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Considering Tesla Solar w/ Powerwalls in North Texas

JayKay80

New Member
May 25, 2020
4
0
Texas
I'm very new to solar and have only been looking into them for the past couple weeks and stumbled across this forum a few days ago. My initial interest was to have a battery backup for frequent power outages in our area and the Tesla Powerwall was the only solution I was aware of, so I started there. I quickly realized that just having a Powerwall without solar was not cost effective and the additional benefits of solar would help me justify the long-term expense.

After trying to take in as much information as I can online, I am ultimately down to 3 quotes I'm really considering:

1. Tesla - 11.34kW system with 3 Powerwalls; net cost of $32,560 ($2.87/W); not sure exactly on equipment being used since it isn't specified in the system design; 10/12/20/25 year warranty, or something like that
2. Local Company 1 - 11.62kW system with 2 Powerwalls; net cost of $56,823 ($4.89/W); All SunPower equipment, A415 panels w/microinverter); 25 year warranty on everything except for Powerwall, which is 10 years
3. Local Company 2 - 11.725kW system with 2 Powerwalls; net cost of $51,015 ($4.35/W); LG335N1K-V5 panels, Enphase IQ7-60-2-US inverters; 25 year warranty on everything, including the Powerwall (verified in their contract)

I didn't know anything about inverters until both the local companies tried to tell me how superior their microinverters were compared to Tesla's string inverter. They went on and on about the single point of failure, and also really hammered on how lousy Tesla's online reviews are, while both of their online reviews are exemplary. Despite all that information, I keep coming back to the Tesla quote and trying to justify it because of the 3rd Powerwall and the great pricing.

Sorry for the long ramble. Here's ultimately where I'm trying to get feedback. Are string inverters in the Tesla system a liability like the local companies are telling me that they are? How concerned should I be about the online reviews of Tesla's solar install and/or service? Even though it's a great warranty option, I'm also concerned about the 2nd local company that is providing a 25 year warranty on the Powerwalls. Hard for me to imagine what that service would really look like beyond the Tesla provided one, especially since the Powerwalls have only existed for a few years. Please, tell me where I'm crazy, dumb, foolish, naive, etc....I can take it.
 

roblab

Active Member
Jul 15, 2008
3,376
2,429
Angwin (Napa Valley) CA
No, you're very smart. Solar needs battery back up, and vice-versa, and inverters are part of the fun, to invert (convert) 12v to 240 v. so you can use it. I have two larger inverters, one for my 32 older roof panels, the other for 36 panels on the ground, about the same kWh you have. We've been using part of these for a dozen years, and haven't paid for electricity during that time, though part of it is reselling when I'm not using, and buying at night when I recharge my cars. But it all works. I have 3 power walls, and I wish I had more.
 
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Feathermerchan

Active Member
Sep 21, 2018
1,127
869
Euless, Tx
So how long will it take to pay back $30-50K? What do you pay for electricity now?
Are you in an area where you can choose your energy provider?
See Powertochoose.org to find out.
 

JayKay80

New Member
May 25, 2020
4
0
Texas
Yes, we are in a deregulated area where we can choose the provider, with Oncor as the actual power company. Our bills range from $100/mo in winter to $300+ in summer. I'm not sure exactly how to calculate the true payback on the systems since the Powerwalls aren't required and are a big chunk of the cost. Best guess is 15 years on the Tesla system, and 20 years on the other ones.
 

gigawatt1010

Member
Aug 21, 2016
461
468
Orange County, New York
You need to start by comparing apples to apples. Factoring in the cost of the powerwall when comparing to your electricity consumption is not a good calculation.

Take your annual average monthly payment that you pay your power company for electric. Compare that to your monthly payment if you’re taking a loan out for your $30k solar system. The goal is to make it equal to, or less.

The cost of the Powerwalls come into equation if you’re planning to install a generator. Get quotes for a whole house gas generator and compare that to the cost of the Powerwalls.

