2 Powerwalls + "Free Nights" Plan...can they pay for themselves?

[darrelld]

Hi folks,

I am moving to a new home in a couple weeks, and am trying to validate whether the plan below is financially viable.

There are several energy plans in my area for "Free Nights and Weekends" where you only pay the TDU charges. I don't get enough regular sun to use solar - but would it make sense for me to get Powerwalls anyway?

I live in South Texas, HVAC use is HEAVY. My power bill in the summer months is about $300, and about $180 in the winter. That breaks down to

Energy: $0.071400 PER KWH
TDU: $0.044700 PER KWH
plus $8 in tax/fees.

If the PowerWalls run my house during the day, I can remove the majority of the "Energy" line, which would save me between $100-200 per month depending on the time of year.

My thought is -- what if I have the Powerwalls and my car charge at night during the "free" period, and then use that energy during the day, so I'm not consuming during peak hours. Rinse and repeat.

I have a brand new 2800 sq ft home with 2 AC units, and I'm thinking 2 PowerWalls would be plenty to keep me running for a full day. I don't know much about the loan length/terms for PowerWalls, but could 2 Powerwalls pay for themselves in this way within the warranty period?

I live in North Texas and have 2 Powerwalls, 2 Trane 17 SEER AC, 5 Ton and 3 Ton. Last summer was my first experience with the heat and PWs handing the load. The PWs did fine with the exception of draining quickly usually to nothing once solar power power dropped. I now have 4KW and 1 PW on order with installation scheduled soon.

My electric plan is free nights and .15 per KW Peak use. Charge my Model Y Performance and Model 3 Long Range during free nights. The PWs will discharge during the free time unless I manually set the mode to backup only from TOU.

I don't calculate payoff time with solar. I look at solar/pw as an investment with a monthly return for me of $200.00.

 

[hill]

curious how it can be that Northern Minnesota pv users find enough solar for panels - yet not in (any part of) Texas (unless and some tall forest with tree cutting prohibitions) ?

 

[holeydonut]

Man, just thinking about what I'd do if I could get "free energy" to charge my Powerwalls at night gets me all excited.

Can I run a really long extension cord from California to Texas?

 

[darrelld]

curious how it can be that Northern Minnesota pv users find enough solar for panels - yet not in (any part of) Texas (unless and some tall forest with tree cutting prohibitions) ?

Typical August day in Texas is 90Kwh use for a 3000 sq ft residence. What is August in Minnesota like?

 

[ScottRiqui]

My electric plan is free nights and .15 per KW Peak use. Charge my Model Y Performance and Model 3 Long Range during free nights. The PWs will discharge during the free time unless I manually set the mode to backup only from TOU.

Sounds like you and I have the same electric plan. I'm still waiting on PTO, so I don't know exactly how my system will behave, but the bolded part of your post is what I was hoping to avoid (the Powerwalls discharging even though there's free grid power available). Did you find that they did that whether you were in "cost savings" or "balanced" mode under the TOU settings?

 

[garrett5688]

Sounds like you and I have the same electric plan. I'm still waiting on PTO, so I don't know exactly how my system will behave, but the bolded part of your post is what I was hoping to avoid (the Powerwalls discharging even though there's free grid power available). Did you find that they did that whether you were in "cost savings" or "balanced" mode under the TOU settings?

I’m not who you were asking, but I am currently on the free nights plan from Green Mountain.

I have to say- I’ve been disappointed in the cost savings mode. I have my peak set 6a-8p, but without manual intervention, the PWs will discharge even during my offpeak free period. It really drives me crazy.

The app needs more control. It’s too simple and lacks customization for different rate plans.

I think there should be a “net metering” Y/N checkbox. Or enter actual costs for each time period, so the gateway optimizes based on your individual plan.

I’ve submitted a service request complaining about the “cost savings” mode behavior, only to be referred back to the website description.

the fact that the PWs discharge to “make room” for future solar is ridiculous to me. Just keep the energy I already have! Why discharge with the hope of future production.

the way I combat the brainless algorithm is to manually raise my reserve each night once off peak starts, and reduce it down again in the morning. I hate that it takes manual control on a daily basis. Hopefully they will add more control/modes as more people not in California get solar/PW systems.

 

[vickh]

Man, just thinking about what I'd do if I could get "free energy" to charge my Powerwalls at night gets me all excited.

Can I run a really long extension cord from California to Texas?

I'm jealous too with only APS here. Surprised why other states don't do have some supplier competiton. Reminds me of ATT days.

the negative of deregulation is what happened with the winter blast, but that's rare...

 

[jboy210]

Anyone know if these types of plans are still available? We are buying an investment property in Austin and I am trying to figure out costs.

 

[MorrisonHiker]

My electric plan is free nights and .15 per KW Peak use. Charge my Model Y Performance and Model 3 Long Range during free nights. The PWs will discharge during the free time unless I manually set the mode to backup only from TOU.

