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Electric Cars

It’s only 7 years before there is a complete ban on selling new petrol and diesel cars.  That’s not long to make sure we have the infrastructure in place to handle delivery of electricity to batteries in the new cars.

The story of electric cars is complicated. Environmental and cost savings attributed to electric cars vary according to the country you live in, the weather, the point of manufacture and infrastructure, indeed in some countries there are no environmental benefits at all as we shall see below.

Manufacturers like to sell the idea of electric cars as zero tailpipe greenhouse gas emissions (GHG), however the electricity to charge a battery has to come from somewhere and its production has a CO₂e footprint.  If a country produces electricity from burning coal such as India and Australia then the CO₂e emissions produced per kWh of electricity are very high. In-fact so high that the CO₂e emissions per kilometre from an electric car are higher than from a diesel or petrol car. In these countries there is no CO₂e benefit if you drive an electric car. The opposite applies in a country such as Norway where much of electricity production comes from renewable sources. 

UK is somewhere in the middle, we have significantly increased our renewable energy production and reduced our reliance on coal fired power stations over the last few years. This means it is marginally better to run an electric car in UK compared to petrol and diesel cars.

1. Buying an electric car – currently the purchase price of new electric cars is very high at around £30,000, compare this to conventional diesel cars at about £19,000 and petrol vehicles at approximately £17,000. Of course, we will expect to see these prices reduce in time as manufacturing volumes increase, however for many this will continue to be a significant barrier to buying an EV. Over time you will recoup this high up-front cost because electric cars have lower maintenance costs, are exempt from car tax and generally cheaper to run. A ‘Which’ survey compared an electric SUV with its equivalent non-electric vehicle and found it would take 7 years of driving before it became the cheaper overall option.

Alternatively, check the second-hand market, this is still small but increasing.

2. Charging your electric vehicle – this can still be a hindrance for the electric vehicle owner. You may have planned your journey using ‘’ only to find a line of vehicles waiting to charge at the same point. Once again this will improve in time as more facilities are provided at service stations, supermarkets, shopping centres etc.

There is also a discrepancy in costs to charge your vehicle dependent on the facility.

Home charging – convenient and low cost. 80% of charging takes place at home. You can use a standard three pin 230V mains socket which draws just 2.3kW of power and costs 34p per kWh but it may take more than a day to fully charge the battery. Alternatively invest in a home EV charger for £700 to £1,500, these draw between 7kW and 22kW and can fully charge the battery overnight for the same price.

AC on street chargers are more expensive than home charging at about 50p per kWh and classed as slow or fast. The costs are still relatively low but they can still take several hours.

DC chargers are classed as rapid or ultra-rapid. They can charge your battery to 80% in 20 to 30 minutes but can be more expensive than filling a car with diesel or petrol.

Cost comparison per km of travel

Annual electricity costs to charge an average electric car e.g. 2018 Nissan Leaf (40kWh battery) with a range of 270km per charge at 93% battery efficiency giving a realistic range of 250km.

Petrol cars – Average km per litre of petrol – 12.75km

Diesel cars – Average km per litre of diesel – 15.18km

Average car mileage in UK –  11,900 kilometres per year

EV battery charging costs per kWh of electricityCost per charge of 40 kWh batteryCost per year (11,900 km) – 48 charges of 40kWh batteryCost per km
Charge at home 34p per kWh£13.60£653£0.055 (5.5 pence)
AC Public charge 50p per kWh£20.00£960£0.08 (8 pence)
DC Rapid chargers 73p per kWh£29.20£1,400£0.12 (12 pence)
  Cost per year 
Diesel car – £1.50 per litre fuel £1,176£0.098 (9.8 pence)
Petrol car – £1.43 per litre fuel £1,335£0.112 (11.2 pence)

At current electric prices the cost to run an electric car compared to a diesel or petrol car is not as attractive as just two years ago. This means that currently less people are inclined to switch to an EV.

The biggest savings come from charging an electric car at home but this is not always possible and we are forced to charge our batteries at other sites. If you are regularly using a rapid DC charger costs are higher than petrol or diesel. If and when electric prices drop then electric vehicles will become a more attractive buy.

