lokisnow Posted May 6, 2019 Share Posted May 6, 2019 (Thread title sung to “riding solo” Jason derulo) so my house is probably going solar because the 30% ARRA subsidy is phasing out after this year and the Tesla power wall subsidy is in the middle of a phase out. We live in California, in a suburb of Los Angeles. and the price of solar panels has dropped 90% in the last decade, so it’s become much more affordable. the financing is quite interesting, you finance 70% of the system on a 3-4% loan for a period of 12-20 years, and your monthly payment that was your electric bill basically becomes your solar system bill. The remaining 30% is financed on an 18 month 0% interest loan that you pay off in full when you receive your tax credit the next year. at the end of the year though settle up with your utility, they credit you for extra power you’ve sent to the grid and charge you for power you’ve taken from the grid. You can combine storage with solar and it just folds in to the overall package price, which makes it eligible for the 30% tax credit as well, there are cash rebates from the state to further reduce the cost of storage. We are probably going with a Tesla power wall 2. Storage takes you even more off the grid, though enough electricity is not stored to charge a car. Averaged over a year, we use about 30 kWh of electricity a day (but about 40-50% of that is overnight car charging.) giving us a bill in the non summer months of about $200 per month. Obviously that can go up a lot in the summer with AC usage, peaking in the $350-400 range. If you break down the figures in more detail, our car charging is about 30-40% of our annual usage. We drive about 1600+ miles electric per month at a cost of about $100 per month so a per mile cost of $0.0625 (this is my high estimate). but when we go solar we change to a “time of use” fee structure so the cost of overnight car charging would drop by half or more (we could do time of use now but the best way I’ve figured the math is that the rates for day time electricity are high enough that with a working from home situation we would either break even or pay 10-20% more if we switched) We got a couple bids for solar, one for 24 panels, which would generate enough power to zero out our “annual” usage, this had a final installed cost with everything (24 microinverters etc) of about $24000 or a monthly payment of about $167 over twelve years. But the caveat here is that they are probably overselling us as they’re just bidding on annual electricity usage which doesn’t really account for 30% of our usage being car charging. we also got a bid for 18 panels with a Tesla power wall 2 at $193 per month over 12 years ($150 / month @ 20 years). And we had them calculate us a bid at 18 panels but no storage which comes to $135/month @ 12 years or $106 / month @20 years. It’s pretty exciting to be pulling the trigger on solar right now, much more affordable than I ever expected. I think we’ll try and get one more bid and also do some more research on panels/inverters as well try to better calculate our exact needs. I’d rather not overbuy too many panels but under buying would also be a mistake. Does anyone know of any resource (that isn’t a solar installer/retailer) that helps you calculate your actual panel needs? This seems to be the trickiest area to figure out and my sense is that with panel prices having fallen so fast so much that overbuying is probably a more common mistake in 2019. Anyone done solar plus electric car charging, hows that impinge on the amount of panels you need? How about experience with solar plus storage? My concern would be that if we are sending excess solar power to charge the battery and then using the battery at night (except for car charging) that would greatly reduce the night time electricity we are buying but would also reduce what we sell back to the grid in the daytime, reducing our credits we accrue in the non summer months. Then when we inevitably go over in the summer because of the AC, we will build up a fairly large electric bill that won’t be offset by enough credits. Or am I just totally off base with that hypothesis? Link to comment Share on other sites More sharing options...
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