Anyone regret having a Powerwall installed?

[KSilver2000]

Tottally happy. In our experience they have improved the efficency of our panels three fold. Before the battery 3/4 of our solar production just went to the grid.

Not following how your panel efficiency went up 3x.

Are you not in a utility that provides NEM?
If so, wouldn’t it be better to send all peak surplus to the grid and make use of the cheaper off-peak rate at night? It’s a 4x difference in PG&E land. Roughly $0.55/kWh peak rate (makes driving an EV more expensive than ICE, lol) and $.13/kWh off-peak.

So, to the OP, having solar panels in PG&E land with NEM, you’re not getting anything out of a Powerwall besides expensive blackout protection.

 

[Odiemac]

Not following how your panel efficiency went up 3x.

Are you not in a utility that provides NEM?
If so, wouldn’t it be better to send all peak surplus to the grid and make use of the cheaper off-peak rate at night? It’s a 4x difference in PG&E land. Roughly $0.55/kWh peak rate (makes driving an EV more expensive than ICE, lol) and $.13/kWh off-peak.

So, to the OP, having solar panels in PG&E land with NEM, you’re not getting anything out of a Powerwall besides expensive blackout protection.

PG&E is rapidly raising prices and monkeying with EV-A to provide less NEM value to solar owners, not to mention instituting public safety blackouts. So the Powerwall decision for us came down to “how much do we trust PG&E over the life of the batteries?” For me, the answer was “not at all”

 

[miimura]

Not following how your panel efficiency went up 3x.

Are you not in a utility that provides NEM?
If so, wouldn’t it be better to send all peak surplus to the grid and make use of the cheaper off-peak rate at night? It’s a 4x difference in PG&E land. Roughly $0.55/kWh peak rate (makes driving an EV more expensive than ICE, lol) and $.13/kWh off-peak.

So, to the OP, having solar panels in PG&E land with NEM, you’re not getting anything out of a Powerwall besides expensive blackout protection.

The person you quoted is in the UK. They do not have NEM. They have what is called a Feed-In Tariff. That means that they get paid a different price (likely rather low) for the energy they feed into the grid than the energy they buy from the grid. However, you can choose your electricity supplier, so you have a choice of many different tariffs. I will leave it to @SimonT to explain where the 3x came from.

Powerwalls will allow you to save money with TOU arbitrage in PG&E territory, as long as you owe money at your annual true-up. If you don't owe them any money, you obviously can't save it. Based on my limited Winter solar generation and my typical Peak period use throughout the year, I estimate that I save $625 per year purely with TOU arbitrage on the EV-A rate plan.

 

[Odiemac]

The person you quoted is in the UK. They do not have NEM. They have what is called a Feed-In Tariff. That means that they get paid a different price (likely rather low) for the energy they feed into the grid than the energy they buy from the grid. However, you can choose your electricity supplier, so you have a choice of many different tariffs. I will leave it to @SimonT to explain where the 3x came from.

Powerwalls will allow you to save money with TOU arbitrage in PG&E territory, as long as you owe money at your annual true-up. If you don't owe them any money, you obviously can't save it. Based on my limited Winter solar generation and my typical Peak period use throughout the year, I estimate that I save $625 per year purely with TOU arbitrage on the EV-A rate plan.

Good points, I would just add that some Community Choice Aggregators in PG&E territory will pay out up to a maximum of $2,500-$5,000 per year at true-up for excess energy sent to grid, so it’s not necessarily just for people who don’t get to zero at true-up. So far through July 20th our NEM balance with East Bay CCA is -$522.

 

[miimura]

Good points, I would just add that some Community Choice Aggregators in PG&E territory will pay out up to a maximum of $2,500-$5,000 per year at true-up for excess energy sent to grid, so it’s not necessarily just for people who don’t get to zero at true-up. So far through July 20th our NEM balance with East Bay CCA is -$522.

Good point. However, my CCA Generation Peak vs. Off-Peak differential is only about $0.20/kWh while the full EV-A tariff differential is $0.38/kWh. PG&E still wipes out any Transmission and Distribution credits you have at true-up.

