The Carbon Footprint of an Electric Car Vs Gas Compared


Electric vehicle technology is often a poster child for clean energy solutions at the consumer level. However, exclusive of tailpipe emissions, do electric cars really have a significantly different carbon footprint than traditional vehicles using a gasoline-powered combustion engine?

Overall, electric cars do have a smaller carbon footprint than gas cars. The difference is smaller than when accounting for direct vehicle emissions, but is still significant across manufacturing, lifetime use, and end-of-life disposal.

Calculating the carbon footprint of a vehicle can be a convoluted process due to the complex nature of vehicle designs and production. If you are looking to purchase an environmentally-friendly vehicle, there are a handful of factors that can be easily considered. Read on to learn more about the carbon footprints of electric and gas cars.

Are Electric Cars Really More Green than Gas Cars?

According to the Environmental Protection Agency, the average carbon dioxide emission of a passenger vehicle is approximately 4.6 metric tons. In standard units, this means a common 4-door sedan will create over 10,000 pounds of CO2 every year.

However, this only accounts for the tailpipe emissions of the vehicle: electric vehicles do not produce any carbon dioxide while in operation, but it would be inaccurate to say that the carbon footprint of an electric vehicle is smaller than that of a gasoline-powered vehicle based on this fact alone.

In fact, the carbon footprint of a vehicle includes much more than tailpipe emissions. Additionally, since each type of vehicle uses a radically different power source from the other, it would be unfair to claim electric cars as the winner of the eco-friendly race without a more detailed look at the many related differences between each kind of car.

How Are Carbon Footprints of Vehicles Calculated?

Many elements must be accounted for when analyzing a vehicle and determining the size of its carbon footprint. Some of these components may include:

  • Carbon emissions of the vehicle manufacturing process, including material sourcing and transport
  • Emissions of the vehicle assembly process, including part sourcing and transport, as well as transport of the completed vehicle
  • Carbon emissions resulting from vehicle use.
  • Emissions from the disposal of the vehicle at the end of its lifespan
  • Carbon emissions as influenced by where the vehicle is used, and how it is driven

Due to the intricacies of these and other processes, the determination of a vehicle’s carbon footprint can be extremely difficult. Furthermore, the calculation of emission from each of these processes independently introduces even more detail, and the sheer amount of information involved staggers even environmental research teams.

There is also convolution and controversy surrounding the methods for obtaining carbon emission data about these factors in the first place, and still more debate about how exactly the data is analyzed.

For example, the footprint of car battery production could be determined by dividing the total battery manufacturing footprint by the kilowatt-hour capacity of the battery. Even disregarding the methodology for finding the carbon footprint of these processes, there is no universal approach to relating this information to the carbon footprint of a vehicle.

The average consumer has no way of collecting this information independently, much less do they have the time, interest, or production capacity to analyze all of it effectively. Fortunately, the exact intricacies can be left to the professionals while an ordinary driver can focus on the emissions of a vehicle over the course of its lifespan.

The Carbon Footprint of Vehicle Production

Vehicle production is a complex, international process that encompasses several potential sources of carbon emissions, even before the car is driven! Electric vehicles are no exception, and the carbon footprint of vehicle production is often overlooked in everyday debates about the ecological impact of differently-powered vehicle types.

Vehicle production generally summarizes, but is not limited to, the following subprocesses of car manufacturing:

  • Sourcing and obtaining base materials
  • Transportation of base materials
  • Manufacturing of individual parts
  • Transportation of individual parts
  • Powering method of part manufacturing plants
  • Assembly of parts into a functioning vehicle
  • Powering method of vehicle assembly plants
  • Transportation of completed vehicles

Each locus of the vehicle manufacturing process is a potential source of carbon emissions that can influence the total carbon footprint of the vehicle, regardless of whether it is powered by gasoline or electricity.

However, the most influential factor in determining the carbon footprint of a vehicle at the manufacturing stage is the production of the car battery. This component provides the largest difference in the manufacturing process of both conventional and electric vehicles, since they both use similar designs in areas other than their fuel source.

Production of Conventional Car Batteries

The kind of car battery that first comes to mind is probably one that can be bought at an automotive parts store or a general retailer. These are the same type found in a typical gasoline-powered car, used to provide the initial power to start the car and power internal lighting.

As a result, batteries of this design are sometimes referred to as ‘Starting, Lighting, and Ignition’ (or SLI) batteries. These batteries are powered by lead-acid electrochemistry, and manufacturing them not only generates carbon emissions, but also other severe concerns regarding environmental damage.

These environmental concerns around the production of lead-acid batteries include the varied damage caused by extensive lead mining, as well as the potential for lead contamination in water sources and the environment. Exposure to these environments or consumption of contaminated water can cause lead poisoning.

