Help me divorce my utility provider

I have an existing PV system but I live in Utah so the greedy utility company functions on a month to month basis. So, in the summer I am giving them free electricity but in the winter they still make me pay them during those low production months. On top of that they aren't very dependable. The final straw was waking up freezing to death because the power was off and it was 4 degrees outside. Time to divorce these incompetent greedy pigs.

So, I need a battery and a generator hookup. I already own a 9000 watt generator. I think I can handle installing the transfer switch but I need advice on the battery. I'm not sure how to install or where to install. I will be looking at batteries and diagrams here and elsewhere but if anyone wants to point me in a specific direction I would greatly appreciate it.

I suggest working out an alimony arrangement.
Good to be fed power by the utility without having to run a generator.

Describe your existing PV system. Maybe it can integrate with batteries.

As much as you would like, you probably cannot divorce the Utility… sad huh.

If you really want to - you will probably need more solar.

Ok, well we're going to need that alimony arrangement then. I don't want to pay those pinheads more than about $20 per month. My current system is fairly large. In the summer I use near 30kwh and my system can handle it as long as it's sunny. What more do you need to know? I believe the mfg is Enphase. At least that's who I use to monitor it.

Enphase makes an optional battery system for their microinverters. The price per kWh is on the higher end. The alternative is to add a completely separate backup inverter and batteries that can AC Couple with the microinverters. This could be done with less expensive generic components but is more complicated and quite likely would end up costing about the same after installation.

Enphase IQ7 with Rule-21 we hear works pretty well AC coupled.
IQ8 didn't, but new firmware made it work.

You can do a grid-backup system with battery inverter that manages Enphase by frequency shift.

You can do AC coupled battery (e.g. Tesla Powerwall) to suck down excess production (minimizing export) and supply power (minimizing import.)

Various systems have different cost (especially battery cost), complexity, capability.
It is nice to have an inverter able to supply starting surge of motors like A/C or well pump (5x nameplate running current.)

Hedges you've just opened a can of worms for me because most of what you wrote I don't understand so I'm gonna have to research every word.

One thing you mention, Bentley, is that it will probably cost the same after installation using generic parts. I would really prefer to do this install on my own. The only thing I've priced is batteries. I estimate 30kwh will be around $8k to 10k for the batteries. How much are inverters and what else am I missing besides connection hardware?

Does anyone want to point me in a direction for newbie instructions?

A large inverter that can support your whole house via the main panel would be something like an EG4 18kpv or a Sol-Ark 15K, $5,200 to $7,000 just for the inverter and that's if you don't need a load controller. The inverter has to be installed in front of the existing main panel with a line side tap which requires other electrical components and wiring as well as good bit of labor and know how. Its a good idea to include a transfer switch (maintenance bypass) such as a double throw safety switch. A 200A version is $1,500 to $2,000. Misc. wiring and hardware??

The above is minimum. As Hedges pointed out we really don't know what your peak demand is, it may require more than 1 inverter. For example, 2 Schneider XW Pros, PDP, Insight Home, Backup Control Switch. Quite bit more labor and technical understanding.

qwazipsycho said:

Hedges you've just opened a can of worms for me because most of what you wrote I don't understand so I'm gonna have to research every word.

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You're in good company.
My work is done here.

qwazipsycho said:

One thing you mention, Bentley, is that it will probably cost the same after installation using generic parts. I would really prefer to do this install on my own. The only thing I've priced is batteries. I estimate 30kwh will be around $8k to 10k for the batteries. How much are inverters and what else am I missing besides connection hardware?

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A few inverters mentioned previously. Also Outback Skybox an Radian, SMA Sunny Island and Sunny Boy Storage, Tesla Powerwall. Others, I'm sure.

An AC coupled battery that just does the opposite of your AC coupled PV is an alternative that relies on the grid. Can't do as much as an inverter that powers the house when grid down, but can be smaller and more economical.

Inserting an inverter between grid and house is more wiring work. Having an inverter backfeed an interlocked "generator" breaker is easier but not automatic.

Anything with batteries, you need to determine what code requires. Called ESS, Energy Storage Sytsem. Do lithium batteries have to be UL listed? Does the pairing of inverter and batteries have to be listed?

qwazipsycho said:

Does anyone want to point me in a direction for newbie instructions?

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Search the form. Enphase and Coupling in the thread title, also storage and enphase.

Thanks Bentley. I don't consider myself incapable of any of this but the understanding is something I need to have solidified before I attempt anything. Now, I could keep asking questions until you're sick of answering them but that's not ideal. What additional information about my system could I give you to help steer me in the right direction?

