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First PowerWall2 installed in Houston TX.
- Thread starter JAWZ2020
- Start date
JasJ
Member
Does this system create a 'mini-grid' so you can go offline for a bit if the main utility goes dark (e.g. in a hurricane)?
Kind of like the system described here: Micro-grid AC Coupling
Kind of like the system described here: Micro-grid AC Coupling
2012MS85
Member
No, his system is expected to produce about 1300 kWh of energy per year for each kW of capacity. So multiply 1300 x 7.56 to get 9828 kWh per year, which is 819 per month. So you'll need an even bigger system.
My 10.4 kW DC system (9.0 ACPV with enphase microinverters) is approaching its 1st Bday June 1st. Its average monthly production is about 1MWh. With a sunny May, I should end the year at 12.5 MWh of total production (AC to my home). And I'm in less sunny Iowa (where snowy winters really kill my average). Yet my annual ratio of kWh /kW will be about 1200 DC and 1400 AC. Since we all really care about how much AC energy is going into our home, it's important to keep in mind whether numbers being quoted are DC or AC. The amount of Direct Current produced by your solar panels is limited by the size of your inverter (or 40 M215 microinverters rated at 225 watts each, in my case).
2012MS85
Member
Wow, on top of the first PW2 installation, your price was amazingly low. Well done!! Solar installed in Iowa averages $3 per watt, although it's slowly falling. If your installed PW2 was TESLA's estimated $7k, then $17k for the solar equates to only $2.25 per watt. You should again feel proud as that may be another record for a residential price. (I've seen utility scale solar at or under $2 per watt installed, but those are MW, not kW.) India just did their world record gigantic solar farm for a bit over $1 per watt, but their permits and labor costs are pennies on the dollar vs USA.
I'd be interested what others are paying around the USA for their installed cost per watt of capacity? Maybe SolarCity/TESLA Energy is giving quantity discounts to promote solar+battery? I had read in years past that SolarCity had usually been quite pricey (since they were covering the financing in most cases).
Tex EV
Member
That's a great deal! I'm also in the Cy-Fair area and my 12.6kW system with no batteries was twice as much installed last year by a local company. I'm currently with Reliant on their solar buy-back plan (11.7c/kWh both ways). Very interested in seeing what the Powerwall is capable of. Please continue to share your experiences.
Per watt, that's cheaper than SolarCity's quotes in California *without* battery storage! I understand that electric rates are much lower in Texas than in California, so perhaps SolarCity/Tesla has to charge less to remain competitive.
I have one question if you wouldn't mind. My understanding is that whenever the grid goes down, your surplus solar production (whatever isn't being used to power your home) will be used to charge the PW2. However, your 7.56 kW PV system will, at midday, generate more power than the maximum charge rate of your single PW2, which is 5 kW. Did SolarCity explain what will happen in that scenario? I am wondering if the PV system would need to disconnect, in which case the battery wouldn't charge at all.
I'm asking because I'll be in the same boat, with an existing 6.48 kW PV system and plans to install a single PW2.
Am I understanding correctly that the local prevailing energy rate is about 11.7c/kWh and the system will save 9882.43 KWh/year, so an annual savings of $1,156/yr. Also assuming after incentives of 30%, the cost was about $16,800 so a pay back period of about 14.5 years (assuming constant local energy pricing and ignoring interest expense)?
It looks like Texas has an exemption in its property tax code for renewable energy additions so your investment shouldn't affect your property taxes. SECO | Renewable Energy
2012MS85
Member
Perhaps @JAWZ2020 can confirm if he owns the system (I assume so since he mentioned he opted for a 10 year loan that I believe SolarCity is financing)? If he's indeed the owner, then your payback calculation should be accurate (since he'll be eligible for the 30% federal tax credit), albeit conservative. I say conservative because the economics would get better (i.e., quicker payback than 14.5 years) if he's able to benefit from load shifting if he has time-of-use rates (don't know if he does, but I have TOU rates in Iowa). The Powerwall 2 lets a user fill up the battery with off-peak (cheaper) electricity (either from the grid, or one's own solar generation), and then pull that electricity out during peak periods (where one avoids paying higher peak rates to the utility). That's how I plan to use my Powerwall 2 once I can get a local electrician to be Tesla certified for my installation. Tesla (my SolarCity rep in Vegas) is supposedly ready to ship my reserved Powerwall 2 once that happens (i.e., their supply of Powerwall 2's has caught up with demand). I hope that proves out to be true; time will tell.
Update on that Powerwall loan term. We can now do Powerwalls for 20 year financing.
Right now there's a $500 incentive (believe that may be for the Houston area) from SolarCity, no local/state incentives (go to Austin for that), but there is the ITC (Investment Tax Credit) of 30% until end of 2019 (or the current administration does away with it)
JAWZ's energy consultant should have walked him through setting up his MySolarCity app. From there he can choose his energy consultant (under "My Account") and JAWZ is now considered a SolarAmbassador. If you provide your email to him, he can "Invite" you from the app and you will receive your first month's bill on SolarCity and JAWZ will receive $200.
Parzival
Member
Question for people with PW2 installed with solar system: Are you guys able to charge from the Grid at night or only from what your solar system produces?
Tesla is restricting me from charging only from solar with my pending 2 PW2 order which is disappointing since I won't be able to take advantage of charging from the grid's cheap Super Off-Peak rates.
Tesla is restricting me from charging only from solar with my pending 2 PW2 order which is disappointing since I won't be able to take advantage of charging from the grid's cheap Super Off-Peak rates.
Parzival
Member
Are you doing this as part of the SGIP program? If so, I think some of that is due to restrictions on the various incentive programs. (Things like that you are required to charge at least x% from onsite renewable, i.e. solar, resources.)