Generation of Carbon Emissions by Manufacturing

The total carbon footprint of car battery production begins in the sourcing of battery materials. As indicated by its design, the production of lead-acid batteries requires large amounts of lead. Raw lead must be extracted from the Earth, and the mining process itself generates carbon emissions through the use of gas-powered mining equipment.

Furthermore, after the lead ore has been mined, it must be transported to a processing plant to be melted down and refined into a usable product. This transportation is another source of carbon emissions in the manufacturing process of traditional automotive batteries.

The factory processing the newly-mined lead must initially heat the ore in a smelter to melt it and burn away certain impurities. As the lead is refined, any impurities burned in the process will also produce carbon dioxide and add to the carbon footprint of the overall process.

Finally, the massive amount of energy required to power both the processing plant and the manufacturing plant is usually provided by electricity from the surrounding area, the production of which may not be carbon-neutral, again furthering the total carbon footprint of the battery and the car.

Other Environmental Concerns of Production

Although carbon emissions are at the forefront of discussion about environmentally-friendly vehicles, there are other environmental impacts of equivalent concern. In the case of conventional vehicles, lead-acid battery manufacturing raises a multitude of interdisciplinary concerns.

The first concern is regarding lead contamination. By necessitating large-scale extraction of lead, lead-acid battery production increases opportunities for lead exposure on an individual and ecological level. Individuals who are overexposed to lead can suffer a myriad of related health problems, such as:

  • Brain damage
  • Kidney damage
  • Anemia
  • Infertility
  • Miscarriage

These health problems are exacerbated in children, who naturally have a much lower tolerance for mineral poisoning than adults. Dangers of even low-level lead exposure can extend into the disruption of normal development by causing irreparable neurological damage and disability.

Environmental contamination that results from mining practices and improper battery disposal also pose risks. In addition to increasing the likelihood of childhood exposure, environmental contamination introduces excess lead into nearby ecosystems that may additionally destroy surrounding plant and animal life via lead poisoning.

Production of Electric Car Batteries

Electric vehicles use a unique kind of battery meant for high storage capacity and intensive use. While this type of car battery may not be available for purchase at the usual pit-stops, it can usually still be purchased from either your car manufacturer or directly from the battery manufacturer.

These highly durable batteries are also known as traction batteries, and are powered by lithium ions. There are several varieties of lithium-ion batteries, but the kind used in electric vehicles will often contain other mineral elements in addition to lithium. The manufacturing of these batteries also comes with its own environmental issues.

Similarly to the lead-acid batteries used in conventional vehicles, the environmental concerns of producing lithium-ion traction batteries lie in the mining and manufacturing processes. However, while lithium poisoning is a possible environmental hazard, the toxicity of lithium is much lower than that of lead.

Generation of Carbon Emissions by Mining

Lithium mining, like lead mining, contributes to the total carbon footprint of the battery production process and therefore the overall carbon footprint of an electric vehicle. However, unlike lead mining, lithium is not the primary suspect of ecological impact.

Lithium-ion batteries for electric vehicles also utilize several other metals in need of extraction and transport, such as:

  • Iron
  • Phosphorus
  • Cobalt
  • Manganese
  • Nickel
  • Graphite

While there is currently no design for a lithium-ion battery that uses all of the above minerals, most use between 1 and 4 in addition to lithium. Additionally, these minerals are not always available in the same mine, or even near each other, requiring additional mining and transport that will increase the carbon footprint of the production process.

Furthermore, these metals are not all processed the same way. For example, lithium is sometimes obtained from salt lakes rather than mines, resulting in lithium salts that are further refined by processes other than smelting, which may mislead efforts to quantify total carbon emissions if the smelting of other metal ores is not considered.

Generation of Carbon Emissions by Manufacturing

Beyond the carbon emissions produced by mining, smelting, and other forms of mineral processing, there are also the emissions produced by the manufacturing process. Lithium-ion batteries are extremely flammable, and can even explode in some circumstances.

As a result, the manufacturing of lithium-ion batteries is carefully controlled and energy-intensive to prevent fire hazards and control explosive gases. Specialized equipment and failsafe measures consume large amounts of electricity that, if generated using fossil fuels, would also contribute to the total carbon footprint.

Furthermore, some chemical processes used to create lithium-ion batteries produce harmful vapors that could escape and precipitate into the environment. Others use water that could carry various mineral and heavy-metal contaminations and cause poisoning to both individuals and the environment if not properly treated.

The Carbon Footprint over Vehicle Lifespan

The most commonly noted fault of combustion engine vehicles, in terms of environmental impact, is the carbon footprint produced over the course of the car’s useful lifespan. From purchase to disposal, gasoline-powered vehicles are inarguably the most criticized for their constant contribution of carbon emissions to the atmosphere.

