To Powerwall or Not to Powerwall?

[Fragger]

Hi folks,

Thinking about dipping our toes in self sustainable energy life... Or at least starting that journey. Our average monthly consumption maybe be under 1000 kWh while we are trying to sign up for a 8.16 kWh system that is expected to produce just that with estimated number at 12,220 kWh for the year...

In the interest of keeping our financial footprint small we are not considering a Powerwall install in our system. We do expect an addition or two in our family in the next 2 to 3 years as well.

With that said, I almost never ever see anyone doing a Tesla install without the Powerwall. We do have a net metering option available with 1:1 ratios for consumption and selling with our local electric companies.

Can someone share their advice around the economics of this thing? Is it wise to order what we need now and make use of cheaper technology in the future? Or take advantage of the higher tax rebates now?

Has anyone done a post panel install of more panels or Powerwall? Can you share your economic experience and advice?

Thank you!

 

[BrettS]

Honestly, with cheap electricity, 1:1 net metering, and no TOU rate a powerwall really will never make sense financially or ‘pay for itself’.

I’m in this situation in Florida and I got powerwalls because I wanted power when the grid went down. When hurricanes happen here we can have multi day power outages, so that’s how I justified my powerwall purchase.

Powerwalls can definitely be added after the fact, but it is usually cheaper to add them at the same time. There are definitely a lot of people who do solar only installs though.

Also, keep in mind the fact that with a solar only install you will not have power when the grid is down, even during the middle of a bright sunny day.

 

[jjrandorin]

Hi folks,

Thinking about dipping our toes in self sustainable energy life... Or at least starting that journey. Our average monthly consumption maybe be under 1000 kWh while we are trying to sign up for a 8.16 kWh system that is expected to produce just that with estimated number at 12,220 kWh for the year...

In the interest of keeping our financial footprint small we are not considering a Powerwall install in our system. We do expect an addition or two in our family in the next 2 to 3 years as well.

With that said, I almost never ever see anyone doing a Tesla install without the Powerwall. We do have a net metering option available with 1:1 ratios for consumption and selling with our local electric companies.

Can someone share their advice around the economics of this thing? Is it wise to order what we need now and make use of cheaper technology in the future? Or take advantage of the higher tax rebates now?

Has anyone done a post panel install of more panels or Powerwall? Can you share your economic experience and advice?

Thank you!

In your situation the economics only pencil out if you are considering powerwall(s) as a generator. Yes, powerwalls can be installed post panel install, no, in general "more panels" are not usually able to be added to your existing install. You normally have to buy a new system (new inverter + panels) to get more panels.

If you have 1:1 net metering, and are not someone who cares about having backup power available, and you also have cheap electricity (texas is super cheap comparatively speaking), you are not going to make the economics make sense.

They make sense if your power is expensive, or you consider them as an auto switching generator (and price them against a whole home generator)

 

[SMAlset]

There are a few Texans on here who asked the same basic question not that long ago. Not sure if Texas was mentioned in the title but a search for Texas in this forum area might be helpful. Do think you’ll find both replies above pretty spot on however.

Are you in an area of Texas that sees storms, tornadoes or flooding where your power could be out for days? Solar alone won’t do anything for you in those situations. Heat and humidity with no AC won’t be much fun, but again depends on what part if Texas you’re in.

 

[Robotpedlr]

I have net meeting and relatively cheap electricity....but am very happy that I have 2 Powerwalls (with solar).

My neighborhood’s power is out currently (small storm) and I am watching TV like nothing happened. It might not pencil out, but definitely nice to have if you can swing it. We dont have a lot of power outages, but hated pulling the generator out the few times we did.

Plus keep in mind that if you buy the PWs to support solar you get the tax credit on their PWs also.

 

[garrett5688]

Like said above re: cheap Texas electricity - powerwall won’t really save you money. It’s more of an insurance policy.