Good luck. The fact that you’re here tells me you’re really leaning on the Tesla system. Cost being one of the main factors of any financial decisions, you can’t go wrong with that price. I don’t think your local guys can touch the price due to Tesla’s economy of scale.
 
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JayKay80

New Member
May 25, 2020
4
0
Texas
You need to start by comparing apples to apples. Factoring in the cost of the powerwall when comparing to your electricity consumption is not a good calculation.

Take your annual average monthly payment that you pay your power company for electric. Compare that to your monthly payment if you’re taking a loan out for your $30k solar system. The goal is to make it equal to, or less.

The cost of the Powerwalls come into equation if you’re planning to install a generator. Get quotes for a whole house gas generator and compare that to the cost of the Powerwalls.

Good luck. The fact that you’re here tells me you’re really leaning on the Tesla system. Cost being one of the main factors of any financial decisions, you can’t go wrong with that price. I don’t think your local guys can touch the price due to Tesla’s economy of scale.

I am leaning toward the Tesla system, but am trying to weigh the pros and cons. There's no doubt we come out the best on price with it as well, and it saves us money each month, AND has the 3 Powerwalls. My struggle is with the equipment and service compared to the other quotes, and is it worth it to spend the extra money.
 

GenSao

Member
Aug 3, 2017
527
895
Pleasant Hill, CA
JayKay80,

Welcome to the TMC. Enjoy your stay.

An advantage to micro-inverters are the benefits of higher production during partial shading and the 25 year warranty. The warranty is covered by the manufacturer. A disadvantage is that roof access is required to replace a faulty micro-inverter.

The Enphase micro-inverters rely on the Enphase IQ Envoy installed in the Enphase IQ combiner for monitoring, command and control. Unfortunately, this is a single point of failure the other installers will forget to mention. Tesla's inverters carry the manufacturer's 10 year warranty. In both cases, they are typically installed on ground level and can be easily accessed and replaced as needed.

IMHO, the cost difference between Tesla and the 3rd party installers alone is worth the consideration. Yes, Tesla's customer service can be a hit or miss and they use "standard equipment"; but their "standard prices" prices are great. If you need total customization, (potentially) better service, at a higher price, go with a well regarded 3rd party installer.

As a side note, a less green, more cost effective solution for backup only would be the installation of a natural gas generator. Depending on local energy rates, the cost of Powerwalls may be recouped by time-of-use rate arbitrage. Rely on solar and battery power duing peak rates.

If you want to save some money (and if they meet your needs) you can downsize to two Powerwalls.
 
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gpez

Member
Apr 25, 2019
634
509
USA
JayKay80,

Welcome to the TMC. Enjoy your stay.

An advantage to micro-inverters are the benefits of higher production during partial shading and the 25 year warranty. The warranty is covered by the manufacturer. A disadvantage is that roof access is required to replace a faulty micro-inverter.

The Enphase micro-inverters rely on the Enphase IQ Envoy installed in the Enphase IQ combiner for monitoring, command and control. Unfortunately, this is a single point of failure the other installers will forget to mention. Tesla's inverters carry the manufacturer's 10 year warranty. In both cases, they are typically installed on ground level and can be easily accessed and replaced as needed.

IMHO, the cost difference between Tesla and the 3rd party installers alone is worth the consideration. Yes, Tesla's customer service can be a hit or miss and they use "standard equipment"; but their "standard prices" prices are great. If you need total customization, (potentially) better service, at a higher price, go with a well regarded 3rd party installer.

As a side note, a less green, more cost effective solution for backup only would be the installation of a natural gas generator. Depending on local energy rates, the cost of Powerwalls may be recouped by time-of-use rate arbitrage. Rely on solar and battery power duing peak rates.

If you want to save some money (and if they meet your needs) you can downsize to two Powerwalls.

My system is an IQ6 + IQ Combiner system and I've been quite happy with it. The equipment wasn't terribly expensive and there is a decent remote interface to the system (though Tesla's app and features are better so that's sort of moot). +1 on GenSao's observation that the combiner is a single point of failure though I would add that it's a different failure type than an inverter failure.

