Electric cars have least greenhouse gas impact, including power generation
Electric cars clearly beat the latest hybrid and internal-combustion models in terms of overall greenhouse gas impact - even when generating the electricity to power them is factored in, environmental body Green NCAP’s latest tests show. Find out how the latest hybrid, petrol and diesel cars fared in comparison below.
A common criticism of the ‘green’ credentials of electric cars is that the car itself may have no tailpipe emissions, but the pollution is simply moved upstream to the power station that generated the electricity instead.
Green NCAP’s tests take this consideration into account, using the typical European electricity generation mix across 27 countries including the UK.
The results show that even with the current average European levels of renewable energy generation, the electric cars tested generate lower greenhouse gas emissions (which cause climate change), especially for carbon dioxide, compared to other types of car.
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What is Green NCAP?
Green NCAP is a relatively new independent initiative funded by organisations including Which?. Similar to Euro NCAP which gives safety ratings on cars from crash tests, Green NCAP’s goal is to assess the environmental impact of vehicles.
In 2022, Green NCAP launched a ‘Well-to-Wheel+’ greenhouse gas assessment, which factors in the extraction, production and distribution of energy from the source to the measured tailpipe emissions. The ‘+’ means the construction of powerplants and refineries is taken into account.
Green NCAP’s ratings combine real on-road tests and laboratory assessments. In 2022 these are now even more demanding too, including a second-stage test process to prove the robustness of a car’s performance under more challenging conditions, for example to see whether a car’s environmental performance holds up at colder temperatures.
Green NCAP’s tests go further than official tests to give more realistic assessments of how a car will actually perform out on the road, to help hold manufacturers to account.
Electric: Audi Q4 e-tron (£43,975**) – 5 stars
The Audi Q4 e-tron electric SUV scores the top five stars out of five in Green NCAP’s tests.
Green NCAP’s tests cover three areas:
- Clean Air tests that check for nasty gases like NOx that contribute to air pollution and related health concerns in cities
- Energy Efficiency assessments that ensure energy isn’t wasted in driving the engine
- Greenhouse Gas tests – this is where the new ‘Well-to-Wheel+’ analysis comes in. Here Green NCAP rates the production of gases like carbon dioxide that contribute to climate change.
The Audi Q4 e-tron has a very efficient electric engine, scoring 9.2 out of 10 for Energy Efficiency, and of course scores a perfect 10 for Clean Air since it has no tailpipe emissions.
In the Greenhouse Gas test it also scores a commendable 9.5 out of 10, thanks to the low energy consumption of the vehicle as well as the relatively low carbon dioxide emissions of European electricity production.
In its latest tests, Green NCAP also rated the budget Dacia Spring small electric SUV, which isn’t yet available in the UK. It has also achieved a perfect five stars out of five, showing that even when factoring in average European electricity generation emissions, the latest electric cars still have better environmental impacts than the latest hybrid and conventionally-powered cars under test.
We haven’t tested the Audi Q4 e-tron yet – but see how other Audi electric cars have performed so far in our tests in our Audi E-Tron and Audi e-Tron GT reviews.
Full hybrid: Honda HR-V (£26,960*) – 3 stars
The popular Honda HR-V SUV scores three stars out of five in Green NCAP’s tests – we might have hoped for better considering it’s a full hybrid, recharging the battery as you drive, for instance when decelerating.
It performs well for its tailpipe emissions, with a Clean Air score of 7.4 out of 10. It scores 4.9 out of 10 for Energy Efficiency, with Green NCAP’s motorway test pulling down the score, with aerodynamic drag from its boxy SUV shape deemed a particular problem.
The Greenhouse Gas test is what really lets it down, with a score of 3.4 out of 10. While tailpipe carbon dioxide emission are close to claims, factoring in the fuel production and electricity supply pulls down the score. Carbon dioxide emissions were elevated in the motorway test cycle.
Are plug-in hybrids any better, you may ask? It’s not available in the UK yet, but Green NCAP rated the Lynk & Co 01 plug-in hybrid SUV and gave it a slightly higher 3.5 stars out of five. In this case, Green NCAP said that its weight – partly due to the size of the battery – harms the energy efficiency of the car, especially when it runs out and the car reverts to petrol power.
Is this Honda a standout car in other areas? Find out what our experts thought in our first drive Honda HR-V review.
Mild hybrid: Hyundai Bayon (£19,804*) – 2.5 stars
The Hyundai Bayon small SUV underperforms in Green NCAP’s tests, despite being a mild hybrid, which means it has a small battery that supports its petrol engine.
Both in lab and road tests, emissions were disappointing, especially for particulates such as soot. Green NCAP said the car’s energy efficiency would have been improved by having a bigger hybrid battery. Carbon dioxide emissions are as expected from the tailpipe, but those for fuel production and supply push down the score.
Does this car have redeeming features that make it worth buying? Our professionals put it to the test in our full Hyundai Bayon review.
Petrol: Toyota Aygo X (£15,405**) – 3 stars
The Toyota Aygo X crossover city car performs reasonably in Green NCAP’s tests, considering it’s only a petrol-engine car.
It scores 6.2 and 6.0 out of 10 for Clean Air and Energy Efficiency respectively. The Greenhouse Gas test (4.8 out of 10) is its weakest area, where carbon dioxide emissions were high in motorway driving. Being a small, light car benefitted its scores overall.
We haven’t tested the new Toyota Aygo X yet, but find out how the previous-generation Toyota Aygo performed in our Toyota Aygo (2014-2022) review.
Petrol: Subaru Outback (£34,820*) – 1.5 stars
Subaru certainly won’t win any accolades for the Outback large estate’s performance in Green NCAP’s tests, achieving a woeful 1.5 stars out of 5.
Tailpipe emissions actually aren’t woeful (4.8 out of 10 in the Clean Air test), but in the Energy Efficiency and Greenhouse Gas tests the car performed poorly (scoring 2.1 and 0.7 out of 10 respectively).
Green NCAP describes the car as being ‘far away from being frugal in its use of fuel’.
Is this a car for those that value practicality over other factors? See what our professionals thought overall in our Subaru Outback review.
Diesel: Genesis G70 (£33,400**) – 2 stars
Hyundai’s luxury brand Genesis’ G70 diesel saloon hasn’t set the world alight for its environmental credentials according to Green NCAP.
Tailpipe emissions are reasonable, scoring 5.8 out of 10 in the Clean Air test. But scores in the Energy Efficiency and Greenhouse Gas assessments are poor (2.9 and 0.7 out of 10 respectively).
Diesel consumption is quite high on the motorway especially, and greenhouse gas emissions are poor for both carbon dioxide and nitrogen dioxide (N2O). Green NCAP said: ‘barely able to score points for greenhouse gases in any of the test runs’.
We haven’t tested the Genesis G70 yet, but see if Genesis is a brand worth considering by checking out our other Genesis car reviews.
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*New prices based on what people pay (including discounts), sourced from 500 franchised dealers across the UK each month.
**For cars we haven’t reviewed yet, these are the on-the-road prices from the manufacturer’s website, correct at time of publishing.
