Solar Install w/ SolarCity

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mmcmonster
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Solar Install w/ SolarCity

Post by mmcmonster » Sat Sep 15, 2018 4:57 pm

Just wanted to write my experience down regarding my solar installation with SolarCity (now Tesla). I started the process in 12/2017 and started generating energy in 9/2018.

The system took longer to install because they were limited by supplies of the batteries and their installation teams are running thin.

My System:
300W Panels * 62 Panels = 18.6 kW system
Estimated yearly energy production: 21,048 kWh
41.5 kWh storage with 3 PowerWalls (each has capacity of 13.5 kWh)
Total system cost $76k prior to deductions (there's a 30% federal deduction on my taxes for next year)

Over the last three years we average ~19,300 kWh @ 12.5cents/kWh ($2400)
We got the PowerWalls instead of getting a home generator and it acts as both generator and whole-house surge protection. Getting a similar propane generator would have cost us $15k (installed).

Using all the above, we figured that $76k*.7 (30% tax rebate) - $15k (generator cost) = $38.2k.

Meaning 16 years to pay off for the Solar installation ($38.2k/$2400). During which time I will (hopefully) get continuous clean power (no over or under voltages) with instantaneous battery backup during outages, which should cover me 100% in days with clear skies.

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unclescrooge
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Re: Solar Install w/ SolarCity

Post by unclescrooge » Sat Sep 15, 2018 5:06 pm

Wow, that's seems really expensive, in terms of pay back time. :shock:

Also, aren't the batteries rated for 10 years of use?

JoeNJ28
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Re: Solar Install w/ SolarCity

Post by JoeNJ28 » Sat Sep 15, 2018 5:20 pm

Thanks for the overview after we do a new roof we plan on having panels installed, so it’s always nice to see prices people are paying out there to get a ballpark of what it will cost.

Balefire
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Re: Solar Install w/ SolarCity

Post by Balefire » Sat Sep 15, 2018 5:21 pm

Where do you live?
What's the approximate 1st floor SQ footage of your house?
Why is the generator deducted from the cost?


Considering putting Tesla solar panels when I build my next house so thanks for the math example

ThriftyPhD
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Re: Solar Install w/ SolarCity

Post by ThriftyPhD » Sat Sep 15, 2018 5:28 pm

Balefire wrote:
Sat Sep 15, 2018 5:21 pm
Why is the generator deducted from the cost?
mmcmonster wrote:
Sat Sep 15, 2018 4:57 pm
We got the PowerWalls instead of getting a home generator and it acts as both generator and whole-house surge protection. Getting a similar propane generator would have cost us $15k (installed).

Big Dog
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Re: Solar Install w/ SolarCity

Post by Big Dog » Sat Sep 15, 2018 6:50 pm

19k kWh seems like a lot of juice. How big is your house? Electric heat/heatpump?

3504PIR
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Re: Solar Install w/ SolarCity

Post by 3504PIR » Sat Sep 15, 2018 6:56 pm

At first glance that seems like a huge system but we really need to know how big your house is. I also think what you’ve done is awesome. I’m looking at a system about 1/3 of yours and debating 1 vs 2 power walls. Based on the size of your home, I’m curious how long 3 would give you assuming no charging occurred.

How much were each power wall?

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Sat Sep 15, 2018 7:33 pm

Some replies to the questions:

We live in the North East Pennsylvania area. About an hour north of Philadelphia, an hour west of New York City.

The panels cover the entire west side (back) of the house and a bit of the south side.

The house is probably 5500-6000 square foot, including a finished basement. Heating is Propane. The excessive electrical usage is because it includes charging for a Tesla Model S which is getting about 1900 miles/month. (Probably should have added that in with the original post!)

Because of the car, I am still dependent on the grid. (if the batteries fill to 100% it gives me 41.5 kWh. My car has an 85 kWh battery.) So I will fill my battery during the day, then excess will go into the grid. When I plug in my car after work I will drain my battery (I keep 5% of the battery as a safety margin) and then use the grid to fill the car. The battery will replenish from the solar the following day. Overnight the house runs off the grid.

The recommendation was to get three PowerWalls so that I could provide the current flow (240V/30 amps) to the car without using the grid. Didn't take into account the total amount of power I would need to completely charge the car.

The PowerWall has two modes of operation. The most common is to fill up with solar during the day and drain down to a minimum amount (I set at 5%) after the sun goes down. A second mode is to stay at 100% and only use when the grid is down. There's also a setting so that it will go into the second mode if a major weather event is in the forecast.

fareastwarriors
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Re: Solar Install w/ SolarCity

Post by fareastwarriors » Sat Sep 15, 2018 7:49 pm

Thanks for sharing. Could you separate the panel cost from the Powerwall cost?

3504PIR
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Re: Solar Install w/ SolarCity

Post by 3504PIR » Sat Sep 15, 2018 8:01 pm

Awesome.