You can do it now with 26% tax credit and discount through Tesla combining with solar... or do it later and hope that the price/capacity improves in the future.

if you don’t live in an area with frequent power outages, it’s not as much a necessity as it is a luxury. So I wouldn’t recommend stretching financially for it.

with expected family growth (and increased energy consumption) you might be better off getting a larger solar array instead of power walls

 

[SoCal Dave]

With that said, I almost never ever see anyone doing a Tesla install without the Powerwall. We do have a net metering option available with 1:1 ratios for consumption and selling with our local electric companies.

Most people posting here are enthusiast so you are going to see a lot higher percentage with Powerwalls. Most solar installs are actually without Powerwalls. Mine included.

 

[jjrandorin]

Most people posting here are enthusiast so you are going to see a lot higher percentage with Powerwalls. Most solar installs are actually without Powerwalls. Mine included.

I see this all the time on forums, lol. When i was active on BMW forums, it seemed like every other person was talking about either their estoril blue M sport 3/4 series, or their M3 in Sakir Orange. If you went by the forums, it seemed like those were super common, but it was the reverse. They were actually pretty darn rare, but were "enthusiast" builds.

In this section of TMC, there are a lot of super knowledgeable people regarding solar and powerwalls, with some early adopters. The percentage of solar + powerwall is likely much lower than it appears here, but is also more common in some states than others.

I feel like powerwalls are more common in CA than other states due to the new phenomenon of PSPS events. Solar works really well in CA in general, and many here want power independence from the utility as much as possible.

OP, dont take online forums for whats really happening... if you almost never see solar without powerwalls, either your circle of friends and contacts really values it, or you are reading forums full of people who are excited about them (like here).

 

[jboy210]

Living the land of PSPS was enough to push me to powerwalls. Being without power for 4 days last year was enough for us.

Speaking of which, NorCal looks to have a red flag warning this weekend. Over 100F in the East Bay with offshore winds up to 50 mph. I guess StormWatch will activate again. Sure hope the SCU complex down the road does not start burning again.

 

[getakey]

Living the land of PSPS was enough to push me to powerwalls. Being without power for 4 days last year was enough for us.

Speaking of which, NorCal looks to have a red flag warning this weekend. Over 100F in the East Bay with offshore winds up to 50 mph. I guess StormWatch will activate again. Sure hope the SCU complex down the road does not start burning again.

I got PWs because of PSPS, but system is down after last brief outage. Went to Tesla Level 2 support and they say some hardware failed. Installer cannot get here until 9/29. I'm going to be pissed if we have a PSPS this weekend

 

[heems]

I ordered Solar roof (9.8KW) + 2 Powerwalls earlier this year. Scheduled for installation first week of November. A couple of points on the economics (for me at least). Btw, I am in San Diego / SDG&E territory.

- I didn't go solar to break even or make money compared to my prior electricity usage. However, running the numbers (theoretical as I don't know actual generation), I think the payback will be long (20+ years).
- Not having PWs didn't make sense to me. Net metering or not, I wanted independence. Less grid usage the better. The project without PW didn't make sense to me.
- I understand that if I didn't bundle the PWs with the solar install, they would not be eligible for the federal rebate if added later. If true, that's a big incentive.
- PWs + Solar also come with a discount from Tesla. You may not get the discount if you unbundle them.
- The federal rebate (and their reducing outlook) is something to think about, but I am not sure it's primary. Mainly because Tesla seems to price match (as they did on the car side) when incentives go away in a market. But if I get more of my taxes coming back to me, hey that's a personal incentive for me.

 

[getakey]

Tax Credit is available for PWs added later

 

[wjgjr]

I ordered Solar roof (9.8KW) + 2 Powerwalls earlier this year. Scheduled for installation first week of November. A couple of points on the economics (for me at least). Btw, I am in San Diego / SDG&E territory.