I will also point out that most CCAs will pay out all Generation TOU differentials while PG&E will not. Before CCAs there were lots of people who had a dollar credit balance at true-up but were still net kWh consumers, so PG&E wiped out that credit. Most CCAs will pay out the Generation portion of that credit regardless of whether you have surplus kWh or not.

 

[KSilver2000]

Powerwalls will allow you to save money with TOU arbitrage in PG&E territory, as long as you owe money at your annual true-up. If you don't owe them any money, you obviously can't save it. Based on my limited Winter solar generation and my typical Peak period use throughout the year, I estimate that I save $625 per year purely with TOU arbitrage on the EV-A rate plan.

Can you describe your specific usage pattern and TOU arbitrage? And did you get the PW with SGIP or did you pay outright? Do you not have any surplus generation and use a ton of electricity during peak period? I can understand PW being beneficial if that was the case.

It may be complicated, but would it not have saved you more money had you bought a bigger PV system rather than buying the PW if you do still owe that much to PG&E at true-up?

 

[SimonT]

Not following how your panel efficiency went up 3x.

Are you not in a utility that provides NEM?
If so, wouldn’t it be better to send all peak surplus to the grid and make use of the cheaper off-peak rate at night? It’s a 4x difference in PG&E land. Roughly $0.55/kWh peak rate (makes driving an EV more expensive than ICE, lol) and $.13/kWh off-peak.

So, to the OP, having solar panels in PG&E land with NEM, you’re not getting anything out of a Powerwall besides expensive blackout protection.

We have had the powerwall fitted for 3 months now.

We dont use it for blackout protection - its not something we gernerally suffer from in the UK.

Our Feed in Tarrif is roughly 1/3 of our buy in rate so there is no point in selling unused electricity to the grid - we are better off storing and using it.

We have been 80% self sufficient on electricity (we dont have gas).

Without the battery this drops to 34% as the solar generated during the day just goes to the grid.

Our average draw from the grid per day has been 4.81kw without the battery it would have been 13.81.

Hope that helps.

 

[inShaneity]

Living in Florida with 1:1 net metering, I kinda do. Had a hard time understanding how that worked... for some reason... and now that I get it I do regret the cost. BUT, also being in Florida, that might change once hurricanes start blowing through here. Had my system on for only a month so haven't dealt with any power outages yet.

 

[TheRedPill]

I regret only ordering two, instead of three.

Can you elaborate more on this? I just ordered two, and am having them installed within the next few days.

 

[Dan123]

Can you elaborate more on this? I just ordered two, and am having them installed within the next few days.

With two, in an event of an outage, there is a chance that I will run out of power at night. With three, I would have more cushion.

 

[Dan123]

Living in Florida with 1:1 net metering, I kinda do. Had a hard time understanding how that worked... for some reason... and now that I get it I do regret the cost. BUT, also being in Florida, that might change once hurricanes start blowing through here. Had my system on for only a month so haven't dealt with any power outages yet.

One thing to consider is the possibility of switching to the TOU rate. If your solar production doesn't cover all of your consumption.

The TOU rate for FPL is about 4 cents for off-peak, and 24 cents for on-peak. With PW you can make sure that you cover all of your on-peak usage with solar.

 

[MorrisonHiker]

Can you elaborate more on this? I just ordered two, and am having them installed within the next few days.

For those who want to add more Powerwalls, they will charge additional installation and permit fees if you add them later (which makes sense since it's a second install).

If you think you might want three, you could probably save $1000 to $2000 or more by installing them all at once versus installing another one at a later date. When we got our first Powerwalls installed, installation was only $200 for each additional Powerwall and there was no change in the permit fees. We're adding another Powerwall and will have to pay a regular installation fee plus new permit fees.

 

[nyprepper]

I am very happy, Zero regrets. 6.6kw PV and two PW's installed last October. In the 10 months that we've had the system running we are at a cumulative 60% offset and have 30% self-powered. My electric bills have been cut in half as my meter just rolls backwards as I feed excess production to the grid.

But the savings is just a bonus ..... the real value prop for me was backup power due to frequent grid outages in my area. Running just essentials (well pump, fridge, LED lights, electronics, etc.) I can pretty much stay off-grid assuming modest solar production. I keep my PW's set at 100%, backup only.....but once it cools down here in late September and we don't need to have the central AC running and our solar production exceeds consumption i'll start using the PW's and set the backup reserve at 50%.