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Sat Sep 15, 2018 8:04 pm

fareastwarriors wrote:
Sat Sep 15, 2018 7:49 pm
Thanks for sharing. Could you separate the panel cost from the Powerwall cost?
They didn't give a breakdown for the PowerWalls. They did say it was roughly ~$7k each, plus installation costs.

emoore
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Re: Solar Install w/ SolarCity

Post by emoore » Sat Sep 15, 2018 8:33 pm

Congrats. We are probably doing the same. Will have Tesla install panels. Don’t have an EV yet but will get one soon. You should be proud and excited with the difference you are making.

runner3081
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Re: Solar Install w/ SolarCity

Post by runner3081 » Sat Sep 15, 2018 8:47 pm

Interesting analysis. As others have mentioned, that is too long of a break-even to interest me.

Here in Arizona, solar sounds great, but there is quite a penalty from the electric company (fees) for going with solar. We looked into it, but our relatively low use of AC would make the payoff even longer than 16 years.

emoore
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Re: Solar Install w/ SolarCity

Post by emoore » Sat Sep 15, 2018 9:09 pm

runner3081 wrote:
Sat Sep 15, 2018 8:47 pm
Interesting analysis. As others have mentioned, that is too long of a break-even to interest me.

Here in Arizona, solar sounds great, but there is quite a penalty from the electric company (fees) for going with solar. We looked into it, but our relatively low use of AC would make the payoff even longer than 16 years.
Sometimes it’s not all about money. My break even is over 10 years but I’m not happy with the electric company progress to renewable energy. It’s great that I have something to say about that now.

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pondering
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Re: Solar Install w/ SolarCity

Post by pondering » Sat Sep 15, 2018 9:34 pm

Is there anything I can put on my roof that would tell me my generating capacity that doesn't cost a lot of money?
--Robert Sterbal | 412-977-3526 call/text, I find speech easier than writing

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Sun Sep 16, 2018 5:41 am

pondering wrote:
Sat Sep 15, 2018 9:34 pm
Is there anything I can put on my roof that would tell me my generating capacity that doesn't cost a lot of money?
The SolarCity rep came to my house and took some pictures of the roof and anything tall enough to put shade on it (we have one tree near the house). He then put all the info into an app that had a Google Map of my house on it, calculated the pitch of the roof, and the program figured out how much electricity a single panel would produce on each side of the roof throughout the year.

I have no idea how accurate it is. Ask me in a year. :D

You can find a SolarCity rep at your local Home Depot. They advertise there. It's a free consultation.

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Sun Sep 16, 2018 5:54 am

runner3081 wrote:
Sat Sep 15, 2018 8:47 pm
Interesting analysis. As others have mentioned, that is too long of a break-even to interest me.

Here in Arizona, solar sounds great, but there is quite a penalty from the electric company (fees) for going with solar. We looked into it, but our relatively low use of AC would make the payoff even longer than 16 years.
Our local electric company with credit us in the form of # of kWh we push onto the grid. They convert that number to a dollar amount once a year. They will let you choose the date of the year that they convert it to the dollar amount.

The idea is that you produce an excess of kWh in the summer, use up the excess in the winter, and re-zero your account in the Spring when you're starting to produce enough so that you are net-producer to the grid.

So if you don't produce over 100% of your usage over the course of the whole year, you never need to "sell" them energy.

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pondering
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Re: Solar Install w/ SolarCity

Post by pondering » Sun Sep 16, 2018 6:35 am

mmcmonster wrote:
Sun Sep 16, 2018 5:41 am
pondering wrote:
Sat Sep 15, 2018 9:34 pm
Is there anything I can put on my roof that would tell me my generating capacity that doesn't cost a lot of money?
The SolarCity rep came to my house and took some pictures of the roof and anything tall enough to put shade on it (we have one tree near the house). He then put all the info into an app that had a Google Map of my house on it, calculated the pitch of the roof, and the program figured out how much electricity a single panel would produce on each side of the roof throughout the year.

I have no idea how accurate it is. Ask me in a year. :D

You can find a SolarCity rep at your local Home Depot. They advertise there. It's a free consultation.
I want to collect data regarding the effect of cloud cover. We have a lot of rainy and cloudy days in western PA
--Robert Sterbal | 412-977-3526 call/text, I find speech easier than writing

Balefire
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Re: Solar Install w/ SolarCity

Post by Balefire » Sun Sep 16, 2018 7:07 am

pondering wrote:
Sat Sep 15, 2018 9:34 pm
Is there anything I can put on my roof that would tell me my generating capacity that doesn't cost a lot of money?
https://www.google.com/get/sunroof#p=0

Valuethinker
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Re: Solar Install w/ SolarCity

Post by Valuethinker » Sun Sep 16, 2018 7:28 am

Balefire wrote:
Sat Sep 15, 2018 5:21 pm
Where do you live?
What's the approximate 1st floor SQ footage of your house?
Why is the generator deducted from the cost?


Considering putting Tesla solar panels when I build my next house so thanks for the math example
You do need to measure the solar insolation but that shouldn't be hard to do (there are also postcode based estimates, I believe).

