How free midday power has changed my EV charging and home heating habits

I recently signed up to Ovo Energy’s Electric Vehicle Plan and thought it would be interesting to compare my consumption before and after the switch.

The plan is a Time of Use tariff with strong price signals, largely:
✅ Free 0c/kWh 11am-2pm
✅ Cheap 8c/kWh electricity 12-6am

Other times are a fairly standard peak and off peak rate and there is also the standard daily supply charge.

The chart shows my average consumption for the two weeks before and after the switch, aggregated into 15-minute blocks. The difference is clear.

Heating and any EV charging are now concentrated into the free 3-hour window in the middle of the day. Loads such as cooking dinner are harder to shift.

I overheat the house by setting the heater to 22°C. While the house may not always reach this temperature, it gets enough heat into it to not need any more heating for the rest of the day. It’s usually still 19°C or 20°C in the evening.

We haven’t had any really cold days yet, if we did I suspect it might be necessary to run the heater again later in the day. Similarly, so far I’ve resisted putting the heater on before 11am but that may change.

This is a well-designed tariff with a very clear price signal. That helps me as a consumer: the heating is now on a timer to run between 11am and 2pm every day.

I have also set the EV charging to run on solar if available, else run at the max 15A charge rate between 11am and 2pm. I currently manage this using ChargeHQ, but since Ovo is powered by Kaluza I can also set up this orchestration through my Ovo app, without the need for a 3rd party product. This will be something to try next.

Average daily consumption has increased from around 20 kWh/day to  around 30 kWh/day, but the house is definitely more comfortable. It can be a little chilly before 11am though!

Thoughts?

See also: The substantial savings from optimised, high renewables, home EV charging

And: How to optimise home EV charging to soak up rooftop solar and overnight troughs

Gavin Mooney is General Manager Australia at Kaluza. Republished with permission from his LinkedIn post.