Powerwall Move / Convince My Wife Powerwalls are Worth it

[TMThree]

The Enphase system still requires means to isolate the home from the grid (Enpower smart switch) and batteries to store energy (Encharge 10 or Encharge 3 storage system) when the sun is down.

There are two versions of the IQ8. You're talking about the grid-agnostic version that makes a local grid when the power company is down, using local battery storage.

The off-grid version will function when the power company goes down and will NOT need batteries to operate. But you will need to be currently generating enough power to support whatever is plugged in.

Don't believe me? The official Enphase youtube account has a live demo of the off-grid functionality in the IQ8:

So for a powerwall alternative (that only runs in sunlight), you'd need solar panels with iq8 (or iq7 in your existing panels and an iq8 downstream), plus a transfer switch. That would definitely keep my freezer going.


PS: I'm not sure if there are actually two versions of IQ8. It could just be one version and it functions regardless if there is a battery or not. The two "versions" could just be describing a specific solution using it.

 

[GenSao]

There are two versions of the IQ8. You're talking about the grid-agnostic version that makes a local grid when the power company is down, using local battery storage.

The off-grid version will function when the power company goes down and will NOT need batteries to operate. But you will need to be currently generating enough power to support whatever is plugged in.

Don't believe me? The official Enphase youtube account has a live demo of the off-grid functionality in the IQ8:

So for a powerwall alternative (that only runs in sunlight), you'd need solar panels with iq8 (or iq7 in your existing panels and an iq8 downstream), plus a transfer switch. That would definitely keep my freezer going.


PS: I'm not sure if there are actually two versions of IQ8. It could just be one version and it functions regardless if there is a battery or not. The two "versions" could just be describing a specific solution using it.

I believe it is the same version. It is cool to see the one panel connected to various devices in the demo video. Likely only works 1:1 for only one solar panel and can not be combined with other modules. May not be permitted to be done outside of the demo.

I agree batteries are not required. It is the other parts that are likely required. The typical, basic Enphase installation has all the micro-inverters connected to the IQ Envoy. I have 20 older Enphase M250 micro-inverters connected to the Envoy installed at our home.

• The IQ Envoy (as part of the IQ combiner) is required for coordination, command and control of the IQ8 micro-inverters.
• The Enpower smart switch is required to isolate your home from the grid.
  
• The Wireless communication kit is required for the IQ Envoy to communicate to the Enpower smart switch (and Encharge batteries if installed)

Perhaps it is possible to wire it a different way that may not require those components. Though, I doubt Enphase would want to lose out on the revenue.

As a side note, I think having several IQ8 micro-inverters in the Encharge batteries is not particularly cost effective.

 

[Jeffgtx]

It is worth it when your fridge stays running during a power outage and you don’t run a gas generator that pollutes.

 

[StoicKiwi]

Wow, thank you all for all of the great input! I really appreciate it and I’ve shown my wife all of these good examples and reasons (even if they don’t get me my PW )

I'll remind you this thread is not about you. The title is "Convince my wife powerwalls are worth it"

So "they are expensive and will not give you any ROI" makes me laugh. It will still depend if he can time shift, or if he has access to any large rebates to decide that. I don't know the answers to that.

As for more details on our programs and rates down here, it is kind of odd down here with how things work:
We don’t have ToU power unfortunately but we have relatively cheap power down here for most months at $0.0691/kWh. Unless you use more than 1,000kWh that month (I think), then it goes up to around $0.086/kWh. During the summer months, they add “Peak capacity charges” and “Regulatory adjustments” that bring it up to around $0.112/kWh.

CPS, our power company, does offer net metering on the “avoided cost” model of bill credits for excess generation, which makes the PW less attractive from a pure financial standpoint.
The power company has rebates, but they are fixed at $2,500 so the larger up-front cost of the system, the more diminishing returns for that there are, but this is helped by the federal tax credit.

Our power is pretty consistent down here as well. With not being prone to major natural disasters, we’ve had only a handful of outages in the past years and only one of them lasting longer than 12 hours or so.

In regards to the housing market down here, it is definitely a sellers market (or at least it was before the current events). The city is growing fast and when we purchased our house, it was listed for less than 24 hours before it was under contract. Solar is also pretty prolific but I haven’t been able to find anyone nearby who has a PW or any backup batteries though many would be familiar with these systems hopefully.

I’m curious about the IQ8 system as well, I may have to look into this!

 

[TMThree]

I’m curious about the IQ8 system as well, I may have to look into this!

