Tag Archives: science of EVs

Electric Cars – The real numbers

Electric Cars

I was thinking about the pros and cons of owning an electric vehicle and decided to do some research. Where we live it is not feasible as we do not have off-street parking to install charging facilities. The car would be parked on the street. Running a power cord across the footpath is probably not going to work.

What I found was both surprising and enlightening. While there is a strong reason to own an electric car for environmental reasons, there is a financial cost to doing so. The car does not run on sunshine as some believe. There are additional costs involved which need to be taken into account.

Range

According to a report by Drive, the range of electric cars varies from 200km for the Mazda MX30 up to  652km for the Tesla Model X. The main group are around 400km including the MG ZS at 385km Nissan Leaf at 385km Volvo C40 at 434km and Mercedes EQA at 426km. If you lived in Sydney you could get from Sydney to Newcastle and back with a little to spare according to the specs. We all know however that like fuel consumption figures, achieving the stated figures is not necessarily a given.

A report from the UK says that cruising at 75 mph (120 kph) will reduce the range by 30%. A car with a range of 400 km driven at that speed will have the range reduced to 280 km. Maybe you need to recharge in Newcastle for the trip home.

All these figures are for pristine new cars with batteries brand new. As batteries deteriorate over time they will not deliver the range of a new set. That is why they have to be replaced during the life of the vehicle. The range will gradually reduce until replacement is required. It is just like a torch where the light gets dimmer as you use it more. Eventually it becomes so dim, it has to be replaced.

Charging

There are three types of charging for EVs.

  • Level 1 is a normal household power point
  • Level 2 is a specially installed unit – usually in the garage at home
  • DCFC (Direct Current Fast Chargers) are commercial units in a charging station.

There are two types of home charging. The first method is to just plug into a standard power point. It is called Level 1 which will take up to 48 hours to charge a car according to an article on Carsguide. The charge rate gives you about 1 km of range every 5 minutes or 12 km per hour.

As a general rule of thumb, you can divide your battery capacity by two to work out the time to recharge using Level 1 – a domestic power point. Most cars are in the 45-65 kWH battery range so will take 22.5 hrs to 32.5 hours to recharge from empty to full. The Tesla Model X is 95 kWH so will take 48 hours.

Regarding cost, the MG ZS EV has a 44.5 kWh battery. If your electricity rate was 20 cents per kWh, that means it would cost a grand total of $8.90 to fully charge the battery – significantly less than the average cost of filling a tank with petrol. 

If you have solar panels and could do it on a sunny day, it would cost next to nothing. Of course, it would have to be over a few sunny days to fully charge from empty. You would have to turn off the charging when the sun went down.

The second way – Level 2 – is to use a fast charger which has to be installed in your garage. The cost can range from $950 to $1500 plus installation for a 2.7 kW charger up to $3,000 plus installation for a 22kw model. If you want a 22kw charger you will have to have 3-phase power which most homes do not have. It can be installed but is likely to cost several thousand dollars to set up.

Fast chargers on a normal single-phase installation can go up to 7.2 kW output which would mean you get 36 km of distance charged every hour. From flat to full would take 9 to 12 hours for the average EV,

Alternatively, if you go for the 3-phase solution you will get 132 km every hour. Some cars however cannot take the fast-charging option and are limited in the charging rate to 7.2 kW.

Normal homes use AC (alternate current) single phase. Commercial charging stations may use DC (direct current)

This is from the RAC in WA.

“There is also fast DC charging at public charging stations (DCFC), that provide from 50kW, 100kW, 150kW and even 350kW of electricity for your EV. Most vehicles are limited to 100kW, older EVs can’t take more than 50kW, but some higher-end performance/luxury models can be fully recharged in a little over half an hour from near-empty.”

So, to summarise, it will take up to a day to a day and a half on a standard power point to charge your average EV from nothing to full charge. A fast charger will take 9 to 15 hours depending on the power of the unit and whether you are using single-phase or 3-phase power. A charging station using DC can be anywhere upwards of half an hour depending on your battery’s capacity and ability to take a high charging rate.

Lifecycle cost

A study was done in 2017 by researchers at the University of Melbourne on the lifecycle cost of an EV. The study was based on a Nissan Leaf. For comparison with a conventional petrol vehicle, a Toyota Corolla was used. The cars are similar in size and fit out.

The key findings were as follows.

 Acquisition phase

“The acquisition cost of the Nissan Leaf has been composed of three components. Firstly, the manufacturer’s suggested retail price (MSRP) of the studied vehicle was obtained for the Sydney postcode with a base configuration. This amounts to a figure of A$39,990. Additionally, the price of a Level 2 standalone charger, including installation and a 3-year user warranty was included at A$3,000. Furthermore, registration, compulsory third-party insurance (CTP) and stamp duty taxes have been included as per regulations in Australia and was extracted from the Roads and Maritime Services (RMS) website. This leads to an additional cost of A$2,352.70.”