If you build in at the design stage, this should be economic. Of course it depends the terms on which your local utility buys back power, but panel prices have come down by so much -- it's the installation that costs the money.

If you go for solar roof tiles for aesthetic reasons that could significantly increase the cost. Flat panels are probably the best, however the shading effect (and thus a lower cooling load) is maximized with panels that are angled to the roof line.

(It depends on latitude but I think that the optimal angle is 30 degrees around typical North American latitudes. I am not entirely sure, though.)

Time of day has a big impact. Maximum productivity is panels faced south (of course). However the most valuable power on an electricity grid is c 4pm - 7pm and in summer, west facing panels (and panels with sufficiently high angle) maximize power then. So, again, local factors count.

https://www.amazon.com/Solar-Power-Your ... 0470596783

probably as good a place to start as any.

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pondering
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Re: Solar Install w/ SolarCity

Post by pondering » Sun Sep 16, 2018 7:28 am

Balefire wrote:
Sun Sep 16, 2018 7:07 am
pondering wrote:
Sat Sep 15, 2018 9:34 pm
Is there anything I can put on my roof that would tell me my generating capacity that doesn't cost a lot of money?
https://www.google.com/get/sunroof#p=0
Much appreciated!
--Robert Sterbal | 412-977-3526 call/text, I find speech easier than writing

ddurrett896
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Re: Solar Install w/ SolarCity

Post by ddurrett896 » Sun Sep 16, 2018 7:56 am

mmcmonster wrote:
Sat Sep 15, 2018 4:57 pm

My System:
41.5 kWh storage with 3 PowerWalls (each has capacity of 13.5 kWh)

Over the last three years we average ~19,300 kWh @ 12.5cents/kWh ($2400)
Am I reading this right? You use on average 19,300 kWh/year and three Powerwallas store 41.5 kWH, meaning once they are full charged, you will have 2 years of whole home run time with grid power?

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Sun Sep 16, 2018 8:52 am

ddurrett896 wrote:
Sun Sep 16, 2018 7:56 am
mmcmonster wrote:
Sat Sep 15, 2018 4:57 pm

My System:
41.5 kWh storage with 3 PowerWalls (each has capacity of 13.5 kWh)

Over the last three years we average ~19,300 kWh @ 12.5cents/kWh ($2400)
Am I reading this right? You use on average 19,300 kWh/year and three Powerwallas store 41.5 kWH, meaning once they are full charged, you will have 2 years of whole home run time with grid power?
Not sure how you got that. ;-) I fully charge during the day and discharge at night. How low I discharge to essentially depends on how much I drive the electric car. But certainly I can potentially fully discharge the battery at night since it holds 41.5 kWh and my car's batteries hold 85kWh.

ddurrett896
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Re: Solar Install w/ SolarCity

Post by ddurrett896 » Sun Sep 16, 2018 9:49 am

mmcmonster wrote:
Sun Sep 16, 2018 8:52 am
ddurrett896 wrote:
Sun Sep 16, 2018 7:56 am
mmcmonster wrote:
Sat Sep 15, 2018 4:57 pm

My System:
41.5 kWh storage with 3 PowerWalls (each has capacity of 13.5 kWh)

Over the last three years we average ~19,300 kWh @ 12.5cents/kWh ($2400)
Am I reading this right? You use on average 19,300 kWh/year and three Powerwallas store 41.5 kWH, meaning once they are full charged, you will have 2 years of whole home run time with grid power?
Not sure how you got that. ;-) I fully charge during the day and discharge at night. How low I discharge to essentially depends on how much I drive the electric car. But certainly I can potentially fully discharge the battery at night since it holds 41.5 kWh and my car's batteries hold 85kWh.
I was trying to determine how much power your house will consume in the event of an outage, since the $15k is deduced from the total in place of a generator.

finite_difference
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Re: Solar Install w/ SolarCity

Post by finite_difference » Sun Sep 16, 2018 10:29 am

ddurrett896 wrote:
Sun Sep 16, 2018 9:49 am
mmcmonster wrote:
Sun Sep 16, 2018 8:52 am
ddurrett896 wrote:
Sun Sep 16, 2018 7:56 am
mmcmonster wrote:
Sat Sep 15, 2018 4:57 pm

My System:
41.5 kWh storage with 3 PowerWalls (each has capacity of 13.5 kWh)

Over the last three years we average ~19,300 kWh @ 12.5cents/kWh ($2400)
Am I reading this right? You use on average 19,300 kWh/year and three Powerwallas store 41.5 kWH, meaning once they are full charged, you will have 2 years of whole home run time with grid power?
Not sure how you got that. ;-) I fully charge during the day and discharge at night. How low I discharge to essentially depends on how much I drive the electric car. But certainly I can potentially fully discharge the battery at night since it holds 41.5 kWh and my car's batteries hold 85kWh.
I was trying to determine how much power your house will consume in the event of an outage, since the $15k is deduced from the total in place of a generator.
Hint: 19300 kWh/year * [1 year / 365 day] ~= 53 kWh/day.

