How Green are Electric Vehicles?

So is switching from ICE to EV really a greener option? We explore in this guide.

Summary

By moving from the internal combustion engine (ICE) to an electric car, you will significantly reduce your carbon footprint and air quality impacts. This guide explores:

  • How green electricity is
  • Which kinds of EV are greenest
  • How driving style affects
  • When charging is greenest

How green is using electricity as energy source?

While it is true that your electric car will be greener with specifically sourced renewable electricity, you may be surprised by how green it is when just plugged into the average UK gridmix.

Nissan LEAF vs Nissan Micra Example

2018 Nissan LEAF 40kWh Nissan Micra VISIA IG 71
Efficiency 0.33 kWh/mile 46.3 miles per gallon
Direct emissions 0 gCO2/km 121 gCO2/km
Fuel production emissions 67 gCO2/km* 39 gCO2/km**
Total emissions 67 gCO2/km 160 gCO2/km


* According to average UK grid emissions first 6 months of 2019 - 222gCO2/kWh
** It is estimated that ~15-40% of total “well-to-wheel” emissions come from extraction and refinement of petrol. We’ve used 32% as a mid-point as an assumption.

The UK has dramatically decarbonised its power generation in recent years, mainly by replacing high emitting coal with less emitting natural gas and increasing the supply of renewable energy. This process continues, as we look to remove the last of the coal, reduce our reliance on gas, and increase our reliance on renewable generation. As such the grid gets greener each year.

Tip: While EVs have gotten twice as green in terms of CO2 emissions in recent years, in operational terms they are typically more efficient in terms of CO2 emissions than equivalent internal combustion engine vehicles even when charged from coal-fired power! So EVs are always winning, but the winnings keep growing.

Not all EVs are equally green...

Production

Much of the Carbon released over the lifetime of an EV is a byproduct of its manufacturing processes and supply chain. At present firm values for the Carbon footprint of EVs are hard to come by. A Ricardo report in 2011 estimated that BEVs have a ~30% Carbon deficit in their manufacture when compared with an internal combustion engine car, but that deficit was typically comfortably overcome within the operational life of an EV.

More recently significant investments in renewable power at factories by the likes of BMW at its Leipzig plant and Tesla, particularly at its Gigafactory, have made an impact on the Carbon intensity of their vehicle production. Meanwhile Volkswagen have made an incredible commitment to Carbon neutral production of their ID range, with Carbon off-setting for the shipment.

Operation

Generally RExs are greener to drive than PHEVs, while BEVs are the most efficient type of EV - as they use no petrol at all. But not all BEVs are equal!

Take a look at our vehicle guides and see the average efficiency of the different models - the most efficient are those that use the least “wh per mile”. You may be surprised at the differences.

Tip: How you configure your car can affect your efficiency. In particular, smaller wheels with larger profile tyres have less rolling resistance, leading to better efficiency and longer range.

Driving style affects how green a BEV is

Just like in a conventionally fuelled car, if you spend your time accelerating hard, you will use more energy than if you pull away more gently. And if you are using more energy per mile, then you are using more Carbon per mile (unless you are charging from pure renewables).

Tip: Of course minimising your energy consumption per mile will increase your range on a charge. As such, check out our guide on “How to optimise your range when driving your EV”.

When EVs are charged effects how green they are

The UK’s carbon intensity varies depending on how much power is required and the grid mix at that time. For example, late on a windy night, the UK’s grid is very green, with demand almost all fulfilled by wind and nuclear (v low Carbon).

There are several tools that show the Carbon content of the grid, and even the types of generation both live and in recent days. We recommend:

    Tip: As a general rule, charging late at night is a green approach, as demand is always lower. This may change as more cars become electric and the grid becomes more renewables base, but it is a good rule of thumb for the medium term.

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