Utility doesn't Home battery backup without solar? (Houston - Centerpoint)

[BarracudaBob]

Sounds like the utility is telling you to go solar

 

[dougbert]

So how are you going to run the huge ac units we use in Texas and the surge loads they have??

ah yes, the AC slaves who live in the lowlands, I forget about those - sorry. I am a 5500+ ft mountain guy

 

[BarracudaBob]

ah yes, the AC slaves who live in the lowlands, I forget about those - sorry. I am a 5500+ ft mountain guy

Just because you won't share some of that cool air. Not nice.

 

[ULR]

Most (if not all) utility companies won't accept that. It must be impossible to export. A setting, easily accessible to the customer won't cut it.

Right. You'd have to replace the inverter with one that is hardwired for offgrid mode, like the EG4 8000 series.

I think you can hook them up through the gridboss, rather than replace the whole shebang.

 

[mciholas]

Just because you won't share some of that cool air. Not nice.

The cold air is shared, it is right above you a mile up.

Lapse rate is about 2C per 1000 ft, so 5000 ft is 10C colder (about 18F) than sea level.

Go to 35,000 ft, it is -55C typically, very cold.

Mike C.

 

[BarracudaBob]

The cold air is shared, it is right above you a mile up.

Lapse rate is about 2C per 1000 ft, so 5000 ft is 10C colder (about 18F) than sea level.

Go to 35,000 ft, it is -55C typically, very cold.

Mike C.

I spent a lot of time in Colorado and the Blue Ridge mountains in Georgia. Beautiful areas.
Wife has a saying that we can visit snow but snow can't visit us.
I'm stuck with the alligators in the Florida Tropics for a while

 

[Quattrohead]

A possible way to do this might be to hook up the grid to the generator port on the GB and not have the grid attached to the grid port at all. The system will use the generator (now grid) when the battery is low and not when it is high, and then work out the TOU settings to get the right behavior.

This could work.

 

[LearningIt]

Base Power Texas's main plan installs a 25kWh battery connected to the grid that they use for power price arbitrage, without solar. They charge the battery when ercot wholesale prices go negative, which frequently happens when there is excess solar on cooler sunny afternoons, and then provide power to the grid when wholesale prices spike.

 

[1201]

Base Power Texas's main plan installs a 25kWh battery connected to the grid that they use for power price arbitrage, without solar. They charge the battery when ercot wholesale prices go negative, which frequently happens when there is excess solar on cooler sunny afternoons, and then provide power to the grid when wholesale prices spike.

And I think you say this to say , base power operates in centerpoint territory, and they don't install solar, so if they are able to install inverter and battery only, then op is able to as well.

 

[LanePilot]

Base Power Texas's main plan installs a 25kWh battery connected to the grid that they use for power price arbitrage, without solar. They charge the battery when ercot wholesale prices go negative, which frequently happens when there is excess solar on cooler sunny afternoons, and then provide power to the grid when wholesale prices spike.

When you sign up for Base Power, they become your REP (Retail Energy Provider), so they are who you are buying your electricity from. Centerpoint is only the Transmission and Distribution Utility (TDU). I assume that is what allows Base Power to do this.

 

[mprindle]

For Centerpoint specifically, here's an interesting regulatory document that states in section 6.1 that single phase systems less than 50kW can operate in parallel as long as there is a visible lockable disconnect with-in 10' of the meter. For reference 50kW @ 220V (typical US split-phase install) is a little over 227A which is just above a typical 200A home service.

There is also a statement in section 7.0 for inverter equipment, with the requirement of a disconnect, submission of a simple diagram, and submitting of documentation for the inverter.

https://www.centerpointenergy.com/en-us/Documents/DistributedGenerationDocs/Customer-Distributed-Generation-specifications.pdf

EDIT: The Gridboss and Flexboss both have there UL 1741 certs on the EG4 website available for download: https://eg4electronics.com/documentation/

6.1 The Customer will be allowed to install and operate single-phase generating
facilities that are 50 kW or less in parallel with the CNP System at most
locations on the radial distribution system if they meet the requirements of
this specification. Depending on the point of connection to the CNP System,
single-phase generating facilities larger than 50 kW may be allowed.