It appears late by a year. I don't know if thats because its just taking longer than expected or if they are running into problems. Last I read, they had people beta testing it. Maybe they needed to make some changes. I'm really looking forward to it too, even though I'm not sure it will do exactly what I want.

It's always good to have options.

Also with 8 cent / kwh power, even solar would be a hard sell. Its going to take a while to recoup their cost.

 

[gpez]

Wow, thank you all for all of the great input! I really appreciate it and I’ve shown my wife all of these good examples and reasons (even if they don’t get me my PW )



As for more details on our programs and rates down here, it is kind of odd down here with how things work:
We don’t have ToU power unfortunately but we have relatively cheap power down here for most months at $0.0691/kWh. Unless you use more than 1,000kWh that month (I think), then it goes up to around $0.086/kWh. During the summer months, they add “Peak capacity charges” and “Regulatory adjustments” that bring it up to around $0.112/kWh.

CPS, our power company, does offer net metering on the “avoided cost” model of bill credits for excess generation, which makes the PW less attractive from a pure financial standpoint.
The power company has rebates, but they are fixed at $2,500 so the larger up-front cost of the system, the more diminishing returns for that there are, but this is helped by the federal tax credit.

Our power is pretty consistent down here as well. With not being prone to major natural disasters, we’ve had only a handful of outages in the past years and only one of them lasting longer than 12 hours or so.

In regards to the housing market down here, it is definitely a sellers market (or at least it was before the current events). The city is growing fast and when we purchased our house, it was listed for less than 24 hours before it was under contract. Solar is also pretty prolific but I haven’t been able to find anyone nearby who has a PW or any backup batteries though many would be familiar with these systems hopefully.

I’m curious about the IQ8 system as well, I may have to look into this!

"Relatively cheap" is a bit of an understatement! Average in Texas is $0.1136/kWh (Electricity Rates by State (Updated April 2020) – Electric Choice) assuming you're in SA as your bio says so your rates are really low. Here in WA state our electricity is about the same as yours and my solar install only made sense on a 10 year return with substantial state and federal subsidies along with full net metering. I'm banking a tiny bit on our utility switching to a more aggressive pricing model since most of our state's electricity comes from hydro which can't really be expanded and the little that comes from sources like coal are being phased out quickly as part of new environmental policies. Combine that with ever increasing demand with the increasing popularity of EVs and I can see our prices increasing or some ToU scheduling implemented sometime in the nearish future. Something maybe to consider?

 

[getakey]

the bad news good news in CA is that rates are very high, but solar payback is quick
My Off peak rate is $.12/kWh and I only get that because I have an EV. Peak goes to .54/kWh in Summer. Partial Peak is around .3o I think

My payback is about 4 years for the solar. I added PWs and I am no longer buying any power during Peak.

 

[TMThree]

the bad news good news in CA is that rates are very high, but solar payback is quick
My Off peak rate is $.12/kWh and I only get that because I have an EV. Peak goes to .54/kWh in Summer. Partial Peak is around .3o I think

My payback is about 4 years for the solar. I added PWs and I am no longer buying any power during Peak.

I don't know if I should feel jealous that you have such a quick ROI or sad you're paying so much for power.

 

[StoicKiwi]

"Relatively cheap" is a bit of an understatement!

Haha yeah it is a perk of living in SAT! The only downside is that with AC running pretty constantly and charging the Model S, I'm rarely going to see that rate as I go over 1,000kWh every month. But still, 9.6 cents / kWh is pretty good

Also with 8 cent / kwh power, even solar would be a hard sell. Its going to take a while to recoup their cost.

I actually forgot another one of the fuel adjustment charges and it is actually 9.6 cents/kWh. I think one of the major advantages of solar would be trying to get under the 1,000kWh mark every month to avoid the rate increase that brings it up to 11.2 cents / kWh.

I plugged everything I could find into PVWatts and with local and federal incentives, it looks like it would be just under a 6-year ROI for a medium system. If you add two PWs in the mix, it becomes over double the ROI.

 

[gpez]

If you add two PWs in the mix, it becomes over double the ROI.

I wouldn't quite agree on two points.

1) Sounds like ToU shifting or night self powered won't help you so the Powerwall would just be for backup meaning it really isn't functionally related to the solar ("functionally" because ITC comes in to play). How much is having the backup worth to you?
2) When you calculate the ROI on the Powerwall it should be independent of the solar ROI due to #1.

As an example my 1xPW came to $12k installed after all equipment, permitting, labor, fees, and taxes. The ITC and other incentives brought that down to about $8,000. Over 10 years at 4% that's $81/mo. Well worth the price for peace of mind during the occasional outage and insurance against the ever looming "big one" earthquake.