In my location Tesla would have bid out my project to a local installer and while the pricing wasn't as wide as what you're seeing @JayKay80 I found working with one directly was quite advantageous (supposedly I was the first residential Powerwall install they did).

I'll note that my choice to go PV+Powerwall was in direct comparison with a home standby natural gas generator. Went with the PV+Powerwall system because:

a) A whole-home natural gas generator quote was close to $15k after permitting, upgrades, parts, labor, fees, and taxes. The Powerwall was $7.5k thanks to the ITC.

b) Part of my backup profile was a hedge against earthquakes, natural gas supply will very likely be disrupted with a moderate+ earthquake. Not sure how your natural gas supply is during emergencies but that may be a factor.

c) Maintenance of a Powerwall is literally $0, a standby generator has to be tested every month, oiled, maintained, etc. Running a Powerwall during an outage costs $0, a standby generator can be quite costly.

d) Even though we don't have ToU pricing today I could easily see our utility changing as EVs become more popular and grid demand trough to peak differences start to widen. It's a bit of a hedge.

e) It's freakin' cool. The Powerwall is a much sexier piece of garage wall candy than a generator ;)
 

JayKay80

New Member
May 25, 2020
4
0
Texas
JayKay80,

Welcome to the TMC. Enjoy your stay.

An advantage to micro-inverters are the benefits of higher production during partial shading and the 25 year warranty. The warranty is covered by the manufacturer. A disadvantage is that roof access is required to replace a faulty micro-inverter.

The Enphase micro-inverters rely on the Enphase IQ Envoy installed in the Enphase IQ combiner for monitoring, command and control. Unfortunately, this is a single point of failure the other installers will forget to mention. Tesla's inverters carry the manufacturer's 10 year warranty. In both cases, they are typically installed on ground level and can be easily accessed and replaced as needed.

IMHO, the cost difference between Tesla and the 3rd party installers alone is worth the consideration. Yes, Tesla's customer service can be a hit or miss and they use "standard equipment"; but their "standard prices" prices are great. If you need total customization, (potentially) better service, at a higher price, go with a well regarded 3rd party installer.

As a side note, a less green, more cost effective solution for backup only would be the installation of a natural gas generator. Depending on local energy rates, the cost of Powerwalls may be recouped by time-of-use rate arbitrage. Rely on solar and battery power duing peak rates.

If you want to save some money (and if they meet your needs) you can downsize to two Powerwalls.

Thanks, @GenSao. That's interesting info on the Enphase system and single point of failure. Definitely not brought up by the other companies that are trashing the string inverters. I agree on the price difference and that's why I keep coming back to it despite any other perceived cons.

The gas generator isn't really an option for us. We briefly looked at a Generac, but the cost, noise, aesthetics, etc, made it a non-starter.

We don't really have any shading issues, so should I not be so concerned with the string inverters from Tesla?
 

jboy210

Supporting Member
Dec 2, 2016
4,849
2,982
Northern California
My system is an IQ6 + IQ Combiner system and I've been quite happy with it. The equipment wasn't terribly expensive and there is a decent remote interface to the system (though Tesla's app and features are better so that's sort of moot). +1 on GenSao's observation that the combiner is a single point of failure though I would add that it's a different failure type than an inverter failure.

In my location Tesla would have bid out my project to a local installer and while the pricing wasn't as wide as what you're seeing @JayKay80 I found working with one directly was quite advantageous (supposedly I was the first residential Powerwall install they did).