So he can power for less than one full day using the powerwalls. But if he can use the Tesla as well to provide power to the house then he has ~ 120 kWh so should be OK for a couple days. Also, presumably he can shut off a bunch of stuff and then he’ll be able to last longer.

Edit: plus he’ll have solar to help reduce the load. So unless it’s extremely cloudy / dark due to wintertime that will help quite a bit as well.
The most precious gift we can offer anyone is our attention. - Thich Nhat Hanh

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Mon Sep 17, 2018 5:14 am

finite_difference wrote:
Sun Sep 16, 2018 10:29 am
ddurrett896 wrote:
Sun Sep 16, 2018 9:49 am
mmcmonster wrote:
Sun Sep 16, 2018 8:52 am
ddurrett896 wrote:
Sun Sep 16, 2018 7:56 am
mmcmonster wrote:
Sat Sep 15, 2018 4:57 pm

My System:
41.5 kWh storage with 3 PowerWalls (each has capacity of 13.5 kWh)

Over the last three years we average ~19,300 kWh @ 12.5cents/kWh ($2400)
Am I reading this right? You use on average 19,300 kWh/year and three Powerwallas store 41.5 kWH, meaning once they are full charged, you will have 2 years of whole home run time with grid power?
Not sure how you got that. ;-) I fully charge during the day and discharge at night. How low I discharge to essentially depends on how much I drive the electric car. But certainly I can potentially fully discharge the battery at night since it holds 41.5 kWh and my car's batteries hold 85kWh.
I was trying to determine how much power your house will consume in the event of an outage, since the $15k is deduced from the total in place of a generator.
Hint: 19300 kWh/year * [1 year / 365 day] ~= 53 kWh/day.

So he can power for less than one full day using the powerwalls. But if he can use the Tesla as well to provide power to the house then he has ~ 120 kWh so should be OK for a couple days. Also, presumably he can shut off a bunch of stuff and then he’ll be able to last longer.

Edit: plus he’ll have solar to help reduce the load. So unless it’s extremely cloudy / dark due to wintertime that will help quite a bit as well.
It's 53 kWh/day including the use of the Tesla. If I have a total loss of the grid, I'll have my wife drive the Tesla to work (if she is working on a day without power :shock: ) and I'll take her gas-powered car. Since her work is 5 miles away and mine is almost 30 miles away, our electrical usage for the day will go down nicely. Hopefully the solar panels can cover the lower load indefinitely.

Also, I don't think I can use the Tesla Model S to power the house. I never heard of that actually happening.

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TomatoTomahto
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Re: Solar Install w/ SolarCity

Post by TomatoTomahto » Mon Sep 17, 2018 6:14 am

Also, I don't think I can use the Tesla Model S to power the house. I never heard of that actually happening.
People have asked about that for years. Won’t work.

If you manage to not kill yourself trying to Jerry rig it, your warranty will evaporate.
Okay, I get it; I won't be political or controversial. The Earth is flat.

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TomatoTomahto
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Re: Solar Install w/ SolarCity

Post by TomatoTomahto » Mon Sep 17, 2018 6:35 am

emoore wrote:
Sat Sep 15, 2018 9:09 pm
runner3081 wrote:
Sat Sep 15, 2018 8:47 pm
Interesting analysis. As others have mentioned, that is too long of a break-even to interest me.

Here in Arizona, solar sounds great, but there is quite a penalty from the electric company (fees) for going with solar. We looked into it, but our relatively low use of AC would make the payoff even longer than 16 years.
Sometimes it’s not all about money. My break even is over 10 years but I’m not happy with the electric company progress to renewable energy. It’s great that I have something to say about that now.
Amen.

Our solar panels “planted” the equivalent of around 4500 trees, or saved the equivalent of 90 TONS of CO2.

Our geothermal (not yet installed) will have a payback period of 10 years or so, but our house will be quieter, more comfortable, and smell better without oil.

We are waiting for Tesla to release 400A gateways before installing Powerwalls (large house). Tesla only has 200A gateways now.

There is value, priceless value, in taking a guilt free shower or setting the thermostat for comfort.
Okay, I get it; I won't be political or controversial. The Earth is flat.

mouses
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Re: Solar Install w/ SolarCity

Post by mouses » Mon Sep 17, 2018 6:52 am

emoore wrote:
Sat Sep 15, 2018 9:09 pm
runner3081 wrote:
Sat Sep 15, 2018 8:47 pm
Interesting analysis. As others have mentioned, that is too long of a break-even to interest me.

Here in Arizona, solar sounds great, but there is quite a penalty from the electric company (fees) for going with solar. We looked into it, but our relatively low use of AC would make the payoff even longer than 16 years.
Sometimes it’s not all about money. My break even is over 10 years but I’m not happy with the electric company progress to renewable energy. It’s great that I have something to say about that now.
I understand various utilities are hiking fees to make off the grid systems less economical. Shame on them, and kudos to the OP.

criticalmass
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Re: Solar Install w/ SolarCity

Post by criticalmass » Mon Sep 17, 2018 8:52 am

mouses wrote:
Mon Sep 17, 2018 6:52 am
emoore wrote:
Sat Sep 15, 2018 9:09 pm
runner3081 wrote:
Sat Sep 15, 2018 8:47 pm
Interesting analysis. As others have mentioned, that is too long of a break-even to interest me.

