New Tesla Solar Owner

[Dr Doom]

After price shopping and comparing between different companies I decided to go with Solarcity/Tesla for the solar panels. Going to install 3 power walls after solar is installed.

A couple questions- time frame- I have been told it could be 3-4 months time frame. Is that average for most who have had Tesla install their panels?

Also what's usual wait time for power wall 2? How has everyone felt about the original estimates of energy production? Thanks! super excited about the installation coming so soon.

 

[Karma]

Dear Dr., start to finish was 6 months for me in Florida. I think installation varies a great deal by location, as permitting authorities can cause great delays (as well as power providers).
My sales rep told me 6 months when we first started, so that I wouldn't have any illusions.

 

[TheTalkingMule]

Don't you have net metering in NY? Not much need for a Powerwall if you do, especially in a region with such high air conditioning demands in summer.

 

[boaterva]

One reason for Powerwalls would be as a form of power outage insurance, for a short time. But is it worth it... trying to figure out that myself. We have net metering in Virginia, and I'm about to get a quote from Tesla now that they seem to have the new(er) panels around.

(Didn't mean to hijack... .)

 

[Dr Doom]

what is net metering? also if i have like three power walls to meet most of my electrical power needs, won't i ultimately save money?

 

[TheTalkingMule]

NY has 'net metering' which means your utility will supply you with one unit of electricity for every unit you push to the grid from your solar panels.

Think of your rooftop solar as a small power plant. During the day you supply(sell) electricity to the grid, at night you can then pull(buy) electricity from the grid using the net metering credits you built up all day.

Under this arrangement the grid essentially acts as your battery. So long as you size your solar array to produce 100% of your electricity demand, there's no need for a battery other than for backup during outages. Doubt you have many outages in NYC.

I also think it's helps force the energy transition when you use the grid in this manner. It provides the grid with power at peak times of peak days when AC demand is high(less new power plants) and also forces utilities to adjust to solar flowing through the grid intermittently(build out infrastructure for renewables).

 

[NuShrike]

A couple questions- time frame- I have been told it could be 3-4 months time frame. Is that average for most who have had Tesla install their panels?

3-4 seems longer than usual. It should be about a month+ for design and permits. Another month for installation, after-inspections, and then permission-to-operate (PTO). PW installation time is currently constrained by production limits.

 

[Dr Doom]

I live in NJ now. I do have net metering with my company rockland electric.

Wouldnt ultimately the power wall benefit me economically? I would be saving having to pull from the power company for most of my electrical needs and charge my car directly from the solar energy?

 

[mongo]

I live in NJ now. I do have net metering with my company rockland electric.

Wouldnt ultimately the power wall benefit me economically? I would be saving having to pull from the power company for most of my electrical needs and charge my car directly from the solar energy?

Imagine your solar makes an extra 10kWh in the day:
Option 1: You send that power to the grid, later you can pull 10kWh from the grid for free.
Option 2: You use the power to charge your PW, later you pull the power from your PW instead of the grid.

Option 1 is actually better because you avoid the round trip loss of charging and drawing from the battery (~90% efficient so you only get 9kWh back from the battery vs 10kWh from the meter).

If you didn't have net metering, Option 2 would be better since Option 1 would not exist (instead you would put 10kWh onto grid and get nothing back).

 

[Dr Doom]

Imagine your solar makes an extra 10kWh in the day:
Option 1: You send that power to the grid, later you can pull 10kWh from the grid for free.
Option 2: You use the power to charge your PW, later you pull the power from your PW instead of the grid.

Option 1 is actually better because you avoid the round trip loss of charging and drawing from the battery (~90% efficient so you only get 9kWh back from the battery vs 10kWh from the meter).

If you didn't have net metering, Option 2 would be better since Option 1 would not exist (instead you would put 10kWh onto grid and get nothing back).

Yes I understand option 1 but i talked to several solar companies and they said the money or credit that the 10kw generates is a fraction of what they charge the customer for the same energy.

 

[mongo]

Yes I understand option 1 but i talked to several solar companies and they said the money or credit that the 10kw generates is a fraction of what they charge the customer for the same energy.

Ah, then it is not net metering. On net metering you are charged (consumed - produced) * rate. With the setup you describe, it is likely better to store locally. If you can provide rates, then we can do an ROI calc easily.

 

[mongo]

Yes I understand option 1 but i talked to several solar companies and they said the money or credit that the 10kw generates is a fraction of what they charge the customer for the same energy.

Rockland and NJ appear to have 100% new metering, so you would be in Option 1.
Net Metering and Interconnection | NJ OCE Web Site

With net metering, your electric meter spins forward when electricity flows from the utility into the home, and backwards when power flows from the home to the utility. Your stored kWhs are "netted," or paid back, on an annual basis.

All electric utility companies regulated by the NJBPU (PSE&G, JCP&L, Atlantic City Electric, and Rockland Electric) and electric suppliers or providers must offer net metering to retail customers that generate electricity through renewable systems.

 

[FlyF4]

Are you folks talking about the solar roof tiles or panels? I'm curious to hear what the efficiency is for the roof tiles. I can't imagine it being very good compared to traditional tiles, but that is just a guess.

 

[mongo]

Are you folks talking about the solar roof tiles or panels? I'm curious to hear what the efficiency is for the roof tiles. I can't imagine it being very good compared to traditional tiles, but that is just a guess.

My understanding is that the cells themselves are within 1-2%(absolute output) or so of standard panels. Area efficiency is much less, of course. The recent installs used a percentage of active tiles based on household consumption and light available.

