Best Setup for California NEM 3?

[CaliCarlos]

I'm helping a family member research a residential solar system with batteries under California's NEM 3. It's going to be a professionally installed system but I'm wondering what setup to look for being as it's going to have solar storage and NEM 3 really changes that up and I feel the installers are going to push what they're use to which may not be the best for NEM 3. My understanding of NEM 3 is that you basically have to run your system off grid most of the day and night because the second you pull from the grid you now owe the utility far more than what you pulled from them unless you repay in the evening which isn't ideal. Attached is a picture of what the estimated cost/credit schedule looks like. So basically it seems that you'd need an inverter that can essentially run you're entire house from the batteries air conditioning and all otherwise you'd have to dump you're battery to the grid during peak evening hours and use cheap electricity during the night which leaves you vulnerable to power outages and creates unnecessary wear and tear on your battery from the extra cycles . The house has gas heating but does have a pool. An 8k system would be a little over 100% annual usage. I'm thinking of the Sol-Ark 15k with server rack batteries because the batteries are cheap in comparison to most of the other options and the 12kw of output from the batteries through the inverter should be sufficient to run the house with some minor load management and 12kw seems to be far more than most battery inverter combos can produce unless you buy 3 or more of them. I also like the fact that it's DC coupled which would be more efficient in an "off grid" scenario. I'm by no means a professional so anyone with advice is more than welcomed to chime in to why the sol-ark is or isn't the right setup and what your recommendation is or to correct me if I'm off on NEM 3. An installer recommendation in the central California area is also very welcomed.

 

[629658]

I'm helping a family member research a residential solar system with batteries under California's NEM 3. It's going to be a professionally installed system but I'm wondering what setup to look for being as it's going to have solar storage and NEM 3 really changes that up and I feel the installers are going to push what they're use to which may not be the best for NEM 3. My understanding of NEM 3 is that you basically have to run your system off grid most of the day and night because the second you pull from the grid you now owe the utility far more than what you pulled from them unless you repay in the evening which isn't ideal. Attached is a picture of what the estimated cost/credit schedule looks like. So basically it seems that you'd need an inverter that can essentially run you're entire house from the batteries air conditioning and all otherwise you'd have to dump you're battery to the grid during peak evening hours and use cheap electricity during the night which leaves you vulnerable to power outages and creates unnecessary wear and tear on your battery from the extra cycles . The house has gas heating but does have a pool. An 8k system would be a little over 100% annual usage. I'm thinking of the Sol-Ark 15k with server rack batteries because the batteries are cheap in comparison to most of the other options and the 12kw of output from the batteries through the inverter should be sufficient to run the house with some minor load management and 12kw seems to be far more than most battery inverter combos can produce unless you buy 3 or more of them. I also like the fact that it's DC coupled which would be more efficient in an "off grid" scenario. I'm by no means a professional so anyone with advice is more than welcomed to chime in to why the sol-ark is or isn't the right setup and what your recommendation is or to correct me if I'm off on NEM 3. An installer recommendation in the central California area is also very welcomed.

I’m not in California but you are on the right track. I think your logic is sound. I have a 15k myself

 

[BentleyJ]

California Time of Use rates are in excess of 50 cents/kWh and so called Off Peak rates are no bargain either so a Self Consumption system makes sense.
An inverter with enough battery capacity to a run the house during the typical time slot of 4pm to 9pm would be the minimum system size IMO.
PV array would then be sized based on partially offsetting late morning and early afternoon utility usage AND fully recharging the batteries by 4pm to be ready for the next Peak Load Shave of the day. This also dependent on how much roof space you have and budget.
I would definitely not oversize the system or plan on a large amount of Sell Back and certainly you would not discharge batteries for Sell Back, those are only for self consumption and outages.
A Sol-Ark 15K would be a good choice as would a pair of Schneider XW Pros. Outback, SMA and Tesla are possibilities as well.

 

[HarryN]

The main challenge that the CA grid has is the August peak power demand curve.

Basically on a hot summer day, the peak temperature is ~ 2 - 7 pm.

Most solar panels here today are facing the sun to produce power from 11 am - 2 pm, producing more or less nothing after 3 pm, so there is a massive glut at the wrong time of day compared to demand.

This forces large numbers of natural gas generators to kick on, very rapidly, to fill this big gap.

What you will want to do is maximize the solar power production to be during the peak demand - to the extent possible.

Battery storage is part of the answer. Having a lot of panels mounted more or less vertical facing the sun in August will help reduce the impact the most. My suggestion is to have at least 50% of your panels facing the August sun at ~ 5 pm.

 

[BentleyJ]

The main challenge that the CA grid has is the August peak power demand curve.

Yes, they like to refer to this as the "Duck" curve.

Battery storage is part of the answer. Having a lot of panels mounted more or less vertical facing the sun in August will help reduce the impact the most. My suggestion is to have at least 50% of your panels facing the August sun at ~ 5 pm.

Agreed, it all depends on the particular roof layout. If possible a South facing as well as a West facing array in CA is ideal.

 

[hwy17]

The battery is still going to be a questionable payoff.

ROI wise, a modestly sized, well priced, grid tie only system, ideally southwest facing, is still going to pay off faster than a battery system, but it is not going to get the bill to zero.

For a professionally installed system, if you can get into VPP with powerwalls that's probably the best option for battery payoff.

You're not going to find professional installers in the primary solar market who are working with Solark. That's a specialty off grid product and you will have to go to specialty installers, and the permitting and inspection process is going to be strained by the building department's unfamiliarity and uncertainty about DC coupled systems. Mainstream pro installers will offer you Enphase or Tesla. It's Coke or Pepsi, and no we don't have Dr Pepper.