I'll note that my choice to go PV+Powerwall was in direct comparison with a home standby natural gas generator. Went with the PV+Powerwall system because:

a) A whole-home natural gas generator quote was close to $15k after permitting, upgrades, parts, labor, fees, and taxes. The Powerwall was $7.5k thanks to the ITC.

b) Part of my backup profile was a hedge against earthquakes, natural gas supply will very likely be disrupted with a moderate+ earthquake. Not sure how your natural gas supply is during emergencies but that may be a factor.

c) Maintenance of a Powerwall is literally $0, a standby generator has to be tested every month, oiled, maintained, etc. Running a Powerwall during an outage costs $0, a standby generator can be quite costly.

d) Even though we don't have ToU pricing today I could easily see our utility changing as EVs become more popular and grid demand trough to peak differences start to widen. It's a bit of a hedge.

e) It's freakin' cool. The Powerwall is a much sexier piece of garage wall candy than a generator ;)

I also looked at a natgas generators and would add:

  • Generator would be noisy to run
  • Powerwall can be use every day to offset my needs for power from the grid. And every dollar I do not give PG&E makes my day better.
 

jaed

Member
Jan 6, 2017
69
84
California
Just looking at the installation cost Tesla seams way cheaper. I had the same thing in the Bay Area. Local installers where 20 to 30k more than Tesla. From what I have read and I could be wrong but the component that breaks the most is the inverter. With a string inverter if an inverter breaks it seams easier to replace being on the wall by your electrical panel. For my system Tesla is going to install a Solar Edge inverter with optimizers seams very standard in the industry.

Few things to consider:
- I hear you only get the Fed tax credit on the batteries if you install when your getting solar at the same time. (Tesla sales guy said this not 100% sure)
- Tax credits are dropping fast. 2020: 26% - 2021 22% - and 2202 10% from then on

With a 20k delta and a extra power wall even if you have some customer service issues I would say it is worth it.
You could replace the inverter a lot of times for that much money.
Tesla has been fine to work with so far even tho we are in the honeymoon stage waiting for the system to be installed.


Here is the warranty info from my contact if that helps:

_____________________________________

Solar panels

Your solar panels are covered by a warranty from their manufacturer. This warranty will be at least 12 years for workmanship and will guarantee at least 80% of nameplate power capacity for at least 25 years. This warranty will be transferred to you automatically when you pay the Contract Price. At your request we will make any claim under this warranty on your behalf and perform any related labor at our cost.

Inverter

Your inverter is covered by a warranty from its manufacturer. This warranty will cover defects for at least 10 years, and will be transferred to you automatically when you pay the Contract Price. At your request we will make any claim under this warranty on your behalf and perform any related labor at our cost. If you need to replace your inverter after this warranty expires, please contact us and we will help you obtain and install a replacement, both at your cost.

Powerwall

Your Powerwall is covered by the Tesla Powerwall Limited Warranty. The Tesla Powerwall Limited Warranty includes the arbitration provision contained in Section 18 below. By approving this Agreement, you accept the terms of the Tesla Powerwall Limited Warranty.

Workmanship

We warrant that (a) our installation workmanship will be free from defects for 20 years from the date your Products are installed (or, in the case of main panel or structural upgrades, 1 year from the date those upgrades were performed); (b) our installation workmanship will not invalidate the manufacturer’s warranty for your solar panels or inverter, or the Tesla Powerwall Limited Warranty; (c) all roof penetrations we make will be watertight for the longer of 10 years or until the end of any existing installation warranty or new home builder performance standard for your roof; and (d) we will not damage your property during our installation of your Products. If we breach this warranty, we will repair the defective work, roof penetration or damage at our cost. If we can’t do this ourselves, we will pay for someone else to do it. This shall not extend the original warranty period, but the remainder of the original warranty period shall apply to the repair work.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
7,799
8,625
Riverside Co. CA
Few things to consider:
- I hear you only get the Fed tax credit on the batteries if you install when your getting solar at the same time. (Tesla sales guy said this not 100% sure)
- Tax credits are dropping fast. 2020: 26% - 2021 22% - and 2202 10% from then on

.

Actually, you can take the Federal Tax credit on the powerwalls as long as they are attached to solar. It doesnt have to be installed at the same time as the solar was, it just has to be connected to (and charged by) the solar.

So:

PV (solar) install = Federal Income Tax credit in place at time of full install (which is scaling down as you noted)
batteries (Powerwall in this case) NOT charged by solar = No federal tax credit, regardless of when installed.
Batteries (Powerwall in this case) Charged by solar = Federal tax credit, regardless of whether it was installed at same time as PV or not.
 
