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Existing SunRun 2.8kWh system, want to add more from Tesla and add Powerwalls

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
Likely the existing PV is tied into the garage subpanel. I don't see any other way this is connected but I could be wrong.

There is no reason why the existing PV couldn't be integrated, but it needs Tesla PV CT's at a minimum. Also, there will need to be a way to rapid shutdown when complete.

The main panel will be maxed per the 100% rule if he lands a 125A breaker on it. No other breakers can be in that MSP if this approach is taken.
The PV is in the main 125A panel. The subpanel was installed 6 years ago and is a 60A feeding just the remodeled kitchen and a bathroom. It connects back with a single FAT feeder wire across about 60 feet through the attic (one story house) to the MSP.
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
Yeah, I kind of conflated NEM and TOU together at first... but you should view the two independently.

NEM sets the rules around the tariffs, fees, and policies governing how your own generation ties in with PG&E's grid. The NEM rules allow PG&E to charge a monthly fee (non-bypassable-charge or NBC) as well as one-time activation interconnection fees. The NEM rules also get to set the boundary by which the effective net energy metering will abide (for example, providing a mechanism for a solar-installation to have a positive ROI). But NEM itself does not set the time of use (TOU) daily schedule or rates.

So, while the NEM people bicker over the NBCs and tariffs, PG&E gets to sneakily move the TOU rates as well. The TOU manipulation bypasses most people's purview since they're spending so much time focusing on the NEM problem. Even though I hate PG&E, I do admit they are some really clever, smart people over there.

Anyway, the rules for TOU manipulation are almost non-existent. All PG&E has to make a case for is that a homeowner "should not" be impacted by higher rates through TOU changes if the homeowner changes their behavior. Changing behavior is "free" therefore a homeowner who doesn't change is intentionally being an energy waster.

Once PG&E won the battle to get rid of 1:1 net metering in NEM 2.0, they've had a almost blank check to just pound people to death with TOU manipulation and very few people seem to care. I don't know if it's because people notice but don't care... or if each small change just isn't drawing enough outrage.

Here's an article from 2019 talking about how PG&E effectively increased rates for EV customers by 25%. Did the public really care? Nah.

I posted about PG&E further increasing "revenue" by 12.4% effective March 2021. Keep in mind the CARE/FERA people only saw their costs go up like 3%. That means other residential should see their costs go up by like 15%. Did you really see this in the news with people drawing attention to the absurdity? Nope.

PG&E is clever because then they'll say that "PG&E doesn't make more money with these higher rates"

The grift is that the people leading PG&E are making personal gains off of the mechanism by which PG&E "invests" its massive allocation of dollars. It's what allows a senior leader to avoid upgrading transmission lines while jacking up special interest payments, investing in a bunch of peaker plants that got shut down early, and executive compensation since those actions keep PG&E's bottom line "flat". Yes, PG&E "makes the same" no matter what as a monopoly. But PG&E wastes the most of any public utility in the USA which necessitates the absurdly high energy costs non CARE/FERA people pay so PG&E "makes the same" as other utilities.

Anyway, the TOU manipulation may not make PG&E more money, but it makes PG&E's interests a ton more money. So they'll do it in the sneakiest way possible and you know it'll get worse in 2022 and beyond. PG&E pushing everyone to TOU is their next step to grift, then starting 2022 you can expect them to further skew the TOU rates to slowly boil the frog through many seemingly small moves.
So will EVERYONE be pushed to TOU in 2021/2022? I'm in Santa Clara county and I saw a schedule that says July 2021. Or will those on E1 still be grandfathered into E1 moving forward?
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
Yeah, I think I see what you're doing... you're basically treating OP's home as a 200A microgrid ... but PG&E is just a "source" of 125A while the home can get 40A (or more) peak from solar, and 60A continuous from batteries.

So in essence on a daily basis the home is simply prioritizing the solar and battery energy first, and only drawing energy from PG&E or sending energy to PG&E if the micro-grid maxes out.