(For comparison the quotes I got for a 11kw standby generator were in the $13.5k range and while it could easily power the whole house it wasn't without its own drawbacks)

 

[arnolddeleon]

**TL;DR:**How much does it cost to move a powerwall to a new home? Can you provide any info that would convince my SO that having a Powerwall + Solar is worth it vs just solar?

---

So I am mulling over getting Medium Solar + two Powerwalls at our home and my wife is really hung up on getting the Powerwalls. She doesn't see the value in having them vs just having solar. Her biggest concern is whether or not the Powerwalls could come with us if we decided to move.

I found some vague info from Tesla saying that the Powerwalls could be moved to a new residence for a fee but it doesn't list the fee anywhere and doesn't offer in-depth details. I reached out to Tesla for more info but they seemed almost rabid for my cell phone number to call me and discuss rather than chat and I'm not ready for all that yet.

Does anyone have experience with getting Tesla to move a Powerwall to a new home?

Can anyone offer me any saved-my-bacon stories or just general awesomeness for Powerwalls that could convince my wife that there is more value in Powerwalls past very long-term money savings?

People have talked about these ideas but I'll take my cut at them.

#1 Understand the various reasons you want solar and powerwall. It's not necessarily just one. They could be: to save money, be green, fun technology, or have backup power. So each one can some value for you. If you are the super analytical type you can convert all of these to dollars. How much would pay to gain each benefit.

#2 For the expected time you will be in the house compare sum of the value the system will give versus how much it will cost you (including what you get at sale). That value is not zero but it may be lower that you expect.

Obviously this super simple if the solar and powerwalls save money to offset their cost for the expected ownership time. If saving money was the only reason it is highly unlikely that you will win unless you know you are going to be at the house for a really long time.

Because prices for solar and powerwalls are still dropping, a house without them is actually more desirable than with them in most cases. This is because the buyer can buy a better or equal system for less money and they will have a newer system. Basically you will be selling your system at a discount. This is true for both solar and powerwall. Subsidies can distort this temporarily for short periods of time. Basically solar and powerwalls are not appreciating assets.

Last year we purchased an investment property that had solar. The offer that we made included adjusting for the present value of the solar. The house we live in has 2 powerwalls to with the solar. I find myself hoping for power outages so the backup will kick in.

A powerwall can potentially have economic value if you can effectively time shift your solar production. As TOU rates have gotten less favorable for solar this has created opportunities for storage systems to add value. My rough calculation for my situation (PG&E in CA with solar) is that my Powerwalls will payback in about 10 years (which happily aligns with their warranty). This means that I get backup power for free. Luckily we plan on living here for a long time so I'm not worried about the complexities resale value.

 

[TMThree]

Because prices for solar and powerwalls are still dropping, a house without them is actually more desirable than with them in most cases. This is because the buyer can buy a better or equal system for less money and they will have a newer system. Basically you will be selling your system at a discount. This is true for both solar and powerwall. Subsidies can distort this temporarily for short periods of time. Basically solar and powerwalls are not appreciating assets.

This is true to a certain point. For example, if new battery tech comes out and you can get twice the capacity. But if the solar panels generate 100% of the household power, then newer technology doesn't really matter.

 

[StoicKiwi]

#1 Understand the various reasons you want solar and powerwall. It's not necessarily just one. They could be: to save money, be green, fun technology, or have backup power. So each one can some value for you. If you are the super analytical type you can convert all of these to dollars. How much would pay to gain each benefit.

#2 For the expected time you will be in the house compare sum of the value the system will give versus how much it will cost you (including what you get at sale). That value is not zero but it may be lower that you expect.

Thanks for your take! I hadn't thought to break down each bit and not only see the value, but estimate how much I value these.

 

[Doom Man]

Can anyone offer me any saved-my-bacon stories or just general awesomeness for Powerwalls that could convince my wife that there is more value in Powerwalls past very long-term money savings?

