Recently we looked at the seasonal solar problem, namely that solar production is at its highest in the summer, but my energy usage peaks in the Winter. As we saw, for now, there is no problem, as I am somewhat of an outlier, and my excess electrons deliver lots of value for Ontario’s summer peaking electricity profile (source). Lets look a little more short term, as we will see, batteries are a great way to cover energy usage during the night.
Looking at my Tesla app, during the night, my house uses anywhere from 10-50 kWh of electricity. Much depends on the EV, as electricity prices are cheapest at night, thats when I charge. If I wanted to go full-solar, well I suppose I would charge during the day on sunny days. Something I used to do before I obtained export permission from my utility.
We like to sleep in a cold space, hence the heatpump is not as busy in the winter, but the airconditioner works hard during the summer nights. Without the EV, the upper end would likely be closer to 20 kWh. So lets say we need to stash 15 kWh for use during the night. Why my powerwall 3 almost covers that, at 13 kWh of rated storage, I suppose I could stretch it a bit and make it through the night on solar power generated during the day.
Indeed, for powerwall 3, a DC expansion pack is now available, which adds storage capacity in units of 13 kWh to a powerwall 3 system (source). Plenty to make it through the night, and if you need more, it is available at a reasonable cost.
Should Toronto’s grid get more solar heavy (currently about 0.5 % of Toronto’s electricity is solar, compared to 18 % in Australia source), all I have to do is reconfigure my powerwall 3 to take advantage and charge up during the day, collecting enough electricity for me to make it through the night.
My EV could also be charged during the day. My 2018 Nissan Leaf, has a simple charge timer, which works perfectly to ensure that you leverage cheap power whenever you can get it. Further, my hot water tank also has a schedule feature (source), something I use to lower my energy bills to the extent possible.
Alltolt, the day-night problem is not a large headache. Your EV and your appliances might have schedule features that allow you to take advantage of whenever cheap power is available where you live. Further a home battery system, such as the powerwall 3 can easily bridge whatever gap remains.
Electric car adventures 