Thursday, April 8, 2021

Will an Electric Ute Plugged into a Shed Save the Australian Electricity Grid?

Car charger at ANU
On my way to the cafe opposite my office at the Australian National University this morning, I stumbled across a new shed, holding the future of Australian motoring and perhaps the salvation of our electricity grid. This shed holds an electric car charger, as part of a vehicle-to-load (V2G) trial. Not only can an electric car be charged, but the energy fed back to the grid later.

I like the very understated, practical and Australian style of the ANU charging station. It is a plain grey steel shed, with a corrugated steel roof, like a rural bus shelter. The corrugated steel roofed shed is part of the Australian ethos. So this could be called V2S: Vehicle to Shed. ;-)

Using a car to power the grid might seem a waste of money: why not just buy a stationary battery? However, range anxiety, along with Australians love of large vehicles, plus business finance and tax deductions, may come to the rescue of the grid.

The average commute is less than 40 km per day, but consumers are demanding electric cars with ranges of more than 200 km. Drivers worry that they will run out of energy and be stranded (so called range anxiety). So the electric cars will have excess battery capacity which could be used to store energy for a home or the grid.

Some newer vehicles come equipped with a plug to not only charge the car, but also return surplus energy back to the household (V2H), or the grid (V2G). A medium sized electric car has sufficient battery capacity to power the average Australian home for a day and still have more than enough power for the daily of commute. This could be particularly useful in Canberra, which has net renewable energy, but limited storage.

The question then is, having purchased an electric car with far more battery capacity than needed day to day, can you convince the consumer to make the surplus capacity available for the grid? One of my students is researching how to Cut City Air Pollution Using ICT.

The use of V2L is an example of where technology works, but how do you get people to use it? What type of interface will make V2L practical? Does this just need a button on the charger to request a top-up for extended driving, or does there have to be an app, where this can be scheduled? Could the system check the family's online schedule and predict when the car will be needed? 

A problem with V2L is ensuring vehicles are plugged into be charged. Peak solar power is produced in the middle of the day, when a commuter's vehicle will not be at home. However, I suggest the vehicle could be plugged in at home, charging overnight from wind farms. After providing power for breakfast (the morning demand for power), the vehicle would be unplugged for the drive to work. Arriving before the mid-day solar peak, the vehicle would spend several hours charging. As the sun sets, the vehicle would be unplugged to be driven home, where it would power the evening peak demand. 

This scenario would require two charging stations for each vehicle: one at home and one at work. It has been assumed that domestic chargers could be low current, as they can charge overnight, whereas public charging stations require high current for driver convenience. An alternative would be to have a higher capacity V2G station at home and a lower capacity, lower cost, charge-only station at work. There would be a cost in installing and maintaining the chargers, and a problem if drivers wanted to use their car at lunchtime, which is the solar peak.

There has been some concern that electric cars would not suit Australia conditions, where large vehicles with long range are needed, as exemplified by the trade's Ute.  However, the world's largest, most powerful land vehicles are electrically powered and several companies are preparing large SUVs and Utes for sale. The large batteries in these vehicles could power a home for several days and offer a solution for grid storage.

Australia folklore has it that the Ute was developed for farmers to take produce to market during the week, and the spouse to church on the weekend. Dual cab utes are now very popular to take tools to work during the week and carry the family's sporting equipment on the weekend. What is less well know are the financial reasons for the ute: classified as a business vehicle the farmer could get a business loan for it. So will today's tradie buy an electric ute with V2G, using a business loan, and tax deductions? This could be called U2G: Ute to Grid, or U2S: Ute to Shed. ;-)

Before dismissing the idea of a ute powered grid, consider that Australia leads the world in solar panels on domestic rooftops. While other countries had policies for large solar farms, Australia almost by accident, has individual householders installing their own panels. Having shown a willingness to invest in home energy, will the same householders embrace V2G, to the extent needed to support the grid?

If 8 million of Australia's 20 million motor vehicles were plugged in with V2G, to provide 25 kWh of storage each for the grid, that would be 200 GWh in total, which is one thousand times the capacity of the SA Big Battery (officially the Hornsdale Power Reserve).

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