1.12.1 - The Life Cycle of a Vehicle

Version 4

    MCB-3.12.1-VEHICLE-LIFE-CYCLE-AND-EMISSIONS -01.jpg

    Environmental impact and life cycle

     

    To evaluate the environmental impact of a product we must consider each stage of its life cycle:


    • The phase in which raw materials and components are obtained until they reach the manufacturing site
    • The manufacturing, assembly, and final product delivery phase
    • The product use phase
    • The end-of-life phase: disassembly, destruction, and recycling


    Each of these stages has an environmental impact which can include depletion of natural resources, one or more types of local pollution (ozone, acidification, etc.), climate change, etc.


    The objective of eco-design is to reduce a product's overall environmental impact at each step.

    A vehicle’s life cycle and CO2 emissions


    A vehicle is a complex product since a large number of components are used to produce it. Each subassembly can be subjected to a Life Cycle Analysis: the platform, the car body, the engine, the battery, the tires, the headlights and windows, the on-board electronics, the catalytic converter, the bumpers, etc.


    These are complicated analyses with results that can vary enormously depending on the country and the assumptions that are made. To simplify things, we will examine overall results and world averages for individual cars and only take CO2 emissions into account. Eco-design and materials recycling are examined in more detail in the factsheet entitled “Vehicles and the circular economy”.


    A) The life cycle of vehicles with internal-combustion engines (ICE)


    1. Energy


    Extracting, refining, and transporting fuel provide an overall yield of 0.87 (source: ADEME). This means that 1 liter at the pump corresponds to 1.15 liters of extracted fuel.


    Let's assume that the average ICE vehicle consumes 5l/100 km. (See the factsheet "Electric vehicles and CO2 emissions - comparison between electric/ICE vehicles”). It will emit around 125g of CO2/km from tank-to-wheel (TTW). If it travels 15,000 km per year for 15 years, it will emit 28.1 t of CO2 TTW.


    Assuming a yield of 0.87 results in overall well-to-wheel (WTW) emissions of 125/0.87 = 143.7g CO2/km (or around +15%) for a total of 32.3 t WTW.


    Extracting, refining, and transporting the fuel produced 4.2t of CO2.


    2. Vehicle manufacturing


    The results can vary by up to 100% depending on the type of vehicle, the manufacturing process, the country's energy mix, and the calculations used by different organizations (see references at the end of the document). We obtain an average estimate of 8 t of CO2 for the previous car.


    3. Maintenance and recycling


    The estimate is 0.5t of CO2.


    4. Total CO2 emissions during the life cycle of an ICE vehicle


    CO2 emissions in tons and in %

    Well-to-wheel fuel

    Vehicle manufacturing

    Fuel use

    Maintenance and recycling

    Total

    In tons

    4.2

    8

    28.1

    0.540.8

    In %

    10.3

    19.6

    68.91.2100


    Close to two-thirds of emissions come from fossil fuel combustion.


    B) The life cycle of battery-powered electric cars


    1. Energy


    The electricity used to recharge the battery has a very different environmental impact depending on the country's energy mix. Electricity produced in thermal power plants creates local polluting emissions and CO2 emissions close to 15 times higher than hydraulic, wind, or nuclear energy (without ignoring a different kind of impact in the case of nuclear power plants - the accumulation of radioactive waste).


    An electric vehicle similar to the previous ICE vehicle and which corresponds to the average of the 13 highest-selling electric vehicles in the world in 2013 consumes around 13 kWh/100 km. This is the vehicle's net consumption. Assuming a yield of 0.86 on a recharge, we obtain gross consumption of 15 kWh/km. In Norway, a country where energy production is almost exclusively hydraulic, this would correspond to 15 g CO2/km. In China, which depends heavily on coal-fired production, this would result in 200 g CO2/km.


    Therefore, for a total of 15 years at 15,000 km per year, we obtain 3.4 t and 45 t of CO2, respectively.


    For more details, please consult the fact sheet “Electric Vehicles and CO2 emissions".


    2. Vehicle manufacturing


    The two main differences between electric and ICE vehicles are in the manufacturing process for the internal combustion engine on the one hand, and the battery, the electric engine, and the associated electronics on the other.


    The methods and assumptions used in different studies on the subject lead to a range of results that vary up to 100 %. However, they all attribute almost half of the electric vehicle’s entire impact to battery manufacturing. Overall, CO2 emissions from electric vehicle production are estimated to be 150 % of those of an ICE vehicle with the same characteristics.


    This corresponds to around 12 t of CO2 for an electric vehicle comparable to the ICE vehicle above.   


    3. Maintenance and recycling

    Even though lithium resources are limited, they should be sufficient to equip close to 20% of the world's cars in 2030 if there is good recycling rate.


    Estimates vary enormously regarding the total energy needed for recycling. A factor of 2 as compared to ICEs seems to be a reasonable average.