 

[Dr Doom]

My understanding is that the cells themselves are within 1-2%(absolute output) or so of standard panels. Area efficiency is much less, of course. The recent installs used a percentage of active tiles based on household consumption and light available.

Also solar tiles haven't been rolled out yet for public use. one lucky customer has installed it in CA but it seems they are years away from taking off. Also much much more expensive than traditional solar panels. I like the look of the solar tiles but I have a brand new roof and don't need to replace it for 20-30 more years.

 

[Dr Doom]

Rockland and NJ appear to have 100% new metering, so you would be in Option 1.
Net Metering and Interconnection | NJ OCE Web Site

I need to talk to my power company tomorrow. this is news to me. The solar companies I spoke to said that there isn't 100% net metering. it would be credit that won't be equivalent to what I pay for the same energy. maybe they got their info wrong.

if this is the case, the batteries really don't make much sense for me. I do want to be off grid but not at a cost of 18-20,000 dollars.

 

[mongo]

I need to talk to my power company tomorrow. this is news to me. The solar companies I spoke to said that there isn't 100% net metering. it would be credit that won't be equivalent to what I pay for the same energy. maybe they got their info wrong.

if this is the case, the batteries really don't make much sense for me. I do want to be off grid but not at a cost of 18-20,000 dollars.

There can also be differences in terms of what part of the fees are covered. It may be that the electricity itself is net, but distribution charges aren't.
Good luck with power company conversation!

 

[TheTalkingMule]

I need to talk to my power company tomorrow. this is news to me. The solar companies I spoke to said that there isn't 100% net metering. it would be credit that won't be equivalent to what I pay for the same energy. maybe they got their info wrong.

if this is the case, the batteries really don't make much sense for me. I do want to be off grid but not at a cost of 18-20,000 dollars.

Sales people who know you're interested in 2-3 Powerwalls are going to bend the narrative to push you in that direction. Batteries are adding $20k+ to the job and they probably get a massive commission bump. It's unfortunate, but that's how we source solar/batteries right now in the US.

I'm not sure of the net metering rules in NY, but in PA you get credit for what you push to the grid and can pull all those units of electricity back for free......up to 100% of your usage. If you produce more electricity than you use, they pay you a rate slightly less for the overage($.08/kWh in Pennsylvania). Overages carry over month-to-month and your credits are balanced out each May. So if you have more credits than you need in May....they pay you $.08 for each one and the whole count starts over from zero.

 

[Dr Doom]

There can also be differences in terms of what part of the fees are covered. It may be that the electricity itself is net, but distribution charges aren't.
Good luck with power company conversation!

Sales people who know you're interested in 2-3 Powerwalls are going to bend the narrative to push you in that direction. Batteries are adding $20k+ to the job and they probably get a massive commission bump. It's unfortunate, but that's how we source solar/batteries right now in the US.

I'm not sure of the net metering rules in NY, but in PA you get credit for what you push to the grid and can pull all those units of electricity back for free......up to 100% of your usage. If you produce more electricity than you use, they pay you a rate slightly less for the overage($.08/kWh in Pennsylvania). Overages carry over month-to-month and your credits are balanced out each May. So if you have more credits than you need in May....they pay you $.08 for each one and the whole count starts over from zero.

I talked to Rockland electric today. I live in northern jersey and unfortunately we don't have any choices. they are the only electrical provider in my area.

The price they would offer for credit for solar power is $0.02 to 0.03 per kwh. The market price may vary slightly but this is average. They charge me about $0.05 to 0.10 per kwh depending on hour usage and market pricing. Especially in summer, when AC is cranked up, it's $0.10 per kwh.

This is a big difference in my opinion. The net metering option 1 doesn't really equate. If I don't have a power wall installed, the solar panel electricity generated won't 100% credit me back the same money what I am charged on electricity later. It may offset it about 30-60% what I am charged later on for the same kwh energy.

To be fair to Tesla, I brought up the Tesla power wall idea and they have not pushed it. In fact, I mentioned it again to the energy consultant today and they kinda reluctantly added me to the reserve list.

If any Tesla power wall owners can chime in and kinda help out with the math and how they figured how many power walls to install or what convinced them to get power wall batteries.

 

[mongo]

I talked to Rockland electric today. I live in northern jersey and unfortunately we don't have any choices. they are the only electrical provider in my area.

The price they would offer for credit for solar power is $0.02 to 0.03 per kwh. The market price may vary slightly but this is average. They charge me about $0.05 to 0.10 per kwh depending on hour usage and market pricing. Especially in summer, when AC is cranked up, it's $0.10 per kwh.

This is a big difference in my opinion. The net metering option 1 doesn't really equate. If I don't have a power wall installed, the solar panel electricity generated won't 100% credit me back the same money what I am charged on electricity later. It may offset it about 30-60% what I am charged later on for the same kwh energy.

To be fair to Tesla, I brought up the Tesla power wall idea and they have not pushed it. In fact, I mentioned it again to the energy consultant today and they kinda reluctantly added me to the reserve list.

If any Tesla power wall owners can chime in and kinda help out with the math and how they figured how many power walls to install or what convinced them to get power wall batteries.

Sound like usage is charged the distribution fees.

So you save 0.02 to 0.07 per kWh by storing locally (adjusted for 90% efficiency). If a PW is 7k, you need to time shift 100,000 kWh to break even (best case kWh pricing). If you have a 10kW system with 5 hours of sun and save 50%, that is 25kWh per day shifted. 100,000/25 = 4,000 days or 11 years to break even. However, 25kWh would require 2 PWs. If they were $14k, you are now at a 22 year pay back. That is using the best case price numbers.
Your numbers/sizing/usage of course will vary.