However, there are more factors to address within the lifespan of a vehicle than fuel type or mileage efficiency. Furthermore, it is often difficult to discuss or compare electric vehicles in this category because they are completely reliant on their battery system, and appear completely independent of fossil fuels in their operation.

This is not entirely true, as exhibited in the discussion of battery manufacturing; other factors that can contribute significantly to the carbon footprint of a vehicle include battery efficiency and upkeep demands.

Lifetime Carbon Emissions of Conventional Vehicles

On average, a consumer will purchase a new car once every six years, while the cars picked off of an American highway at random will generally be somewhere around eleven years old. So generally speaking, it can be argued that the lifespan of the usual gasoline-powered vehicle will be around ten years.

Over the course of a ten-year period of active, daily use, the sources of carbon emission most accessible to the consumer are not limited to the fuel types. Additional carbon emissions can come from the battery, as well as the type and frequency of routine maintenance or repairs.

Carbon Emissions at the Tailpipe

The first thing to consider when calculating the carbon footprint of a vehicle is the tailpipe emissions. The most effective internal combustion engines found in passenger vehicles are the gasoline-powered variety. However, tailpipe emissions are a bit more complicated than simple fuel efficiency.

While a single car can produce over ten thousand pounds of carbon dioxide every year on average, the carbon emission of a vehicle is dependent on both its design and its use. For example, industrial vehicles like those used in mining, shipping, and construction are not included in this average.

Another factor in this emission category is the production and transportation of gasoline. The use of gasoline can increase the carbon footprint of a vehicle through the entire fuel production process, including:

  • Locating, drilling, and extraction of crude oil
  • Transportation of crude oil to refineries
  • Refinement of crude oil into gasoline
  • Preparation of gasoline for shipment
  • Transportation of gasoline

Fossil fuels, including gasoline, are consumed and burned throughout the entire manufacturing process. Additionally, fossil fuels other than gasoline may burn and produce different amounts of carbon dioxide throughout the process, further influencing the carbon footprint of a conventional vehicle beyond its fuel efficacy.

Lifetime Carbon Emissions Related to the Battery

The production of lead-acid batteries has innumerable potential sources of carbon emission, but since these batteries are only used for ignition and minor electric supply in conventional vehicles, their use offers no apparent opportunity for additional carbon emissions.

However, there should be some consideration taken in regards to the lifespan of the batteries themselves. Depending on the vehicle, how it is used, and the driving environment, a typical 12V lead-acid battery can last four to six years before needing replacement.

As a result, roughly 100 million lead-acid automotive batteries are produced in America every year, such that while the battery may not produce carbon emissions directly, the short lifespan increases the carbon footprint of the vehicle through the battery manufacturing process every time it needs to be replaced.

Lifetime Carbon Emissions Related to Maintenance

Conventional vehicles require regular engine maintenance to maximize fuel efficiency, as well as for overall vehicle health. In addition to battery replacements, which may be needed two or three times within a ten-year period of use, gasoline-powered vehicles also require routine oil changes and other fluid replacements.

This increases the carbon footprint of traditional cars significantly: oil changes alone require many of the same processes for producing and transporting the oil. Furthermore, the recommended schedule for their completion is about three to four times every year.

Considerations should also be made for the creation and transportation of other routine maintenance materials as well, such as:

  • Transmission fluids
  • Radiator fluids
  • Oil filters
  • Fuel filters

The manufacturing and shipping procedures for each of these have the potential to increase the lifetime carbon footprint of a conventional vehicle over that of an electric vehicle.

Lifetime Carbon Emissions of Electric Vehicles

The hallmark trait of completely electric vehicles is that they have no tailpipe emissions. In fact, many electric car designs forego even decorative tailpipes! However, this does not mean that electric cars produce no carbon footprint during use over the course of their lifespan.

Additionally, electric motors tend to be less complex, less fragile, and require less maintenance. Unlike the combustion engine, which needs an entourage of related mechanical systems to function properly, electric motors do not require most of these systems, and as such do not require oil changes, fluid replacements, and related filters.

Lifetime Carbon Emissions Related to the Battery

Since electric vehicles require no fossil fuels for immediate operation, the sole focus of mileage efficacy is on the battery. While the battery itself produces no carbon dioxide from being discharged during operation, charging the battery may have unexpected environmental impacts depending on how it is charged.

Many consumers that invest in electric cars also invest in some form of home power system specifically for the purchased vehicle. This power system is usually connected to the local area’s power grid. Vehicles that do not need unique charging units still rely on local electricity production to charge through home outlets and at stations.

Regardless of the exact method, electric cars are regularly charged with electricity from the same power plants as the rest of the connected power grid. This means that if a local power plant consumes fossil fuels to generate electricity, then the vehicle using that electricity shares a respective portion of the power plant’s carbon footprint.

However, if the car is charged in a local utilizing zero-carbon electricity generation, or with a sustainable home power system such as those using solar panels, then the carbon footprint of the car as the result of use can be reduced to negligibility.