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Reactions: gigawatt1010

GenSao

Member
Aug 3, 2017
527
895
Pleasant Hill, CA
Thanks, @GenSao. That's interesting info on the Enphase system and single point of failure. Definitely not brought up by the other companies that are trashing the string inverters. I agree on the price difference and that's why I keep coming back to it despite any other perceived cons.

The gas generator isn't really an option for us. We briefly looked at a Generac, but the cost, noise, aesthetics, etc, made it a non-starter.

We don't really have any shading issues, so should I not be so concerned with the string inverters from Tesla?

I am glad you did take a look at the generator option. Gpez and Jboy210 make great points.

With no shading issues, I would not worry too much about the use of string inverters. If for some reason the inverter fail past the 10 year warranty period, the cost should not be too bad ($2,000?). Might as well consider re-configuring the solar at the same time to match the new inverter and add solar panels to match current power use.
 

bob_p

Active Member
Apr 5, 2012
3,643
2,778
We installed a 15.4 KW/4 PowerWall system in Houston a few months ago.

Texas has only a few net metering plans, and if you use any net electricity from the grid, that will cost more than normal flat rate plans.

Our goal was to generate at least 50% of our energy from our new system. The PowerWalls are used to store energy during the day and then use that energy to power the house overnight. On fully sunny days, we have been able to operate off grid for multiple days. But when there are clouds, we'll use more electricity.

Without net metering, PowerWalls are a critical element - providing power to the house when there isn't any sun.

When we estimated our "break even" point, we subtracted $10K from our system cost (for the purpose of estimating break even) because we were also planning to use the system for emergency backup power (hurricanes), and a generator would have cost us at least $10K.

Our current electricity plan costs us $.091/KWh. When that plan expires in a few weeks, we may shift to a "free nights" plan, charging a higher rate for electricity from 9AM to 9PM and providing unlimited free electricity between 9PM and 9AM. Using smart meter data (at 15 minute intervals), I'm going to compare what our electricity costs would be under a new fixed rate plan vs. a free nights plan, and based on data collected this year, it looks like a free nights plan could reduce our electric bill by another 50%.

As to the OP's comparison of Tesla's system cost vs. others - until Tesla has evaluated the specific installation, it's possible their actual costs could be higher than the estimate pulled from the Tesla website.

For example, on the Tesla website, it's estimate a 15.12 KW/4 PowerWall system would cost around $56K (before federal tax credits). The actual cost would have been higher, because of complications with our installation (on a concrete spanish tile roof).

Though if Tesla is providing a $10K credit for installing 4 PowerWalls together with the solar, that's a pretty good deal and something none of the other installers may have difficulty matching.
 

ZBB

Emperor
Feb 27, 2013
1,549
270
Scottsdale
We installed a 15.4 KW/4 PowerWall system in Houston a few months ago.

Texas has only a few net metering plans, and if you use any net electricity from the grid, that will cost more than normal flat rate plans.

...

Our current electricity plan costs us $.091/KWh. When that plan expires in a few weeks, we may shift to a "free nights" plan, charging a higher rate for electricity from 9AM to 9PM and providing unlimited free electricity between 9PM and 9AM. Using smart meter data (at 15 minute intervals), I'm going to compare what our electricity costs would be under a new fixed rate plan vs. a free nights plan, and based on data collected this year, it looks like a free nights plan could reduce our electric bill by another 50%.
Just curious, what did you end up doing?

We're now in Houston and are in process of ordering Tesla Solar+Powerwall (reviewing the layout stage). Been thinking through how to compare the free night plans vs net metering plans. Curious about others experiences...

One of the complications we have is that the house is new construction, and we moved in last July. So I don't have a full year's worth of energy use yet. Plus our AC system wasn't balanced properly until late Sept -- so our usage was much higher than it needed (several vents were closed off, resulting in the system running much more than necessary)...
 

bob_p

Active Member
Apr 5, 2012
3,643
2,778
When we had the system installed, I signed us up for the lowest fixed price 6 months plan that was available.