Operation phase

To calculate the operational costs they took into account insurance, maintenance, electricity usage and tyres. While tyres and maintenance were approximately the same in an electrical and petrol car, insurance is significantly higher for electric vehicles.

Nissan says the replacement of batteries is 8 years or 100,000 km. The cost of battery replacement is $7,300. The study estimated there would be at least one battery replacement over the life of the vehicle which was estimated to be 200,000 km.

From the report

“Higher insurance is to be expected as the insurance of novel technology is usually expensive due to uncertainty in performance and failure risk. The expenses attributable to battery replacement and the electricity required to recharge the Nissan Leaf, are additional key contributors.”

Disposal phase

Battery disposal is estimated at $1,935. The remaining disposal is the same as for a conventional car.

Conclusion

“The Nissan Leaf’s total cost of ownership calculated in this study was 0.46 A$/km. This embodies the costs involved in the acquisition of the vehicle, its operation and disposal. The conventional ICEV (internal Combustion Engine Vehicle) vehicle used for comparison had a total cost of ownership equivalent to 0.37 A$/km, which results in a cost premium of 0.09 A$/km for operating the Nissan Leaf in Australia.”

Owning an EV costs nine cents per kilometre more than a conventional car. The average car does around 14,000km annually. That amounts to $1,260 per year.

PHEV

Plug-in Hybrid Electric Vehicles. These are vehicles that have both an internal combustion engine (ICE) and an electric motor. The electric motor has a range of 50 to 80 km. The ICE both drives the car and generates electricity to recharge the batteries.

A German study by The International Council on Clean Transportation (ICCT) found fuel consumption was much higher than stated by manufacturers.

“Plug-in hybrids, which typically offer a fully-electric driving range of between 50 and 80 kilometres before the petrol engine takes over, claim average fuel consumption of between 1.6 to 1.7 litres per 100 kilometres on the WLTP cycle – but the paper claims the real figure is closer to 4.0 to 4.4L/100km.”

“As well as higher consumption, it alleges exhaust emissions are on average between 90 to 105g per kilometre – much higher than the 37-39g/km achieved using the WLTP standard.”

“While a number of reasons are listed for the discrepancies, the paper says many cars in the real world are not fully charged before being driven, meaning owners are not taking advantage of the maximum all-electric driving range available from their vehicles.”

PHEV vehicles are also heavier than a non-EV model because they carry batteries and motors for the electric operation as well as all the components for a petrol or diesel engine. Taking the Mitsubishi Outlander, the standard model weighs 1985 kg and the PHEV weighs 2370 kg. That is almost 20% heavier. More weight equals more fuel and more wear and tear. Since there are dual power sources, purchase price and maintenance will also be higher.

Other considerations

If you are travelling long distances, you will rely on regular recharging points every 300-400km and will need to build in time for the charge. That would mean a stop of perhaps an hour to do a full charge assuming a recharge station is available. If all the points are occupied, you may have to wait longer.

Should you buy a new car, and sell it before the battery replacement is due, the cost of a new set of batteries can be avoided, hence the cost per kilometre will be reduced. On the other hand, the sale price of the car will probably reflect the pending cost of a battery replacement.

The price of petrol and electricity obviously fluctuate over time. This will change the balance of cost as time goes on. The study in the lifecycle exercise was done in 2017. Since then, both petrol and electricity have become more expensive so one probably cancels the other.

Over time, the cost of electric vehicles will drop. Technology will improve and the cost of the batteries and other components will reduce. The range will increase. This will happen gradually over decades rather than significant changes year on year.

Charging electric vehicles requires electricity from either a power station or solar. If it comes from a power station, you need to consider the pollution produced by generating that power. If it is coming from a dirty, coal-burning plant, perhaps the benefits are reduced or eliminated. Since most charging is done at night, it makes solar recharging impossible.

In the future, we might use EVs as batteries to power the home. This assumes the EVs are not driven during the day and can be charged using solar. If they power the home during the night, that means their battery is run down by morning. It may limit how much they can be used during the following day.

Conclusion

Electric vehicles have an obvious benefit for the environment. That is undeniable. It should not be assumed that the savings from filling the tank will make the car cheaper to run. What you save on petrol or diesel will be exceeded in other areas. They are more costly over the life of the car.

EVs come with several challenges including the need for charging in the home, limits on long-distance travel and having the time to wait for them to be recharged. They may suit some people and not others. The positive thing is that over time, they will become cheaper, more charging stations will be available, the range will increase and recharge times come down.