Realistic goal to get started with solar before tax credit expires?

[cr0]

Taken a while to focus in on this but I'm now looking to setup a microgrid at home for energy resilience, environmental benefits and cost savings. I realize the OBBB is ending the solar tax credit in 2025, meaning only expenditures put into service within 2025 get 30% rebate when filing taxes. For that reason I'm trying to work out what is realistic to get in service before year end. I know this is a longer-term project, but nice to get a 30% discount and make some progress/investments sooner than later.

I juggle a few other things so my time to focus on this is limited. For that reason, I expect it's not realistic in 2025 to reach my family's goal of generating all our own energy needs for basics. So I'm wondering, what steps can I realistically accomplish in 2025 that will benefit our journey to energy sufficiency on our couple of acres? I can probably focus 10-20hrs/wk on this, and recruit friends or hire my trusted professional electrician as needed.

Here's what I'm working with:

• Current equipment: I have a 2yr old Bluetti AC200P as a mobile power station. Also an older 100Ah Renogy 12V LiFePO battery kept over from a past project, still in great shape. So, 3.2kWH energy storage in different forms. No solar panels yet. I have some basic tools for DC circuits and most basic tools for AC electrical work. We also own a first gen Chevy Bolt with a new 60kWh battery + level-2 charger. We are much tighter on time than funding and can invest up front, but we are doing this to be frugal and want to use our budget efficiently.
• Main panel: Our 200A panel was replaced last year after 60 yrs of service (we moved here in last few years). It used to have a transfer switch in the form of a separate panel with 12 circuits that could be toggled for power from either grid power or a generator. With panel replacement, got a SquareD Q0 panel with interlock and a 30A 240V breaker to act as the transfer switch, powering the panel from a 30A 240V outdoor receptacle.
• Backup power: We have a 5000W continuous/5600W surge gas generator that came with the house. Needed some work but is now functional and effective. With the interlock mentioned above, we can choose what circuits to power when on generator backup. It works for bare minimum at least: well pump, microwave, mini-split, fridge, chest freezer, and small devices/lights.
• Setting: We get plenty of sun and wind on our gentle sloping 2ish acres. Our home is about 1200sqft and has a decent space for ground mounting within 150ft of load center. All appliances are electric but we heat with a wood stove. In addition to the house, 160-200ft from house there's also a barn - just block walls and metal roof, apx. 20x40ft - which could be good for experiments but seems too far away to serve as an off-grid power house (how would it power our water well, electric appliances, or EV?)
• Goal is ultimately to run home (or at least essentials) from renewables. Enough generation & storage for the well pump (20A 240V circuit), mini-split, fridge, chest freezer, and one of the following at a time: level-2 EV charger (50A 240V circuit, 7.7kW power use), hot water heater (30A 240V circuit), electric range (40A 240V circuit), or smaller appliances.
  • Considering solar, we initially planned to hire a company to tackle all that for us sometime in 2026-27. Digging into this more, it seems like progress can be made with DIY and our regular electrician's help, plus a solar company wouldn't be able to get something in service before 2025 ends.
  • As an easier goal, a solar backup system for critical loads would be useful, basically replacing/supplementing the 5000W gas generator we have. To power our well pump we'd need it to plug into the 30A 240V receptacle, or modify our load center which would be nice to avoid. Are there steps we could take to power our well pump's 20A 240V breaker at least, or is that a big lift in itself? Ideally I'd setup a way to use our existing Renogy 100Ah 12V LiFePO battery & Bluetti AC200P if possible, adding on PV and components to charge that up, and maybe upgrading an inverter or getting something like EG4 GridBoss+FlexBoss18 so we can run the load center from batteries and keep building out our storage & generation over time.

I'm thinking the most strategic move for 2025 would be to tackle the up-front costs that could be modular (like those EG4 units), starting as a backup generator replacement and expandable to cover more circuits or even go hybrid/connect to grid in the future. But it feels premature to get into that without designing a full system, especially with house fast tech is evolving.

Being new at this, I'd appreciate suggestions on what to focus on first, to make some modular and useful progress while making the most of the 30% tax credit before it expires.

 

[DIYrich]

Buy all the panels, inverter, and battery you can afford. Lay the panels on the ground, and have it supply power to your home (disconnect from grid). Take a picture of it working (placed in Service).

Then work on a permanent install when you can afford it.

 

[cr0]

Makes sense, thanks for the suggestion. I'm trying to wrap my head around the microgrid powering my home disconnected from the grid. It seems like a critical choice about what inverter I go with, being able to power circuits in my main panel without disconnecting those from the grid.

I was about to post a separate question about this: Does EG4 6000XP or 12000XP allow for the main load center to be run off solar primarily, batteries secondarily, and grid or generator tertiary? Sort of a hybrid system but with no ability to backfeed into the grid?

 

[Verbs]

What DIYRich is saying is you can remain connected to the grid... To get the credit, buy every thing, install it, but when you turn it on, disconnect from the grid temporarily. All it has to do is provide some power to your home, doesn't say how much. After you verify it works and prove it supplied power, shut it back down, reconnect to the grid and take your time finishing the install, and getting approved to interconnect with the grid.

This works as long as the solar inverter is designed to work both on and off grid.

Your existing batteries are of no use in a 48v system which would be the most common battery storage available. Do not use 12v LFP batteries to build a 48v system, it never ends well. If you truly plan to have the system for backup, batteries couple be the highest cost of the whole system. It was for me as I have 60kWh of battery, which allows me to effectively run off-grid for the summer months.