After monitoring usage under that plan, I was able to confirm a Free Nights plan would be less expensive. When our 6 month plan came up for renewal, we switched to a 12 month Free Nights plan from Direct Energy - with free electricity from 9PM to 9AM and paying around $.20/KWh from 9AM to 9PM. Also shifted some of the loads (pool equipment, EV charging) into the Free Nights period to help reduce costs.

During the first 5 months of 2020, under the fixed price plan, we paid $549 for electricity, compared to $1745 in 2019 before the solar panels - almost a 70% savings with the solar panels and PowerWalls.

But, if we had been under the Free Nights plan, our electric costs for the first 5 months would have dropped to $250 - and additional savings of $300!

In 2019 our electric costs were $4726 for the entire year - under the Free Nights plan, we would have reduced that to $788 - an 84% reduction in our electric costs!

Of course, we were also in a pandemic, so driving was down - which meant we were charging our Model S and X less - and that contributed to some of the cost savings last year.

According to our usage numbers for last year - 22% of our electricity usage was during the prime 9AM to 9PM period. Our house circuits used 30.2MWh, the solar panels generated 17.8MWh, we used 14MWh of grid power (days and nights) and sent back .5MWh of excess power back to the grid. I estimated we used around 5.6MWh to charge our S & X - under the free nights plan - this charging is free.

After we installed our system, we ran some tests to identify the largest energy draws in the house. We replaced the bulbs that are on the most with LEDs. We have a pool with a main pump and a waterfall pump (in 2019 - the pool pumps used 30% of our electricity!). When the pool was installed, we used a variable speed pump for the main pump - allowing us to save electricity by lowering the pump speed to the minimum needed. But, the second pump was a fixed speed pump - for the waterfall. We didn't realize how much electricity that pump was using (for a purely cosmetic effect) - we were running the pump 7 hours a day - and it used 6.2MWh of power (15% of our power usage!) - just for a decorative waterfall! After installing the solar panels - we modified the pool pump schedule to reduce electricity cost - and we recently replaced the waterfall pump with a variable speed pump, drastically reducing the energy. And when we shifted to the Free Nights plan - programmed the system to run the pumps as much as possible between 9PM to 9AM.

Once the system is installed, it's pretty easy to see how much load devices are generating by using the Tesla app to monitor power consumption/generation.
 

h2ofun

Active Member
Aug 11, 2020
1,656
271
auburn, ca
When we had the system installed, I signed us up for the lowest fixed price 6 months plan that was available.

After monitoring usage under that plan, I was able to confirm a Free Nights plan would be less expensive. When our 6 month plan came up for renewal, we switched to a 12 month Free Nights plan from Direct Energy - with free electricity from 9PM to 9AM and paying around $.20/KWh from 9AM to 9PM. Also shifted some of the loads (pool equipment, EV charging) into the Free Nights period to help reduce costs.

During the first 5 months of 2020, under the fixed price plan, we paid $549 for electricity, compared to $1745 in 2019 before the solar panels - almost a 70% savings with the solar panels and PowerWalls.

But, if we had been under the Free Nights plan, our electric costs for the first 5 months would have dropped to $250 - and additional savings of $300!

In 2019 our electric costs were $4726 for the entire year - under the Free Nights plan, we would have reduced that to $788 - an 84% reduction in our electric costs!

Of course, we were also in a pandemic, so driving was down - which meant we were charging our Model S and X less - and that contributed to some of the cost savings last year.

According to our usage numbers for last year - 22% of our electricity usage was during the prime 9AM to 9PM period. Our house circuits used 30.2MWh, the solar panels generated 17.8MWh, we used 14MWh of grid power (days and nights) and sent back .5MWh of excess power back to the grid. I estimated we used around 5.6MWh to charge our S & X - under the free nights plan - this charging is free.

