Environmental Impacts of Internal Combustion Engines and Electric Battery Vehicles

Posted on June 3, 2019 by duquark in Contest Pieces

By Andrew Nickischer

ABSTRACT

Electric vehicles continue to gain popularity as society encourages us to reduce the pollution in our environment. Since electric vehicles produce no tailpipe emissions, the production and decomposition of their components must be analyzed to compare the pollution of electric vehicles and internal combustion engines. The differences in the life cycle pollution of electric vehicles and internal combustion engine vehicles have been quantified. Overall, internal combustion engines create 1.2 – 1.6 times more CO2 than electric battery vehicles create. This data shows that electric cars are better for the environment, but they are not perfect. With continued research, we will see more eco-friendly electric vehicles in the future.

KEYWORDS: Electric vehicles, Internal combustion engine, pollution, carbon footprint, lifecycle comparison

INTRODUCTION

Automobiles have contributed to the destruction of our environment in the form of carbon dioxide since their creation. Emitting carbon dioxide into the environment increases the global-mean surface warming ¹, and about 20 percent of all CO₂ emissions originate from road traffic ². However, internal combustion engine and electric vehicle technology is constantly advancing, with changes to fuel economy and emissions year by year ³. From just 2005 to 2017, the average fuel economy of all vehicles in the United Sates has increased by 5 mpg ³. This increase in fuel economy is especially helped by the addition of many electric vehicle models ⁴. Electric vehicles (EV) and plug in hybrid vehicles (PHEV) have tripled in quantity from 2012 to 2017 ⁵. Fully electric vehicles produce no tailpipe emissions; however, it must be noted that electric vehicles still contribute to the destruction of the environment through the carbon footprint generated by their production and disposal.

This paper will compare the environmental impacts of internal combustion engine vehicles and electric vehicles. Specifically, this paper will focus on passenger vehicles as they make up over 80% of all light duty, personal vehicles on the road today ³. To examine the differences, both types of vehicles’ carbon foot prints will be examined over the vehicles’ entire life span. This includes the vehicle’s environmental impact of its production, operation, and disposal.

INTERNAL COMBUSTION POLLUTION

Internal combustion engines make up most of the vehicles on the road today because of their old, reliable technology. The technology has had countless hours of research to lower production costs and efficiency. It is important to note that among internal combustion engines, diesel fuel combustion engines produce less emissions than gasoline, ⁵ and both are accounted for in all the studies used in this comparison. Biofuel combustion engines are also considered, but they make up very little of the automotive population, so they have a small effect on the data.

Vehicle Operation Pollution

The bulk of an internal combustion engine’s air pollution comes from its day-to-day operation. Comparing many internal combustion engine mid-sized vehicles, they create, on average, 150.4 g CO₂ eq per kilometer ⁶. Comparing many SUV class internal combustion engine vehicles, they create, on average, 269.2 g CO₂ eq per kilometer ⁶. This would mean that a mid-sized car with 100,000 miles would’ve produced approximately 24 million g CO₂ over its entire operation. A SUV class vehicle with 100,000 miles would’ve produced approximately 43 million g CO₂ over its entire operation.

Another study states that a combustion vehicle with 160,000 miles will produce approximately 45 metric tons of CO₂over its entire operation which is 45 million g of CO₂ ⁷.

Vehicle Production and Decomposition Pollution

The production and decomposition of the combustion engine itself creates a smaller amount of pollution when compared to the carbon dioxide produced from the engine when operating ⁶. This is because, to create the engine itself, only the metal components must be formed and assembled. The metal components themselves are not particularly harmful to the environment. Internal combustion engine vehicles require approximately 10 million grams of CO₂for their production and decomposition ⁷.

ELECTRIC BATTERY VEHICLE POLLUTION

Electric battery vehicles are a relatively new form of transportation. On the market as of 2017, there were only under twenty new electric vehicle models being produced ³. This number can be compared to five years earlier, when there was only one third the amount of electric vehicles being produced ³.

Vehicle Operation Pollution

The environmental impact of the operation of electric battery vehicles can vary greatly, because the electricity used to power these vehicles can be sourced from many different types of power plants. Nuclear, wind, and hydro plants generate the smallest environmental burden, but they only account for a small amount of energy when compared to the large amounts that coal and natural gas produce ⁶. Considering all types of power plant energy, mid-sized electric vehicles can create from 73.9 g CO₂ eq per kilometer to 131.5 g CO₂ eq per kilometer ⁶. An SUV class electric vehicle can produce 119.3 g CO₂ eq per kilometer to 196.45 g CO₂ eq per kilometer ⁶. This would mean a mid-sized electric battery vehicle with 100,000 miles will have produced from 12 million to 21 million g CO₂ from its operation on the road and a SUV class will have produced from 19 million to 32 million g CO₂ from its operation on the road.