I guess if we had like an entire week of rain/cloudcover (or stifling smoke from wildfires caused by PG&E), then dabreutx may run into an issue where his solar and batteries are insufficient alongside PG&E to power 200A worth of loads on a daily cycle.
True, but in that case I will be at least back to 125A 'guaranteed' and can economize for that week by turning off some egregious crap like the pool (which I hate but my wife loves - no angst here I promise - NOT!). That would work for me, a 200A-250A microgrid of my own with PG&E as a 'fallback' 125A source. If this can fly with PG&E and permitting, etc. I think this is a brilliant idea.
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
Correct on many points. My assumption is if the OP is not popping the 125A main breaker now, the addition of more power generation will not make that any worse. In fact if site control is set it will get a lot better, as he could pull more than 125A for short periods, as long as the PV and Powerwall were generating the excess. Rare is the 2-3000 sqft home pulling 200A or close to it for long periods.
Glad to hear this as well. We have 2400 s.f. It's just that our usage has crept up to be quite high over the past 3 years since we got the Model 3. Didn't notice the 125A breaker popping, but we had some weirdness with the double ovens where they were just shutting down (no breakers popping) until I killed the pool pump and shut off the AC (it was 100F outside that day - a rare thing in San Jose to be fair).
My general thoughts are:
1. Save cost over the long term (5-7 year time horizon).
2. Add amps to my house as our needs have potentiallly grown past 125A, I think.
3. Clean up the system for safety.
4. Have a backup power to be almost off the grid.
 

h2ofun

Active Member
Aug 11, 2020
2,424
411
auburn, ca
Yeah, I installed it myself :). And yeah, I intended to protect the cables, but never got around to it. I probably should huh? Will take care of that when I get this stuff done. And yes, I want to leave the existing piece as UNTOUCHED as possible in the hope that it will simplify things logistically and cost-wise. Will be chatting with @Vines tomorrow. Thank you to him and everyone else for your advice, keep it coming!!! Really appreciate you all!
Did you get permits for the work? Talking to the installer today who was here for the final, he told me how amazed he is at folks they go to quote solar and have lots of the home having no permits. They just have to leave since they cannot do work on homes without permits for work.
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
Did you get permits for the work? Talking to the installer today who was here for the final, he told me how amazed he is at folks they go to quote solar and have lots of the home having no permits. They just have to leave since they cannot do work on homes without permits for work.
I needed a permit to install a Sense system? Didn't think so.
 

arnolddeleon

Supporting Member
Jul 21, 2012
788
859
SF Bay Area
True, but in that case I will be at least back to 125A 'guaranteed' and can economize for that week by turning off some egregious crap like the pool (which I hate but my wife loves - no angst here I promise - NOT!). That would work for me, a 200A-250A microgrid of my own with PG&E as a 'fallback' 125A source. If this can fly with PG&E and permitting, etc. I think this is a brilliant idea.
125A is still a lot. That's 24kW continuous.

Pool pumps can be upgraded to be more efficient (e.g. double the run time, half the flow rate, 1/4 the power so half the energy total to move the same amount of water)

Car charging can be scheduled.

Modern HVAC systems are remarkably efficient.

The only time I break 10kW is when I'm charging a car.
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
125A is still a lot. That's 24kW continuous.

Pool pumps can be upgraded to be more efficient (e.g. double the run time, half the flow rate, 1/4 the power so half the energy total to move the same amount of water)

Car charging can be scheduled.

Modern HVAC systems are remarkably efficient.

The only time I break 10kW is when I'm charging a car.
Yeah, this makes sense. Happy that I am investigating this now and hopefully will augment with solar and be able to keep my existing 125A which doesn't seem to need being upgraded.
 

holeydonut

Supporting Member
Jun 27, 2020
1,487
873
East Bay NorCal
Yeah, as long as you're smart about not turning on everything at once, @Vines proposal will work great so-long as PG&E doesn't crap all over it if they think your generation facility is too large for 125A. You may need to move Sunrun's precious meter, but otherwise their equipment can stay on the current lease. I just hope they didn't use up all the prime real-estate on your best solar-producing roof plane.

I've noticed on some of the houses in my neighborhood that when solar was sized a certain way they clearly just made things look "prettier" since they weren't using all the available roof space for maximum and could worry about aesthetics a bit.
 

Vines

Active Member
Jul 20, 2018
1,873
2,197
Silicon Valley, CA
I'm wondering: Does my 125A panel deliver 125A per rail? Or is it 125A total split across the two rails?

Service equipment is typically rated for continuous duty at 80% of its rating, So a 125A panel is tested to pass 100A through it all day long, with spikes higher than that.

Each rail is one leg of a 240V service so 125A is available on either bus at 120v with one bus, and 240v with 2 bus.
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
So here is where I stand right now for equivalent systems from LG (Ameco would install) and "Earth Solar" - a local company, who one of my good friends used. Essentially looking at a $3400 price difference between the two (LG/Ameco is cheaper).

10,500 kWh per year generation
10kW inverter (because apparently my system maxes out due to the existing solar and existing utility service (125A).
Both companies would replace my main service panel with a 200A and relocate existing loads to it. Feed the new MSP from a single 125A breaker in a small panel that they would add as well, into which they would feed my existing utility service. This should help me 'easily' upgrade my utility service if I care in the future.