3. Batteries – this essential part of an electric vehicle has come a long way since the early days. The lithium-ion batteries now supplied with electric cars are a real game changer. They don’t need changing every 2 or 3 years, in-fact it turns out that 92% of electric car owners have not had to change their battery in the eight year / 160,000 km warranty that electric car manufacturers give their batteries.

The other main concern is battery degradation, once again not as bad as you may think. Typically, they lose on average, 9% efficiency over 7 years. In other words, if your car had a range of 320km when brand new, it drops to around 290km after 7 years.

Note: it has recently emerged that mining of raw materials such as lithium and cobalt for batteries is causing major environmental and social problems in South America. We have to question the supply line before it gets out of hand.

 4. Range – it is not surprising that many of us have range anxiety when thinking about buying an electric car ie the distance travelled before the battery runs flat. In the very early days of electric vehicles the maximum distance driven could be as little as 50 km on a full charge. Not much use if you wanted to visit your friends 200 km away and had to find 3 charging points on the way. Today the lowest range we found for a 2022 car was 185 km and the greatest a whopping 830 km. This, of course, is based on the size of the battery in the vehicle and the efficiency of the car. Alongside an increasing number of charging points in UK this should allay some of the feelings of range anxiety.

Range calculation – we are all used to the traditional method of measuring fuel economy as miles per gallon, however, electric vehicles use a different set of parameters to estimate range. The first is battery capacity measured in kilowatt hours (kWh), this can be anything from 15kWh for a small city car right up to 100kWh for larger models. Then there is the efficiency of the engine which is measured in kilowatt hours per 100km (kWh / 100km) An average is around 21 kWh /100km.

To estimate the potential range of your vehicle simply divide the battery capacity by the efficiency of the engine and multiply by 100 e.g.

Car has battery capacity of 50 kWh and an engine efficiency rating of 20 kWh

50 ÷20 =2.5

2.5 x 100 = 250km range.

5. Green credentials of electric cars

You may often hear people say that electric cars produce zero greenhouse gas emissions from the tailpipe. Yes, that is absolutely true, but the electricity to charge the battery has to come from somewhere and generating electricity has its own greenhouse gas footprint.

The overall level of this footprint depends on the combination of energy sources to generate the electricity.

In order of carbon dioxide emissions per Kilo Watt Hour of electricity generated for various energy sources see below

Coal – 950g CO₂e / kWh

Petroleum – 320g CO₂e / kWh

Natural Gas – 350g CO₂e / kWh

Renewable energy sources: Nuclear, Hydropower, Wind, Geothermal, Solar and Biomass –  4-6g CO₂e / kWh

This means that the more the dependence on fossil fuel sources such as coal for electricity production, the less the benefit to reducing CO₂ emissions when running an electric car.

Here is a quick CO₂ emissions comparison between running an electric car and a diesel car in UK.

On average a car running on diesel emits 124g CO₂ per kilometre, whereas an electric car emits just 42g. On the face of it very good, but there is another factor we need to take into account, that being the embedded energy in the car itself. This is the combination of energy required to source all the building blocks of the car, the manufacturing process, the transport process and the marketing of the vehicle. The basic car manufacture is similar between electric and diesel cars but there is a huge discrepancy when it comes to battery production. Electric car batteries require a lot of energy to manufacture and can themselves represent a CO₂ imprint of many tonnes dependent on the size of the battery. This has the effect of reducing the green credentials of an electric car.

The illustration below gives an indication of CO₂ emissions taking everything into account over a 7 year life cycle of a car. In UK the big gains in CO₂ reduction when driving your car are offset to some degree by the large CO₂ imprint from embedded energy.

6. Toxic emissions from diesel and petrol cars.

One other factor we need to take into account when comparing electric vehicles to petrol or diesel cars is the emission of toxic compounds and particulates

When we burn diesel and petrol in a vehicle, some greenhouse gases are emitted – carbon dioxide (CO₂) we know about, but there are other harmful greenhouse gases called nitrogen oxides (NOx). These are particularly harmful to us and thought to be responsible for up to 40,000 deaths in the UK every year.

7. Conclusion

We hope the information above will give you a better understanding of electric cars and allow you to a more informed decision when you are purchasing your next vehicle. It is not an easy decision because benefits are still marginal.