Here in Arizona, solar sounds great, but there is quite a penalty from the electric company (fees) for going with solar. We looked into it, but our relatively low use of AC would make the payoff even longer than 16 years.
Sometimes it’s not all about money. My break even is over 10 years but I’m not happy with the electric company progress to renewable energy. It’s great that I have something to say about that now.
I understand various utilities are hiking fees to make off the grid systems less economical. Shame on them, and kudos to the OP.
It may not be gouging as you may think. Solar power production can start & stop suddenly due to changing weather, yet most customers expect their power to be available regardless of weather. Across a wide area, that can be very rough on a grid, and can require utilities to build more peaking fossil fuel plants that can start & stop rapidly without destabilizing the grid. This is no small feat in a rapid time sequence. This peaking plant capital and operating expense is borne by all customers unless the folks who use the grid as a battery or backup pay fees.

smitcat
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Re: Solar Install w/ SolarCity

Post by smitcat » Mon Sep 17, 2018 9:19 am

TomatoTomahto wrote:
Mon Sep 17, 2018 6:35 am
emoore wrote:
Sat Sep 15, 2018 9:09 pm
runner3081 wrote:
Sat Sep 15, 2018 8:47 pm
Interesting analysis. As others have mentioned, that is too long of a break-even to interest me.

Here in Arizona, solar sounds great, but there is quite a penalty from the electric company (fees) for going with solar. We looked into it, but our relatively low use of AC would make the payoff even longer than 16 years.
Sometimes it’s not all about money. My break even is over 10 years but I’m not happy with the electric company progress to renewable energy. It’s great that I have something to say about that now.
Amen.

Our solar panels “planted” the equivalent of around 4500 trees, or saved the equivalent of 90 TONS of CO2.

Our geothermal (not yet installed) will have a payback period of 10 years or so, but our house will be quieter, more comfortable, and smell better without oil.

We are waiting for Tesla to release 400A gateways before installing Powerwalls (large house). Tesla only has 200A gateways now.

There is value, priceless value, in taking a guilt free shower or setting the thermostat for comfort.

Perhaps other issues to consider when making choices....
https://money.cnn.com/video/technology/ ... index.html

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Mon Sep 17, 2018 11:17 am

criticalmass wrote:
Mon Sep 17, 2018 8:52 am
mouses wrote:
Mon Sep 17, 2018 6:52 am
emoore wrote:
Sat Sep 15, 2018 9:09 pm
runner3081 wrote:
Sat Sep 15, 2018 8:47 pm
Interesting analysis. As others have mentioned, that is too long of a break-even to interest me.

Here in Arizona, solar sounds great, but there is quite a penalty from the electric company (fees) for going with solar. We looked into it, but our relatively low use of AC would make the payoff even longer than 16 years.
Sometimes it’s not all about money. My break even is over 10 years but I’m not happy with the electric company progress to renewable energy. It’s great that I have something to say about that now.
I understand various utilities are hiking fees to make off the grid systems less economical. Shame on them, and kudos to the OP.
It may not be gouging as you may think. Solar power production can start & stop suddenly due to changing weather, yet most customers expect their power to be available regardless of weather. Across a wide area, that can be very rough on a grid, and can require utilities to build more peaking fossil fuel plants that can start & stop rapidly without destabilizing the grid. This is no small feat in a rapid time sequence. This peaking plant capital and operating expense is borne by all customers unless the folks who use the grid as a battery or backup pay fees.
Sound like the power companies need to invest in battery technology. The Tesla batteries are able to take up sudden increases in load nearly instantaneously (much faster than any generator or power plant could spin up).

https://news.slashdot.org/story/18/05/1 ... 90-percent

criticalmass
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Re: Solar Install w/ SolarCity

Post by criticalmass » Mon Sep 17, 2018 3:23 pm

mmcmonster wrote:
Mon Sep 17, 2018 11:17 am
criticalmass wrote:
Mon Sep 17, 2018 8:52 am
mouses wrote:
Mon Sep 17, 2018 6:52 am
emoore wrote:
Sat Sep 15, 2018 9:09 pm
runner3081 wrote:
Sat Sep 15, 2018 8:47 pm
Interesting analysis. As others have mentioned, that is too long of a break-even to interest me.

