Under the hood: the lowdown on EVs and low-emission vehicles
ACCORDING to a Climate Council analysis, transport is Australia’s third largest source of greenhouse gas emissions and have been increasing faster than any other sector of the economy. Cars are responsible for roughly half of all transport emissions.
In the UK, US, Europa and China, governments have been encouraging the development and rollout of electric vehicles (EVs) and hybrids. But Australia has been comparatively slow to adopt electric vehicle (EV) technology, with only about 4000 EVs on the road in Australia compared to 250,000 in the UK, for example.
Why do Australians still prefer petrol and diesel cars to EVs? Do the myths about electric cars, for and against, stack up? ECOS asked the CSIRO’s Dr Christopher Munnings, a senior research scientist with CSIRO Energy Technology who leads the Centre for Hybrid Energy Systems (CHES) in Melbourne.
What are EVs?
DR CHRISTOPHER MUNNINGS: You can think of vehicle technologies as a spectrum, starting with conventional petrol- or diesel-fuelled cars.
The Toyota Prius is an example of a conventional petrol-electric hybrid vehicle. They use an electric motor when pulling away or at low speeds and have a petrol engine that cuts in at high speeds.
From the petrol-hybrid, the next step is the plug-in hybrid which, in addition to regenerative braking for recharging the battery, can also be charged from the grid. With a plug-in hybrid, you can drive for the first 50–100 km just on electricity. Once the electrical power is used up, the car’s engine turns on and it works in the same way as a conventional hybrid.
Beyond the plug-in hybrid is an electric vehicle (EV) with range extender. A large 20–40 kWh (kilowatt hour) battery can do 80–90 per cent of your driving, while a small petrol or diesel engine turns on to charge the battery once it gets past a certain depleted level. The petrol engine never runs the wheels, it’s just a generator.
Then there’s the ‘pure electric’ vehicle. These typically have fast-charging capability. With a pure electric car and some electric cars with range extenders, you could drive for 200 km, stop at a fast-charging station for 20 minutes, and get about 80 per cent of your battery charged in that time.
Finally, a technology that runs parallel to the pure electric vehicle and that would be a replacement for a plug-in hybrid or battery-electric vehicle with a range extender is the hydrogen fuel-cell vehicle. Instead of having an internal combustion engine, it has a fuel cell and a fuel tank that you fill with hydrogen, similar to filling up with LPG or natural gas, and it takes about as long to fill up as a conventional car. The hydrogen fuel cell is best suited to vehicles that are weight constrained – such as garbage trucks and freight trucks – or for vehicles that can’t be charged overnight.
What about running out of charge?
CM: The technical term for that is ‘range anxiety’. There are no two bones about it, electric cars have a lower range than petrol or diesel cars, but what if you just filled your car at home every day, rather than at a service station every two weeks? How much range would you need?
That’s exactly what you do with an electric car, you plug it in and go to bed – every morning you have a full tank. Most people don’t drive more than 100 km in a day. That’s well within the range of EV technology – even ‘old’ technology from five years ago.
It’s still a bit scary buying an electric car, especially when it’s your only family car. Our family did three-and-a-half years ago. The first few months you get nervous every time the ‘fuel gauge’ drops below 50 per cent but after a while, there’s a change of mentality. If I’m about to go somewhere, I think, okay, that’s a 100 km round trip, so I need to have 100 km worth of range. You become more aware of distance but the fear subsides pretty quickly.
One of the challenges with low numbers of EVs on the road is the lack of public-charging stations. In the UK, there’s a fast charging station at every service station on the freeway – that pretty much kills range anxiety stone dead. An electric vehicle won’t just all of a sudden run out of power, you get plenty of notice, so if all you are worried about is a 20-minute unplanned stop, there’s not much to worry about.
Also, over the last five years, the price of batteries has dropped significantly. So now you can put a bigger battery in your car. The Nissan Leaf released in 2011 had a 24 kWh battery. By 2015, it had a 30 kWh battery and the next generation car on its way to Australia in the next 18 months has a 40 kWh one.
