Are electric vehicles as green as they seem?

Monday 29th June 2020

Electric vehicles are a key part of the government’s green agenda. Their zero tailpipe emissions are major factor in reaching the UK’s target of bringing all greenhouse gas emissions to net zero by 2050. As a result, they have attracted grants and tax incentives designed to encourage their adoption by individual drivers and business fleets. On the other hand, some argue that electric vehicles may not be as environmentally friendly as they first appear and that driving emissions are only part of the picture. The truth, as is often the case, may be somewhere in between.


The emissions argument

All pure-electric vehicles produce zero direct emissions

No matter how fuel and energy efficient a traditional petrol or diesel car claims to be, driving an electric vehicle means a 100% reduction in carbon emissions. To put it another way, a recent EDF Energy report shows that just one electric car can save an average of 1.5 million grams of CO2 every year. That sounds impressive – and it is. As their report goes on to say, that’s the equivalent of 4 return flights from London to Barcelona. And speaking of London, it is estimated that around half of London’s air pollution is caused by on-road transportation. In fact, Green House Gases (GHG) emissions from road transport are responsible for around a fifth of the UK’s entire amount.

As we all know, the drive to cut emissions is intrinsically linked with the fight against global warming, the importance of which cannot be overestimated. But, at a more local level, it’s worth remembering that air pollution is responsible for the premature deaths of between 28,000 and 36,000 people in the UK every year.

This alone is enough for many to conclude that electric vehicles are the only viable solution to reducing road related air pollution and helping to combat global warming. This may be true, but are tailpipe emissions all there is to it?


The manufacturing argument

Zero-tail pipe emissions is not the same as a zero-carbon footprint

Whatever their fuel type, all vehicles need to be manufactured and it is here that things get a little more complicated. Every manufacturer has their own production process and energy management controls. This data is hard to come by and is understandably commercially sensitive. As a result, accurately assessing and comparing the manufacturing related carbon footprint is extremely challenging. Of course, when we compare electric vehicles against internal combustion engines (ICE) there is one obvious difference. The lithium-ion battery.  

Studies show that battery production is associated with anywhere between 56 to 494kg of carbon dioxide per kilowatt-hour (kWh) of battery capacity. The same report also looks at the equivalent amount of emissions emitted over the lifetime of a vehicle and finds that this equates to 1-2g/km per kWh of capacity.

In any study such as this, there needs to be a whole raft of assumptions and caveats in interpreting the data, but the key point here is that zero tailpipe emissions are not equivalent to a zero-carbon footprint. As the report goes on to say, around a third of the lifetime emissions connected with an electric car comes from the initial manufacturing process.

This might not sound like particularly good news, but we should remember that current batteries are estimated to last 10-20 years before they need to be replaced and most manufacturers will guarantee them for between five and eight years.

Batteries can also be recycled when they reach the end of their useful life. For example, Volkswagen Group currently recycle 53% of all raw materials and they aim to bring this up to 97% with initiatives such as their battery recycling plant in Salzgitter, Germany.

In summary, whilst electric vehicles can sometimes have a manufacturing process with a slightly higher carbon footprint than their petrol or diesel counterparts, this is more than outweighed by the lifetime CO2 savings of zero-emission driving. And, as they technology involved in manufacturing and recycling batteries continues to improve, so will the results.

The power source argument

The UK generates more electricity from zero-carbon sources than fossil fuels

We all know that ICE vehicles use fossil fuels, but what about EVs? Electricity still needs to be generated and globally over 60% of this power comes from burning fossils such as coal, gas or oil. The good news here is that, for the UK at least, it’s a greener picture.

Since 2010, electricity generation from fossil fuels has halved and in the third quarter of 2019 renewables were responsible for more electricity than fossil fuels. To put this into perspective, this is the first time in 140 years of public electricity generators that wind, biomass, and hydro plants have generated more electricity than coal, oil or gas combined.

In the interest of balance, it is worth noting that biomass may be renewable, but it is not zero-carbon. Around two-thirds comes from plant biomass such as wood pellets, which is usually sourced from sawdust produced in lumber mills and other wood product manufacturing plants. That said, biomass accounts for only 8.5% of UK electricity. This means that, taking everything into account, zero-carbon power is now the largest source of electricity in the UK.


The hydrogen fuel-cell argument

Hydrogen based cars have zero carbon emissions, but they’re also missing a refueling infrastructure

It could be argued that for zero-emission driving, Fuel Cell Electric Vehicles (FCEVs) such as the Toyota Mirai offer as many benefits as a battery. This is a fair point, especially when you consider that FCEVs store energy as hydrogen and then use a fuel cell to convert it to electricity which in turn powers the car.

This all sounds like a great option until you realize that there are less than 20 hydrogen refilling stations in the UK, compared to over 11,000 for battery electric vehicles. This means that even before weighing up any marginal losses or gains in the manufacturing or recycling process, without a nationwide refueling infrastructure, FCEVs aren’t even close to being considered as a feasible option.


The final equation

Pure-electric vehicles may not be zero-carbon, but they are still the greenest viable choice

It’s clear that once on the road, electric vehicles win hands down. The carbon footprint associated with the manufacturing process cannot be ignored, but it shouldn’t be given undue weight either. And when it comes to a power source, not only is the UK increasingly committed to zero-carbon sources for the National Grid, businesses and individuals can make a conscious decision to choose a provider that offers 100% renewable electricity.

In short, whether electric vehicles are as green as they seem depends on your definition of green, but they are clearly the greenest viable option on the market today – and will be for many years to come.