Here in Arizona, solar sounds great, but there is quite a penalty from the electric company (fees) for going with solar. We looked into it, but our relatively low use of AC would make the payoff even longer than 16 years.
Sometimes it’s not all about money. My break even is over 10 years but I’m not happy with the electric company progress to renewable energy. It’s great that I have something to say about that now.
I understand various utilities are hiking fees to make off the grid systems less economical. Shame on them, and kudos to the OP.
It may not be gouging as you may think. Solar power production can start & stop suddenly due to changing weather, yet most customers expect their power to be available regardless of weather. Across a wide area, that can be very rough on a grid, and can require utilities to build more peaking fossil fuel plants that can start & stop rapidly without destabilizing the grid. This is no small feat in a rapid time sequence. This peaking plant capital and operating expense is borne by all customers unless the folks who use the grid as a battery or backup pay fees.
Sound like the power companies need to invest in battery technology. The Tesla batteries are able to take up sudden increases in load nearly instantaneously (much faster than any generator or power plant could spin up).

https://news.slashdot.org/story/18/05/1 ... 90-percent
If you can produce enough battery power economically for a utility to power the grid for a city, state, or FERC/ISO region, I am sure that many utilities would love to invest in your technology. And distribution utilities are likely to get ratepayers to pay for technology upgrades.

Do the Tesla batteries create toxic waste or use toxic materials for their construction like lithium batteries? That would be a serious barrier for utilities to consider en masse.

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Mon Sep 17, 2018 5:08 pm

criticalmass wrote:
Mon Sep 17, 2018 3:23 pm
mmcmonster wrote:
Mon Sep 17, 2018 11:17 am
Sound like the power companies need to invest in battery technology. The Tesla batteries are able to take up sudden increases in load nearly instantaneously (much faster than any generator or power plant could spin up).

https://news.slashdot.org/story/18/05/1 ... 90-percent
If you can produce enough battery power economically for a utility to power the grid for a city, state, or FERC/ISO region, I am sure that many utilities would love to invest in your technology. And distribution utilities are likely to get ratepayers to pay for technology upgrades.

Do the Tesla batteries create toxic waste or use toxic materials for their construction like lithium batteries? That would be a serious barrier for utilities to consider en masse.
What I'm saying is that getting a large enough battery on the grid, which is what one of the states in Australia did, will allow the utility to smoothen out those load spikes and dips near-instantaneously, allowing the production to rely more on renewables and less on coal or gasoline turbines.

https://www.reuters.com/article/us-aust ... SKBN1DV3VR

I don't know how economical it is, but it already exists in the state of South Australia and apparently stabilized the power system there.

Keeping us on-topic: Consider investing in battery tech and companies that can do large scale deployments to improve the electrical grid.

Thesaints
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Re: Solar Install w/ SolarCity

Post by Thesaints » Mon Sep 17, 2018 5:13 pm

If you have lots of sunlight and a small, dispersed, population, batteries + solar certainly make sense.
In other situations they might be a terrible solution.

kacang
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Re: Solar Install w/ SolarCity

Post by kacang » Mon Sep 17, 2018 6:43 pm

For those who have installed power walls, did this affect your home insurance?

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Tue Sep 18, 2018 4:04 pm

kacang wrote:
Mon Sep 17, 2018 6:43 pm
For those who have installed power walls, did this affect your home insurance?
I told my insurance agent (State Farm) about the installation. They increased my coverage by about the same as the total cost of the installation. He also came by and took pictures of the panel layout and number of panels.

The SolarCity rep suggested an umbrella polity of at least $2M (I already had that amount as my umbrella). The Solar City warranty does not cover hail (or, presumably, other weather damage).

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Sat Sep 07, 2019 12:50 pm

mmcmonster wrote:
Sat Sep 15, 2018 4:57 pm
Just wanted to write my experience down regarding my solar installation with SolarCity (now Tesla). I started the process in 12/2017 and started generating energy in 9/2018.

The system took longer to install because they were limited by supplies of the batteries and their installation teams are running thin.

My System:
300W Panels * 62 Panels = 18.6 kW system
Estimated yearly energy production: 21,048 kWh
41.5 kWh storage with 3 PowerWalls (each has capacity of 13.5 kWh)
Total system cost $76k prior to deductions (there's a 30% federal deduction on my taxes for next year)

Over the last three years we average ~19,300 kWh @ 12.5cents/kWh ($2400)
We got the PowerWalls instead of getting a home generator and it acts as both generator and whole-house surge protection. Getting a similar propane generator would have cost us $15k (installed).

Using all the above, we figured that $76k*.7 (30% tax rebate) - $15k (generator cost) = $38.2k.

Meaning 16 years to pay off for the Solar installation ($38.2k/$2400). During which time I will (hopefully) get continuous clean power (no over or under voltages) with instantaneous battery backup during outages, which should cover me 100% in days with clear skies.
(Not mentioned originally, I drive a Tesla ~1900miles/month and my house is 5500-6000 sq foot. In addition, heating for the house is via liquid propane.)

Adding in some data, as I've just completed one year with the system on.

