Protect The Grid While You Charge Your Electric Car
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A recent report from Ergon Energy highlights the need for electric vehicle driver encouragement to charge intelligently to protect the grid. CleanTechnica has published many articles about grid resilience and EV charging installs. In my ignorance, I did not realise the complexity of the issue until I was contacted by Ergon and asked to identify a block of units where they were installing chargers. Ergon wants to study the effect of local charging hubs on local transformers. At the grid level, all is secure, but they are still trying to identify weak spots. I did not supply the information. There are other people far more qualified.
The EV SmartCharge Queensland Insights Report available here tracks the charging habits of 167 EV drivers over 19 months and makes recommendations for protecting the grid. Although it has been asserted that the UK, US, and Australian grids are quite capable of handing the power needs, there are some issues. The biggest one is timing the charge. If everyone has an EV and they all plug in during peak periods (4:00pm–9:00pm) while they are also running their electric stoves, there will be problems. Energy companies need to send a clear message — charge in the middle of the day from solar or charge at night. Treat your car like you do your hot water system.
While the world’s grids are still predominantly powered by coal-fired power stations, there will be cheap power available at night time. When that is not the case, the position will have to be reassessed. Just as there are people who forget to charge their phones or fill up their cars with petrol, there will be people who forget to plug in their cars, or plug them in at the worst time. We need to minimise that.
Ergon recognises that although EV penetration in Australia is slow, the potential is there for rapid adoption. Indeed, in the last 24 months, EVs have gone from less than 1% of new car sales to nudging 8%. Charging at home (most drivers’ preferred option) has the potential to double the electricity demand of a residential property. Ergon is concerned that EV charging may affect “localised parts of the network infrastructure.”
There are currently 18,704 EVs (excluding motorcycles) registered in Queensland. Ergon sees an opportunity in this: “Integration of this flexible EV managed load with the grid has the potential to greatly assist in stabilising system level electricity demand and support increased utilisation of renewable energy within the grid at all levels.”
EV volumes in Queensland. Copyright Energex Limited and Ergon Energy Corporation Limited. Used with permission.
Analysis of the data from the 167 EV drivers revealed that peak charging took place at home, at 1:00 am. This is likely in response to cheaper tariffs. Owners with home solar systems tended to charge during the day. Charging contributed 0.75 kW per vehicle during peak times. EV drivers tended to drive 20% more than ICE drivers. Charging frequency decreased during the study as drivers became more comfortable with the range of their vehicles. The report concludes that EV charging can be very flexible and be managed for the owners’ benefit.
Driver charging behaviour was found to be smart (responding to tariffs or using home solar) and responsive. People were willing to learn. As more EVs enter the system, more charging options will become available — for example, in parking stations for commuters and work-based charging options. These will be able to take advantage of the solar surge during the middle of the day.
“The research also uncovered some challenging charging behaviours that could cause network issues locally in the short-term (should EV ownership clusters evolve due to demographic influences on distribution transformers) and potentially significant medium to longer term network issues, unless managed.” Administrators are facing a lot of unknown unknowns!
The report seeks to educate the general public by listing charging levels and by describing the types of electric cars.
Selection of electric vehicles at the recent Coffee Cake and EVs event in Bracken Ridge, Queensland. Photo courtesy of Majella Waterworth.
“Charging levels:
Level 1 charging — up to 15 Amp (approx. 3.6kW) Level 2 charging — greater than 3.6kW and
equal to or less than 22kW
Level 3 charging — greater than 22kW and equal to or less than 50kW
Level 4 charging — greater than 50kW
Level 1 and 2 charging is predominantly home charging, whilst Levels 3 and 4 is destination and highway (fast or ultra-fast DC public charging).”
Most drivers in the study came from South East Queensland. Most were also early adopters and had solar installed on their rooftops. Some had battery backup systems at their homes. Most lived in detached houses with a dedicated home charger.
A further study should include EV owners living in apartment buildings. I would expect this to reveal quite a different pattern of charging. Ergon is on the lookout for uneven take-up of EVs across suburbs, clusters of dense penetration, and dumb charging. They name that “coincidental convenience charging.” Ergon has modelled that coincidental evening peak charging would average 1.5 kW per EV.
“BEV large vehicles will continue to have the most significant charging requirements for the grid to enable, with annualised consumption on average of 3,990kWh per vehicle.”
The study highlights that for EV drivers: “Charging EVs became part of the total home energy management routine for those who had a home battery and solar PV. There was a clear preference to avoid using the grid and leverage solar power to charge EVs and home batteries and a common charging behaviour of ‘topping-up’ the EV battery to meet travel requirements for the next day, with an allowance of additional kilometres as a ‘safety buffer’.”
In an attempt to discover the ability to modify charging behaviour, Ergon invited 60 participants to be part of the trial. A financial incentive was offered for those who charged when instructed — so as to avoid peak hour, and to take advantage of solar power. Participation was designed to be easy and not to interrupt their daily lifestyle.
“Participants were highly responsive and willing to change their charging behaviour with incentives provided. Greater than 90% of participants reached the capped threshold ($150) demonstrating extremely high participation in almost all events by all participants.”
Will these behaviours continue for the mainstream adopters to come? Can energy providers adapt the process for the mass market? Will new EV drivers shop around for cheap power, just as they now shop around for cheap petrol for their ICE cars? Australia’s electricity providers hope so. This is the best way to protect the grid.
A future study could concentrate on Tesla owners (more than 60% of EVs on the road are Teslas) and make use of data provided by the Tesla app. The biggest issue is obviously managing EV charging behaviour — more than improving the grid. With power prices in Australia set to increase by about 30% in June, there will be even more incentive for EV owners to be smart about how they charge.
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