Don't worry about battery cycling, the battery is there to get used.

 

[HarryN]

In my mind, the main advantage of having even a small battery pack is resiliency.

If your solar power system is grid feed only, then "when not if" the grid goes down, you will have no power.

If you have even a modest size battery pack, your house will still have power - at least enough to keep the refrigerators running and some light cooking.

Just in the past 2 weeks, there were areas east of Sacramento without power for multiple days and people with solar most definitely experienced this effect.

 

[k490]

The EG4 PowerPro Wall mount 14.3KW battery has been approved by the California Energy commission by far the cheapest approved battery on their list at 26 cents a watt based on Signature solar pricing. Hopefully this is just the start of batteries becoming lot cheaper. Eventually prices will be low enough to make it worth while. I noticed here in Phoenix they now require the fire department to approve a battery system and have a limit of 80KW in batteries for residential systems. The problem we have is in the summer afternoons peak temps hit 115F-120F last year that went on for weeks. I'm using up to 65-68kwh a day. Through out the night I'm using 60kwh of power until sun is up enough to generate power. I would need at least 80kwh to go all night without using power from the grid. If prices on a battery like the PowerPro were to drop to $1500 5 batteries gets me to 71kw. Just a few days ago Corporate commission added a solar connect fee it's clear yet exactly what the fee is.

 

[Punk9721]

California Time of Use rates are in excess of 50 cents/kWh and so called Off Peak rates are no bargain either so a Self Consumption system makes sense.
An inverter with enough battery capacity to a run the house during the typical time slot of 4pm to 9pm would be the minimum system size IMO.
PV array would then be sized based on partially offsetting late morning and early afternoon utility usage AND fully recharging the batteries by 4pm to be ready for the next Peak Load Shave of the day. This also dependent on how much roof space you have and budget.
I would definitely not oversize the system or plan on a large amount of Sell Back and certainly you would not discharge batteries for Sell Back, those are only for self consumption and outages.
A Sol-Ark 15K would be a good choice as would a pair of Schneider XW Pros. Outback, SMA and Tesla are possibilities as well.

I was going to say is it even possible to discharge a battery back into the grid?

 

[Punk9721]

Yes, they like to refer to this as the "Duck" curve.

Agreed, it all depends on the particular roof layout. If possible a South facing as well as a West facing array in CA is ideal.

West? Interesting everything I read says south or east, my house on the CA coast face ~116 East-southeast, I have potential for 3-4 panels to face south but there is potential shading at time in the late day in the deep winter from neighbors house and my stupid pge electric pole, but most of the day it’s getting pounded by sun. so don’t know if it’s worth it there as my SE and IF W facing roof are unobstructed. So I’d ideally like to use a string inverter as it’s cheaper and less complicated.

Two questions for you
1- thoughts on the south, facing 3 to 4 panels given the situation?
2-should I split my panels to face east and west

 

[addision]

I was going to say is it even possible to discharge a battery back into the grid?

Yes you can. But in many places it is not cost effective since they changed the amount the pay you for it.

 

[Hedges]

I think under NEM 3.0, credit for backfeed between 6:00 and 8:00 PM is supposed to be greater than retail, at least for the next few years.

I think a PowerPro costs $0.05/kWh assuming 6000 cycle life (16 years daily). Together with one EG4 18kPV, I think it comes to $0.12/kWh over that time. (ignoring all balance of system materials and labor.)

PG&E won't let you charge from grid and discharge into grid, but you can charge from PV and discharge to grid.

A system like this, with about enough PV to meet your annual needs on average (and battery as large as daily production, so possibly multiple PowerPro) should let you produce power for $0.03/kWh and time-shift it to evening for another $0.12/kWh. So you pay $0.15/kWh for all the power you use year round, rather than $0.40 to $.60/kWh grid rates. As an alternative point of view, break-even could approach 5 years.

That's counting hardware cost only, not labor. So assumes DIY, or higher cost turnkey and lower or zero savings depending on price.

Be sure to run the numbers yourself, using whatever quotes you get. With labor and markup included in a turnkey installation, I'd expect cost to be 3x as much, 15 year break-even, not worth doing. But that depends on whether battery system markup is as great as PV system markup (shouldn't be, less labor per hardware $$.)

 

[HarryN]

West? Interesting everything I read says south or east, my house on the CA coast face ~116 East-southeast, I have potential for 3-4 panels to face south but there is potential shading at time in the late day in the deep winter from neighbors house and my stupid pge electric pole, but most of the day it’s getting pounded by sun. so don’t know if it’s worth it there as my SE and IF W facing roof are unobstructed. So I’d ideally like to use a string inverter as it’s cheaper and less complicated.

Two questions for you
1- thoughts on the south, facing 3 to 4 panels given the situation?
2-should I split my panels to face east and west

In a perfect world, a person would mount solar panels around the house to capture sunlight all day long, from early morning until the sun is completely set. There would be enough panels to capture the power needed at that time of day, plus enough to store for later or the next day or two. Not so easy, but that would be idealistic.

Imagine if you were completely off grid or the grid was down. The battery pack would be largely depleted in the morning from having to power the house all night with no energy input, so that morning sun is very helpful to get the charging started.

The big power use for both you and the grid is usually going to be mid afternoon and then until the sun sets, so that will eventually be the most expensive power, one way or another. Any wall or roof that you can use to capture energy during this late afternoon period that doesn't ruin your home's aesthetics is a good idea. Panels are cheap compared to the rest of the effort.