Here are the warranty details (LG/Ameco vs. Earth):
Inverter warranty: 25 vs. 12
Workmanship: 40 vs. 25

Decided to not do batteries at this time since we almost never lose power here.

I checked reviews for Ameco on Yelp and they seem fine. LG/Ameco would therefore seem the clear winner here, except I have a GLOWING recommendation from my friend for "Earth Solar" and also stellar Yelp reviews. What do you think? Should I try to beat Earth Solar down? Or just stick with the LG/Ameco deal?

Appreciate your advice.
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
So here is where I stand right now for equivalent systems from LG (Ameco would install) and "Earth Solar" - a local company, who one of my good friends used. Essentially looking at a $3400 price difference between the two (LG/Ameco is cheaper).

10,500 kWh per year generation
10kW inverter (because apparently my system maxes out due to the existing solar and existing utility service (125A).
Both companies would replace my main service panel with a 200A and relocate existing loads to it. Feed the new MSP from a single 125A breaker in a small panel that they would add as well, into which they would feed my existing utility service. This should help me 'easily' upgrade my utility service if I care in the future.

Here are the warranty details (LG/Ameco vs. Earth):
Inverter warranty: 25 vs. 12
Workmanship: 40 vs. 25

Decided to not do batteries at this time since we almost never lose power here.

I checked reviews for Ameco on Yelp and they seem fine. LG/Ameco would therefore seem the clear winner here, except I have a GLOWING recommendation from my friend for "Earth Solar" and also stellar Yelp reviews. What do you think? Should I try to beat Earth Solar down? Or just stick with the LG/Ameco deal?

Appreciate your advice.
Correction: There was a miscalculation in the Federal rebate in the Earth Solar proposal, so now the difference is $2200 between the two.
 

BGbreeder

Member
Jun 19, 2020
228
125
Bay Area
I wouldn't put too much weight on the warranty as it is a total crapshoot as to whether the company will be around in 10, 20, 40 years.

We used a different vendor, CleanSolar, so I can't comment.
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
I wouldn't put too much weight on the warranty as it is a total crapshoot as to whether the company will be around in 10, 20, 40 years.

We used a different vendor, CleanSolar, so I can't comment.
They have a GREAT reputation, but they are hesitant to take on my build which is an add-on (despite it being a totally different system we want to add on).
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
Some more details:

LG: 27 panels @ 335W each = 9.045 kW
Earth Solar: 22 panels @ 360W each = 7.92 kW

Yet their "annual production" numbers are the same. This tells me Earth is more aggressive in their % energy generation estimation vs. LG. That is the only explanation I can think of. Is this right?

So now, SunRun is quoting me 34 panels @ 360W each = 12.24 kW. I am going to ask them to take their quote down to 9-9.36 kW and let's see what THAT pricing ends up being.

Am I on the right track here?
 

dabreutx

Member
Apr 17, 2021
42
0
San Jose, CA
Here's where I stand as of today. LG seems to have the best deal by far and I will probably go with LG. PPW (after Federal rebate):
LG: $2.06
SunRun: $2.46
Earth Solar (local Bay Area company): $2.80
Tesla: $1.49 - but they won't touch my system unless I buy out my SunRun contract, in which case, I'd pay SunRun $2000 more than I owe them over the next 10 years, AND, lose my warranty with SunRun instantly. Not sure if I should care about this or not.

Now I'm also wondering with the move to NEM 2.0 and TOU (will either do ETOU-C or EV-2A, vs. right now I am on NEM 1.0 and E1), whether adding a single battery, e.g. a 10kWh from LG would help me use my own solar energy during peak times rather than feeding off the expensive grid during peak times. I wanted to see if I had the data to make a decision here, still digging in:

I have had a Sense energy monitor for the past 2 years or so. I went and grabbed the day (Aug 16, 2020) when I had the single largest usage over the past 12 months. No surprise it was the AC, even though I am in San Jose, CA where generally we have decent weather. And look at Aug 15, 2020, when it started to heat up. We had some hot days! https://www.accuweather.com/en/us/san-jose/95110/august-weather/347630?year=2020

Since then I also realized that my HVAC system was undersized for my house and also extremely poorly designed. Unable to reach the part of the house where we spend the day (the large kitchen/living room). So now we have addressed that issue as well by adding a mini-split for the kitchen/AC which will help with heating and cooling, and they added dampers to increase airflow to the 'bedroom side' of the house, which is now 90% served by the older attic AC/furnace air handler.
 

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