Are Electric Vehicles Truly Green?

Electric vehicles (EVs) are often heralded as the future of sustainable transportation, a key development in the global push towards reducing greenhouse gas emissions and combating climate change.

Governments, automakers, and environmental advocates frequently tout EVs as the best and greenest alternative to traditional internal combustion engine (ICE) vehicles.

But are they as green as we’re being led to believe?

What are the positives of EVs?

Electric vehicles (EVs) operate without the need for gasoline or diesel, relying instead on electricity to power their motors.

This transition from fossil fuels to electricity offers the potential for significant reductions in greenhouse gas emissions, especially if the electricity used is generated from renewable sources.

Added to this is the fact that direct emissions from EVs are virtually non-existent, meaning that were EVs to be widely adopted, pollutants such as nitrogen oxides (NOx) and particulate matter (PM) would reduce, leading to an improvement in urban air quality.

Moreover, the efficiency of electric motors is considered to be significantly higher than that of internal combustion engines (ICE).  While ICE vehicles typically convert about 20-30% of the energy from fuel into actual motion, EVs can convert more than 60% of the electrical energy from the grid to power at the wheels.

This increased energy efficiency means that, even when powered by electricity from fossil fuels, EVs can have a lower carbon footprint per mile compared to their ICE counterparts.

What are the downsides to EV manufacturing?

Although EVs may seem a no-brainer at this juncture, there are downsides to consider, most notably the manufacturing process.

The manufacturing process of EVs, in particular the production of the batteries they use, are resource-intensive and come with environmental challenges.

In order to understand whether EVs are green, the entire lifecycle of the vehicle – from the extraction of raw materials to the manufacturing process, right up until the end-of-life process – need to be considered.

Is the production of EV batteries harmful?

The heart of an electric vehicle is its battery, typically a lithium-ion battery, which stores and supplies the energy needed to power the electric motor. The production of these batteries requires a range of raw materials, including lithium, cobalt, nickel, and graphite.

The extraction and processing of these materials are fraught with environmental and ethical concerns. Let’s take a look at these methods in more detail.

What is the problem with Lithium extraction?

One of the primary reasons that lithium and lithium-ion batteries are considered to be harmful is because the extraction of lithium is extremely damaging to the environment.

There are two main methods of commercial lithium extraction- salt flat brine extraction and open-pit mining.

Salt Flat Brine Extraction: Lithium is a key component of most electric vehicle batteries, and is primarily extracted from lithium-rich brine deposits in subterranean reservoirs in regions such as either South America’s Lithium Triangle (comprising parts of Argentina, Bolivia, and Chile) or through hard rock mining in Australia and China.

What is the Salt Flat Brine Extraction process?

The process of extracting lithium from brine is highly water-intensive, requiring approximately 500,000 gallons (almost 2 million litres) of water per tonne of lithium produced. It takes the following steps:

1. Pumping the brine: Extraction begins with the pumping of lithium-rich saltwater from underground reservoirs (anywhere from 30 – 100 metres below the surface).
   
2. Evaporation ponds: The extracted brine is then channelled into large evaporation ponds. These ponds are shallow and spread over large areas to maximise surface exposure to the sun. Over a period of 12 to 18 months, solar radiation and dry conditions cause the water to evaporate, gradually increasing the concentration of lithium in the brine.
   
3. Concentration of the Lithium: As the water evaporates, the remaining brine becomes more concentrated with lithium, and forms a mixture containing manganese, potassium, borax, and lithium salts. This mixture is then filtered and transferred to evaporation ponds.
   
4. Chemical processing: Once the lithium concentration is sufficiently high, the brine is transferred to a recovery facility.
   
   Here, various chemical processes, including precipitation and filtration, are used to extract lithium carbonate or lithium hydroxide, the compounds used in battery production.

Open-Pit Mining: The other form of commercial lithium production involves hard rock mining. This is a much more complex and intensive process than the salt flat brine extraction. 

Australia is home to the majority of the world's open-pit mining operations, though smaller operations also exist in Brazil, Portugal, South Africa, and China. Finland and North America are also expected to open lithium mines in the coming years. 

What is the Open-Pit Mining Process?

Open-pit mining contains a number of complicated steps.

1. The extraction of the ore: Open-pit mining begins with the removal of overburden (the soil and rock covering the lithium-rich ore). Heavy machinery is used to drill, blast, and remove large quantities of rock to access the lithium-containing spodumene ore beneath.

2. Crushing and milling:  Once mined,  the ore goes to a processing plant where it's crushed into smaller pieces to increase the surface area for the extraction process. This initial crushing helps in the subsequent steps of lithium extraction.

3. Heating and conversion: The crushed ore is then heated to high temperatures in a kiln. This heating process, known as calcination, transforms into lithium-rich mineral called beta-spodumene.

4. Acid Leaching: The beta-spodumene is then cooled and finely milled before being treated with sulfuric acid in a process known as acid leaching. The acid reacts with the lithium to form lithium sulphate, which is soluble in water.

5. Separation and purification: The lithium sulphate solution is then subjected to various chemical treatments to remove impurities. This process often involves precipitation, ion exchange, and solvent extraction methods to isolate and purify the lithium.

6. Conversion to Lithium Carbonate or Lithium Hydroxide: For the final step in the process, the purified lithium sulphate is converted into either lithium carbonate or lithium hydroxide – the compounds used in battery production. For this conversion process, the lithium sulphate is made to react with either sodium carbonate or calcium hydroxide.

