The benefits of electric vehicles (EVs) as a potential solution to climate change and dependence on fossil fuels are becoming more widely recognized. As the number of electric cars on the roads rapidly increases, so does our knowledge about their carbon footprint – as well as concerns that threaten to undermine their green status.
How do Electric Cars Work?
EVs first hit the car market in 2010 and were hailed as a greener alternative to petrol-powered cars. Today you can easily purchase or rent a green vehicle for personal and commercial needs. Companies such as STS-Global have implemented a reliable spare parts supply to help organizations maintain both green and traditional vehicles. But are electric cars green?
One of the more commonly quoted statistics regarding electric cars is that they are three times more efficient than gasoline vehicles because an electric motor uses approximately 30% of the energy stored in gasoline to move a vehicle just one kilometer.
EVs are made up of four main components: the body, the electronic motor, the transmission and differentials (or gears), which make up 6% of total vehicle weight, and the battery pack (65%), which is made up of lithium-ion cells that store electrical energy in chemical form. The remaining 29% of total vehicle weight is taken up by wiring for power distribution, connectors, and fuses.
The advantage of using this type of battery is that it can be recharged when depleted, thousands of times over its lifetime without loss in capacity or performance. That means EVs do not require much maintenance because there are no oily parts or filters to replace – resulting in less pollution.
The Problem of the Carbon Footprint
EVs are touted as environmentally friendly because they run on electricity rather than gasoline. However, some recent reports question whether EVs are greener given that some power plants that provide the required electricity can be a source of pollution themselves. Recent studies found that EVs are often gassier than what has been reported.
The problem is the emissions generated from power plants to generate electricity.
If EVs are charged by coal-fired power plants, they may be as bad as conventional cars. According to a study published in the Proceedings of the National Academy of Sciences (PNAS), electric vehicles powered by average U.S. electricity produce two to four times more global warming emissions than gasoline-powered vehicles.
The same study also found that hybrids have a larger carbon footprint than conventional vehicles because much of their battery-charging is done using coal-fired power plants.
Benefits of Electric Cars for the Environment
Electric cars are seen by some as a panacea for transport-related CO2 emissions. However, the benefits of EVs depend on many factors, including how they are driven and charged, and what electricity they use.
While electric cars produce no tailpipe emissions when driving (although the power stations used to generate their electricity may still emit greenhouse gasses), producing batteries and electric motors is an energy-intensive process that can result in high carbon footprints – particularly if manufacturing takes place in countries with polluting fossil fuel-driven energy grids.
For many people, switching to an electric car is seen as a way to reduce greenhouse gas emissions regardless of these factors – but this view needs to be carefully examined.
When It Comes to Being Environmentally-Friendly, Size Matters
The amount of energy that goes into making batteries can significantly affect their lifecycle carbon footprint. For instance, even though lithium-ion EV batteries typically only last for between five and 10 years before they need replacing, they account for around half of the total manufacturing CO2 output over the vehicle’s lifetime.
More powerful EVs tend to use larger and heavier batteries with rare components such as cobalt, which is mined in less sustainable ways, creating greater carbon emissions.
Of course, the size of an electric car’s battery doesn’t have to be directly related to its power. Other factors can impact vehicle range, such as motor efficiency. EVs use a variety of different motor types including induction motors powered by rare earth materials and permanent magnet motors with neodymium magnets and strontium ferrite magnets.
Another factor is the method used for recharging an EV’s battery. While most electric cars can now be recharged by regular outlets, the larger batteries in EVs used to need fast DC chargers that could only be installed at “fast-charging” points – which are not yet widely available. Fast chargers typically use more energy than standard charging points, so where they are used they contribute to a car’s manufacturing emissions.
The Case for Rechargeable Batteries
One way of limiting the impact of these factors would be to use rechargeable batteries rather than replaceable ones. That would reduce battery production emissions and give automakers greater flexibility with the size and styling of their electric vehicles.
While rechargeable EV batteries may last longer, requiring replacement less often than replaceable models, over the long term they may cause greater emissions than replaceable batteries because their shorter lifespan means more will be needed.
Comparing Emissions from Manufacturing Electric and Petrol-Powered Cars
An alternative to electric vehicles powered by lithium-ion batteries is hydrogen fuel cell EVs (FCEVs), which emit zero emissions while driving but produce water vapor as a byproduct of the chemical reaction that creates electricity within the car’s “fuel stack.” However, FCEVs currently need hydrogen refueling stations to fill up on gaseous hydrogen – which can create significant upstream CO2 emissions depending on how it is produced.
However, their production process creates significantly less CO2 per kilometer of driving than traditional gasoline-powered cars, making them almost as environmentally friendly as conventional hybrids. They can also be charged at home or work overnight using existing power sources – just like EVs – so are likely to have similar life cycle carbon footprints once they are being mass manufactured.
The Bottom Line
While still in the early stages, the potential impact on carbon emissions is one of several factors that may give rechargeable electric cars an advantage over EVs with replaceable batteries. However, they are likely to have a greater environmental impact during their production phase, which needs to be taken into account when designing them for mass production. Despite all the potential problems, they are truly greener than traditional cars.