We brought our solar plant online around 15-Nov-2024. It wasn’t until months after that that we got the house re-wired and started using significant amounts of solar, and the full transition off propane (originally powering the refrigerator, the water heating, and the cooking range) was a long and slow process taking many months. Still, if we take the full 484 days between first light and now, that’s about 28 kWh per day or 1.2 kW average power use. That seems about right. The house idles at around 400 watts but any time we charge the car, run the clothes dryer, heat up the hot tub, or use the hot water at the kitchen sink our usage goes way up.
As far as my goal of not burning anything for energy, we’re not 100% there but we’re close. I miscalculated badly on the amount of transportation energy we’d need, thinking we’d go into town only every couple of weeks but it ends up being more like three trips per week. I also underestimated how much energy it takes to heat water for the kitchen sink. I was thinking 1-2 kWh/day but reality is much closer to 3.
Is this bad? Not really. It means that we have to drive Timmy the Titan (a big diesel pickup truck) somewhat more than I’d thought and we end up having to use the backup generator when we have a run of rainy days in winter. We’re in the middle of a significant storm right now, so we’ve been burning 2-3 gallons of gas per day for the last few days. (What looks like grid input on the inverter display is actually our generator.) I think we’re close to the sweet spot of minimizing our fossil fuel use without radically overbuilding our solar plant, though I do wish I’d made it at least a little bit bigger.
Were we on the grid, we’d be paying about 53¢/kWh for energy. Yeah, it’s pricey here. The highest in the nation. That’s about $7,200 we would have spent for power. The actual energy-generating and storage pieces of the plant came out to around $25,000, so that’s a pretty good return. Even better, we got pretty much all of that $25k back as a tax credit which really makes it a good investment, but that subsidy is gone now.
In all, even without the tax subsidy, going all-electric and solar+battery is making economic sense for us.
—2p