 

[gpez]

Happy here and would do it again. 1x Powerwall2 and a 8.6kw system (not Tesla). Powerwall used exclusively for backup.

That said there is still a lot of kinks to work out, both on the Tesla side but mostly due to how crazy fragmented the energy system is. Even here in the states things can be different provider to provider, let alone state to state or a place like Puerto Rico. The Powerwall applications vary too from time of use shifting, grid backup, and total off grid. A lot of that is not Tesla's fault but I think they can do much better managing the landscape.

 

[miimura]

Can you describe your specific usage pattern and TOU arbitrage? And did you get the PW with SGIP or did you pay outright? Do you not have any surplus generation and use a ton of electricity during peak period? I can understand PW being beneficial if that was the case.

It may be complicated, but would it not have saved you more money had you bought a bigger PV system rather than buying the PW if you do still owe that much to PG&E at true-up?

Here's my situation. I installed solar when the house was built in 2012. I could only afford enough solar at that time to cover the household use. Now I have two EVs. So my usage is heavily skewed to Off-Peak and the extra usage leads to owing at true-up.

I heard about Powerwalls and a company that was early to push the SGIP program when Tesla wasn't talking about the rebate at all. So, I got in SGIP Step 1 in 2017 but the Powerwalls were not installed until February 2018. Back in 2017 I wasn't sure that they would really be able to get me the rebate and I wasn't in a hurry, so I just let the deposit ride until something came of it.

The other thing that complicates my situation is that I'm on NEM 1.0. As such, I don't pay any Non-Bypassable Charges. If I were to increase my solar to the point that I could zero out my bill, I would be pushed into NEM 2.0 and I would have NBCs on my overnight EV charging. I would have to depend on my CCA payout to compensate for that. I have also already used the best roof area with my existing solar. Given my limited roof area, I would probably have to also replace my existing 240W panels with 300+W panels and place panels in non-ideal orientations. My remaining roof areas are SE and NW facing. I have not asked for bids to increase the solar, but it would probably be more financially prudent to increase the solar than to get Powerwalls today, mostly because of the poor Powerwall rebate situation. Without Powerwalls I could probably build a battery system with salvage EV batteries and wire it into the generator wiring that I had installed during the new house construction and use that as a backup system. However, the circuits connected to that are much more limited than what I have now with the Powerwalls.

Anyway, the arbitrage calculation for my situation basically goes like this:
Summer Peak usage is ~10kWh/day. Weekday generation is Part-Peak, weekend generation is Off-Peak. EV-A differentials give $485/year savings.
Winter Peak usage is limited by generation averaging 5kWh/day. Rate differentials are smaller, so the Winter contributes $140/year savings.
That is how I arrived at the $625/year savings. If you use air conditioning in the Summer, you can shift a lot more usage and save a lot more money. Same in the Winter, if you have more solar, you can shift more energy. My Powerwalls are just bouncing off the Reserve every day from about Nov-Feb when the generation is below 10kWh/day. Since I don't have central A/C, my daytime usage is higher in the Winter because of the central heat air handler running and a little more lighting loads.

 

[KSilver2000]

Here's my situation. I installed solar when the house was built in 2012. I could only afford enough solar at that time to cover the household use. Now I have two EVs. So my usage is heavily skewed to Off-Peak and the extra usage leads to owing at true-up.

I heard about Powerwalls and a company that was early to push the SGIP program when Tesla wasn't talking about the rebate at all. So, I got in SGIP Step 1 in 2017 but the Powerwalls were not installed until February 2018. Back in 2017 I wasn't sure that they would really be able to get me the rebate and I wasn't in a hurry, so I just let the deposit ride until something came of it.

