Agency holds high hopes for electric cars

07:39, Jun 21 2012
CLEAN CAR: Nissan's electric-powered LEAF.

The Government's energy efficiency agency is upbeat about the role electric cars can play in lifting the amount of renewable energy used to power transport in this country.
That is despite widespread doubts that electric vehicles will be able to meet the high hopes held for them anytime soon. Among the issues confronting electric vehicles is the distance they can travel between recharging, the time taken to recharge, and cost.

The four-seater i-MiEV electric car is around $60,000, while the five-seater Nissan Leaf is about $70,000.

A presentation to an electric vehicle workshop in Wellington this week showed transport accounted for around 200 petajoules a year of the energy used by consumers in New Zealand, while electricity was a little under 150PJ.

Energy Efficiency and Conservation Authority transport partnerships manager Elizabeth Yeaman said that while 75 per cent of the electricity used in this country came from renewable sources, very little of the energy used in transport did.

A goal of the transport partnerships is to increase the amount of renewable energy used in transport.

Nearly 60 per cent of the energy used in transport was in light passenger vehicles, and that was the main area where the greatest potential was seen for electric vehicles, Yeaman said.

The excitement was not just because oil could be substituted with 75 per cent-renewable electricity, but also because electric vehicles were much more efficient than petrol or diesel vehicles.

With petrol or diesel-fuelled vehicles, most of the energy was lost as excess heat.

"That's the reason you have radiators in cars, you have to get rid of the waste heat … An electrical vehicle doesn't have a radiator, and much more energy goes into turning the wheels," Yeaman said.

While the oil price had fluctuated and no one could predict where it would go, the long term trend was for the price to go up.

In contrast, the price of electricity was much lower and more stable.

Ministry of Economic Development figures put the price of petrol around $50 per gigajoule, rising to around $100 by about 2030. In comparison the wholesale electricity price is expected to rise from around $25 to $30.

To illustrate the difference in running costs, an energy efficiency label like those used on cars when they were being sold had been prepared for the four-seater Mitsubishi i-MiEV all-electric vehicle.

It showed the annual cost of energy for the electric car to be $280, compared to $2020 for a typical compact car.

The comparison was based on both vehicles travelling the same distance, Yeaman said.

She acknowledged electric cars were "a bit pricey" now, but said the cost was expected to come down in time, although it was not known how fast that would happen.

Also electric cars were more like luxury cars, than more standard cars in their size range, she said.

All-electric cars had only entered the market in this country this year, and about 60 had been brought in so far.

There are also hybrid electric vehicles, including many of Wellington's taxis, which combine internal combustion engines with electric propulsion. Energy that would otherwise be wasted is also used to recharge the vehicle's batteries, including the energy used in braking.

With plug-in hybrids, the first of which could arrive in this country by the end of the year, the battery is charged by both an internal combustion engine and by plugging into a standard electrical outlet.

Yeaman is confident electric cars would work for many people in this country already.

Ninety per cent or cars were driven less than 85km a day, which was well within the range of all-electric cars on the market..

Electric cars could be charged from a domestic supply. In this country 85 per cent of homes had garages, and a full recharge would take seven hours.

"While sleeping you can plug in," she said.

She was also hopeful that the 52 per cent of households with two or more vehicles, could have at least one that was powered electrically.


Fairfax Media