7.3 For inverter systems, the Customer shall provide a one-line diagram showing
the relationship of the generating facilities tied into a breaker or breakers in
the electrical panel and the CNP meter location. The AC disconnect switch
shall be between the inverter and electrical panel and must be a lockable,
external handle, visible and readily accessible disconnect switch and typically
installed within ten feet of the CNP meter. If the AC disconnect switch is
installed more than ten feet of the CNP meter, a weather-resistant, easily read
placard must be installed within ten feet from the CNP meter, clearly
identifying the location of the AC disconnect switch.

7.4 The Customer shall provide manufacturer specifics for the inverter and
disconnect switch. The inverter specification sheet shall show that the anti-
islanding protection has been certified by IEEE 1547 or UL 1741.
Otherwise, the Customer shall test the inverter pursuant to PUCT
requirements, as specified in Articles 4.2.1 and 4.2.5 of this specification.
CNP shall receive notice and be present for the inverter testing.

 

[LanePilot]

For Centerpoint specifically, here's an interesting regulatory document that states in section 6.1 that single phase systems less than 50kW can operate in parallel as long as there is a visible lockable disconnect with-in 10' of the meter. For reference 50kW @ 220V (typical US split-phase install) is a little over 227A which is just above a typical 200A home service.

There is also a statement in section 7.0 for inverter equipment, with the requirement of a disconnect, submission of a simple diagram, and submitting of documentation for the inverter.

https://www.centerpointenergy.com/en-us/Documents/DistributedGenerationDocs/Customer-Distributed-Generation-specifications.pdf

EDIT: The Gridboss and Flexboss both have there UL 1741 certs on the EG4 website available for download: https://eg4electronics.com/documentation/

Those are the specifications for an interconnected system. I believe you still have to obtain an interconnect agreement from Centerpoint. I know I did 20 years ago when I first got mine.

 

[Madcodger]

Most (if not all) utility companies won't accept that. It must be impossible to export. A setting, easily accessible to the customer won't cut it.

Amen, @timselectric . This is a big thing that too many people overlook, and then end up in a bind.

<Begin rant, so I can later just copy and paste this on about a hundred future threads. > Look, people: Unless you intend to enter into a net metering agreement, purchase equipment that is incapable of sending electricity back to the grid. We've heard too many people say something along the lines of, "Well, I thought I MIGHT want to send power back to the grid one day". OR, they get all starry-eye dazzled by the latest product that makes grid export possible without any clear plan to actually do that, and fail to realize that they're buying a feature that actually makes their project much harder, if not impossible.

If you don't SPECIFICALLY INTEND to grid-tie, folks, don't buy equipment that CAN do that, unless you are prepared for the rules, paperwork, actions, expense, and bureaucracy involved with owning such equipment. It's a lot like buying a semi-truck to run errands around town, then wondering why you need a commercial drivers license. If you use the wrong equipment, you're going to be held accountable for what that equipment might be able to do, not how you claim you're going to use it. <End rant >

 

[1201]

Amen, @timselectric . This is a big thing that too many people overlook, and then end up in a bind.

<Begin rant, so I can later just copy and paste this on about a hundred future threads. > Look, people: Unless you intend to enter into a net metering agreement, purchase equipment that is incapable of sending electricity back to the grid. We've heard too many people say something along the lines of, "Well, I thought I MIGHT want to send power back to the grid one day". OR, they get all starry-eye dazzled by the latest product that makes grid export possible without any clear plan to actually do that, and fail to realize that they're buying a feature that actually makes their project much harder, if not impossible.

If you don't SPECIFICALLY INTEND to grid-tie, folks, don't buy equipment that CAN do that, unless you are prepared for the rules, paperwork, actions, expense, and bureaucracy involved with owning such equipment. It's a lot like buying a semi-truck to run errands around town, then wondering why you need a commercial drivers license. If you use the wrong equipment, you're going to be held accountable for what that equipment might be able to do, not how you claim you're going to use it. <End rant >

That's just not correct. In many parts of the country there's not a lot of red tape to get connected, and being connected has huge advantages that off grid does not have, even if you do not plan to export.