End-of-life Carbon Footprint

When a vehicle is retired from service, pieces of it can end up in a lot of places: landfills, scrap yards, recycling plants, home decor projects, outer space, and everywhere in between. How a vehicle and its parts are disposed of can also impact its net carbon footprint.

There is a multitude of recycling programs for car parts, with foci ranging from tires to electric components to metal chassis. Conventional and electric cars overlap in many of these categories, and so further examination of recycling programs for unique parts is necessary to understand the carbon footprint of the vehicle as a whole.

Carbon Emissions of Retiring Conventional Vehicles

In terms of disposal and recycling, conventional cars have an important advantage over electric vehicles due to their lead-acid battery. In spite of the high carbon emissions of manufacturing lead-acid batteries, their short lifespan, and their many other environmental hazards, recycling programs for these batteries are very advanced.

According to the Environmental Protection Agency, approximately 90-99% of lead-acid batteries are recycled each year. Recycling programs are also well regulated and easily accessible, so it is likely that this rate will continue to be consistent for the foreseeable future.

The high recycling rate of lead-acid batteries does put a sizable dent in the total carbon footprint of a conventional vehicle; however, it does not mitigate carbon emissions that result from sourcing and preparing battery materials, and is also not substantial enough to offset the quantity of carbon dioxide produced by burning gasoline.

Furthermore, the environmental hazards that accompany industrial lead usage are still present during recycling. Lead contamination can still leak from battery recycling plants and into the environment. Even if it were impossible for lead to escape from a given recycling plant, consideration must still be made for how the plant is powered.

End-of-Life Carbon Emissions of Electric Vehicles

Of the many environment-conscious categories that electric vehicles excel in, battery recyclability is unfortunately where they fall short at only 5%. However, this is not necessarily because the battery itself cannot be recycled. In fact, lithium-ion batteries can be easily recycled in many cases.

There are three primary factors in the low recycling rate of automotive lithium-ion batteries:

  • Longevity of the battery
  • Reuse of the battery
  • Complexity of recycling options

The first component in lithium-ion battery recycling may be the most surprising: its lifespan. While there is data on the recycling of small lithium-ion batteries, such as those that may be found in hardware tools or certain kinds of children’s toys, there is not much data available on the recycling of automotive lithium-ion batteries.

This dearth of data is the result of the battery’s lifespan. Automotive lithium-ion batteries are incredibly hardy in regards to their functioning, capable of full charge and discharge hundreds of times over before beginning to lose charging capacity. Even then, it can take many hundreds of cycles more before the performance difference is noticeable.

As a result, there are more lithium-ion car batteries that are still in use rather than in need of recycling. Electric vehicle batteries are also reusable, and can be ‘retired’ to a low-power role even after extensive use as a car battery because the threshold for poor performance in a car is much higher than for considering the battery incapacitated.

There is, however, a looming issue: as there are many varieties of lithium-ion batteries in general, recycling processes must be created specifically tailored to each variety. Traction batteries tend to have a more consistent design, but current recycling methods may not be able to operate at the volume necessary to address future recycling needs.

The Verdict: Electric Car Impact Is Lighter

It is widely estimated that the complete and total exchange of combustion-engined vehicles for electric vehicles is necessary to achieve America’s climate change goal of net-zero emissions by 2050. Between now and then, however, which type of car is best for you?

Carbon emissions aside, current electric vehicle technology is expensive and complex, while traditional vehicles are much more accessible and affordable for several reasons:

  • Traditional vehicles are still more common than electric ones, which means that the cost of a gas-powered passenger car is much lower on average than that of an electric car.
  • Gasoline may be a more cost-effective fuel than electricity in areas where power demand is extremely high.
  • Due to their mechanical nature, conventional vehicles tend to be easier to maintain, repair, and modify than electric vehicles, whose electric components may be inaccessible to the driver.

However, if your goal is a long-term investment, then an electric vehicle will last longer than a conventional one. Additionally, even though America theoretically may not complete its move away from combustion vehicles until January 1st, 2050, an electric vehicle is likely to become the more legislatively acceptable car in the future.

Conclusion

Since electric vehicles rely only on the power supplied by their batteries, the driving force behind the differential carbon footprints of gas-powered vehicles and electric vehicles is found in the carbon footprint of the battery. All other traits held constant, the net emissions of a gas car can be traced back to its fuel source, from the need for an S.L.I. lead-acid battery to routine maintenance.

This is the same for an electric vehicle, as the use of electricity mitigates the need for other emission-intensive support systems. As a result, an electric vehicle will have a lower carbon footprint than a conventional vehicle. This is certain to continue into the future, as gas cars show few (if any) signs of becoming more environmentally friendly without changing engines, while electric vehicles will continue to become more efficient.

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