Green NCAP study unveils small CO2 advantage for EVs

Green NCAP has concluded its first lifetime cycle assessment (LCA) analysis, investigating greenhouse gas emissions and energy consumption for 61 car models with different drivelines. Adding to the debate on how positive the CO2 emissions of battery-powered vehicles really are, the data reveal a smaller than expected benefit. At least, for the moment and depending on where you live and how you drive.

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In an LCA, the environmental impact of a car is broken down into all of its different phases, from manufacturing to recycling and everything in between. Numerous studies have preceded the youngest one, from Green NCAP, which in a unique fashion, stages real life consumption data and includes ambient factors such as cold temperatures. These unveil that an EV isn’t always more sustainable than a combustion car.

Gap of 7%

Despite emissions from battery production, EVs emit on average less greenhouse gas (GHG) than ICE models. From all the cars tested, the Fiat 500e represents the smallest carbon footprint (31 tons of CO2), while the first ICE car comes in at sixth place with 41 tons: the diesel engined Skoda Octavia 2.0 TDI. However, if you compare the latter with a similarly sized EV, like the VW ID.3 (35 tons of CO2), the gap narrows to 7%. Significant, which is small.

While the GHG emissions for BEVs are mainly attributed to production (both vehicle and battery) the principal source for ICE models are tailpipe emissions, aka operational use. In the case of electric cars, considerable gains are also possible in this usage phase. If the charged electricity comes from renewables, GHG emissions of EVs can drop to half of those of similar cars with a combustion engine.

Primary Energy Demand

But there’s more. In every phase of LCA, primary energy demand (PED) plays an equally significant role as GHG emissions, according to Green NCAP. PED is the energy consumed to make, run or recycle a car. It doesn’t matter if it comes from coal, wind or nuclear, in a sustainable scenario the industry should use it sparingly.

Ranked by PED, the all-electric Fiat 500e drops to fourth place, while the previously named Skoda Octavia 2.0 TDI jumps to the top of the ranking. So, where an electric driveline tops the ranks for CO2, a diesel model replaces it as overall energy consumption is considered. It shows that the question for the most sustainable driveline doesn’t render a clear-cut answer.

Green NCAP concludes that EVs overall show the best LCA numbers in the European average, but admits that it sometimes is a close call with ICE models.

The Polish example

However, electric cars can increase their lead, as electricity production shifts to renewables. In that respect, with Green NCAP accounting for both frugal (best case) and unattentive drivers (worst case) the analysis shows the importance of the production process. An example shows that a sporty-driven EV in Poland performs worse than an economically used diesel because the country produces its electricity mainly from brown coal.

Finally, Green NCAP points out that pollutant emissions such as NOx or particulate matters, a bigger issue on ICE cars, should also be reckoned with. Their LCA analysis left them out of the equation.

Lessons to be remembered:

  • LCA can provide useful insight into the influence of mass on the estimated vehicle’s greenhouse footprint. Larger cars have a worse LCA, regardless of the powertrain.
  • Battery packs with higher energy density profoundly impact CHG emissions.
  • The relative differences for consumption in cold or warm weather are much more significant for (PH)EVs. Electric cars consume twice as much at -7°C.
  • Toxic emissions (particulate matter, NOx, sulfur) shouldn’t be disregarded and favour EVs.
  • The usage phase has the biggest share in LCA regardless of drivetrain. So, educating drivers can have a profound impact on energy demand and emissions.
  • Renewable electricity can halve the GHG impact of an EV in comparison to a conventional car.
  • Plug-in hybrids only reduce their greenhouse gas output and the effect on the climate if they are charged regularly.

Image source: Fiat

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