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Add powerwall to existing system
- Thread starter ctopher2391
- Start date
Because of the unfavorable changes to the Net energy metering agreements that are going to happen.
At a high "TL ; DR " type of level, even if your proposed solar generates 100% of usage, that may not be enough to get a bill to go to Zero. Due to the way Time of use will likely work, with the value of the energy you put into the grid worth even less than it is now, having storage is the only way to hedge against that.
In (made up) more simple terms, if you counted a solar kWh as "beans", when you put in 1 bean earlier in the day, to withdraw that bean during peak time will cost you the 1 bean you put in, plus like 3-5 more beans as a cost. 1 bean in, = 4.5 as a cost when it comes back out. There will also be a charge just for being connected to the grid of X per amount of "beans" you can generate.
The only partial way around this is to not send your bean to them in the first place, but to store it in your garage and then use it yourself later (storage).
I am over simplifying, but like analogies. I would either prefer to store most of my beans in my garage to be used later or not sign up to get beans in the first place.
When you're doing this calculation for a rental property, you are going to be hiding some of the externalities of the electrical cost from your tenant.
Are you going to give them electricity included - i.e. increase the rent by a fixed amount, so that then you become the "bank" to smooth out the actual import/export over the year, or are you just providing it as a benefit that the renter takes advantage of.
The TOU rates will have more expensive peak costs, which we here understand and deal with, but your average renter may not appreciate that even though there is solar on the roof, they still have to cut back on summer AC usage 4pm-9pm to avoid expensive bills.
I can easily see it biting you back; the renter complaining that the electric should have been closer to zero, but isn't.
Are you going to give them electricity included - i.e. increase the rent by a fixed amount, so that then you become the "bank" to smooth out the actual import/export over the year, or are you just providing it as a benefit that the renter takes advantage of.
The TOU rates will have more expensive peak costs, which we here understand and deal with, but your average renter may not appreciate that even though there is solar on the roof, they still have to cut back on summer AC usage 4pm-9pm to avoid expensive bills.
I can easily see it biting you back; the renter complaining that the electric should have been closer to zero, but isn't.
jjrandorin - got it - totally understand and agree. I guess where I'm getting hung up is it's going to cost me ~$10K for a powerwall (12K + tax - incentive) and I think we are talking almost literal beans - the (mostly likely small, though growing) delta between what PG&E pays me for my excess energy and what they sell it back to me for. Given Solar will ineviatably (I assume?) put you in the lowest cost bucket, even if they credited me nothing, the surge pricing will be in the lowest use bucket, right? I.e. I think we may be talking about tens of dollars/month difference due to what you're rightly pointing out vs. an average bill of $150/month (reason to go solar vs. standard) and $10K today with little residual value (reason for no powerwall today).
@tomuo - I'm currently paying electric and gas for my tenants, so as long as they stay I'll be collecting any reduction dollar for dollar. I probably won't do that for future tenants, and will just say here's the monthly electrical cost since solar has been installed, so factor that into your calculus for what you can afford to pay in rent - i.e. you can expect electricity to be ~$15/month vs the $200/month you're used to paying.
I'm guessing you're in a type of situation where you have tenants rent rooms in a house so they can't split the bill? That's the only reason I could imagine why anyone would want to pay electricity for renters.
Before I had batteries, and pre-covid no work from home, I used like 75% of energy during peak times, and 25% off peak. So if you paid 2-3x during peak pricing when you are home, without batteries, you'll never zero out your bill just because you export at a lower NEM value vs. what you actually used.
That was partly my case for batteries because of ToU rates. Expect ToU rates to keep getting worst because I'd guess 95% of solar installs in the past had no energy storage. The utilities know this and will take advantage of consumers who can't work around using no power when the sun is not shining and you're forced to buy at whatever a utility charges.
@sunwarriors Nope - I offered to split utilities with them when they started the lease, and ultimately it became too much of a hassle dealing with sending them bills, so we just adjusted the rent to account for the past 12 months of utility usage. It does create a perverse incentive for them, but after they've been in my house for nearly 3 years, I got comfortable with the arrangement (and they haven't abused it). I won't do it for the next tenants, and will go with the more standard you take all utilities.
But you're (and JJ as well) right - very unlikely that I will zero it out unless I produce a lot during the day and don't use a lot during peak usage, but at this point I'd be happy to save myself (or my future tenants) $100/month, which I think should be highly do-able without batteries (I think?).
But you're (and JJ as well) right - very unlikely that I will zero it out unless I produce a lot during the day and don't use a lot during peak usage, but at this point I'd be happy to save myself (or my future tenants) $100/month, which I think should be highly do-able without batteries (I think?).
Depends on how the NEM 3.0 program finally shakes out, and if you can get installed before "whatever that is" is in effect. Unless you can guarantee you get installed before that (which I am not following super closely but think is currently proposed for end of may? someone will correct me I am sure), I would "re pencil out" any savings you think you might or might not be getting with PV, in California.
Yeah that's fair. I watched a video from a guy in Utah whose clickbait youtube headline was "I should not have bought a powerwall" and I think he articulated the argument pretty clearly: the utility is buying energy from him at exactly what he buys it for from the utility, so the powerwall is really just a backup generator. That price is going down to 40% over the course of the next decade, so it's going to start paying dividends, but I think my point is even if they cut it to 40%, which seems rapacious to someone getting 100%, it's still small peanuts enough vs. the cost of a powerwall (which I think will depreciate ~$1,000/year, $125/month, assuming a 10 year life) the math just won't add up.
Also I placed my order last night sans PW.
Also I placed my order last night sans PW.
Right now it doesnt, thats true.