 

[Madcodger]

That's just not correct. In many parts of the country there's not a lot of red tape to get connected, and being connected has huge advantages that off grid does not have, even if you do not plan to export.

Then we'll just have to agree to disagree. I still don't understand why anyone would purchase a sledgehammer when they just need to pound regular 10d nails. But you do you, and if others agree, they can do as they please. Many of us have seen too many situations where someone is just getting into solar, and because they don't understand the responsibilities and requirements that go along with purchasing equipment capable of exporting to the grid (but then find they don't want to do so), they're stuck with the need to go through all the utility / government red tape that would be required if they were actively exporting. If you're in a place that that's not the case, then great - have at it. But for most of the US, at least, once you have equipment capable of exporting power to the grid, you've bought yourself the red tape that goes along with that capability. Texas is known to have a mind of its own on many things, including grid connections (even to other grids). But for most of the country, grid-capable equipment is a much bigger headache if you're not actually connecting to that grid. And FWIW, I haven't missed the grid for one second of my off-grid, very electricity-dependent, life. Huge advantages? Nah.

 

[1201]

Then we'll just have to agree to disagree. I still don't understand why anyone would purchase a sledgehammer when they just need to pound regular 10d nails. But you do you, and if others agree, they can do as they please. Many of us have seen too many situations where someone is just getting into solar, and because they don't understand the responsibilities and requirements that go along with purchasing equipment capable of exporting to the grid (but then find they don't want to do so), they're stuck with the need to go through all the utility / government red tape that would be required if they were actively exporting. If you're in a place that that's not the case, then great - have at it. But for most of the US, at least, once you have equipment capable of exporting power to the grid, you've bought yourself the red tape that goes along with that capability. Texas is known to have a mind of its own on many things, including grid connections (even to other grids). But for most of the country, grid-capable equipment is a much bigger headache if you're not actually connecting to that grid. And FWIW, I haven't missed the grid for one second of my off-grid, very electricity-dependent, life. Huge advantages? Nah.

What red tape? An application? If you are building the system to code there are no additional hoops to jump through.

An "off-grid" system doesn't usually support all loads and if it does it is going to be a lot larger and more expensive than a grid connected system which, incidentally, can support all household loads with a smaller inverter and smaller battery and fewer panels.

You're not worried about startup surges with a grid connected system. You're also not worried about "blips" when the system is switching back and forth between the grid/Gen and the inverter.

 

[ULR]

I still don't understand why anyone would purchase a sledgehammer when they just need to pound regular 10d nails.

Because a grid-interactive system has other advantages over an "off grid" system, besides being able to backfeed the utility's grid.

In particular, it is able to combine its inverter's output with the grid power. This means:
- It can supply all the power for the load up to the limit of its inverter or the combination of its batteries plus solar input. If the load needs more, it is seamlessly provided by the grid. So you only pay for gird power to make up the load's requirements beyond the ability of the inverter and the batteries plus solar input. The transition does not interrupt power to the loads.
- If you have partitioned your loads into backed-up (must have power during a grid outage) and non-backed-up (only have power if the grid is live), the system can provide battery + solar power to the non-backed-up loads as well, with the grid only supplying (and billing for) the excess power beyond the inverter or battery + solar limit.

This lets you get away with a much smaller system, at least while the grid is up. The honking big grid feed handles your big loads and you only have to size to cover the backed-up loads plus as much of the non-backed loads as you want to not pay for. You can let the grid handle motor starts and occasional big stuff, rather than buying an inverter powerful enough to handle the peaks, which can be several times the typical steady-state load.

An off-grid system can only supply the (backed-up) loads from the inverter and battery + solar OR the grid, not both.
- If the load calls for more it must shut down the inverter and switch so that ALL the power for the load is purcha$ed from the grid.
- There is a short outage when it switches between inverter and grid in either direction. (This is problematic if, say, the big air conditioner trying to start is what caused the switch.)
- If the loads are partitioned into backed and non-backed, all the power for the non-backed loads is purcha$ed from the grid all the time - even if the inverter is running and has enough capacity that it could have provided it.