(As i typed that Hedges response popped up)

Thanks Hedges. Now you're speaking a language I can understand. Thank you. I will do some reading. Again, any additional info I can tell you about my system that may narrow things down?

Enphase model. PV panel wattage. Quantity.

Summer and winter utility kWh consumption. On and off peak if you have that.

Make yourself an inventory list of appliances. For large motors, note the "LRA" if given. Note FLA. and voltage.
Electric dryer? Furnace? Water heater?

Some inverters like SolArk an I think EG4 18kpv have 200A pass-through, but the loads they can power when grid down is less than that. A way to switch off excess loads, and all but critical loads, is useful.

Woah. You're gonna make me work to make this happen aren't you Hedges? OK, I'm on it. It may take me a while but I'll be back.

Those questions were based on the idea of building a system that can work while the grid is down.

Re-reading your original post, "month to month" - does that mean you get net metering during the month, but lose any leftover when you enter the next billing cycle?

If so, no need for generator or batteries. Generator costs much more than utility grid, so only used to keep power on when the grid is down. Batteries can store power for night or the next day but not for the next season. Your monthly net metering plan already does that for you.

If your rates vary during the day, a battery to save power during times of low rates (either from grid or from PV) to use during high rates could be beneficial. If you can save PV production from times of low rates and export it during times of high rates, that may be beneficial.

A powerwall can do that without having to start motors and carry the whole house, although some may be able to.



It sounds like you make more power from PV during the summer than you use. That's fine if it costs you less to roll your own kWh.
In winter, you don't make enough to match consumption. Evaluate whether it is cost effective to install more PV.

It is not cost effective to heat the house with power stored in batteries. You can power an electric blanket.
Consider wood, gas, oil, etc. for backup heating.

Hedges said:

Those questions were based on the idea of building a system that can work while the grid is down.

Re-reading your original post, "month to month" - does that mean you get net metering during the month, but lose any leftover when you enter the next billing cycle?

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You are correct. Month to month net metering which is why I call them greedy S.O.B.'s.

Hedges said:

If so, no need for generator or batteries. Generator costs much more than utility grid, so only used to keep power on when the grid is down. Batteries can store power for night or the next day but not for the next season. Your monthly net metering plan already does that for you.

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I don't understand. How does my month-to-month net metering plan store power for the next season?

Hedges said:

If your rates vary during the day, a battery to save power during times of low rates (either from grid or from PV) to use during high rates could be beneficial. If you can save PV production from times of low rates and export it during times of high rates, that may be beneficial.

A powerwall can do that without having to start motors and carry the whole house, although some may be able to.

https://www.tesla.com/support/energy/powerwall/learn/how-powerwall-works

It sounds like you make more power from PV during the summer than you use. That's fine if it costs you less to roll your own kWh.
In winter, you don't make enough to match consumption. Evaluate whether it is cost effective to install more PV.

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I have a huge house and it's somewhat old and not very efficient. My initial goal in buying PV 5 years ago was to kill the $1000 electric bill in July and August from running the AC. I spent $73000 on PV and had a total of 68 panels put on my roof. So yeah, I produce a lot in the summer. Double what I use. So can I install more panels? Yeah, there is room. Is it cost effective? I can get hit with $200 electric bill in December and January due to short days and bad weather. I honestly have no idea how much adding panels would be at this point. Maybe that's something I could do myself??

Hedges said:

It is not cost effective to heat the house with power stored in batteries. You can power an electric blanket.
Consider wood, gas, oil, etc. for backup heating.

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No, we have 2 gas forced air furnaces but they don't turn on without electricity. I will be installing a wood burning stove at some point but electric heat is a dumb idea.

I hate the power company and would like nothing more than to disconnect from them entirely. But I understand that isn't practical. I think my goal in batteries was indepence from the grid. But I'm not sure you're wrong in the idea that all I need is a generator. On average we've seen the power go out maybe 6 times per year and the longest outage was about 6 hours. I guess I need to weigh the cost of more panels vs batteries. If I install more panels and eliminate the monthly bill, what benefit would batteries be at that point? Unless I'm looking at it from a doomsday scenario, I don't see it. Thoughts?

@qwazipsycho

I also live in Utah, Heber City to be exact with Heber Power and Light

are you in Northern Utah? You might be with those cold temps we just had. If so we can get together and look at your system

if in southern, I don't get down there that often

and you are probably with Rocky Mountain Power, correct?