I'm in south Louisiana (not as hot as San Antonio, but the humidity makes up for it). I don't have time of use pricing, just a straight 10 cents per kw including the various regulatory fees and "undercoating" type charges that appear on my bill. I'm not going to make money by owning a PW, but I've got two PW's for hurricane backup and to gap-fill for a glitchy local grid. Here's what you do:
1) On a hot day, ask your wife to sit in your unconditioned attic or garage for 20 minutes, then remind her that this is what life is like without electricity. Be sure there is no air movement whatsoever. She will want backup electricity.
2) When she says a whole-house generator will be cheaper up front, tell her she's right, then pour her a glass of sparkling rose' and have her sit near a running generator for 20 minutes and try to have a conversation with her over the noise. Ideally, she would also be downwind to get the exhaust, but this is not required. (Don't put her so close to the generator that she permanently loses hearing or dies from CO poisoning.) She will not want a generator because PW's are silent and generators: not silent.
3) Tell her that a guy on the internet (moi) used to have a generator, but the noise at night -- when you need your a/c in Louisiana and Texas -- made it hard for her to sleep. And that once or twice a year the generator would break down and need to have spark plugs and valves adjusted or replaced, so you never knew if it was going to work the next time the power went out. Then remind her how she felt during #1 above.
4) Tell her that the periodic repairs and maintenance add $300+ per year to the operating cost of a generator -- call it $3000 over 10 years of a PW warranty, $4-5k+ over realistic PW life of 15+ years. And each day of running generator power uses maybe $50 of natural gas, depending on generator size.
5) If she suggests a $300 gas generator, get her to carry a 5-gallon can of gasoline from the back of her SUV (it's Texas) to wherever the generator would sit (I suggest outside of her crafting nook or the baby's room (it's Texas)), then pour the gasoline into another gasoline tank to simulate refilling a generator. Then get her to drive to the gas station and do that a few times a day to keep the a/c running. Alternatively, if there's no way in heck she'd risk hair and makeup and nails by hauling gasoline, you can splash a little gasoline on your hands a few times a day and then go anywhere near the baby, to simulate life with a $300 generator.
6) Fire up a chainsaw or leaf blower when she's not expecting it, to remind her of what the weekly generator "exercise" will be like.

You're welcome.

 

[gpez]

I'm in south Louisiana (not as hot as San Antonio, but the humidity makes up for it). I don't have time of use pricing, just a straight 10 cents per kw including the various regulatory fees and "undercoating" type charges that appear on my bill. I'm not going to make money by owning a PW, but I've got two PW's for hurricane backup and to gap-fill for a glitchy local grid. Here's what you do:
1) On a hot day, ask your wife to sit in your unconditioned attic or garage for 20 minutes, then remind her that this is what life is like without electricity. Be sure there is no air movement whatsoever. She will want backup electricity.
2) When she says a whole-house generator will be cheaper up front, tell her she's right, then pour her a glass of sparkling rose' and have her sit near a running generator for 20 minutes and try to have a conversation with her over the noise. Ideally, she would also be downwind to get the exhaust, but this is not required. (Don't put her so close to the generator that she permanently loses hearing or dies from CO poisoning.) She will not want a generator because PW's are silent and generators: not silent.
3) Tell her that a guy on the internet (moi) used to have a generator, but the noise at night -- when you need your a/c in Louisiana and Texas -- made it hard for her to sleep. And that once or twice a year the generator would break down and need to have spark plugs and valves adjusted or replaced, so you never knew if it was going to work the next time the power went out. Then remind her how she felt during #1 above.
4) Tell her that the periodic repairs and maintenance add $300+ per year to the operating cost of a generator -- call it $3000 over 10 years of a PW warranty, $4-5k+ over realistic PW life of 15+ years. And each day of running generator power uses maybe $50 of natural gas, depending on generator size.
5) If she suggests a $300 gas generator, get her to carry a 5-gallon can of gasoline from the back of her SUV (it's Texas) to wherever the generator would sit (I suggest outside of her crafting nook or the baby's room (it's Texas)), then pour the gasoline into another gasoline tank to simulate refilling a generator. Then get her to drive to the gas station and do that a few times a day to keep the a/c running. Alternatively, if there's no way in heck she'd risk hair and makeup and nails by hauling gasoline, you can splash a little gasoline on your hands a few times a day and then go anywhere near the baby, to simulate life with a $300 generator.
6) Fire up a chainsaw or leaf blower when she's not expecting it, to remind her of what the weekly generator "exercise" will be like.

You're welcome.

