New Tesla Solar Owner

[Dr Doom]

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.

PW is not 7k. it's 5900 dollars per power wall 2.0. First power wall you have to pay I think 700 dollars for initial installation of one. Each subsequent power wall is 200 dollars for installation costs.

The math isn't so simple. There are so many variable costs and factors to count. For example, you are assuming power company does not increase cost of electricity to keep up with cost of inflation. Also it depends when majority of power is being used.

 

[mongo]

PW is not 7k. it's 5900 dollars per power wall 2.0. First power wall you have to pay I think 700 dollars for initial installation of one. Each subsequent power wall is 200 dollars for installation costs.

The math isn't so simple. There are so many variable costs and factors to count. For example, you are assuming power company does not increase cost of electricity to keep up with cost of inflation. Also it depends when majority of power is being used.

Definitely true! Don't forget any tax credit/ rebates that will knock the cost down. I think if you install the batteries along with the solar, the solar credit extends to them also, but verify for your situation.

 

[Az_Rael]

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.

Timeline-wise I signed my contract in Sept 2017 for solar plus 2 powerwalls. We just passed our city inspection yesterday on the install and I have a few more weeks wait to turn the system on once my utility approves. This timeline was fully driven by Powerwall availability I believe.

 

[Dr Doom]

Definitely true! Don't forget any tax credit/ rebates that will knock the cost down. I think if you install the batteries along with the solar, the solar credit extends to them also, but verify for your situation.

Yep battery will get the 30% tax rebate if the energy used to charge battery is from a renewable resource like solar panel.

I might lose out on the full 30% because it's phasing out soon. I might not get a power wall until 2020 and that might be 25-27% tax rebate.

 

[Dr Doom]

Timeline-wise I signed my contract in Sept 2017 for solar plus 2 powerwalls. We just passed our city inspection yesterday on the install and I have a few more weeks wait to turn the system on once my utility approves. This timeline was fully driven by Powerwall availability I believe.

Congrats! did you get the 2 power walls already? also are they power walls 2.0?

 

[Az_Rael]

Congrats! did you get the 2 power walls already? also are they power walls 2.0?

Sure did! You can see my install here: Tesla Energy Solar + 2 Powerwall Install SoCal

I don't have a lot of feedback on the powerwalls yet as they are still turned off. I did get to see them working when the installer set up our app, so I am looking forward to turning the system on.

 

[NuShrike]

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.

Credit isn't the same thing as net-metering. Even the utilities here in California only offer $0.02 to $0.03 per kWh, but that's AFTER net-metering.

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.

Are you asking them about net-metering or credits for excess electricity? Maybe you need to talk to somebody else.

As for ROI using a battery, you'll never make it back for this generation of tech.

 

[Dr Doom]

Credit isn't the same thing as net-metering. Even the utilities here in California only offer $0.02 to $0.03 per kWh, but that's AFTER net-metering.

Are you asking them about net-metering or credits for excess electricity? Maybe you need to talk to somebody else.

As for ROI using a battery, you'll never make it back for this generation of tech.

I asked them about net metering. if I don't have any power wall or battery, the energy I would be producing would be giving me credit for energy I use later on.

Yep. That is true about the battery. I probably won't get the money back. To me, it's also about energy independence.

 

[Dr Doom]

Sure did! You can see my install here: Tesla Energy Solar + 2 Powerwall Install SoCal

I don't have a lot of feedback on the powerwalls yet as they are still turned off. I did get to see them working when the installer set up our app, so I am looking forward to turning the system on.

Love how the panels look and great that you got more efficient panels for the same cost. What made you get two power walls versus three or one? Thanks!

 

[Az_Rael]

Love how the panels look and great that you got more efficient panels for the same cost. What made you get two power walls versus three or one? Thanks!

Mostly costs. The state rebate here caps out at 2 powerwalls for small residential installs. Getting 2 allowed more flexibility of circuits covered (you can have larger circuits backed up if you have two). So jumping to 3 would have been a lot of extra costs for not much gain. We don't get a huge number of power outages at my house, so that would have been the only reason to consider more than 2 units. With two I should still be able to run the house in an extended outage, but will have to turn off the A/C, car chargers, etc.

 

[SongjinDK]

I am not sure about other power companies, I am in the San Francisco Bay area (with PG&E), here is how solar and net meter works:
1. During day time, I am selling power at peak rate ($0.45/kwh in summer) and get credit.
2. I charge my car during off peak hours (11pm to 7am) at $0.12/kwh.
So for each kwh solar generates, I can use 3.57 kwh to charge for free.