Another study has determined that electric battery vehicles produce approximately 25 metric tons of CO₂over their entire operation ⁷ which is 25 million g of CO₂.

Vehicle Production and Decomposition Pollution

The production and decomposition of electric battery vehicles requires more energy and complicated labor ⁸. In this area, electric vehicles are less eco-friendly than internal combustion engines. A lithium ion battery is the most popular battery type used in electric battery vehicles ⁹. This is because the lithium ion battery is low-maintenance, safe, affordable and efficient, especially when compared to that of the older technology, ZEBRA batteries ⁹.

Despite lithium ion batteries being the best battery technology for vehicles, the production of these still emits 1.43 times more CO₂ than the production of combustion engines ⁶. Lithium ion batteries are not fully decomposed until 8 to 20 years after they are done being used ⁷. With a lifetime of only around 10 years ¹¹, the batteries often take longer to decompose than they last in the vehicle. An alternative to decomposing batteries is to recycle them. This will reduce the overall CO₂footprint, as it removes the need to produce and decompose a whole new battery for each vehicle. Recycling is also a better choice, because there is not enough lithium to meet the future demands of electric battery vehicles ¹¹.

COMPARISON

In some cases, a vehicle’s environmental impact cannot be assessed alone by its CO₂ production. This section includes factors that should be considered when analyzing the difference between electric vehicles and internal combustion engine vehicles.

Energy Comparison

One study looks at the differences between two identical vehicles that differ only by their engine (one electric and one internal combustion vehicle) ¹². The internal combustion engine vehicle used approximately 3 times more energy than the electric vehicle ¹². The comparison of a vehicle’s energy consumption does not directly correlate with CO₂ production, because the energy is produced in different ways. However, this study does show how much more efficient electric battery vehicles are than internal combustion vehicles. A different study used a similar procedure and determined that internal combustion engine vehicles used 2.7 times more energy than electric vehicles ¹³.

Cost Comparison

It is also important to note that electric vehicles are much more expensive than internal combustion engines ⁷. This includes production, decomposition and ownership costs. An electric battery vehicle is much cheaper to operate than a gas vehicle ⁷. This is because the fuel prices are much more than the electricity costs that are needed to power the vehicle. However, an owner may pay for this difference in initial power cost, as electric vehicles tend to be more expensive to purchase, when comparing similar power and quality. Repairs to an electric vehicle are also more expensive when involved in an accident or collision ¹⁴. A reason for this may be, as stated earlier, there will not be enough lithium to meet the future demands of these vehicles ¹¹. In order to push electric battery vehicle technology to more consumers, the initial cost must be lowered to create a greater incentive for purchasing. In the long term, battery research will put more electric vehicles on the road, improving the air quality and climate on earth.

Other Studies

Another study shows that the lithium ion battery production, maintenance and end of life treatment of an electric battery vehicle, make up approximately 10 to 15 percent of its total environmental burden ⁹. This category is something that does not exist for an internal combustion vehicle. From the study, we see that the overall environmental burden of internal combustion engines is about 120 to 160 percent more than a battery electric vehicle ⁹. For a quantitative comparison between these two types of vehicles, reference (Table 1). As expected, electric hybrid vehicles produce approximately 200 g CO₂ per kilometer when operating ¹⁵. This makes sense, because it fits right in between the data of the two extremes.

CONCLUSION

Overall, both electric battery vehicles and internal combustion engine vehicles contribute to harming the environment. However, they contribute in different ways. Overall, electric battery vehicles contribute less to harming the environment than internal combustion vehicles. The future of all vehicles is to create more energy sustainable technology that is less harmful to the earth, and the best way to encourage this is to increase the number of electric vehicles on the road. Research must be done to improve the cost efficiency and lessen the environmental burden of the production of lithium ion batteries.

Table 1. Quantitative comparison of CO₂ produced from electric battery vehicles and internal combustion engine vehicles. *Results were computed based on averages of relatively new vehicles (2010-present) using two sources (6,9), assuming that each of these vehicles has traveled one hundred thousand miles ^6,9.

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