Are Electric Vehicles Really Less Polluting Than Fossil-Fuel Ones?

There has been considerable press attention around a recent report from Greenpeace and Transport & Environment, which argues that plug-in hybrids (PHEVs) are a “wolf in sheep’s clothing”. The report claims that PHEVs produce 2.5 times more CO2 in real life than they do in the lab, with both the BBC and (unsurprisingly) Mail Online picking up on the news with gusto. Although the report’s conclusions revolve around the hardly earth-shattering idea that you need to actually plug in a plug-in hybrid to get the most benefit, they also highlight a wider issue – how can you measure the overall pollution of a vehicle, and if you do, are EVs really as ecological as they’re made out to be?

The Greenpeace / Transport & Environment report’s research states that while PHEV manufacturers cite official test results showing CO2 emissions averaging 44g per km, they actually emit more like 117g per km in real use, which is much closer to the value for petrol and diesel cars of 164-7g per km. This is because the true emissions of a PHEV depend on how you drive it. If you don’t plug it in, a PHEV behaves like a conventional hybrid, except with about 200kg more batteries, which are being lugged around for no reason. Also, if you drive a PHEV fast, the fossil-fuel engine will fire up anyway, negating the emissions benefits of battery power.

Based on these findings, Greenpeace is arguing that car manufacturers are simply using PHEVs as an excuse not to stop manufacturing polluting internal combustion engines, and that this vehicle type should be banned alongside pure petrol and diesel in a decade or so as a result. Their arguments are not completely lacking in merit. Lots of people will have purchased a PHEV for the reduced tax due to their low official CO2 emissions, and once they’ve bought the car don’t care about driving it in a way that actually produces this ecological outcome. Both the manufacturers and owners can pretend to adopt green behaviour without actually bothering to do so.

This is a classic example of the dilemma when a radical change is needed. You can create better technology, but it only makes a difference if people use it as intended. The PHEV is meant to be a “gateway drug” to full battery-electric vehicle (BEV) ownership. With a PHEV, you can get used to the idea of an electric vehicle you charge regularly at home, but without having to worry about charging on a long journey. Used as intended, they can essentially be a BEV for local journeys, and only revert to a fossil-fuel car if you venture further. Should you get stuck in traffic on that longer journey, PHEVs are still much better than a conventional car because they will mostly use electric power when creeping along in a near-stationary jam, and just fire up the engine when the speed increases. If you buy a PHEV and drive it the way it was designed, it can be a very economical and ecological vehicle indeed. Sadly, the Greenpeace / Transport & Environment research implies that a lot of PHEV owners don’t do this.

ou can see why Greenpeace is accusing manufacturers of knowing this would happen. There has been a lot of dubious vehicle marketing where eco-friendliness is concerned. Dieselgate was the highest-profile controversy, but at the beginning of 2020 one of Toyota’s ads was banned in Norway for making unsubstantiated claims. This ad for a so-called “self-charging hybrid” implied that Toyota’s premium Lexus vehicles had “infinite range” because you didn’t need to plug them in to charge – ignoring the fact that you will of course have to refuel them with petrol from time to time. This clear attack on BEVs sounded like Lexus had invented some form of perpetual motion machine. Lexus hybrids are still being marketed as “self-charging” as if this is something new, when all hybrids ever made have worked in this way. But the claims have been toned down and Lexus will be launching a BEV called the UX 300e very shortly anyway.

However, where the CO2 emissions argument is concerned, eco-friendliness is about much more than just what comes out of the tailpipe. As the PHEV debate raged on, new EV-only brand Polestar made a rather timely release, arguing that manufacturers should be more transparent about the carbon footprint of the manufacturing process. This echoes a regular argument that you will come across online, where angry EV haters claim electric cars produce more CO2 during manufacture than internal combustion ones, so they’re not really ecological. This is quite often true, and Polestar has admitted that its Polestar 2 creates a 26-ton carbon footprint before leaving the factory, which is more than its sister company Volvo requires to make a petrol-powered HC40 SUV. However, because the all-electric Polestar 2 can then be powered from renewable energy with no carbon footprint, after 50,000km the HC40 is more polluting.

This is a step in the right direction but takes the argument down a potentially deep rabbit hole. Finding the true carbon footprint of a car manufacturing supply chain is far from easy, with so many components arriving from so many global sources. Polestar has done this for its vehicle, but with so much economic interest at stake, convincing other manufacturers to follow suit is unlikely when it could make them look as bad as Dieselgate did for VW. What the Greenpeace PHEV research illustrates is that there is an ecological game of cat-and-mouse taking place, where governments set green targets and manufacturers try to fulfil them with as little disruption to their business models as possible. Unfortunately, this game means there will be many more questionable claims to work through as we transform our transport to vehicles that really do have less impact on global warming and urban air pollution.