Since they are talking about tearing up existing agreements right now, what you are looking at right now as far as implementing storage "later" has zero bearing on what that might or might not look like. We all signed contracts with NEM 20 year agreements, and they are talking about "changing that" even though we have signed contracts.
I don't think anyone believes PWs will simply stop working after 10 years so like a car after 3 years, it's still not worth $0 and it's a bit unfair to assume that even though that's the warranty period. It could be fine/useable for 20-30 years and if you/anyone lived in the home during a power outage (which seems like a weekly thing for bay area folks), you'd wish you had some battery storage simply due to the constant hassles.
@sunwarriors - Understood; that said the residual value (what you could sell it for) will probably be close to $0, especially if you actually tried to sell it because I can't imagine the price paid for a 10 year old PW - uninstall - installation cost with new owner for 10-year old tech/cells will be anything but $0. But you're right, in terms of value that it will provide to the homeowner, it won't magically go to $0 at year 10. Or even thought about another way, what value will the next buyer of your home ascribe to the 10-year old powerwall? $10K (nope). $1K (maybe?). $0K (probably).
Today, you can pick up a brand new powerwall (exclusive of shipping) for $8K-ish on the secondary market...I think previously used ones are $4-5K?
Anyway, tl;dr point is they depreciate in a not immaterial way, whereas the monetary value they contribute by smoothing out usage does appear immaterial (though growing off an immaterial base as you rightly point out).
Also, I'm in Palo Alto and I don't think I've had a power outage here in the last few years, and definitely never more than a few hours?
Today, you can pick up a brand new powerwall (exclusive of shipping) for $8K-ish on the secondary market...I think previously used ones are $4-5K?
Anyway, tl;dr point is they depreciate in a not immaterial way, whereas the monetary value they contribute by smoothing out usage does appear immaterial (though growing off an immaterial base as you rightly point out).
Also, I'm in Palo Alto and I don't think I've had a power outage here in the last few years, and definitely never more than a few hours?
I think with home prices what they are, similar to solar now, no buyer cares much about your pw compared to the cost of the house, if they're even lucky to get 'picked' to buy the house. Your case is unique because you don't live in the place you are considering solar nor get much power outages at...all that changes I feel if it's your own place.
On power outages, ask the folks in Placer County who were supposed to be without power for 2+ weeks? from someone's post here. But yeah, I'm in So Cal and my power is pretty reliable and I rarely get power cuts too. The ToU shift alone is worth it as my 75/25% shows though.
Back to the battery, is a 10 year old Tesla worth $0? If it still works, it has value and a 10 year old PW, I assume has value to people who lose power a lot.
Also, with install costs, complexity of batteries, they're a pain to deal with on a solar install (my opinion as I had issues...just so much more work).
I heard of folks with batteries and it made no difference. Not enough solar to recharge. So batteries in the winter might be good for a day or two, but that is it! Time to get the generator turned on.
Yes, well not everyone had snow sweepers to be able to clean their panels either.
I guess that I look at the constraints of an outage the other way around.
"Ok, the power is out, and solar has been averaging (say) 8kWh/ day, so we have to trim consumption to get under 8kWh to deal with an outage of unknown length?"
With overcast/smoke, the solar budget for us, at least, may actually be smaller than what we can achieve, and then, yes, back to generators.
I can tell you that both PG&E and AT&T were reporting being short handed because they had moved staff up into the Sierras to deal with downed lines.
All the best,
Peter
For me, it's really the sun or no sun. A few days ago, I hit ~35kWh (and another day 30kWh+) so being in So Cal, winter, with sun is very easy to push through. Last few days has been no lower than 15-20+ as well. Fires/smoke cover will be very bad, but I will probably research the cost for a generator hook up after this NEM3.0 is finalized and see what the terms will be.
Just nice to have options/flexibility if needed, but power has been pretty reliable here in SD.
Thanks for all your thoughts - I did go without a PW. My thoughts:
0. It does not make economic sense today.
1. At $12K, I think there’s a lot of “supply chain” pricing in there currently (when I priced my Solar Roof last year, the PW was included free).
2. Battery prices always go down (corollary to Moore’s law?)
3. There’s uncertainty about reimbursement for power pushed to the grid; once there is clarity and the economics of a PW is clear, adding it at that point (when hopefully prices have also come down) will be costly, but the free option between now and then seems to make sense because there is no guarantee that NEM3.0 or beyond will make the PW economic.
Other considerations that I will find out about also in the future:
Will tenants pay extra for solar?
Will they care if solar just reduces, rather than eliminates, their electrical bill?
0. It does not make economic sense today.
1. At $12K, I think there’s a lot of “supply chain” pricing in there currently (when I priced my Solar Roof last year, the PW was included free).
2. Battery prices always go down (corollary to Moore’s law?)
3. There’s uncertainty about reimbursement for power pushed to the grid; once there is clarity and the economics of a PW is clear, adding it at that point (when hopefully prices have also come down) will be costly, but the free option between now and then seems to make sense because there is no guarantee that NEM3.0 or beyond will make the PW economic.
Other considerations that I will find out about also in the future:
Will tenants pay extra for solar?
Will they care if solar just reduces, rather than eliminates, their electrical bill?
Merrill
Merrill
I wanted the powerwalls for the PSPS and other outages, had I not been able to get the SGIP incentive I probably would not have had powerwalls installed. I am running the house off the powerwalls from 4 to 9 peak, if I see that there will not be any sun for the next few days I just go back to Selfpowered.
Smart! I would never have gotten batteries if not for SGIP. I probably would have not have gotten solar without fed write off. I sure would not have gotten solar with NEM3!!!! My generator is the best bang for the buck for my whole house, IMO! May not be sexy, but works and no issues dealing with the government!!!
