need estimated cost of going from grid tie to hybrid

[cdstyle]

I got a quote from contractor , $65k for a 16.94kw pv system with 20kWh battery.

They messed up the inverter in the quote since the include inverter is rated for 7kw input while my system is 16.95kw)
Assuming they are going to SolarEdge SE10000H-US when I ask them for correction.
Panels: 44 Jinko Solar 385W Bobs
Inverter: 1 SolarEdge SE3800H-US[SI1] RGM
Battery: 2 SolarEdge Energy Bank (non-backup)

However, this is a grid tie system, not hybrid, so if grid is down, system is down, even though it has battery.
They want $15k extra to upgrade the system from grid tie to hybrid.
Does it really cost that much to upgrade from grid tie to hybrid?

From what I have been researching, the magic of going from grid tie to hybrid mostly lies in having a hybrid inverter (AC coupling), is that right?
I plan to diy my pv system, so I want to know how complicated it is to perform AC coupling

 

[sunshine_eggo]

This is a DIY forum. Those costs are outrageous.

GTI can't form their own grid. This requires either replacement of the GTI with a hybrid inverter or an AC coupled inverter to form the grid. 17kW of grid-forming hybrid or AC coupled inverter isn't cheap. $15K is high.

Having batteries without grid-forming inverters is completely pointless.

Even if you went DIY with 2X EG4 18K PV units, that's $10K, but they would completely replace your GTI and perform the GT function themselves.

 

[Quattrohead]

You found out how not to do it, now read around here and find out how to do it and save yourself an absolute fortune. Do you need plans and inspections for code or not?

 

[SoggyShoes]

However, this is a grid tie system, not hybrid, so if grid is down, system is down, even though it has battery.

As The Great Eggo said there is no reason to have batteries in a grid tied system unless they are there as a backup when the grid is down. In a grid tied system, the grid is essentially your battery!

I would really question trusting any installer that tried to get you to buy batteries without being part of a grid down backup.
Also, the inverter is kind of the core of a system. So to screw that up is a pretty big deal.
You should look for a new contractor.

For pricing, a contractor has to pay for labor, overhead, and some profit; so you should expect the cost to be a good 3 times the cost of materials.

 

[cdstyle]

This is a DIY forum. Those costs are outrageous.

GTI can't form their own grid. This requires either replacement of the GTI with a hybrid inverter or an AC coupled inverter to form the grid. 17kW of grid-forming hybrid or AC coupled inverter isn't cheap. $15K is high.

Having batteries without grid-forming inverters is completely pointless.

Even if you went DIY with 2X EG4 18K PV units, that's $10K, but they would completely replace your GTI and perform the GT function themselves.

So a hybrid pv system always have 2 inverters where 1 of them would act as the grid so the other inverter thinks it is always connected to the grid?

 

[cdstyle]

As The Great Eggo said there is no reason to have batteries in a grid tied system unless they are there as a backup when the grid is down. In a grid tied system, the grid is essentially your battery!

I would really question trusting any installer that tried to get you to buy batteries without being part of a grid down backup.
Also, the inverter is kind of the core of a system. So to screw that up is a pretty big deal.
You should look for a new contractor.

For pricing, a contractor has to pay for labor, overhead, and some profit; so you should expect the cost to be a good 3 times the cost of materials.

They added battery because the system is in California, where net metering value went down by 75% for new systems, and Time of use rate is ridiculously high.
But yeah, time to go down the diy route, seems super feasible based on what i found so far

 

[sunshine_eggo]

So a hybrid pv system always have 2 inverters where 1 of them would act as the grid so the other inverter thinks it is always connected to the grid?

No. The reason I included 2 inverters is because 1 likely isn't big enough.

If you already have a pure GTI system, either you replace it or add a grid forming inverter.

They added battery because the system is in California, where net metering value went down by 75% for new systems, and Time of use rate is ridiculously high.
But yeah, time to go down the diy route, seems super feasible based on what i found so far

Okay, I take it back. If the system can use the batteries for peak shaving, it's not worthless.

 

[Citlalatonac]

I think I misread the question

 

[zanydroid]

Okay, I take it back. If the system can use the batteries for peak shaving, it's not worthless.

In California there is bad value for peak shaving since there are no demand charges.

The value comes from the fact that you can only bank at 20% now, maybe 5% in 5 years, for intra day consumption. And you get punished for this off peak too.

So you have to have a battery to self consume to offset your bills with same day production

 

[zanydroid]

One 18kpv can do it all.

AC coupling is only complicated when grid is down.

 

[45North]

What's your breakeven?
Are you paying for it by selling power back to the grid or just by not having to pay for your own consumption?
Don't forget to factor in the "opportunity cost", ie the interest on the loan or what you could have earned/saved elsewhere eg by paying off a mortgage.

