Electric Vehicles - Will They Significantly Impact Global Greenhouse Gas Emissions

Electric vehicles do produce less greenhouse gas emissions than internal combustion engine cars, but the IEA study shows this is not the whole story.  (source: BBC)

Electric vehicles do produce less greenhouse gas emissions than internal combustion engine cars, but the IEA study shows this is not the whole story. (source: BBC)

The rate of purchase of electric vehicles is significantly increaseing each year. (source: IEA)

The rate of purchase of electric vehicles is significantly increaseing each year. (source: IEA)

Some countries have pledges to ban internal combustion engine vehicles, which should significantly boost sales of electric vehicles. (source: IEA)

Some countries have pledges to ban internal combustion engine vehicles, which should significantly boost sales of electric vehicles. (source: IEA)

Science Focus, the online home of BBC Focus Magazine, teamed up with the folks behind BBC World Service’s CrowdScience to answer questions on the topics of:

  • Are electric cars finally about to catch on?
  • How do electric cars compare with petrol cars?
  • Are hydrogen cars greener than electric cars?

They found that manufacturers are now convinced that they can build electric cars with a comparable range and speed to internal combustion engine vehicles (ICEVs). The key is developing cheaper and lighter lithium-ion technology with higher energy storage capabilities.  But, EV technology still hasn't gone fully mainstream: in the UK, just 1.5 percent of cars come with plugs, and in the US, its even less at 0.2 percent.  However, in Norway, where there are huge tax breaks and perks like being able to use bus lanes, it’s up to 29 per cent. This shows that, with government policies that provide incentives, people are willing to start driving EVs.  The study also noted that sales are predicted to spike when the price falls to the level of a ICE equivalent, which is forecast to happen in the early 2020s.

The BBC study noted that the "green credentials" of of EVs depend on how power is generated where you live.  If the community is using very low greenhouse gas (GHG) emission energy generation technologies like solar farms, wind farms or nuclear power plants, then life-cycle CO2 emissions per kilometer traveled are significantly lower than if you're getting your energy from fossil fuel power plants where you’re "just shifting your greenhouse gas emissions from your exhaust to its chimneys."  But even in areas with the dirtiest coal-fired plants, electric cars will still have lower CO2 emissions by about 50% on a per kilometer traveled basis taking into account emissions from propelling the car, emissions from making and transporting the fuel, and emissions from generating electricity.  The study found that plug-in hybrids emitted 42% less, hydrogen fuel cell cars 50% less, and battery electric vehicles (BEVs) 54% less CO2.

These numbers, in general, are corroborated by those in the International Energy Agency (IEA) Global EV Outlook 2018 report, which stated that, "The IEA (2017a) observed that in 2015 electric cars in Europe, on a well-to-wheel (WTW) basis [complete vehicle fuel-cycle analysis], emitted about 50% less CO2 than gasoline cars and 40% less than diesel cars."  However, the IEV report goes on to note that when emissions associated with the vehicle manufacturing are also included, the resulting CO2 emission savings are lower.  The report states, "when taking into account the entire life cycle of the vehicle (manufacturing, use and disposal), the current European generation mix enables battery electric vehicles (BEVs) to deliver roughly 30% GHG emission savings compared with gasoline ICEVs. To ensure that EVs have lower climate change impact than ICEs in countries with carbon-intensive power generation, it is of primary importance to reduce the CO2 intensity of power generation, and to reduce the impact of the battery production and vehicle manufacturing phases."

The report provides copious information on sales of new electric cars, which surpassed 1 million units in 2017 (for a global stock of more than 3 million vehicles).  This represents a growth in new electric cars of 54% compared with 2016.  China had the largest electric car global stock with 40% of the total.  Impressively, electric cars accounted for 39% of new car sales in Norway in 2017 – the world’s most advanced market of electric cars in terms of sales share. Iceland and Sweden, the next two most successful markets, achieved 11.7% and 6.3% electric car sales share, respectively, in 2017.  China, with 580,000 electric vehicles (EVs) sold in 2017 (up 72% from 2016) currently dominates the global market and is aggressively pursuing EV technologies.  China's higher EV adoption rate allowed them to account for 3% of global CO2 emissions avoided.

The report also noted the important role of the charging infrastructure and that it closely mirrored EV growth.  Private chargers at residences and workplaces still comprise the most widely used charging installations for EV owned by both households and fleets, with most all of them in China.  It further notes the importance of fast chargers, especially to urban environments, but that most charging infrastructure is comprised of slow charging outlets.

Batteries are still the number one reason for higher upfront costs of EVs.  However, advances in lithium-ion (Li-ion) battery technologies have reduced their cost, facilitated increased production and justified investment in continued research and development.  Key cost and performance drivers identified for the further improvement of Li-ion batteries include battery chemistry, energy storage capacity, manufacturing scale and charging speeds. Continued advancement in Li-ion battery research and technology development show potential to improve performance and further reduce costs, but much of the technology readiness level (TRL) is still low.  Investment in large-scale battery manufacturing facilities confirms that there is increasing confidence in the future of electric mobility and that augmenting production capacity is likely to catalyze further battery cost reductions.  These solutions indicate that Li-ion batteries will likely remain the technology of choice for EVs during the next decade. 

Although electric two-wheelers are not currently a prime focus in many regions, sales are also expected to experience significant growth with 39% of the world's two-wheelers expected to be electric by 2030.  In 2017, sales of electric two-wheelers were estimated at 30 million, primarily driven by markets in China and India.

Bottom Line - While life cycle emissions of various EV technologies varies depending on their particular electricity generation and manufacturing life cycle GHG costs, they still have lower overall life-cycle GHG emissions than ICEVs by approximately 30%.  And, the EV sales rate growth is projected to significantly increase year-over-year during the next decade bolstered by Government GHG reduction and other policies along with decreasing costs associated with improvements in technology, manufacturing scaling, and charging infrastructure availability.  This should continue to help reduce global GHG emissions.


For the complete BBC Focus Magazine article, see: How Environmentally Friendly are Electric Cars?

For the complete IEA report, see: Global EV Outlook 2018.

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