Did you try using Advanced Time-based control to limit when the Powerwalls are actually used? Even if you don't have ToU, you can set schedules so that they shouldn't be discharged during your free time. We typically power our house from Powerwalls and solar about 20 hours a day. Our Powerwalls will always stop at the start of our set off-peak period. Usually they won't discharge during that period unless they have a high SoC and the sun is starting to come up.

Edit: I see you did mention TOU so I guess you tried that. Do your Powerwalls continue discharging at the start of off-peak or do they discharge at another time? Ours always stop exactly when scheduled for TBC-Balanced.

 

[darrelld]

Did you try using Advanced Time-based control to limit when the Powerwalls are actually used? Even if you don't have ToU, you can set schedules so that they shouldn't be discharged during your free time. We typically power our house from Powerwalls and solar about 20 hours a day. Our Powerwalls will always stop at the start of our set off-peak period. Usually they won't discharge during that period unless they have a high SoC and the sun is starting to come up.

Edit: I see you did mention TOU so I guess you tried that. Do your Powerwalls continue discharging at the start of off-peak or do they discharge at another time? Ours always stop exactly when scheduled for TBC-Balanced.

They stop discharging at the start of off-peak and usually early morning 1:00 am they will start discharging again. This is frustrating because Texas weather is constantly in flux so my PW will not take into account the next days forecast of mostly cloudy.

Right now the only work around is to watch the weather and manually set backup only mode for next day rain or mostly cloudy forecasts.

I would like to just follow a schedule like my $20 smart home devices.

 

[MorrisonHiker]

They stop discharging at the start of off-peak and usually early morning 1:00 am they will start discharging again. This is frustrating because Texas weather is constantly in flux so my PW will not take into account the next days forecast of mostly cloudy.

Right now the only work around is to watch the weather and manually set backup only mode for next day rain or mostly cloudy forecasts.

I would like to just follow a schedule like my $20 smart home devices.

There are some desktop apps that can let you schedule changes in Powerwall functionality. We haven't bothered with them since ours work as we'd program them to in the app. It would be nice if the Tesla app had a few more options so that it would work for your situation.

While the regular daily functionality works for us, I do wish they'd add a "delay" or "confirm" Storm Watch option so that the Powerwalls wouldn't charge during peak periods. Typically we'll know a day or two in advance if snow is coming but the Powerwalls will start charging as soon as Storm Watch is enabled which more often than not is right during our peak period. It can be sunny and 70 and Storm Watch will be activated for a winter snow storm that is days away. Once I notice Storm Watch has been activated (since I no longer get the Storm Watch notifications), I typically disable it and set an alarm to turn it back on after peak or part-peak. Likewise, after the storm passes, the warning often lasts for several hours so I will have to manually disable Storm Watch temporarily so that the Powerwalls can discharge during peak.

 

[miimura]

I agree with the people above that want more settings. Here are my suggestions:

- Storm Watch - Avoid Grid Charging during Peak
- Avoid Discharge during Off-Peak
- Shoulder Operates as Self-Powered.

 

[garrett5688]

They stop discharging at the start of off-peak and usually early morning 1:00 am they will start discharging again. This is frustrating because Texas weather is constantly in flux so my PW will not take into account the next days forecast of mostly cloudy.

Right now the only work around is to watch the weather and manually set backup only mode for next day rain or mostly cloudy forecasts.

I would like to just follow a schedule like my $20 smart home devices.

FYI I’ve noticed that switching between advanced and backup only screws up the peak/offpeak stats. Leaving it in advanced and raising the reserve during offpeak is what I do.

 

[oholladay]

I’m not who you were asking, but I am currently on the free nights plan from Green Mountain.

I have to say- I’ve been disappointed in the cost savings mode. I have my peak set 6a-8p, but without manual intervention, the PWs will discharge even during my offpeak free period. It really drives me crazy.

The app needs more control. It’s too simple and lacks customization for different rate plans.

I think there should be a “net metering” Y/N checkbox. Or enter actual costs for each time period, so the gateway optimizes based on your individual plan.

I’ve submitted a service request complaining about the “cost savings” mode behavior, only to be referred back to the website description.

the fact that the PWs discharge to “make room” for future solar is ridiculous to me. Just keep the energy I already have! Why discharge with the hope of future production.

the way I combat the brainless algorithm is to manually raise my reserve each night once off peak starts, and reduce it down again in the morning. I hate that it takes manual control on a daily basis. Hopefully they will add more control/modes as more people not in California get solar/PW systems.

I completely agree. I have to do the same thing. I have free nights and run bitcoin miners during my free hours, but they use a lot of energy. If I forget to adjust the reserve percentage, the Powerwalls go down to what I had set it at the day before. It would at least be helpful if the algorithm took into account the expected cloudy weather, which, in the Houston area, is quite common, before "making room" for solar that may never come.

 

[oholladay]

Hi folks,

I am moving to a new home in a couple weeks, and am trying to validate whether the plan below is financially viable.

