the fight it is simply a business fight, disguised in environmental and energy efficiency problems. The first shortcoming is given by that reality that the hybrid car manufacturer does not find energy efficiency in the worldwide car use; they do not look it to be more efficient and competitive; they look for capturing a market that it is irrelevant to their solutions. Table 1 presents the index of energy efficiency [2] for hybrid cars in the market. Table 2 presents this same index in comparison with hybrid and non-hybrid cars in the market. This Energy Efficiency represents the global cost per mile considering the car construction and the energy involved in the car life, as fuel, maintenance, etc.


Hybrid Car

Energy Efficiency [$/mile]

Honda Insight


Ford Escape


Honda Civic


Toyota Prius


Honda Accord


Table 1: Energy index for hybrid cars.


Energy Efficiency [$/mile]

Ford Escord


Toyota Echo


Hyundai Elantra


Toyota Corolla


Honda Insight Hybrid


Toyota Prius Hybrid


Audi A6


Table 2: Energy index for different cars.

The second point is that hybrid cars do not provide cost-effective solutions to the biggest energy and environmental problems, which undermine the policy case for having the government intervene in the marketplace to support them. The environmental alternatives don't provide a cost effective solution, and they need government support. Last, these technologies get government support through a huge media and people pressure for what is necessary to convince the people that the supposed environmental alternatives are better in other way. This often favors business opportunities and outcomes, hiding information and a fair analysis of the problems and associated solutions.

The third point that energy efficiency is not always analysed in a complete and global study is demonstrated in tables 1 and 2. The GHG and contamination will be analysed in more detail in Section III. The U.S. Energy Independence and Security Act of 2007 focalizes the fuel efficiency in cars with a schedule by 2011, 2015 and 2020. The law also focuses on alternatives fuels as biofuels, research in hydrogen and hybrid cars, but the focus is on efficiency in combustion engine cars.

As summary, there have historically been six major barriers to hybrid cars success:

-          High first cost for vehicle

-          On-board fuel storage issues

-          Safety and liability concerns

-          High fuelling cost

-          Improvements in the competition

-          Hidden environmental problems


3        environment and hybrid cars


The incomplete analysis of the environmental problems associated with hybrid cars ignores battery disposal, electricity pollution, electricity cost, and technical availability of alternative sources of electricity that would have a serious impact on a complete analysis for each case and jurisdiction.

The hybrid cars most promising AFV pathway is a hybrid that can be connected to the electric grid. These so-called plug-in hybrids will likely travel three to four times as far on a kilowatt-hour of renewable electricity as fuel cell vehicles [1] [5].

Hoyer [3] does a more global analysis of problems associated with hybrid cars. The everlasting question concerning the source of electricity still exists, as it was posed in discussions some hundred years ago. If the electricity comes from the ordinary grid dominated by nuclear and fossil power production, the total environmental gains are not all obvious. This would also be the case for plug-in hybrids.

There are several concerns about the environment and energy efficiency of hybrid cars that are generally omitted by the promoter and supporters of hybrid car technology. In order to make a fair judgment on the environmental and energy efficiency of hybrid car technology it is necessary to discuss the following issues:

-          Batteries and groundwater contamination

-          cost and energy use for producing the car

-          environmental issues associated with the electricity generation (for plug-in hybrids)


3.1        Batteries and Contamination

Hybrid cars require a battery pack to store the energy that they will use leading to inefficient energy use as well as contamination associated with battery disposal.

The Toyota Prius is promoted as one of the most efficient hybrid cars; it can run without plug-in it, producing electricity through the combustion engine. Also, this car uses a more efficient and environmental friendly battery pack; it is based on 38 modules of nickel metal hydride battery with a life of around eight years, according to the car manufacturers.

Figure 1 shows that effectively, these kind of batteries, are today the best for hybrid car use [4].

Figure 1: Characteristics of some types of buffers, year 2005. ‘‘Number of cycles’’ reflects how long the buffer can be used before it loses performance and needs replacement.

Batteries for the Toyota Prius are produced in Ontario for North America market. Production of these batteries is a major source of pollution. The nickel of the Prius’s battery is mined and smelted at a plant in Sudbury, Ontario. This plant has caused so much environmental damage to the surrounding environment that NASA has used the ‘dead zone’ around the plant to test moon rovers. The area around the plant is devoid of any life for miles. The plant is the source of all the nickel found in a Prius’ battery and Toyota purchases 1,000 tons annually. Dubbed the Superstack, the plague-factory has spread sulfur dioxide across northern Ontario, becoming every environmentalist’s nightmare [7] [8].


3.2        Cost and energy for car production

In [2] there is a detail of energy costs involved with building a car.  Table 1 presents the energy efficiency index for the most popular hybrid cars. Table 2 provides a comparison of energy efficiency of hybrids and combustion engine cars. Different publications show the high cost of Prius, and they compare with the Hummer, one of the most expensive car considering environment and energy use. Indexes for the Prius are close to and even exceed those of the Hummer H3 [2][7][8].


