Study finds EV running costs cheaper

THE cost of energy to run an electric vehicle is only about 15 per cent of what a petrol car costs to run, excluding the price of the battery, a new study has found.

And there are several areas of EV design where that advantage in energy consumption can be greatly improved, according to Tim Olding, the chief engineer at EV Engineering.

Mr Olding, who is also an employee of infrastructure provider Better Place, said the results of real-world driving tests around Melbourne suggest that taxi drivers and others who use their vehicle as a tool of trade could save thousands of dollars a year.

The study compared the operating costs of a standard V6 Holden Calais with an identical car that had been converted to electric operation by EV Engineering, for a direct back-to-back comparison between electricity and petrol.

Running cost calculations were based on the current range of domestic electricity prices – 13c/kWh at night and 35c in the day – and petrol prices ranging from $1.31 to $1.51 per litre.

“At best, an EV is costing a bit over 2c/km for energy, if you can buy your energy at the low electricity price,” Mr Olding told the ‘Plug in 4 Power’ conference at Swinburne University

From top: EV Engineering chief engineer Tim Olding EV Engineering images.

“At best, an equivalent-sized petrol car can cost anywhere between 10c and 14c/km at the low petrol price.

“But you should remember we are replacing petrol not just with electricity but primarily with a battery – which is the most expensive component of the EV and can cost between $10,000 and $15,000 itself – so you also have to look at the total cost of that system.”When the cost of the battery and the electricity are combined, the cost of electricity represents 15 per cent of the total and the battery 85 per cent.

Of course, the EV is also cleaner in terms of CO2 emissions than a comparable petrol-powered car, except at constant freeway speeds, when there is no electricity regeneration available.

Under those conditions, the EV is slightly worse based on the average emissions of electricity generators around the country, which Mr Olding said varied widely from state to state, with Tasmania being the best thanks to its large proportion of hydro-electric power and Victoria being the worst because its generators mainly use coal.

However, Mr Olding said he used the national average emissions of the power generation industry for the comparison, which left the EV comfortably ahead of the petrol car under most circumstances.

Mr Olding also stressed that electric vehicles had more potential in terms of improving their efficiency than do internal combustion engine (ICE) vehicles.

“The other point to make is we are comparing a first-generation proof-of-concept electric Holden Commodore versus a fully developed state-of-the-art petrol car,” he said.

In answer to a question after his address, Mr Olding said the tests showed that EVs are suitable for taxi drivers and others who do many kilometres a year.

“The earliest, smartest application of EV technology is in cars that do a lot of kilometres a year. It gives a return on battery investment and other investment.”A major saving for these operators would come in the form of minimal maintenance requirements.

Mr Olding said an ICE taxi doing 100,000 kilometres a year would probably need a $300 engine service every three or four weeks, which would add almost $4000 to its running costs.

“With an EV, there is no scheduled maintenance. These days, transmissions are sealed for life and the EV drivetrain only has two bearings, which makes it essentially maintenance-free.” The one caveat Mr Olding placed on the comparison between the electric Commodore and the ICE version was that the climate-control system was not used during the driving tests, which covered five different routes of varying speed, terrain and traffic conditions.

“The nice thing about an ICE vehicle is that you get your heat for free. There is no energy penalty when you turn your heater on.

“For an EV, you actually have to use battery power to generate the high temperatures to heat your cabin. Therefore that energy from the traction battery cannot go to moving the car down the road.

“The worst case is in slow driving conditions, where heating can take up to 35 per cent of range.”A switch to reverse-cycle technology, like that found in domestic air-conditioners, could cut the energy cost by 75 per cent.

Another area where improvement could be made is in the charging of the vehicle’s battery, he said. It is important that the recharging system should be a “smart” one, able to turn itself off when the battery is full.

“Managing the charging process is very important in achieving good overall electricity consumption and, hence, emissions and operating cost.

“If you plug your EV into a standard power point it wastes electricity because, at the end of the charge, it will still draw some energy, just like a TV on standby.

“If you plug in your EV on a Friday night and don’t drive it until Monday morning, you might consume 200W continuous power over that period, and that drastically alters your efficiency.

“However, plugging into a controlled EV charge point and having live communication between the vehicle and a charging network means the car can be powered-down once the charge is completed.

“Each of our EV Engineering Commodores has a telemetry link back to Better Place, for example, so that we can remotely monitor charging and make decisions about when to shut down charging.”EV Engineering is a consortium of car parts manufacturers (Air International, Bosch, Continental and Futuris) and other organisations (Better Place and GE) to design and build seven proof-of-concept battery-switchable electric Holden Commodores, using the V6 Holden Calais as the starting point.

Making good use of its easily swapped battery pack, an EV Engineering Commodore recently beat the world record for distance travelled by an EV in a 24 hour period, covering 1886km on a constant loop between Port Melbourne and Geelong.