There are several energy plans in my area for "Free Nights and Weekends" where you only pay the TDU charges. I don't get enough regular sun to use solar - but would it make sense for me to get Powerwalls anyway?

I live in South Texas, HVAC use is HEAVY. My power bill in the summer months is about $300, and about $180 in the winter. That breaks down to

Energy: $0.071400 PER KWH
TDU: $0.044700 PER KWH
plus $8 in tax/fees.

If the PowerWalls run my house during the day, I can remove the majority of the "Energy" line, which would save me between $100-200 per month depending on the time of year.

My thought is -- what if I have the Powerwalls and my car charge at night during the "free" period, and then use that energy during the day, so I'm not consuming during peak hours. Rinse and repeat.

I have a brand new 2800 sq ft home with 2 AC units, and I'm thinking 2 PowerWalls would be plenty to keep me running for a full day. I don't know much about the loan length/terms for PowerWalls, but could 2 Powerwalls pay for themselves in this way within the warranty period?

If you shop around, you may be able to find a free nights plan that covers the TDU charges as well. I live in the Houston area, where Direct Energy offers 12 hours of free power each night and credits you for both the energy and TDU charges (so it is truly free nights, 9a-9p). Powerwalls and solar run during the day. I mine bitcoin at night and really take advantage of the free power. So far, bills have barely exceeded $10 per month.

 

[TSLA Pilot]

Hi folks,

I am moving to a new home in a couple weeks, and am trying to validate whether the plan below is financially viable.

There are several energy plans in my area for "Free Nights and Weekends" where you only pay the TDU charges. I don't get enough regular sun to use solar - but would it make sense for me to get Powerwalls anyway?

I live in South Texas, HVAC use is HEAVY. My power bill in the summer months is about $300, and about $180 in the winter. That breaks down to

Energy: $0.071400 PER KWH
TDU: $0.044700 PER KWH
plus $8 in tax/fees.

If the PowerWalls run my house during the day, I can remove the majority of the "Energy" line, which would save me between $100-200 per month depending on the time of year.

My thought is -- what if I have the Powerwalls and my car charge at night during the "free" period, and then use that energy during the day, so I'm not consuming during peak hours. Rinse and repeat.

I have a brand new 2800 sq ft home with 2 AC units, and I'm thinking 2 PowerWalls would be plenty to keep me running for a full day. I don't know much about the loan length/terms for PowerWalls, but could 2 Powerwalls pay for themselves in this way within the warranty period?

First, you will likely need far more than two PW's.

If your builder is like most, they installed the cheapest, lowest quality HVAC units available. These units have a very high amp load ("LRA" on model ID sticker) on start up and this will overtax the available power from the PW's, unless you have a lot of them. See:

What Can Powerwall Back Up | Tesla Support

Learn more about the variety of home appliances and EV charging equipment that Tesla Powerwall can backup.

www.tesla.com

Second, one can no longer buy PW's without a solar array, so you should find a way to install at least SOME solar. That will help with your plan regardless as it allows off-grid operation, possibly for weeks on end, when the grid goes down again.

Third, be sure to write a review of your builder so that others will avoid buying from him/her. There should be a cost for builders that consistently find the cheapest, lowest quality HVAC equipment.

 

[bob_p]

Planning to game the system by charging PowerWalls from the grid at night, using a free nights plan, and then using the PowerWalls to power the house during the day (when electricity is more expense) - won't work in the long term. Energy companies are likely to detect this and put in exclusions for homes with only energy storage and no energy generation.

We were expecting to meet resistance when our current free nights plan came up for renewal - since we are only paying for 22% of our electricity usage. But Direct Energy came back offering us a 10% reduction in the electricity costs during the day and a 2 year renewal - which we snapped up immediately.

For anyone considering purchase of only PowerWalls, a couple of additional factors to consider:

1. Without solar panels, you won't qualify for the federal energy tax credit (currently 22%); if installed with solar panels, PowerWalls get the tax credit
2. Tesla changes the warranty when PowerWalls are charged exclusively from the grid, putting a cap on the number of charge cycles - which could shorten the warranty period

 

[Ampster]

Energy companies are likely to detect this and put in exclusions for homes with only energy storage and no energy generation.

Unless you send power to the grid from energy stored in a battery/inverter what is there to detect? It would only show up as a shift in load.
My strongly held belief is that we can do whatever we want behind the meter as long as we have a building permit. Other than noise, emissions and economics I have not heard of any reason someone could not supplement his home energy with a generator.
One caveat is a public utility run by a City which also controls the building code. Another caveat is a subsidized purchase which would have strings controlling how it is used.

 

[bob_p]

We have a private company responsible for the grid in our area, and their approval would likely be required even if we would only be adding energy storage - since that energy storage could potentially be sent back to the grid.

It's likely Direct Energy knows we have solar panels and PowerWalls - but so far, they aren't excluding homes like ours from the Free Nights plan, even though we may not be paying enough for electricity to cover their costs for our house.