This can make the grid-interactive system worth the extra bux to some users.

The downside, of course, is that a grid-interactive system does these tricks by monitoring the power transfer between the utility and the rest of the system and adjusting the inverter output to produce only the power that the load is demanding - up to the limit of its ability. When a big load shuts off the control loop is too slow to turn down the output to match the demand immediately. So the system will occasionally backfeed short "unintentional" bursts of power even if you've set it to not backfeed. Smart meters can detect this and rat you out to the utility. So you have to be on a plan that allows short bursts of backfeed, which gets you into the approval and deal-with-the-utility process, even if the utility has a simplified plan where you don't get paid for the backfed power but the utility agrees to accept short bursts as a gift rather than punishing you for making them take it.

Does this make sense now?

 

[Madcodger]

Well, as noted earlier, we just need to agree to disagree. I stand by my earlier opinion: If you don't intend to grid tie and net meter, don't buy equipment that includes those capabilities. You gain nothing, but add a whole host of limitations and complexity because the local utility will (correctly) make you design your system so that you can connect safely if you have that ability.

I'm not at all opposed to people having zero export equipment and a grid connection if they want it - that's a good design! I'm just tired of hearing from people who buy equipment designed to feed back into the grid, who then whine and complain because the local utility forces them to install that equipment SAFELY, and without relying on just their "scouts honor" pledge that they (or a future owner) won't one day turn on that export capability, even by accident. All of that is avoidable by just purchasing equipment that can't export, if you don't intend to do that.

To answer the comments above, arguing for grid connections: As for red tape, my system went live on almost the same day a friend's professionally installed, grid-connected system in the same town was finished and ready to go live. I was up and running for months - MONTHS! - while he waited on the local utility to inspect and finally allow him to turn on. He had NOTHING that needed to be changed or repaired and he had followed their process to the letter. It just took them that long to get their inspections and paperwork done. So maybe that's not the case for some parts of the country, but in others, grid tie and net metering is a big PITA. Does it have benefits? Of course! But the question is, do those outweigh the downsides?

As for powering bigger loads, being able to use smaller inverters, etc.: If I wanted a hobby system, I'd have designed and built that. There's nothing I can't power easily, that I need and want. If I want to weld while the heat pumps are running, we're doing laundry, and my wife is using the induction range, I just do it. What on earth are you people trying to power?? A well designed, properly sized off grid system can handle anything almost anyone can do with a grid-connected system. Just don't expect a toy to do real work, and you'll be fine.

 

[Philcaps]

I got a company to install home battery backup without solar. The system include EG4 Gridboss, Flexboss21, and battery. Everything seems fine with the consultant and they did site survey. Then I got a call back that the utility doesn't permit home battery backup without solar. It doesn't make any sense as why solar is requirement for home backup. I don't want to push power back to the grid. I just want to charge the battery during the night and use it during the day. My house is located in Houston and Centerpoint is the utility.

Most people usually pair solar with home backup, so I can't find the answer online. Anyone encounter this?

Updates? Also who installed the eg4 equipment and price?

 

[Striker]

Updates? Also who installed the eg4 equipment and price?

I cancelled the contract with that company since they said I need solar. I haven't got anyone else doing it yet as it's hard to find someone to do EG4 installation.

My other option is going with Tesla 8.2 Kw solar and 1 Powerwall3 and 2 Powerwall Expansion for about $41,000 before 30% tax credit. I really don't want to do solar because my roof is 15 years old.

 

[mprindle]

My other option is going with Tesla 8.2 Kw solar and 1 Powerwall3 and 2 Powerwall Expansion for about $41,000 before 30% tax credit. I really don't want to do solar because my roof is 15 years old.

Do you have the space for a backyard pergola (patio cover) or a parking cover? That could keep it off of your roof and provide usable shaded space.

 

[Striker]

Do you have the space for a backyard pergola (patio cover) or a parking cover? That could keep it off of your roof and provide usable shaded space.

I do have a big covered patio and that would be my last resort. I have a two-story house and the house would shade it toward the evening.