After we installed our system, we ran some tests to identify the largest energy draws in the house. We replaced the bulbs that are on the most with LEDs. We have a pool with a main pump and a waterfall pump (in 2019 - the pool pumps used 30% of our electricity!). When the pool was installed, we used a variable speed pump for the main pump - allowing us to save electricity by lowering the pump speed to the minimum needed. But, the second pump was a fixed speed pump - for the waterfall. We didn't realize how much electricity that pump was using (for a purely cosmetic effect) - we were running the pump 7 hours a day - and it used 6.2MWh of power (15% of our power usage!) - just for a decorative waterfall! After installing the solar panels - we modified the pool pump schedule to reduce electricity cost - and we recently replaced the waterfall pump with a variable speed pump, drastically reducing the energy. And when we shifted to the Free Nights plan - programmed the system to run the pumps as much as possible between 9PM to 9AM.

Once the system is installed, it's pretty easy to see how much load devices are generating by using the Tesla app to monitor power consumption/generation.
I have noticed I have been doing the same thing. With the tesla app, I can see in real time what is happening to house loads.
 

ZBB

Emperor
Feb 27, 2013
1,549
270
Scottsdale
Thanks for the update! I'll have to play with our meter data to see what I can estimate would be the best plan based on usage since we moved in...
 

mully

Member
Oct 5, 2016
26
18
Cypress, TX
When we had the system installed, I signed us up for the lowest fixed price 6 months plan that was available.

After monitoring usage under that plan, I was able to confirm a Free Nights plan would be less expensive. When our 6 month plan came up for renewal, we switched to a 12 month Free Nights plan from Direct Energy - with free electricity from 9PM to 9AM and paying around $.20/KWh from 9AM to 9PM. Also shifted some of the loads (pool equipment, EV charging) into the Free Nights period to help reduce costs.

During the first 5 months of 2020, under the fixed price plan, we paid $549 for electricity, compared to $1745 in 2019 before the solar panels - almost a 70% savings with the solar panels and PowerWalls.

But, if we had been under the Free Nights plan, our electric costs for the first 5 months would have dropped to $250 - and additional savings of $300!

In 2019 our electric costs were $4726 for the entire year - under the Free Nights plan, we would have reduced that to $788 - an 84% reduction in our electric costs!

Of course, we were also in a pandemic, so driving was down - which meant we were charging our Model S and X less - and that contributed to some of the cost savings last year.

According to our usage numbers for last year - 22% of our electricity usage was during the prime 9AM to 9PM period. Our house circuits used 30.2MWh, the solar panels generated 17.8MWh, we used 14MWh of grid power (days and nights) and sent back .5MWh of excess power back to the grid. I estimated we used around 5.6MWh to charge our S & X - under the free nights plan - this charging is free.

After we installed our system, we ran some tests to identify the largest energy draws in the house. We replaced the bulbs that are on the most with LEDs. We have a pool with a main pump and a waterfall pump (in 2019 - the pool pumps used 30% of our electricity!). When the pool was installed, we used a variable speed pump for the main pump - allowing us to save electricity by lowering the pump speed to the minimum needed. But, the second pump was a fixed speed pump - for the waterfall. We didn't realize how much electricity that pump was using (for a purely cosmetic effect) - we were running the pump 7 hours a day - and it used 6.2MWh of power (15% of our power usage!) - just for a decorative waterfall! After installing the solar panels - we modified the pool pump schedule to reduce electricity cost - and we recently replaced the waterfall pump with a variable speed pump, drastically reducing the energy. And when we shifted to the Free Nights plan - programmed the system to run the pumps as much as possible between 9PM to 9AM.

Once the system is installed, it's pretty easy to see how much load devices are generating by using the Tesla app to monitor power consumption/generation.
I am happy to hear how well the Direct Energy Free Nights plan is working for you. We are finalizing our Tesla solar order right now with a similar set-up having a Model X and a pool. I will most likely be switching to Direct Energy once we make the switch. My current electricity plan is not over until next March, but it sounds like it will be worth the $150 fee to cancel and switch to the Free Nights plan as soon as my system comes online.
 

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