Storage and electric vehicles may be slow to take off but the CSIRO is looking far ahead to understand how the technologies can be best absorbed into daily life, senior research scientist Dr Christopher Munnings tells EcoGeneration.
The way energy is generated and used will always change. The more that’s supplied, the more uses we will find for it. We live in a world where plentiful energy is frittered on fanciful luxury that would never have been dreamt of only a few generations ago. If generation from renewable energy sources is built out to replace the polluting variety, we can carry on a comfortable existence without too much anxiety. The transition will be very complex, with a few surprises along the way, no doubt.
Solar has pushed ahead as a viable solution, with rooftop applications appealing to Australians’ DIY spirit. The obvious problem is that PV’s generation profile is almost a perfect opposite of overall demand. Storage of solar energy for later use, then, is a primary problem – and the nation’s science lab, the CSIRO, is onto it.
As batteries slowly become part of the energy landscape consumers will need to understand how to compare the different brands and technologies, says Dr Christopher Munnings, the senior research scientist who leads the centre for hybrid energy systems at the CSIRO’s high-efficiency thermal and electrochemical technologies group in Clayton, Melbourne.
There are two lifetimes with a battery, he says: calendar life and cycle life. It’s unlikely the battery in a car will be cycled as frequently as a battery connected to a residential solar system, so the battery in an EV can be expected to last quite a long time, he says. A battery that reaches the end of the calendar life of a car – 10 to 15 years, say – may have another five years of good cycle life in it, for a lower-powered application like a household. (Batteries in EVs are much more powerful than the typical-sized residential unit.)
More storage on the way
In Australia, EVs are in the very early stages of adoption. No-one really can predict how drivers here will use EVs and what their charging behaviour will be, so it is far too early to estimate how much life will be left in EV batteries after 10 to 15 years or so. Some owners may hold on to older EVs that have suffered less wear and tear than petrol equivalents and make do with lower range and power.
“They might run the battery right down to the point it has very little usable life left in it,” Munnings says. Others will decide to swap out the battery pack and keep driving the same car. In that case, EV batteries with plenty of life left in them will be looking for a new job.
“There are going to be a lot of EV batteries around in the future, so we have to understand how to recycle them and if there is any second life opportunity.” The copper, aluminium, graphite and cobalt and nickel in batteries makes them valuable to recycle, but they must be presented to recyclers in a safe state and stored at collection points without risk of fire.
Other work in Munnings’ inbox includes looking at second-life applications for electric vehicle batteries, including putting them to use in residential systems. “At the moment it’s early stage,” he says. “But that’s one application that would certainly make sense.” Most EV battery packs include modules that resemble “giant tuna cans”, each about 0.5kWh, and it may be possible for five or six of them to make up a battery pack that would satisfy many households.
Munnings is also contributing to work on the Australian standard for battery performance, to set down parameters for power rating, definitions for a cycle and what to expect of a battery at the end of what the manufacturer defines as its lifetime. The standard will mainly cover small-commercial and household batteries, he says, and use temperature tolerances more relevant to Australia than some international equivalents.
“Most of the [residential] products coming through – and there are always going to be exceptions – are relatively safe to operate under Australian conditions,” he says. “The challenge is, are they going to give you the performance you expect? That’s where we are doing a lot of work with this standard, to try to define the test methods that will allow you to see that.”
After all, there isn’t much point buying a battery to power air-conditioning on very hot days if the battery can’t cope with the heat – even though the brochure made you think it could. The same stringency will need to apply as residential batteries are employed to top-up EVs on hot days once the sun’s gone down.
On the road
The CSIRO last year released results of work it had done with battery and inverter manufacturer Delta to optimise EV charging using solar PV and stored solar rather than deferring to the gird. “The system will typically mean that you’re charging your car over 80% with solar or solar and battery, so the emissions from your vehicle will be lower even if you are on the dirtiest part of the grid,” Munnings says.
A method of pre-emptive queuing for charging is being trialled as a solution for apartments with shared power boards that are less suited to rapid charging and heavy loads, where EVs that require less of a top-up will have priority over those requiring a deeper charge. The solution allows up to four charging stations to be plugged into a single hybrid inverter.
Fast-charging in remote areas is a difficult problem to solve, “because you need a lot of power fairly infrequently – and that makes it quite an expensive installation.” As EVs replace old-fashioned petrol-propelled rolling technology around the country more drivers will pay to use remote infrastructure and it will become “reasonably” self-sustaining.
A million EVs should add a few percentage points to total electricity demand across Australia, he says, which isn’t too much of a concern. The trick will be orchestrating owners’ charging behaviour to ensure everyone doesn’t plug in at once. “That sort of issue is a decade away,” he says.
Australia is leading the world in adoption of solar and storage, he says, but we are proving to be sluggish converts to EVs. It’s hard to change the way people value energy.
“Generally a consumer will buy the biggest car they can afford or the biggest house they can afford,” Munnings says. “That kind of behaviour is a challenge in the energy world.
“People will be very reluctant to put PV on a brand-new house they’re building but they’ll be happy to blow an extra $20,000 on the kitchen or bathroom.”