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 by the Distributed Energy Resource Laboratory (DER-Lab). 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. So this approach could be called V2S: Vehicle to Shed. Add solar panels to the roof for Silicon Shed. ;-) The corrugated steel roofed shed was made a design icon by architect Glenn Murcutt, with his Lerida Estate Winery building outside Canberra.

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 V2G is an example of where technology works, but how do you get people to use it? What type of interface will make V2G 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? Does the car owner need a cash incentive to plug in "Plug in now and receive a $5 cash bonus".

A problem with V2G 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 peak demand), 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 (something as simple as an ordinary power point). There would be a cost in installing 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 one quarter of homes with their own solar 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 half of Australia's homes with PV panels were each plugged in to a vehicle providing 20 kWh of storage for the grid, that would be 20 GWh in total. This is one hundred times the capacity of the SA Big Battery (officially known as the Hornsdale Power Reserve). 

However, V2G also presents a challenge to the current energy providers. With enough storage for several days use, available essentially for free, a household could decide to provide its own energy from their rooftop solar for all but a few days a year. Energy companies will receive no revenue from selling energy for most of the year, as it is used is "behind the meter", but then have to provide on demand for a few days. Companies will need to provide households an incentive to have their batteries for part of a grid system.


  1. Delighted to have had my electric Ute to Shed proposal included in the Expert Reaction to the US Climate Summit 2021 from the Australian Science Media Centre.

  2. The V2G shed might incorporate a home or neighborhood battery. Both the battery and car charger need high capacity cabling and a data connection. These could be shared in the one structure.