Also the credit are accumulated for a year, then if you net is positive (in dollar amount), you pay it. Otherwise if negative, you lose them. This means you can use a lot more electricity than you generate (in my case, about 4000 kwh per year) and pay zero due to price difference between peak and off peak hours.

So it would be better to sell the solar generated power to the grid at 45c and buy it back at 12c than store in PW. If I install PW, I would charge it at night from grid and sell it back to grid during peak hours. Is this allowed?

 

[Az_Rael]

If I install PW, I would charge it at night from grid and sell it back to grid during peak hours. Is this allowed?

Not yet. It is a feature that is coming though.

 

[Dr Doom]

I am not sure about other power companies, I am in the San Francisco Bay area (with PG&E), here is how solar and net meter works:
1. During day time, I am selling power at peak rate ($0.45/kwh in summer) and get credit.
2. I charge my car during off peak hours (11pm to 7am) at $0.12/kwh.
So for each kwh solar generates, I can use 3.57 kwh to charge for free.

Also the credit are accumulated for a year, then if you net is positive (in dollar amount), you pay it. Otherwise if negative, you lose them. This means you can use a lot more electricity than you generate (in my case, about 4000 kwh per year) and pay zero due to price difference between peak and off peak hours.

So it would be better to sell the solar generated power to the grid at 45c and buy it back at 12c than store in PW. If I install PW, I would charge it at night from grid and sell it back to grid during peak hours. Is this allowed?

$0.45 is really high even for peak hours for solar credit. Are you sure you have the numbers correct? I am going to charge my cars off peak hours.

 

[SongjinDK]

Not yet. It is a feature that is coming though.

With that feature, 2 PWs can generate about $2000/yr credit just by charging at night at 12c per kwh and selling it back at 42c per kwh in summary and 32c per hwh in winter, which is 16,000 kwh of charging at 12c at night. Are you sure power companies will allow this?

 

[Az_Rael]

Are you sure power companies will allow this?

Good question. Although with the various rebates most folks are probably using, being able to actually do grid arbitrage may be difficult. I believe to take the Solar Federal Tax credit on your batteries, the batteries have to be charged from some percentage of your solar.

I know Tesla will be enforcing the SGIP discharge requirements on folks who get that rebate, but the federal one is claimed by the homeowner, so not sure about that one. SGIP does allow power arbitrage though I believe.


Besides if you actually ended up +$2K in credits at your true up, then you wouldn't get paid that much - you only get pennies on the dollar at that point.

 

[TheTalkingMule]

Some very early adopters in some markets may be able to charge off the grid and sell during peak, but it won't last long. Payback at peak is high because that's where they need the supply right now, but solar greatly trims peak demand and batteries quickly smooth out supply shortfalls.

Hopefully the system moves rapidly to simple supply/demand pricing model based on something like blockchain.

All these dozens of unique payback schemes are purposely confusing so the utilities and fossil interests can maintain centralized dominance.

 

[cwied]

With that feature, 2 PWs can generate about $2000/yr credit just by charging at night at 12c per kwh and selling it back at 42c per kwh in summary and 32c per hwh in winter, which is 16,000 kwh of charging at 12c at night. Are you sure power companies will allow this?

I'm pretty sure PG&E will not allow this. My interconnect agreement with PG&E specifically calls out the system as a "non-Net Metering eligible power storage system." That means that power that comes exclusively from the powerwall cannot be fed back into the grid for net metering purposes. It's only my solar system that is net metering eligible, so while I can feed all the power from solar back to the grid, I can't do that from the powerwall.

Also note that charging from the grid makes you ineligible for the ITC. Tesla's approach to this seems to be to disallow any charging from the grid in the US for all powerwalls, irrespective of whether or not you want to claim the ITC.

 

[SongjinDK]

Thanks for all the helpful info. Do you have to have solar to buy PW? If not you have to charge it from grid.

 

[SongjinDK]

Besides if you actually ended up +$2K in credits at your true up, then you wouldn't get paid that much - you only get pennies on the dollar at that point.

You can use the $2k credit to charge your cars or power AC and Heat pump (without using gas furnace).

 

[Az_Rael]

You can use the $2k credit to charge your cars or power AC and Heat pump (without using gas furnace).

Oh, agreed if you size your system accordingly. I sized my solar system to take full advantage of net metering, even though Tesla wanted to put a much bigger system up. My goal was to zero out for the year using the net metering calculation in my favor. I could have sized my solar even smaller if I had taken into account arbitrage on the Powerwalls, but I am claiming the federal tax credit, so won’t actually be able to take advantage of that since my batteries have to be charged by my panels.

But if I just had Powerwalls with no solar, I would have done the sizing calculations based on arbitrage.