 

[DIYrich]

Go to Sol-ark's website, and search for an installer in your area. Get a quote from them.

Map

Use the Sol-Ark® Distributor & Installer map to find the nearest certified installer for your next home, commercial, or industrial energy storage project.

www.sol-ark.com

 

[ksmithaz1]

16.9kw is a good bit of panel. 7KW seems a tad light on the inverter side, but it depends on your objective. If you are just trying to shave your bill, probably OK. They seem to be playing it that way, minimal battery supplemental power only, no intent to have a critical loads panel, feed output direct to your panel and keep it under the 120% rule. Maybe a little high price wise, not over the top for a legitimate contractor. Mounting 44 panels is non-trivial. Battery in this case is just to smooth the inverter output, you don't give the capacity. The battery is going to be the most expensive thing

I would take my time, and read thru the forums a bit more. A big SolArk or EG4 with 50A of output tied to a critical load loads panel would be much more useful. The bulk of the cost should be in the labor to mount all those panels and wire everything up. What racking system?

 

[zanydroid]

What's your breakeven?
Are you paying for it by selling power back to the grid or just by not having to pay for your own consumption?
Don't forget to factor in the "opportunity cost", ie the interest on the loan or what you could have earned/saved elsewhere eg by paying off a mortgage.

Usually there is still < 10 year break-even in California even without net metering. We pay $0.40 off peak and $0.60 summer peak. Winter peak in half the state is $0.40, so not terrible lol. The other half of the state, doesn't give much of a winter discount.

 

[Lawrence_SoCal]

I got a quote from contractor , $65k for a 16.94kw pv system with 20kWh battery.

Price is unmistakably high, for what some would definitely argue is not high-end premium product
then again, neighbor quoted $3K for purchase and install of a $500-600 hot water heater (and he felt good shopping around and negotiating down to $2K... hearing that I simply replaced my hot water heater on my own)

44 panels ... roof- or ground-mounted?

However, this is a grid tie system, not hybrid, so if grid is down, system is down, even though it has battery.
They want $15k extra to upgrade the system from grid tie to hybrid. Does it really cost that much to upgrade from grid tie to hybrid?

A grid-forming hybrid Inverter won't cost anywhere near that much.... BUT, done right, there is usually a whole lot of extra wiring to do (though not enough to justify Inverter + installation = US$15K). There could be that much wiring, for example if your main load center was maxed out, and you want a service upgrade from PoCo... etc... but much of that would be driven by large PV array, not battery-back up...
Maybe if there was a bunch or circuit changes, creation of critical load panel, and more... but even then...

From what I have been researching, the magic of going from grid tie to hybrid mostly lies in having a hybrid inverter (AC coupling), is that right?

Uh, one I'm no expert in this, but no
The 'magic' is the grid-forming capability (ie allow house grid, on battery and/or solar PV production while grid is down) which has _nothing_ to do with whether AC or DC-coupled PV array (can be either)

I plan to diy my pv system, so I want to know how complicated it is to perform AC coupling

Uh, DIY with contractor quote? was that just to get a system config idea? I recommend against taking too much from that quote (interesting education, sure, but contractors pick things to resell/install that includes reasons other than what may best fit a consumer's (your) needs .. which may or may not be an issue ... like so many things... it depends).

I personally went micro-inverter / AC coupled roof-mounted PC array, as I have a chimney in middle of back roof with all panels on it, and daily shade is a consideration. But there are good arguments to be made for Micro-inverter, DC power optimizer, and bare string connections .. each has its own cost factor and Pro's & Con's. And some of latest devices long-term reliability is unknown (probably biggest impact on lifecycle ROI). I personally (possibly biased by rationalizing existing purchase?) am attracted to the reliability (risk spread) of micro-inverter based approach. But, I recognize ... it depends..

As for complications, the nice part is that by using micro-inverters on the roof (and hoping they last as long as the panels) is that once you come off the roof (I went thru attic vs ugly surface mounting along roof and side of house) that you are dealing with standard 120V 20A circuits... simple Romex (though my installer used THHN with both circuits (19x425W panels) in a single conduit even in the attic. My installer put in their own dedicated sub-panel (and my main load center was full anyway, and installer like the separation to minimize warranty issues) with both PV circuits, their monitoring system, and a circuit to main load center. Had I a newer, larger main load center, the sub-panel would have been unnecessary). The fact that it isn't complicated is a possible upside to AC coupling. DC coupling isn't harder it is just different with different risk factors.

Today, I would not consider an install without a grid-forming inverter. I don't have one as my install was 19 months ago on NEM2, and I am counting on battery tech to improve greatly and my local grid is very reliable (and I'm on a non-curtailment circuit). So I plan to get hybrid inverter and whole house battery... in a couple of years-ish