- I didn't go solar to break even or make money compared to my prior electricity usage. However, running the numbers (theoretical as I don't know actual generation), I think the payback will be long (20+ years).
- Not having PWs didn't make sense to me. Net metering or not, I wanted independence. Less grid usage the better. The project without PW didn't make sense to me.
- I understand that if I didn't bundle the PWs with the solar install, they would not be eligible for the federal rebate if added later. If true, that's a big incentive.
- PWs + Solar also come with a discount from Tesla. You may not get the discount if you unbundle them.
- The federal rebate (and their reducing outlook) is something to think about, but I am not sure it's primary. Mainly because Tesla seems to price match (as they did on the car side) when incentives go away in a market. But if I get more of my taxes coming back to me, hey that's a personal incentive for me.

I understand about the idea of PWs for independence. I think for people like me in a full net metering area, that is the best argument for PWs, though it is harder to quantify the value of that. You are also correct that there is currently a discount for bundling solar+PW that you would not otherwise get.

As far as the federal credit, it does not matter if they are installed at the same time. As long as the PWs are entirely charged from solar, they are eligible. Also, the federal rebate change between 2020/2021 is not huge (4% of the qualifying amount) and I agree Tesla may well drop prices to offset. However 2022 is currently a 0% rebate, so that is a huge difference and I find it hard to believe Tesla would be able to fully offset that. Of course, it is still very possible the residential ITC could be extended, but it is not guaranteed it will be or at what level.

 

[heems]

Thank you for the clarification on the credits. All good points.

Edit: I have a TOU plan were nights is $0.09/kwh (vs peak $0.43/kwh). Tesla advised me the PW will learn/know to charge during this time to minimize my peak usage (4-9PM when solar is not producing much). If this also is true and pans out, it could bring my payback time frame down quite a bit. And maybe this was why I was told the federal credit would not apply if I added the PWs later.

 

[gpez]

I live in a similar area to @Robotpedlr where our local utility is inexpensive (~9.22c/kwh) with no ToU and full net metering. Powerwalls make little sense when all three of those things are true so my Powerwall investment is purely for backup. Luckily we didn't lose power in those storms but just up the street about 1,200 homes lost power for about 6 hours. That's the reason I got a Powerwall.

 

[getakey]

Thank you for the clarification on the credits. All good points.

Edit: I have a TOU plan were nights is $0.09/kwh (vs peak $0.43/kwh). Tesla advised me the PW will learn/know to charge during this time to minimize my peak usage (4-9PM when solar is not producing much). If this also is true and pans out, it could bring my payback time frame down quite a bit. And maybe this was why I was told the federal credit would not apply if I added the PWs later.

You cannot charge the PW at night during low rate. It can only charge from Solar. You can use PW to power house during Peak from charging during morning from solar

 

[jboy210]

I got PWs because of PSPS, but system is down after last brief outage. Went to Tesla Level 2 support and they say some hardware failed. Installer cannot get here until 9/29. I'm going to be pissed if we have a PSPS this weekend

Ouch. I would be pissed also.

 

[heems]

You cannot charge the PW at night during low rate. It can only charge from Solar. You can use PW to power house during Peak from charging during morning from solar

I see. I seem to be getting conflicting information from Tesla on this:

Powerwall Time-Based Control | Tesla Support says in balance mode (available with Solar only) that it does perform off peak charging. This seems to imply load shifting is possible. Maybe I am reading this wrong ?

Yet this page Combining Systems | Powerwall Support explicitly says you cannot charge from grid when using solar, supporting your assertion.

 

[getakey]

PG&E has Off Peak, Partial Off Peak (Shoulder), and Peak
I charge from solar during Shoulder and power house from PW during Peak. During summer, that gives me about a $.25/kWh benefit

You can only charge from the Grid in Stormwatch mode

 

[jjrandorin]

I see. I seem to be getting conflicting information from Tesla on this:

Powerwall Time-Based Control | Tesla Support says in balance mode (available with Solar only) that it does perform off peak charging. This seems to imply load shifting is possible. Maybe I am reading this wrong ?

Yet this page Combining Systems | Powerwall Support explicitly says you cannot charge from grid when using solar, supporting your assertion.

You wont be charging from the grid during off peak in san diego, if you have solar installed (with the exception of stormwatch mode)