     

    4. Total CO2 emissions during a battery-powered vehicle’s life cycle


    CO2 emissions in tons and in %

    Well-to-wheel emissions

    Vehicle manufacturing

    Vehicle use emissions

    Maintenance and recycling

    Total

    Hydraulic or nuclear electricity (t)

    3.4

    12

    0

    1

    16.4

    Hydraulic or nuclear electricity (%)

    20.7

    73.2

    0

    6.1

    100

    Coal-fired power (t)

    45

    12

    0

    1

    58

    Coal-fired power (%)

    77.6

    20.7

    0

    1.7

    100

     

    As the results show, the primary mode of electricity production in the country where the vehicle is operated is critical. In a country that produces the majority of its electricity from coal, we can even inverse CO2 emission tendencies for ICE and battery-powered electric vehicles.


    C) The life cycle of fuel cell-powered electric vehicles


    1. Hydrogen fuel cells


    Hydrogen can be obtained from electrolysis or reforming. In both cases, it's the primary source of electricity that determines the amount of CO2 emissions. This time the yield for the chain between primary energy and available electric energy is 0.31.


    For the previous vehicle which consumed 130 Wh/km, gross consumption is 419 Wh/km (130/0.31) and CO2 emissions depend on the source of primary energy and the means of hydrogen production (electrolysis or reforming).  (See Electric vehicles and CO2 emissions).


    We obtain the following figures for well-to-wheel g CO2/km:


    Primary energy

    Hydrogen obtained from electrolysis

    Hydrogen obtained from reforming

    Coal

    336

    190

    Nuclear

    6

    3

     

    2. Vehicle manufacturing


    As in the previous cases, estimates vary widely depending on the methods used and assumptions made. The impact of fuel cell manufacturing will be taken to be equivalent to that of battery manufacturing in regards to CO2 emissions. We will thus use the same figure of 12 t for the vehicle’s life cycle.


    3. Maintenance and recycling


    The electrodes require catalysts made of precious metals such as platinum or palladium. The cost of these materials means that recycling occurs systematically. For lack of specific data on the energy impact, we will take it to be the same as battery recycling.


    4. Total CO2 emissions over the life cycle


    We will continue to assume a vehicle with 15,000 km travelled per year for 15 years.


    Emissions in tons and in %

    Well-to-wheel fuel

    Vehicle manufacturing

    Fuel use

    Maintenance and recycling

    Total

    Non-coal-fired power / electrolysis (t)

    1.4

    12

    0

    1

    14.4

    Non-coal-fired power / electrolysis (%)

    9.7

    83.3

    0

    7

    100

    Non-coal-fired power / reforming (t)

    0.7

    12

    0

    1

    13.7

    Non-coal-fired power / reforming (%)

    5.1

    87.6

    0

    7.3

    100

    Coal-fired power / electrolysis (t)

    75.6

    12

    0

    1

    88.6

    Coal-fired power / electrolysis (%)

    85.3

    13.5

    0

    1.2

    100

    Coal-fired power / reforming (t)

    42.8

    12

    0

    1

    55.8

    Coal-fired power / reforming (%)

    76.7

    21.5

    0

    1.8

    100

     

    Summary of CO2 emissions during vehicle life cycles


    Given the following assumptions, the comparative results are as follows:


    CO2 emissions in tons

     

    Non-coal-fired power

    Coal-fired power

     

     

     

     

    ICE

    41

     

     

    Battery-powered vehicle

     

    16.4

    58

    H2 fuel cell from electrolysis

     

    14.4

    88.6

    H2 fuel cell from reforming

     

    13.7

    55.8

     

    It's obvious that electric vehicles only present an advantage in regards to CO2 emissions in countries with electricity production from hydraulic, nuclear, or renewable energy.


    In countries with electricity production that is based on coal and natural gas, the balance of CO2 emissions over the vehicle's life cycle is only positive when consumption is less than 10 kWh/100 km - unless power plants are equipped with CO2 sequestration technologies.


    Life cycle and polluting emissions


    Similar estimates can be made for polluting emissions: the results remain the same. However, the major advantage of electric vehicles is that they don’t produce any local pollution, which is critical, especially in urban areas.


    It also makes more sense to treat power plant fumes than the exhaust pipes of all the cars on the road. 


    Life cycle and consumption of natural resources


    A vehicle is made of 75 % steel on average. Efforts to reduce consumption through weight savings have led to the use of special steels, aluminum, and plastics in particular.


    The electric engine’s magnet production and Ni-MH battery production as well use "rare earth" that, by definition, are hard to find and become the object of political strategies.


    The catalyzers that are necessary to operate catalytic converters and electrodes in fuel cells are made of precious metals such as platinum, rhodium, and palladium, among others. A catalytic converter uses between 1 and 2 g of these precious metals depending on the vehicle's power. (1 g of platinum cost around €35 in August 2013).


    Other raw materials that were once abundant are now becoming more rare. This is true of copper, which is used as an electrical conductor in engine wires and coils, and which may be completely depleted within a few decades.


    Around 1,100 million vehicles are on the road all over the world, with an average lifespan of 15 years - this represents a market of 73 million vehicles per year!


    This industry is now required to make smart choices in terms of materials, develop entirely new materials, and establish competitive recycling programs: this is the circular economy.