This is great and made me LOL, super passive aggressive! Your wife must love you

 

[StoicKiwi]

I'm in south Louisiana (not as hot as San Antonio, but the humidity makes up for it). I don't have time of use pricing, just a straight 10 cents per kw including the various regulatory fees and "undercoating" type charges that appear on my bill. I'm not going to make money by owning a PW, but I've got two PW's for hurricane backup and to gap-fill for a glitchy local grid. Here's what you do:
1) On a hot day, ask your wife to sit in your unconditioned attic or garage for 20 minutes, then remind her that this is what life is like without electricity. Be sure there is no air movement whatsoever. She will want backup electricity.
2) When she says a whole-house generator will be cheaper up front, tell her she's right, then pour her a glass of sparkling rose' and have her sit near a running generator for 20 minutes and try to have a conversation with her over the noise. Ideally, she would also be downwind to get the exhaust, but this is not required. (Don't put her so close to the generator that she permanently loses hearing or dies from CO poisoning.) She will not want a generator because PW's are silent and generators: not silent.
3) Tell her that a guy on the internet (moi) used to have a generator, but the noise at night -- when you need your a/c in Louisiana and Texas -- made it hard for her to sleep. And that once or twice a year the generator would break down and need to have spark plugs and valves adjusted or replaced, so you never knew if it was going to work the next time the power went out. Then remind her how she felt during #1 above.
4) Tell her that the periodic repairs and maintenance add $300+ per year to the operating cost of a generator -- call it $3000 over 10 years of a PW warranty, $4-5k+ over realistic PW life of 15+ years. And each day of running generator power uses maybe $50 of natural gas, depending on generator size.
5) If she suggests a $300 gas generator, get her to carry a 5-gallon can of gasoline from the back of her SUV (it's Texas) to wherever the generator would sit (I suggest outside of her crafting nook or the baby's room (it's Texas)), then pour the gasoline into another gasoline tank to simulate refilling a generator. Then get her to drive to the gas station and do that a few times a day to keep the a/c running. Alternatively, if there's no way in heck she'd risk hair and makeup and nails by hauling gasoline, you can splash a little gasoline on your hands a few times a day and then go anywhere near the baby, to simulate life with a $300 generator.
6) Fire up a chainsaw or leaf blower when she's not expecting it, to remind her of what the weekly generator "exercise" will be like.

You're welcome.

Not only is everything in this outstandingly hilarious, but it's also absolutely true (especially everything near the "it's Texas" quote )
My wife DEFINITELY found this helpful and hates filling the lawn mower up with gas, much less a generator. Not to mention someone MAY have put oil in the gas tank of said lawn mower once... Imagine doing that with our expensive generator.

 

[TMThree]

I'm in south Louisiana .... two PW's for hurricane backup...When she says a whole-house generator will be cheaper up front, tell her she's right, then pour her a glass of sparkling rose' and have her sit near a running generator for 20 minutes and try to have a conversation with her over the noise. Ideally, she would also be downwind to get the exhaust, but this is not required. (Don't put her so close to the generator that she permanently loses hearing or dies from CO poisoning.) She will not want a generator because PW's are silent and generators: not silent.

Only problem with your description is that hurricanes come with bad weather. Storms. If there is no power in your area and you have solar and PW, and there are clouds, your panels may not be refilling your powerwall.

Meanwhile if you had a whole house natural gas generator that cost half as much as your two PWs, it could basically run indefinitely. Yeah, it makes some noise, but t his is for emergency situations, not for daily use.

Just something to keep in mind.

 

[gpez]

Only problem with your description is that hurricanes come with bad weather. Storms. If there is no power in your area and you have solar and PW, and there are clouds, your panels may not be refilling your powerwall.

Meanwhile if you had a whole house natural gas generator that cost half as much as your two PWs, it could basically run indefinitely. Yeah, it makes some noise, but t his is for emergency situations, not for daily use.

Just something to keep in mind.

This is a very good consideration. For us out on the west coast the earthquake threat is actually the opposite - even a moderate quake could knock out natural gas service rendering standby generators useless.

Additionally, and this may just be a local market thing, the all-in price of a 11kW home standby generator was about the same price as 2x Powerwalls for me.

 

[TMThree]

This is a very good consideration. For us out on the west coast the earthquake threat is actually the opposite - even a moderate quake could knock out natural gas service rendering standby generators useless.

Additionally, and this may just be a local market thing, the all-in price of a 11kW home standby generator was about the same price as 2x Powerwalls for me.

On the west coast, I'd take powerwalls all day long. Just for the time shifting of power makes it worth it, plus you have tax incentives.

 

[jboy210]

On the west coast, I'd take powerwalls all day long. Just for the time shifting of power makes it worth it, plus you have tax incentives.

I went with Powerwalls because the threat of wildfires. Or more correctly, the threat of PG&E proactively cutting off my power for days, like they did last year.

The stars aligned for us October 2019. Tesla announced solarglass V3 roof and PG&E cut off our power for a total of 4 days on 2 separate incidents. That was enough for use to pull the trigger on the SolarGlass roof plus 2 PowerWalls.