(NorCal) Solar and PG&E: Pull the trigger now?

[rw99]

Hi, all... I'm looking for your opinions on an home install that Tesla Energy is currently designing for us. I know many of you have done your full due diligence on the economics of your systems, many of which are also in Northern California... as a solar newbie, I'm hoping to get feedback on these questions:

1) With tariffs looming, I assume that installing my system NOW is a no-brainer. Correct?

2) SGIP seems like a total roll of the dice. Anyone know if it's possible to contract separately with Tesla to perform a 2x Powerwall install at a later date ONLY IF my SGIP application is funded?

3) Is the Net Surplus Compensation rate (stated to be 0.03 - 0.04 /kWh) stable? Any reason to expect that overproduction will have less compensation in the future?

4) Here's my bonus question: my Copperopolis home (1400 sq ft; no gas, electric only) also needs an EFFICIENT heat pump. Got any recommendations?



Thanks very much in advance for your help,


Rich

 

[kiwiguy]

If you are expecting over production credits then your system is too large.
It only makes financial sense to eliminate the $0.20+ / kWhr energy usage.
You won't get a payback for eliminating the cheapest power (10c / kWh).

Also make sure you are on the EV rate with PG&E. TOU with no Tiers.

For heat pumps you could look at Daikin (I have one for a small apartment).

 

[Az_Rael]

My experience with Tesla Energy for sizing my system was they sized it too large. They basically sized it to offset my energy almost 100% which is not a cost effective way to go with netmetering as it works today as mentioned above. Their system size was quite a bit larger than all the other bids I got.

I did my own calculations using PVWatts, my energy data, etc and figured out what I thought was an appropriate size. Turns out it was what the other companies had quoted me. Upon quizzing the TE rep, he did not have a basic understanding of how netmetering worked, hence the oversized design.

Got a new quote from TE, saved myself quite a bit of money and I think we are going to be much happier with the system.

I am taking my chances with SGIP and installing my Powerwalls now. That way I at least get the federal tax credit on them. (It is not super clear that you can get the federal credit on a battery add on later as far as I know. TE has been giving mixed messages on that).

 

[Kbra]

1) With tariffs looming, I assume that installing my system NOW is a no-brainer. Correct?
In my case i found running two powerwalls on the TOU software (ETA 1Q18) was cheaper and better than also installing solar.

2) SGIP seems like a total roll of the dice. Anyone know if it's possible to contract separately with Tesla to perform a 2x Powerwall install at a later date ONLY IF my SGIP application is funded?

A friend of mine ordering a powerwall was told he was not committed to pay for the powerwall until his SGIP application was approved. On that note i've heard the residential funds for SGIP are significant and still plenty funded. They used to be in the same bucket as commercial, which drained them quickly.


3) Is the Net Surplus Compensation rate (stated to be 0.03 - 0.04 /kWh) stable? Any reason to expect that overproduction will have less compensation in the future?

You will be grandfathered into whatever rate you choose. So if they take it away or reduce it in the future, you will only be effected if you make a large change to your solar system or rate structure.

 

[SoundDaTrumpet]

1. With regards with tariffs, it will always be unpredictable. The last step function was during the Net Energy Meter (NEM) 1.0 to NEM 2.0 transition. I got in before the transition. The next step function is the Federal Incentive Tax Credit from 30% to 26%. This occurs in a few years. This ITC is retained currently AFIK in both senate and house bills.
2. Yes, that is what I did. Uncertain if Tesla is okay with this today. Call and ask. Your deposit is refundable.
3. The Net Surplus rate is new and only been effect for ~ 1 year. It went into effect with NEM 2.0. No history that it is stable. Those who are under NEM 2.0, this makes Powerwall a better choice. (Powerwall operation is $0.10/kWh... so really you save $0.03 in tariffs, so the cost to own a Powerwall is $0.07/kWh!) [Assumption 2 PW install at the minimum $900 install price]

The cost of installation minus ITC divided by the warrantied lifetime of the system typically comes out at $0.09 per kWh. Why spend $0.09 to make $0.03? (Total price * (1 - 30%) / 25 years / PVWatts Annual Energy in kWh) [Tesla Energy warranty is 30 years no?]

Below is applicable to PG&E:

I always recommend a slightly undersized system because you are still on the hook for the mimimum ~$10/mo electricity charge. Often I recommend to not size for charging an EV (many disagree) because $0.12/kWh off peak to charge EV vs. $0.09/kWh just to add more panels. The range anxiety with owning EV is a downer for me. I sized my system at 110% without an EV. With the EV rate, half my EV mileage is covered by solar. I basically have prepaid electricity. If I don't use it I lose it. The only sensible thing is to continue owning an EV.

I likewise created a complex spreadsheet. Most if not all do not do real TOU calculations. It is easiest to do tiered rate. I will point out there is a huge difference between EV rate and E-TOU rates from PG&E. The E-TOU-A is practically identical to tiered rate. I will explain: the way the TOU rate schedule is structured so there is very little price difference during the day PERIOD! It is essentially flat rate pricing for the whole day without tiers. It's only a couple of cents different for peak and off peak hours. Much more true during the 6mo winter window. The EV rate plan is 4:2:1 peak/partial_peak/offpeak ratio in pricing during the summer and 3:2:1 in winter. The pricing deltas are very advantageous to solar under EV rate plan.

PG&E online tool shows: Using me as an example: My estimated bill under EV is $250. My estimated bill under tiered E-1 is $790. My estimated bill under E-TOU-A is $780. EV rate is way advantageous. If I abandon my EV thus losing the EV rate option, I have three rate options vs. two ONLY because I am grandfathered into NEM 1.0. Sorry to rub that part in.

I hope this helps.

 

[rw99]

Excellent information. Thanks!

 

[abasile]

4) Here's my bonus question: my Copperopolis home (1400 sq ft; no gas, electric only) also needs an EFFICIENT heat pump. Got any recommendations?

I've done some research into heat pumps, as we hope to install one. Mitsubishi seems to be the preferred brand with the best long-term reputation. In the Bay Area, you probably don't need a Mitsubishi "hyper heat" model, as those are more for areas that get very cold. Look for units with high SEER ratings. Google around and you'll find some decent-looking online wholesalers that let you compare models.

The range anxiety with owning EV is a downer for me.

I'm guessing that maybe you own a non-Tesla EV? Range anxiety is sometimes a concern with our Nissan LEAF, but our Model S is great and it saves time because our family's day-to-day use doesn't need to involve stopping to fuel up or charge.