The EV industry is saying that long before 2020, it will have a 60 kWh hour battery. That means your range goes from around 110–120 km in 2011, to 250 km in 2018, to 300–350 km by 2020.
CM: Basically, one litre of petrol equals 10 kilowatt-hours (kWh) of energy. A Nissan Leaf with a useable battery capacity of 20 kWh has an energy equivalent of a two-litre fuel tank. That will allow it to drive for about 110–120 km.
So the EV’s efficiency is equivalent to about 1.6 litres per 100 kilometres – this compares to about 10–11 litres per 100 km for an average Australian car.
What effect will EVs have on the grid? And on consumer power bills?
CM: The first effect is on the high-voltage grid, the poles and wires that connect power stations to cities. The high-voltage network will not have any major issues with EVs – one million new EVs would increase our average energy use by just 2 per cent. It will take more than 10 years to get to that number, giving the grid time to expand in the places it needs too.
The second effect is on the low-voltage grid, the wires and 230V power points in your house. If you’re a domestic user, an electric car will double your electricity usage. But most of that will be off-peak, so that has big advantages for the grid because you end up shifting energy use to off-peak.
It’s good for electricity networks to have shallower dips and lower peaks. That reduces the comparative cost of the poles and wires because they’re used more effectively.
There are issues that will come from the fact that EVs have a reasonably high power-draw – about the same as an electric oven or split system air conditioner – and are sometimes parked a long way from where you would traditionally expect to find power.
Most EV drivers currently use a 10 A (ampere) plug socket in their garage. As batteries get bigger and people want to charge at home more quickly, they may need more power to their house, which will add to the upfront cost of a new car.
In terms of power bills for the domestic consumer, a Nissan Leaf requires 0.16 kWh per kilometre to run. At an off-peak electricity rate of 15 cents a kilowatt hour, if you drove 20,000 km in a year, you would be paying $480 annually in total fuel costs. A conventional vehicle that requires six litres of petrol to travel 100 kilometres at price of $1.30 per litre for petrol would cost $1560 a year.
Do EVs really cut CO₂ emissions?
CM: There are emissions from power generation, of course. The average emissions from the Australian grid is around 850 grams of CO₂ per kilowatt hour. So if you multiply that by 0.16, that gives your EV an average of 136 grams of CO₂ emissions per kilometre.
If you take a petrol-fuelled Corolla, you’re probably emitting 130–140 grams of CO₂ per kilometre. But the thing that isn’t counted in that calculation is the amount of CO₂ produced by making that fuel, then transporting and distributing it.
The long tailpipe analysis is where you look at where the electricity comes from. The idea is that even if you haven’t got a tailpipe emitting CO₂ in Melbourne, the EV’s ‘tailpipe’ effectively goes all the way down the power cable to, say, the Latrobe Valley.
One of the things that CSIRO is developing is a solar charging station using domestic household photovoltaic (PV) solar cells. That’s the ‘gold standard’ way of guaranteeing that your emissions are lower for electric vehicle than a petrol one.
Once you’re charging on renewables, the argument is pretty clear – an EV will emit less CO₂ over its lifetime than a regular petrol-powered car.
Let’s not forget that another important thing about vehicle emissions from petrol and diesel cars is that, in urban environments, they’re bad for the health of people living there.
Finally, what about the battery disposal problem?
CSIRO is looking at this. When batteries get to the end of their life, there’s two things you can do with them. One is a ‘second life’. You take the batteries out of the car, select the good ones and use them for another application, such as in the home, and send the bad ones for recycling.
Recycling EV batteries is a challenge. We’re working with battery recyclers in Australia to see how we can recycle them. While there are existing recycling programs, as with all new technologies, they’re not as developed as we’d like them to be.
If you’re interested in the world of electric transportation – such as a new VW concept EV that pays homage to the much-loved Kombi van, or the new plug-in TX London Black Cab with range extender – check out the Fully Charged Show on YouTube.