I built my own system over the past 24 years, with several phases where old equipment has been retired and new stuff added.
Link to my build is in my signature below. In my first post, I have schematics of my system as it is implemented today. Like @BentlyJ I also am a Schneider XW Pro based system, which is a Hybrid system - that allows selling to the grid - BUT I DO NOT DO NET METERING - I want nothing to do with that on my house. I cannot tap my "credits" if the grid is DOWN. I run the house as OFF grid with a battery, but I do use the grid when my battery get low after cloud cover, like we have right now. Hope is to add more panels to reduce need for grid backup

As others mentioned above, the EG4 18kw/PV is another Hybrid system

I think it is a great idea to view many different installations in order to do DIY installation because you need to know a lot to get good coverage on things.

qwazipsycho said:

I don't understand. How does my month-to-month net metering plan store power for the next season?

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It can't, but batteries can't either.

I meant monthly net metering saves kWh from PV for later that day or later that month. Batteries save if for later that day or next day. So why buy batteries?

qwazipsycho said:

I have a huge house and it's somewhat old and not very efficient. My initial goal in buying PV 5 years ago was to kill the $1000 electric bill in July and August from running the AC. I spent $73000 on PV and had a total of 68 panels put on my roof.

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That's more like what I spent 20 years ago.

qwazipsycho said:

So yeah, I produce a lot in the summer. Double what I use. So can I install more panels? Yeah, there is room. Is it cost effective? I can get hit with $200 electric bill in December and January due to short days and bad weather. I honestly have no idea how much adding panels would be at this point. Maybe that's something I could do myself??

No, we have 2 gas forced air furnaces but they don't turn on without electricity. I will be installing a wood burning stove at some point but electric heat is a dumb idea.

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Do you know what's using $200/month? Furnace air handler? Something you can reduce?
How does winter consumption and production compare to summer?

I've tried to burn off my net metering surplus, but slipped and used up $600 of credits one month. Switched to gas after that, but flame sensor is malfunctioning and it doesn't work.

Electric heat obviously isn't the way to go, glad you've got gas.
I'm going to install 15kW PV on my new place, and electric heat (in addition to existing gas) because I'll have net metering for 20 years.

qwazipsycho said:

But I'm not sure you're wrong in the idea that all I need is a generator. On average we've seen the power go out maybe 6 times per year and the longest outage was about 6 hours.

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Generator can be useful, but about $1/W

qwazipsycho said:

I guess I need to weigh the cost of more panels vs batteries. If I install more panels and eliminate the monthly bill, what benefit would batteries be at that point? Unless I'm looking at it from a doomsday scenario, I don't see it. Thoughts?

Click to expand...

Batteries are nice to have a system run when the grid is down. I just finished my system during Covid, then the power went out. I estimate the cappuccinos I enjoyed cost $1000 apiece.
But the system did let my wife work from home, earning money (we had multiple localized power failures.)

By the way, I put GT PV hardware at $1/W. If free DIY labor, gives you power for $0.025/kWh (amortized over 20 years.) Turn-key installed about 3x that price.

Batteries may be as low as $0.05/kWh (over their cycle life.) I haven't worked out inverter cost to support them, some hybrids would hit my GT PV estimate and handle batteries at no extra cost. Some batteries and battery inverters are more expensive.

dougbert said:

@qwazipsycho

I also live in Utah, Heber City to be exact with Heber Power and Light

are you in Northern Utah? You might be with those cold temps we just had. If so we can get together and look at your system

if in southern, I don't get down there that often

and you are probably with Rocky Mountain Power, correct?

I built my own system over the past 24 years, with several phases where old equipment has been retired and new stuff added.
Link to my build is in my signature below. In my first post, I have schematics of my system as it is implemented today. Like @BentlyJ I also am a Schneider XW Pro based system, which is a Hybrid system - that allows selling to the grid - BUT I DO NOT DO NET METERING - I want nothing to do with that on my house. I cannot tap my "credits" if the grid is DOWN. I run the house as OFF grid with a battery, but I do use the grid when my battery get low after cloud cover, like we have right now. Hope is to add more panels to reduce need for grid backup

As others mentioned above, the EG4 18kw/PV is another Hybrid system

I think it is a great idea to view many different installations in order to do DIY installation because you need to know a lot to get good coverage on things.

Click to expand...

Hey Dougbert, yeah I'm in Hooper, just west of Ogden. So, Heber isn't too far. And yes, the money grubbing scum is known as Rocky Mountain Power. I would love to stop by and take a look at your setup sometime and pick your brain.

qwazipsycho said:

Hey Dougbert, yeah I'm in Hooper, just west of Ogden. So, Heber isn't too far. And yes, the money grubbing scum is known as Rocky Mountain Power. I would love to stop by and take a look at your setup sometime and pick your brain.

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good, you are in the north

I am retired now and am at home almost all the time. You are welcome to stop by. very small house and lot, but I have fun. will PM you contact and address

BTW I love the title of this thread