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Electric vehicles

Automotive sector GHG emissions

Automotive manufacturing is one of the most important industries worldwide. Its massive growth and development over the past years have led to huge greenhouse gas (GHG) emissions and a dramatic increase in air pollution. According to a report by the European Union, the transportation sector in 2018 was responsible for 29% of total economy-wide greenhouse gas emissions in the EU, with light-duty vehicles (passenger cars and vans) being their greatest contributors, with nearly 52% of the total share, as shown in this figure below (source:

Share of EU-27 economy-wide greenhouse gas emissions in 2018 by transport subsector

According to the Inventory of U.S. Greenhouse Gas Emissions and Sinks transportation accounted for the largest portion (29%) of total U.S. GHG emissions in 2019 and light duty vehicles had the biggest share of it (58%) as shown in the figure.

2019 U.S. Transportation Sector GHG Emissions (source:

From these numbers it clearly appears that transportation (especially light passenger’s vehicles) plays a significant role in GHG emissions, and therefore with climate change. It is in fact a key sector in this matter. In this perspective, most developed countries are encouraging the use of Electric Vehicles to help reduce air pollution, GHG emissions and energy consumption.

Electric Vehicles (EVs) are vehicles that use electricity as their primary source of energy. There are two main types of electric vehicles (EV):

  • Battery electric vehicles (BEV) or plug-in electric
    • Uses only batteries for energy storage and must be plugged in to be recharged.
    • Doesn’t produce any tailpipe emissions.
  • Plug-in hybrid electric vehicle (PHEV)
    • Uses both batteries and liquid-fuel storage with refueling systems.
    • Doesn’t produce tailpipe emissions when running on electricity but it does when running on fuel.

Passenger vehicle EV sales—including plug-in hybrid and battery EVs—have increased massively since 2011. The figure below shows this growth. It is important to mention that this growth represents only a 2% share in the annual new vehicle market, which means that EVs still represent a very small fraction of the whole number of passenger vehicles in use.

BEV and PHEV sales in US from 2011 to 2019 (source:

Most important technical components of an Electric Vehicle

The following table and figure show the main components of an EV (source: Elmers & Marx).


Charges with electricity either when plugged in the power grid via a charging device or during braking through recuperation.


A crucial component, its efficiency can vary between 60% and 97%.

Motor controller

Supplies the electric motor with variable power depending on the load situation

Electric motor

Converts the electric energy into mechanical energy


Main components of an EV

EV emissions compared to conventional vehicles (source: )

All-electric vehicles produce zero tailpipe emissions, and PHEVs produce no tailpipe emissions when on electric-only mode. When it comes to life cycle emissions these are generated when fuel or electricity is produced and during manufacturing, the life cycle emissions of an EV largely depend on how the electricity is generated and how much a PHEV’s engine is being used. The following figure gives a comparison between EV’s and conventional vehicles  emissions .

Average annual CO2 emissions of EV and conventional vehicles

Benefits of EV

Compared to conventional vehicles, driving EV presents various benefits that are shown in the table below.

Volkswagen EV emissions compared to gasoline and diesel vehicles

Volkswagen EV CO2 emissions vs. diesel and gasoline vehicles (source:

Volvo EV emissions compared to a conventional vehicle

Carbon Footprint for XC40 ICE and XC40 Recharge, with different electricity-mixes in the use phase used for the XC40 Recharge. Results are shown in tonne CO2-equivalents per functional unit (200 000 km lifetime range)

Life cycle GHG emissions from Nissan Leaf EV vs Conventional car

The following figure compares the estimate of lifecycle emissions for a typical European conventional (internal combustion engine) car, the hybrid conventional car with the best available fuel economy (a 2019 Toyota Prius Eco), and a Nissan Leaf electric vehicle for various countries, as well as the EU average (source: EV emissions comparison - Nissan vs

Life cycle GHG emissions from Tesla EV vs Conventional car

The following figure shows the estimate of lifecycle emissions for a Tesla EV and a conventional vehicle (source:

Tesla EV’s gallery



CITROEN EV’s gallery
BMW EV’s gallery
Mercedes Benz EV’s gallery

EVs batteries

The most important challenges facing EVs development are battery-related. The battery, is indeed a key component in an EV since the successful market adoption of EVs is strongly dependent on the availability of a battery technology that allows reliable on-board storage of electric energy, that is cost affordable and that is environment respectful.

Electricity Storage Systems

The following table summarizes the characteristics of some storage systems used in electric vehicles (source:

Battery type



High power-to-weight ratio, high energy efficiency, good high-temperature performance, and low self-discharge. Most components can be recycled, but the cost of material recovery remains a challenge for the industry.

Nickel-Metal Hydride

Offer reasonable specific energy and specific power capabilities, much longer life cycle than lead-acid batteries and are safe and abuse tolerant. The main challenges are their high cost, high self-discharge and heat generation at high temperatures, and the need to control hydrogen loss.


High power, inexpensive, safe, and reliable, low specific energy, poor cold-temperature performance, and short calendar. Advanced high-power lead-acid batteries are being developed, but these batteries are only used in commercially available electric-drive vehicles for ancillary loads.


Store energy in a polarized liquid between an electrode and an electrolyte. Energy storage capacity increases as the liquid’s surface area increases. Can provide vehicles additional power during acceleration and hill climbing and help recover braking energy.

The following figure compares these different battery types characteristics (source:


Initially, EVs batteries were very expensive. For example, lithium-ion batteries for the Nissan LEAF represented one third of the cost of the entire vehicle; but over the past years, these prices have fallen and are expected to further decrease in the upcoming years. The following figure, shows the decrease in EVs battery packs prices (

Volume-weighed average price of battery packs for Evs ($/kWh) – (source:

The figure below illustrates lithium-ion batteries price evolution over the past years.

The high demand for lithium batteries is set to further increase even more in the years to come. Mining operations to manufacture these batteries require important water resources and generate chemical waste and it has already been blamed for air, water and soil pollution at many sites around the world. In order to face this problem, legal measures have been introduced in the EU concerning recycling of EV batteries (

Recycling Evs batteries

The recycling of an EV’s battery faces a double challenge ( :

  • Reducing the amount of waste generated by a battery at the end of its life
  • Encouraging the reuse of as many components and resources involved in its manufacture as possible.

As EV batteries reach end-of-service, they are still able to store at least 70% of their original capacity which can be repurposed for “second life” energy storage uses in new applications such as: electrical grids and communications towers, energy storage for solar farms, wind farms, and other renewable sources.

As manufacturers produce battery packs with varying mechanical and chemical complexities, one of the key challenges for the industry is to achieve a degree of standardization across global manufacturers to enable repurposing initiatives to be implemented.

The following figure illustrates the life cycle of an EV battery (source:

The figure below presents the recycling shares of different battery types.

Battery charging methods

Batteries can be charged at home or in public stations, as summarized below.


The future of EV in Europe

The EU is committed to pushing manufacturers to embrace EVs by implementing policies, reforming taxes and improving access to charging infrastructure, the EU Commission proposed a 55 per cent reduction of CO2 emissions compared to 2021 and declared that by 2030, “at least 30 million electric cars” are expected to be reached.

The European Commission had also unveiled a proposal that would effectively ban the sale of both petrol and diesel vehicles in the EU from 2035. In 2021, European manufacturing strongly opposed this planning and were asking to postpone the ban to 2040.


This Chapter was synthesized from Internet sources by Nassima MOUMNI (Ingénieur Polytechnique Alger).