The Queensland owner of a Hyundai Ioniq 5 has kept his electric vehicle running costs for the month of September lower than the cost of a single litre of petrol (at current prices) by charging at home using mostly grid-sourced electricity.
Andrew Wilson, a self-confessed energy nerd who recently shared his learnings from four years of home solar and storage with The Driven sister site One Step Off The Grid, took to LinkedIn this week to share news on his battery on wheels.
“In September my home EV charger delivered 120 kWh of energy, enough to drive ~750 km,” Wilson writes, adding that while around 30 per cent of this came from his home solar system, the vast bulk – 70% – came from the grid.
“What was special about this month? It was the first being exposed to the spot price instead of a standard tariff.
“How did it go? The total cost of charging for the month was $1.90!
“That’s right – a month’s worth of driving for less than the cost of a SINGLE litre of petrol at current prices!”
Wilson is with the retailer Amber Electric, which charges a $19 a month flat fee in return for access to the spot tariff and software to manage it, plus smart controls via an app.
His charging set-up currently includes a 32A Wallbox Pulsar Plus, used in conjunction with the Charge HQ configured with Amber Electric real time pricing and a “simple charge below X threshold.”
The idea behind Amber’s retail offer is to incentivise customers to change their energy habits, including by consuming more during the middle of the day when there are ultra-low (and at the moment, often negative) grid prices due to rooftop solar flooding the grid.
As Wilson notes, the flip-side of being able to access the really low grid import prices is that there is effectively a charge to export solar at those times of negative grid prices. That is, you pay to be able to send your excess solar to the grid.
“This can be a big mental barrier, but can be managed by charging the home battery and shifting loads run during this time. As a last resort, rooftop PV production can also be curtailed to avoid negative prices (just like large generators do),” he says.
Amber’s exposure to the wholesale market also encourages customers to minimise their consumption during daily demand peaks in the late afternoons and early evenings, when prices are high.
Households with batteries can do this by using the solar power they stored through the day. They can also make a bit of money by sending their stored solar to the grid during peak periods.
“You’ll see [in the table above] that the majority of my exports took place in the early evening when export prices were high. This is due to the battery selling ‘spare’ energy to the grid during these periods while still leaving enough left over to get through the night,” Wilson says.
“This is the wholesale market price signal working exactly as designed – incentivising supply and demand to align as closely as possible.
All up, Wilson says his first month with Amber has delivered great results.
“[It’s] proof that incentivising consumers to respond to market signals can be good for the grid and lucrative for the consumer.
“And a good excuse for more roadtrips.”