* Actual energy production over the past 12 months: 21,179 kWh.
* Estimated amount saved: $2,417 in first year.
* My cost of electricity in 2018 was 11.8¢/kWh. My cost in 2019 was 11.3¢/kWh.
* I still get a bill from the electric company in months that I generate more than I use. The excess cost is a distribution charge, essentially to have an electric service). It comes out to $17.18/month, but this amount has gone up over the last few months. In March it was $16.38.
* In May 2019, the electric company reimbursed me for excess I produced at a rate of 7.04¢/kWh, sending me a check for $89.18. This is because the company zeroes all the kWh credits in May and I start from scratch, building up credits in the Summer and using them up in the Winter. Since I will be creating more than I use starting in March, my guess is that I will always get a check of about this much every May and will always pay for electricity in January and February.
* Six power outages for which I used battery backup over the year. Five of them were power outages lasting ~1-5 minutes each. One of them lasted ~1.5 hours. I never noticed any of the events (lights didn't appreciably flicker), except that the phone app told me that I was suddenly using battery power.

Overall, still very happy with the decision. A little less happy as the electric company is lowering the cost of electricity (lowering my potential savings) and increasing the distribution cost (increasing my fixed monthly expense). I'm concerned that as more people in my area get solar, they will increase the distribution cost more.

Valuethinker
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Re: Solar Install w/ SolarCity

Post by Valuethinker » Sun Sep 08, 2019 6:22 am

Thank you for the update.

I suggest that you write to your local Public Utility Commission and Express your concern. These letters do get read and they are factored into rate hearings for the local Distribution Network Operator (DNO - British term at least).

At some point you might wish to consider either Air Source or Geothermal heat pump. The main issues are then that you would be totally dependent upon your electricity supply for AC and heat as well.

And HP efficiency is inverse to the gap between input and output temperatures. Thus the output temp unless the electric bar heating has kicked in will feel cold compared to propane/ gas furnace. Works best with well insulated very airtight houses which only the most modern North American houses approximate. HPs run best all the time rather than the "bursts" which we do with propane or gas.

As a rule of thumb if you convert your BTUs into kwhr (lots of online calculators out there but from memory 3466 BTUs is 1 kwhr) then assuming you have a 90 per cent plus efficient furnace (ie one w a secondary heat exchanger) each kwhr heat output is c 0.23 kg of carbon dioxide (plus various other pollutants but much cleaner than say auto exhaust).

Running the same calculation on your utility electricity is tricky. They may publish a figure for average carbon intensity. But it varies greatly as baseload is coal and nuclear usually, mid merit is coal plus combined cycle gas turbine and peak is gas. Renewables being semi randomly all over the shop.

FYI

Per kwhr coal is about 1.1 kg (plus lots other nasties in particular the sum PM 2.5 particles, future generations are going to wonder why we ever unleashed these on the air we breath).

1000 kg = 1 metric tonne = c 2254 lbs from memory.

Combined Cycle Gas Turbine is about 0.54 kg. But very few other pollutants.

Open Cycle Gas Turbine (essentially an aero engine stationary) is around 0.8 from memory (it's only half as efficient as a combined cycle plant).

Using natural gas in an efficient furnace is about 0.23. However a heat pump is 2x to 4x kwhr of heat moved per kwhr electricity used so the efficiency for heating of the above is say 90 per cent and for a HP 200 to 400 per cent.

Somewhere around 20 degrees F the electric bar (resistance) heating coil kicks in and efficiency is then 100 per cent ie pretty close to a propane heater.

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DanMahowny
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Re: Solar Install w/ SolarCity

Post by DanMahowny » Sun Sep 08, 2019 10:19 am

$76,000 !!!

Now, that's a big electric bill. WOW!
Funding secured

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mmcmonster
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Re: Solar Install w/ SolarCity

Post by mmcmonster » Sun Sep 08, 2019 12:51 pm

DanMahowny wrote:
Sun Sep 08, 2019 10:19 am
$76,000 !!!

Now, that's a big electric bill. WOW!
As I mentioned in my initial post, I essentially pre-paid my electric and car gas bills for 16 years. :beer

Dilbydog
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Re: Solar Install w/ SolarCity

Post by Dilbydog » Sun Sep 08, 2019 1:27 pm

OP... I’m very interested to see what your actual annual generation numbers look like. With the majority of your modules facing westward, I would think your production would be less than what Solar City ‘estimated’.

Did they install micro-inverters or string inverters for your system?

The power wall setup, does that feed your entire home? (IE every outlet and fixture) My understanding is that the power wall system would need to be hooked up to a sub panel with an ATS to prevent the battery system from back feeding the grid during an outage.

Thegame14
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Re: Solar Install w/ SolarCity

Post by Thegame14 » Sun Sep 08, 2019 2:45 pm

if you have the money to buy a tesla, and the solar panels, love the idea.

We got solar two years ago, system is PV system power 7.9 kWP annual production estimate of 9,904 kwH/kWP. We paid $28K for the panels before the 30% credit, so about $20K for the panels, we save $2K a year in energy costs, and get about $2K per year in SREC's so payback is around 5 years not including financing costs, but those are also tax deductible.

we talked about getting the battery, but our solar company said it is SUPER expensive still and there are new manufacturers coming out and the price should drop a lot on the batteries and we can add them later. Id love to add some more panels, add batteries and get a tesla eventually, but right now all my money goes to two small kids, and trying to get safer vehicles, hopefully it is in the future plans...