The other thing that complicates my situation is that I'm on NEM 1.0. As such, I don't pay any Non-Bypassable Charges. If I were to increase my solar to the point that I could zero out my bill, I would be pushed into NEM 2.0 and I would have NBCs on my overnight EV charging. I would have to depend on my CCA payout to compensate for that. I have also already used the best roof area with my existing solar. Given my limited roof area, I would probably have to also replace my existing 240W panels with 300+W panels and place panels in non-ideal orientations. My remaining roof areas are SE and NW facing. I have not asked for bids to increase the solar, but it would probably be more financially prudent to increase the solar than to get Powerwalls today, mostly because of the poor Powerwall rebate situation. Without Powerwalls I could probably build a battery system with salvage EV batteries and wire it into the generator wiring that I had installed during the new house construction and use that as a backup system. However, the circuits connected to that are much more limited than what I have now with the Powerwalls.

Anyway, the arbitrage calculation for my situation basically goes like this:
Summer Peak usage is ~10kWh/day. Weekday generation is Part-Peak, weekend generation is Off-Peak. EV-A differentials give $485/year savings.
Winter Peak usage is limited by generation averaging 5kWh/day. Rate differentials are smaller, so the Winter contributes $140/year savings.
That is how I arrived at the $625/year savings. If you use air conditioning in the Summer, you can shift a lot more usage and save a lot more money. Same in the Winter, if you have more solar, you can shift more energy. My Powerwalls are just bouncing off the Reserve every day from about Nov-Feb when the generation is below 10kWh/day. Since I don't have central A/C, my daytime usage is higher in the Winter because of the central heat air handler running and a little more lighting loads.

Ah, I see. A unique situation indeed.

I still stand by my opinion for people just starting to look into solar who lives within NEM utility. But, then again, maybe my situation is unique as well. I’m on PG&E and I’ve never had mandated blackouts ever. I’ve also only experienced (very) temporary power loss maybe a handful of times in the last decade+ (for sure none in the last 2-3 years). So, that’s why I say it makes much more sense to max out panels before thinking about PW.

 

[MorrisonHiker]

Ah, I see. A unique situation indeed.

I still stand by my opinion for people just starting to look into solar who lives within NEM utility. But, then again, maybe my situation is unique as well. I’m on PG&E and I’ve never had mandated blackouts ever. I’ve also only experienced (very) temporary power loss maybe a handful of times in the last decade+ (for sure none in the last 2-3 years). So, that’s why I say it makes much more sense to max out panels before thinking about PW.

We never had an outage that lasted more than a couple hours in the past 24 years...until we had a 46 hour outage in March and then a 5.5 hour outage in May. Past performance is not a predictor of future results.

 

[KSilver2000]

We never had an outage that lasted more than a couple hours in the past 24 years...until we had a 46 hour outage in March and then a 5.5 hour outage in May. Past performance is not a predictor of future results.

Of course not. But, I’ll take my chances given my impeccable history with my utility. An hour or so of outage every five or so years is not worth insuring against with an expensive PW. Better to get more utilization and value out of having more panels.

Do you also tend to buy ESA for all your cars?

 

[abasile]

I'm glad we installed Powerwalls because we're in a semi-rural mountain area that's subject to power outages, particularly during winter, and our utility (SCE) is likely to preemptively shut down the grid when there's a high risk of wildfire. Since installing the Powerwalls, we've never had to go without power! We also get the benefit of some TOU load shifting, but the cost savings aren't all that high.

My biggest disappointment is that, back in August and October 2017 when we reserved and contracted for our Powerwalls, Tesla salespeople promised that we'd qualify for the California SGIP rebate. Well, that ship has sailed - no rebate for us. Tesla maxed out their developer cap with SGIP, but they didn't do a good job of coordinating expectations with their sales team.

Last winter, we also had issues charging our Powerwalls from solar during grid outages. This hasn't been an issue during warmer weather. I've been corresponding with the Powerwall Support team to make sure this issue has been (or will be) addressed.

 

[MorrisonHiker]

Of course not. But, I’ll take my chances given my impeccable history with my utility. An hour or so of outage every five or so years is not worth insuring against with an expensive PW. Better to get more utilization and value out of having more panels.

Do you also tend to buy ESA for all your cars?

Our utility had an impeccable history for 24 years until they dropped the twice ball this year.

No. I've never bought an ESA.

As for solar, we put in the maximum number of kW (16.5 kW) that our utility company allowed, based on our annual usage. Our Powerwalls were free, fortunately.