How an EV helps the environment

After a long dalliance with climate change denial, Australians seem once again concerned about rising temperatures and freaky weather – which could be something to do with floods in Queensland and bushfires in Tasmania... at the same time.

But many Australians remain reluctant to admit that sales of electric vehicles on a large scale could have any sort of impact on CO2 (carbon dioxide) emissions. At a barbecue or dinner party the lines of demarcation are very clear, and few sit on the fence.

You're either a believer or a sceptic.

In theory, electric cars are zero-emissions vehicles. In practice it's not that simple, critics say; the 'whole of life' CO2 emissions need to be taken into account in any discussion of the merits of EVs.

Let's be frank about it, mining of brown coal (any coal, for that matter) and lithium does diminish the environmental benefits of electric vehicles. In an ideal world there would be no power generation from coal, but that's not to say there's no benefit at all from operating EVs – it's just that the benefit is incremental and delivers with greater sales volumes.

CO2 (carbon dioxide) emitted during production of an EV is actually discharged in higher volumes than for conventional models powered by internal-combustion engines.

In a 2011 report from engineering and environmental consultancy Ricardo PLC the CO2 footprint of a typical EV was estimated to be 18 tonnes over the whole of its life.

The report estimates that as much as 8.8tCO2e (8.8 tonnes of CO2 emitted) goes into the production of the EV. That equates to 46 per cent of the car's whole of life carbon footprint before it has even left the manufacturing plant.

In contrast, according to the same report, building a conventional petrol-engined passenger car of medium size results in just 5.6tCO2e (5.6 tonnes of CO2). Most of the difference between the two types of vehicle is due to the lithium-ion technology to store electric power.

In response, supporters of EVs admit that manufacture of EVs is carbon-intensive, but as the vehicles produce no direct CO2 during their working life, the overall CO2 volume is 18 tonnes -- six tonnes less than the conventional car mentioned above.

Toyota's manufacturing plant for the Prius range of hybrid vehicles uses solar panels on the roof to generate power – and the Prius is somewhat cleaner over the whole of its life than similarly-sized rivals as a result of that.

In fact, Toyota claimed at the launch of the third-generation Prius that after just 20,000km of driving the scales would tip in favour of the Prius – emitting CO2 at lower levels across the whole of life from that point than a conventional car of similar size.

According to other reports, an all-electric car (as opposed to a hybrid) would have to travel up to about 120,000km to offset the CO2 produced during the manufacturing process.

At around 15,000km a year on average – which might be considered an excessive figure for short-range, city-focused runabouts – that means eight years of driving just to offset the CO2 produced during manufacture.

The Prius uses nickel-metal hydride – not lithium-ion – battery technology to store electric power and the storage capacity of the Prius is only rated at 1.3kWh, because the Prius relies heavily on its internal-combustion engine for motive power.

On the other hand, the much larger lithium-ion pack of even the low-power 60kWh Tesla Model S is bound to result in a lot more CO2 expelled during the manufacturing process. Most plug-in hybrids (PHEVs also employ lithium-ion battery tech.

Vehicles – not just the electric kind – are transported across the world from the manufacturing plant by diesel trucks and on ro-ro vessels (roll-on/roll-off container ships) that sail for weeks at a time between the port of departure and their destination.

More CO2 is produced by trucks transporting the vehicle from the destination port to bond store and then to the local retailer. The shipping industry is known to be looking at ways of offsetting its carbon emissions.

Many argue that the vehicle that emits the lowest level of CO2 is one that has already been on the road for 10 years. Its carbon footprint has been in steady decline ever since it left the factory.

If there is a retort to the argument that used cars are environmentally the cleanest in the long term, it's this: allow an electric vehicle the same longevity in regular road-going use and the CO2 produced will be lower still.

Sooner or later – usually sooner – critics denounce EVs on the grounds that they contribute to CO2 pollution just as much as conventional cars.

Electric cars, according to the critics, are recharged using power generated (in Australia, particularly) from coal-fired power stations, well-known producers of CO2. Drawing on electricity generated by coal is no better than a conventional vehicle powered by an internal-combustion engine, the critics say.

Even if the electricity is sourced from coal, electric motoring in Australia is already cleaner than driving a diesel or petrol-fuelled machine, says Tim Washington, Director of JET Charge.

"Your EV gets cleaner as our electricity network transitions towards renewable energy.

"The great thing about all of this is that for most people, who buy EVs for economical and performance reasons, the environmental benefits just happen in the background. You get to contribute to cleaning up your country's air, and ensuring fuel security to boot, just by driving."

Back in 2009, for a media event showcasing the Mitsubishi i-MiEV, an expert told local motoring journalists that the tiny Mitsubishi would be no cleaner to run in Victoria than the third-generation Toyota Prius, an energy-efficient hybrid that was new to market at the time.

Things have changed since then. The very dirty Hazelwood power plant has closed in Victoria and renewable sources of energy are now cheaper and more prolific than traditional means of power generation.

Currently up to 20 per cent of the energy needs for the Australian market are supplied by renewables. The other 80 per cent of sources are a mix of coal and gas.

But by 2025, according to ANU renewables could account for up to 50 per cent of power generation in Australia, as long as the country's record-breaking progress continues.

As more renewable energy comes on line, the dependence on coal-fired power for electric transport will diminish.

Research by BloombergNEF has revealed that in some markets a vehicle solely reliant on an electric motor for its drive system can be up to 40 per cent cleaner than conventional internal-combustion cars. That is driven by the growing trend to renewable energy available to recharge them in any given market.

The cost in terms of CO2 production to replace the battery pack in an electric vehicle is another factor in the whole of life CO2 figure for an EV.

If the battery fails outright, or gradually loses its ability to hold charge as it ages, the only known fix currently is to replace it, which raises the whole of life CO2 figure once again.

But old batteries can be recycled and reused in stationary power storage (ie: not for electric vehicles), and cars like the Tesla Model S use thousands of cells, not all of which necessarily have to be replaced at the same time.

So the whole of life CO2 may climb again to a new peak when batteries or individual cells are replaced, but immediately thereafter the CO2 emissions for the individual vehicle begin to drop back again, with each passing kilometre.

The life of batteries will vary in accordance with the recharging regime, the size of the battery and the long-term operating conditions. Larger batteries, as in a Tesla, for instance, will tend to last longer than that of an i-MiEV, because the Tesla won't need to be recharged as often.

"Most manufacturers have an exceptional warranty on their batteries – with around eight years [and] unlimited kilometres warranty being the standard," says Tim Washington.

"Battery degradation happens – but nothing like your phone. EVs have much better battery management systems that maximise the health of the battery."

Owners have been reporting degradation of up to about 10 per cent in the Tesla Model S after 160,000km, reports one online publication.

The assumption from all this is that, at present, EVs are only a marginal improvement on internal-combustion cars already on the road in terms of CO2 production.

However, the 'internal-combustion cars' already on the road that produce fewer CO2 emissions than an i-MiEV or a Nissan LEAF are either light hatches and micro-cars, or a hybrid like the Prius or a plug-in hybrid – which is essentially electric anyway.

And neither automotive technology – including batteries – nor recharging infrastructure will tread water over the coming years, so the transition to electrification will help the environment, but the biggest contributing factor will be wider acceptance of the technology from consumers.