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TomatoTomahto
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Re: Solar Install w/ SolarCity

Post by TomatoTomahto » Sun Sep 08, 2019 2:55 pm

Thegame14 wrote:
Sun Sep 08, 2019 2:45 pm
we talked about getting the battery, but our solar company said it is SUPER expensive still and there are new manufacturers coming out and the price should drop a lot on the batteries and we can add them later.
A lot also depends on how often your grid goes down. Just last week, we (and 1100 other homes) were down for almost 2 hours, on a beautiful summer day. Apparently “animal activity.” We seem to have 5 or more outages per year, especially when Nor'easters hit. Since our heating is geothermal, with no carbon-based backup, it matters a lot if we are out of power for a couple of days.

In your situation: wait. They’ll be more affordable some day.
Okay, I get it; I won't be political or controversial. The Earth is flat.

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FrugalInvestor
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Re: Solar Install w/ SolarCity

Post by FrugalInvestor » Sun Sep 08, 2019 2:58 pm

mouses wrote:
Mon Sep 17, 2018 6:52 am
I understand various utilities are hiking fees to make off the grid systems less economical. Shame on them, and kudos to the OP.
If you are off the grid how can the utility company charge you fees?
IGNORE the noise! | Our life is frittered away by detail... simplify, simplify. - Henry David Thoreau

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TomatoTomahto
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Re: Solar Install w/ SolarCity

Post by TomatoTomahto » Sun Sep 08, 2019 4:24 pm

FrugalInvestor wrote:
Sun Sep 08, 2019 2:58 pm
mouses wrote:
Mon Sep 17, 2018 6:52 am
I understand various utilities are hiking fees to make off the grid systems less economical. Shame on them, and kudos to the OP.
If you are off the grid how can the utility company charge you fees?
Many states (MA, for one) require that you remain on the grid, even if you generate all the power you consume. They benefit from our homes’ power and batteries to smooth peak demand.
Okay, I get it; I won't be political or controversial. The Earth is flat.

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ClevrChico
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Re: Solar Install w/ SolarCity

Post by ClevrChico » Sun Sep 08, 2019 5:05 pm

unclescrooge wrote:
Sat Sep 15, 2018 5:06 pm
Wow, that's seems really expensive, in terms of pay back time. :shock:

Also, aren't the batteries rated for 10 years of use?
+1, I agree having recently looked at solar. I'd want a five year payback time or better to pursue it. OP's system seems very expensive. I'd rather spend the money on energy efficiency, windows, etc.

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SmallCityDave
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Re: Solar Install w/ SolarCity

Post by SmallCityDave » Sun Sep 08, 2019 6:47 pm

That's a heck of a system. We got solar last week our intent was financial not political nor was it to save the planet.

Here is a quick snapshot of our system and the finances behind it, I won't go into too much detail. Our system is rated at 7.2kw plus they added the .8kw system (home built) that we already had so 8kw combined for $15,800 - after taxes credits it should be $10k.

Last week our utility company charged us $.108kwh and that will go down to $.08kwh in November (because we are on solar) plus they will pay $.064 when we export that price will be locked in for 10 years. I was hoping that the system would pay for itself in 10 years but looking at all thee numbers I'm hopeful it will be less.

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unclescrooge
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Re: Solar Install w/ SolarCity

Post by unclescrooge » Sun Sep 08, 2019 7:19 pm

SmallCityDave wrote:
Sun Sep 08, 2019 6:47 pm
That's a heck of a system. We got solar last week our intent was financial not political nor was it to save the planet.

Here is a quick snapshot of our system and the finances behind it, I won't go into too much detail. Our system is rated at 7.2kw plus they added the .8kw system (home built) that we already had so 8kw combined for $15,800 - after taxes credits it should be $10k.

Last week our utility company charged us $.108kwh and that will go down to $.08kwh in November (because we are on solar) plus they will pay $.064 when we export that price will be locked in for 10 years. I was hoping that the system would pay for itself in 10 years but looking at all thee numbers I'm hopeful it will be less.
What were your previous utility bills?

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SmallCityDave
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Re: Solar Install w/ SolarCity

Post by SmallCityDave » Sun Sep 08, 2019 8:29 pm

unclescrooge wrote:
Sun Sep 08, 2019 7:19 pm
SmallCityDave wrote:
Sun Sep 08, 2019 6:47 pm
That's a heck of a system. We got solar last week our intent was financial not political nor was it to save the planet.

Here is a quick snapshot of our system and the finances behind it, I won't go into too much detail. Our system is rated at 7.2kw plus they added the .8kw system (home built) that we already had so 8kw combined for $15,800 - after taxes credits it should be $10k.

Last week our utility company charged us $.108kwh and that will go down to $.08kwh in November (because we are on solar) plus they will pay $.064 when we export that price will be locked in for 10 years. I was hoping that the system would pay for itself in 10 years but looking at all thee numbers I'm hopeful it will be less.
What were your previous utility bills?
$180 per month using 1350kw per month , all electric home.

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