What about extraction methods for other metals contained in lithium batteries?

The damage wrought to the environment does not begin and end with extracting lithium. Contained within lithium and lithium-ion batteries are several other elements, including:

Cobalt and Nickel Mining: Cobalt is another critical material for lithium-ion batteries, particularly those designed to have higher energy density and longer lifespans.

More than 60% of the world’s cobalt supply comes from the Democratic Republic of Congo (DRC), where mining conditions are often hazardous, and child labour is a documented concern.

The demand for cobalt has increased its price, and along with it a rise in artisanal mines – ad-hoc setups that often rely on child labour to extract the material.

Added to the impact on human lives, the environment also suffers, as unregulated dumping of toxic waste produced by these mining methods damages landscapes and contaminates crops and water sources.

The process of extracting nickel involves several high-risk steps. The ore is typically mined from open pits or underground mines and then processed to extract the nickel. This processing releases plumes of sulfur dioxide and dust containing nickel, copper, cobalt, and chromium, which are known to be harmful to human health. Sulfur dioxide is a significant air pollutant that can cause respiratory problems and acid rain, while the dust can be carcinogenic.

Nickel mining, although less controversial than cobalt, involves several high-risk steps. The ore is usually mined from open pits or underground mines, and then processed to extract the nickel itself.

This process releases plumes of sulphur dioxide and dust that contains nickel, copper, cobalt, and chromium, which are harmful to human health. In particular, sulphur dioxide is a dangerous air pollutant that can cause both respiratory problems as well as acid rain. The dust of sulphur dioxide can also be carcinogenic.

For nickel that is sourced through open-pit mining, soil and water pollution is of significant concern.

Graphite Mining: Graphite, used in the anodes of lithium-ion batteries, is primarily mined in China. The production process can release large quantities of dust and waste gases, contributing to air pollution. Additionally, the chemical processing of graphite can lead to the contamination of local water supplies with harmful chemicals such as hydrofluoric acid.

The overall manufacturing process

The use of the above-mentioned minerals are crucial in the creation of lithium-ion batteries, meaning that the use of fossil fuels to mine those materials and heat them to high temperatures is unavoidable. And, depending on the energy mix used in the manufacturing process, particularly the proportion of fossil fuels, the carbon footprint of EV production can also be substantial.

For example, in countries where coal is the dominant energy source, the carbon intensity of electricity generation is high, which translates to a higher carbon footprint for EV manufacturing. A study by the Swedish Environmental Research Institute found that manufacturing a medium-sized EV battery (with a capacity of about 30 kWh) could emit between 150 and 200 kilograms of CO2 per kilowatt-hour of battery capacity.

This means that producing a battery for a Tesla Model S (with a 100 kWh battery) could emit between 15 and 20 tons of CO2, which is roughly equivalent to the emissions from driving an average gasoline-powered car with an internal combustion engine (ICE) for several years.

What are the challenges of EVs once on the road?

Once on the road, the environmental benefits of electric vehicles depend heavily on the source of the electricity used to charge them.

In regions where the electricity grid is heavily reliant on fossil fuels, the operational emissions of EVs can be significant. For instance, if an EV is charged using electricity from a coal-fired power plant, the emissions associated with that electricity can offset some of the benefits of zero tailpipe emissions.

However, in regions with a high penetration of renewable energy, such as hydroelectric, wind, or solar power, the operational carbon footprint of EVs can be significantly lower.

Do EV batteries degrade over time?

Yes. Over time, the performance of lithium-ion batteries diminishes, leading to reduced range and efficiency. This degradation is influenced by various factors, including the frequency of fast charging, operating temperatures, and the depth of discharge cycles.

As the battery degrades, the energy efficiency of the vehicle decreases, potentially leading to increased electricity consumption and, consequently, higher operational emissions if the grid is not fully green.

Can lithium-ion batteries be recycled as part of an EVs end-of-life process?

The final stage of an electric vehicle’s lifecycle is its disposal. Unlike standard vehicles, which have established recycling processes for most of their components, EVs pose unique challenges due to their batteries.

Lithium-ion batteries are complex to recycle because they contain a variety of materials, some of which are hazardous and difficult to separate.

Currently, only a small percentage of lithium-ion batteries are recycled, primarily due to the high cost and technical difficulties associated with the process.

Recycling involves disassembling the battery, extracting valuable materials like lithium, cobalt, and nickel, and then processing these materials for reuse. However, the recycling process is energy-intensive and can generate toxic waste if not properly managed.

The environmental impact of improper disposal of EV batteries is significant, as they can leak toxic substances into the environment, posing risks to both human health and ecosystems.

So are EVs really green?

The answer to whether electric vehicles are truly green is not a simple yes or no. While EVs offer considerable advantages in terms of reducing operational emissions and improving air quality, their overall environmental impact is influenced by a range of factors, including the methods used to extract raw materials, the energy mix in manufacturing and operation itself, and the handling of batteries at the end of their life.

Considering also that, from 2035, the sale of new liquid petroleum gas, petrol and diesel cars, as well as hybrid vehicles, will be banned across the UK, and it’s clear to see that EVs will undoubtedly play a crucial role in transportation going forward.

However, to ensure that they deliver on their promise of being a greener alternative to ICE vehicles, it is essential to address the human and environmental challenges associated with their production and overall lifecycle.