3.3        Environmental electricity implications

The promotion of plug-in hybrid cars is based on ignorance of the resources used. The references used for alternative electricity generation sources ignore several implications including:

-          Availability of the resources; wind is not always blowing, sun is not always shining, hydrogen is still not obtainable in an environmental friendly manner, and biomass energy produces GHG and increases food costs;

-          Cost: all of the technologies mentioned in the point above are more expensive than electricity generation by hydro, coal, or nuclear power plants.

-          Contamination in electricity generation: some jurisdictions have high GHG emissions from power plants because the power matrix generation is based on Coal, Natural Gas or other fossil fuels. Some jurisdictions use other power matrix generation such as hydro and nuclear, with less GHG but with other environmental implications.

-          Overall efficiency; in North America, around 8% of the power generated is lost in transitions lines [9]. The efficiency of energy use for Plug-in cars is therefore decreased by this same percentage.


Electricity generation is based on different sources dependent on availability of resources in each jurisdiction. Prior analyses of hybrid car technology have obtained erroneous outcomes. Each jurisdiction and its energy production methods must be taken into consideration to analyze the global environmental impact of technologies like hybrid cars.


4        the use of hybrid cars in diferents jurisdictions


The use of hybrid cars does not represent an environmental friendly solution; on the contrary, they could lead to more GHG emissions, in addition to the environmental implication of their increased battery use.

The electricity consumption for the new generation of hybrid cars is from 0.26 to 0.7 kWh/mi [10]. For example, the Honda Insight consumes 0.52 kWh/mi and the Toyota Prius, which is considered the most efficient hybrid car consumes 0.26 kW·h/mi

If we assumed that these cars are plug-in hybrids that exclusively use their electric engines and run for 20000 km/year, their electricity consumption is:





Ec: electricity consumption in the year

Vc = Vehicle electricity consumption


Table 3 presents the consumption for Honda Insight and Toyota Prius



Ec [kWh]

Honda Insight Hybrid


Toyota Prius Hybrid


Table 3: Electricity consumption per year considering as plug-in car

The GHG emission for the kWh usage in Table 3 is dependent on the jurisdiction. Table 4 shows the GHG emissions for the electricity usage in Table 3 by jurisdiction across Canada based on 2005 GHG emission data for the electricity industry expressed in gtCO2e/kWh is [6]:




GHG emission [gCO2e/kWh]



British Columbia




New Brunswick


Nova Scotia


NF and Labrador




Prince Edward Island






Table 4: Electricity GHG emission in Canada

Considering the use of the cars in each province for one year, Table 5 displays the total GHG emission per car per year:



Toyota Prius

GHG emission [kgCO2e]

Honda Insight

GHG emission [kgCO2e]




British Columbia






New Brunswick



Nova Scotia



NF and Labrador






Prince Edward Island









Table 5: Emission for each hybrid car in each Canadian province

According to their manufacturer, standard combustion engine cars such as the Ford Focus have a GHG emission of 130 gr/km and the Toyota Yaris, 127 gr/km. For 20000 km per year, the total GHG emissions are shown in Table 6:



GHG emission [kgCO2e]

Ford Focus


Toyota Yaris


Table 6: GHG emission for classical combustion engine cars in one year

A comparison of tables 5 and 6 indicates that in Alberta and Saskatchewan it, the use of classical engine cars is more environmentally friendly to use of hybrid cars. Nova Scotia is very closes the GHG emission for both technologies. In New Brunswick and Nova Scotia, classical engine cars produce less GHG than the Hybrid Honda Insight but not the Toyota Prius.


5        conclusions


Promotion of the use of plug-in hybrid cars should be reconsidered. There little to justify such promotion as hybrid cars are more expensive and are not an environmentally friendly solution in dependency of each jurisdiction.

The promotion of this kind of technologies only has commercial interest; if all the variables are taking in consideration, this promising technology should not be used until:

-          Battery contamination resolution

-          The electricity GHG emission improves in each jurisdiction


The first item is a worldwide concern while the second item depends of each jurisdiction.




[1] J. Romm, “The car and fuel of the future”, Energy Policy 34, 2609-2614, 2006.

[2]   CNW Research, http://cnwmr.com/, consulted September 12, 2007.

[3]   K. Georg Hoyer, “The history of alternative fuels in transportation: The case of electric and hybrid cars”, Utilities Policy (2007), doi:10.1016/j/jup.2007.11.001.

[4]   J. Hellgren, “Life cycle cost analysis of a car, a city bus and an intercity bus powertrain for year 2005 and 2020”, Energy Policy 35, 39-49, 2007.

[5]   H. Lund and W Clark, “Sustainable energy and transportation systems introduction and overview”, Utilities Policy (2007), doi:10.1016/j/jup.2007.11.002

[6] Environment Canada, National Inventory Report, 1990-2005: Greenhouse Gas Sources and Sinks in Canada, http://www.ec.gc.ca/, consulted February 15, 2008.

[7]   National Center for Policy Analysis, http://www.ncpa.org, consulted March 12, 2008.

[8]   Central Connecticut State University, http://www.ccsu.edu/, consulted March 12, 2008.

[9]   P. Fedora, “Reliability review of North American gas/electric system interdependency” System Science, System Sciences, 2004. Proceedings of the 37th Annual Hawaii International Conference on

[10] Green Hybrid cars, http://www.greenhybrid.com/, consulted December 10, 2007.