Electric Cars: Benefits?

The Question

In another blog you can read about the history of electric cars however one of the most commonly asked and debated questions is whether electric or hybrid cars are beneficial for the environment? The reason for much of the confusion is that the answer is more complex than it may appear. There are three key components to this answer:

  • impact as they’re driving,
  • where the energy comes from,
  • how intensive the cars are to manufacture.

When Driving

The first element is the least controversial. Most noticeably in electric cars is the fact that they produce no harmful emissions at the point of use. In the case of hybrids or plug in hybrids emissions at the point of use are much reduced. By emissions we’re not only talking about carbon dioxide but also about other harmful emissions such as sulphur dioxide or nitrogen dioxide and other particulate matter.

In recent years, the impact of vehicles to the atmosphere, of cities in particular, has drawn significant focus and the relative benefits of ultra-low emission cars such as electric and plug in electric vehicles have drawn significant financial incentives. By this measure alone, these types of vehicles are clearly beneficial.

Where the power comes from

The second measure is the impact of the lifecycle of the energy that is required to move these vehicles. This argument is often the pushback to the “green” credentials of electric mobility. To charge an electric vehicle in most cases the electricity needs to come from the electricity grid where it was generated, transported and distributed – we cover numerous generation methods, transportation and distribution in detail in many blogs.

The electricity which we use comes from a mix of many sources including high polluting sources such as oil and coal and low carbon sources such as hydro, wind and nuclear. In most countries it’s possible to find the mix of sources used and often in real time such as the UK. The UK currently averages between 200 and 300 grams of carbon dioxide per kilowatt hour generated and there are aims to reduce this to 100 grams per kilowatt hour by 2030. Comparing this to conventional vehicles is quite straightforward as they are required to publish their carbon intensity for all new vehicles in Europe. Many of the best in class cars will aim for around 100g of carbon produced per kilometre of driving. An equivalent electric vehicle will produce up to 5 kilometres per kilowatt hour therefore in the UK would average 60g per kWh under the worst average figures and this is set to continue to fall. Many people will opt to purchase renewable guarantees for their electricity which would ensure that their carbon is offset and effectively meaning a zero carbon impact of their electricity.

Note that transmission and distribution of electricity are also highlighted as sources of additional carbon. This is certainly true given the losses the system incurs, energy used to build and maintain infrastructure etc however for me this comparative if not a lot less than the carbon intensity of the distribution requirements for oil and gas products e.g. extracting from hard to reach geological formations, refining, transporting these globally then distributing them locally. The petroleum supply chain is incredibly carbon intensive before it even reaches your car. On this measure too, electric cars and hybrids are measurably more beneficial.

UK Carbon Intensity from Electricity Generation

Manufacturing the car

Our third measure is the production of electric cars vs standard cars. Let us take a like for like comparison for new comparative cars. Statistics on this measure is more hard to come by than many others given the commercial sensitivities. There also is a significant geographical variance for example German energy and resource efficiency is on average significantly better than those of less technologically developed economies. All evidence however I’ve seen suggests that electric cars are indeed more energy and resource intensive than standard cars to the tune of around 30%. This is not an insignificant figure therefore to get the net effect, we need to understand the proportion of energy used in the creation of a car vs the energy used to run the car for an average lifetime distance. Manufacture of a car on average may lead around 6 metric tonnes of CO2 with an additional 1-4 metric tonnes for the battery and other components in an electric car. This figure however is only about 10% of the total emissions of an average car that would reach 200,000 miles.

In conclusion, electric cars seem to be on average better for the environment dependent on the electricity sources and manufacture process of car. The carbon payback could come as soon as around 20,000 miles travelled. This figure is also likely to reduce with improvements in efficiency of the manufacturing process.

I have not covered technological improvements such as regenerative braking, no idling energy use etc nor have I covered the impact of the toxicity of the battery components or conversely the toxicity of oil extraction processes. As a side note it is important also to note that the efficiency of conventional cars is not going to increase to match electric vehicles for the simple reason that the maturity of research and development in efficiency of engines means that they are already close to their maximum theoretical efficiencies given that there is only so much energy in a litre of petrol or diesel.

What are your thoughts on the impacts of electric vehicles?

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