A single FB18 will cover most things in your house all at once, other than run the EV charger at full rate. I have a FB21 and a Bolt as well. I derate my EV charger to 12a, even though it could do 32a. If I do need to charge at the high amps, I have to make sure other large loads won't kick in and overload the inverter. I plan to connect the EV charger to a smart port on the GB to accomplish that.

Other thing to think about would be a heat pump hot water heater. That would help significantly reduce your electrical load, and the credit is going away on those too.

I really can only speak to hybrid inverters, in my case it was required as I still need my system to interact with the grid as I am not able to provide all the power I need in winter months. By going hybrid, it allows the inverter to automatically power what it can, and supplement with grid without interruption or flipping any switches.

 

[cr0]

Very helpful, thanks! Good to hear about your GB + FB18 setup and how the Bolt fits into that.

We hadn't thought of replacing our hot water heater. I need to double check but think it is >10yo, has worked fine for us and looks fine from the outside. Thanks for the tip, good point.

On the hybrid inverter point - is the GB + FB18 able to automatically power what it can, supplementing with grid without interruption, but without backfeeding to the grid? I was looking into the EG4 6000XP or 12000XP as off-grid inverters that seemed to be able to incorporate grid power but without backfeeding. I need to get a better understanding of how these inverter options connect to my meter and load center.

 

[Verbs]

Yes, the GB/FB is able to interact with the grid but not export. There is a tiny bit that will leak out, just simply because of how fast systems can react, but it's less than .1kW a month in my experience.

As an example of how it works, this is the energy graph from home assistant on my system for July. Green (above the 0 line) is the FB using stored battery energy to power loads, orange (above the 0 line) is the FB directly using PV power to power loads, pink (below the 0 line) is the FB storing power in the battery, purple (below the 0 line) is the FB exporting excess power to the grid, blue (above the 0 line) is the FB importing power from the grid to power loads.

Before July 7th, the FB was configured for zero export to the grid. Excess PV generation that couldn't be stored in the battery was simply "lost".



In the month prior, I only had 6.4kW of PV installed until the 21st when the rest was installed to bring it to 18.8kW total. You can see how it worked very nicely to supplement the import of grid power, sending nothing back.

 

[cr0]

That is super helpful, thanks. The graphs help articulate what we're trying to do. Is the 'home assistant' that generated those graphs part of the EG4 apps?

For now our plans are shaping up as: install EG4 GridBoss + FlexBoss18 along with sufficient battery storage to cover us in 24hr outages (worst we've had in a few years), then small amount TBD of simple ground mounted solar panels to get the system started. In the future we can expand with more panels, as I figure those are relatively cheap and thus not as important to fit in our 30% tax credit window, compared with these other components. To start, we'd not export to the grid (to help speed up the project in theory), and we'd just offset our grid usage and add some backup power. Eventually, we'd expand generation and capture that extra energy with sellback to the grid (our energy provider offers net metering) and/or more batteries.

I'm reaching out to some electricians for help. One big factor will be whether we can install all this without the same extent of permitting/inspection/etc as if we are selling back to the grid anyway. If it doesn't save us time, that might change plans.

 

[Verbs]

That is super helpful, thanks. The graphs help articulate what we're trying to do. Is the 'home assistant' that generated those graphs part of the EG4 apps?

No. https://www.home-assistant.io/

There are two ways to get the values into Home Assistant. The most popular is to use Solar Assistant. This costs money. The other option is to use the LuxPython_Dev repo. This takes a bit more work, with a confidence in some light computer work, but it's free. I use the LuxPython_Dev option.

You may be perfectly fine with EG4's monitoring site. I like to do more automation around my house depending on what's going on. I can use the system to do scenarios like turning off non-critical loads during outages, etc.

For now our plans are shaping up as: install EG4 GridBoss + FlexBoss18 along with sufficient battery storage to cover us in 24hr outages (worst we've had in a few years), then small amount TBD of simple ground mounted solar panels to get the system started. In the future we can expand with more panels, as I figure those are relatively cheap and thus not as important to fit in our 30% tax credit window, compared with these other components. To start, we'd not export to the grid (to help speed up the project in theory), and we'd just offset our grid usage and add some backup power. Eventually, we'd expand generation and capture that extra energy with sellback to the grid (our energy provider offers net metering) and/or more batteries.

I'm reaching out to some electricians for help. One big factor will be whether we can install all this without the same extent of permitting/inspection/etc as if we are selling back to the grid anyway. If it doesn't save us time, that might change plans.

In Illinois, doesn't matter if you plan to export or not, if you are interacting with the grid in the way these inverters do, you need approval. The power company wants to make sure a safety switch is installed and they mark your site as interacting with the grid. It's possible that a lightning strike or other malfunction in the systems could cause the software/relay based safeties to fail, and they need to know who to go check if they are still backfeeding when they shouldn't.

You could run "off-grid" by running the inverter and your house not connected to the grid and using a chargeverter to charge the batteries from the grid. There would be no AC interconnection that would get you in trouble. Not as efficient use of power though.

 

[cr0]

Good to learn about those open source projects! I'm more experienced with the computer science side of technology than all the electrical so that'll come in handy.

As for any kind of grid connection needing a permit, that makes sense. I'm contacting some electricians so we'll see about navigating all that. Even if permitting takes longer, I could at least put the off-grid inverter capabilities in service prior to having any connection with my main panel.

One scenario I wonder about, if not getting grid connection until 2026 or later but wanting to put this kind of system to use in my main home's circuits:
Would the FlexBoss18 output 240V power usable by circuits in my home (well pump, sump pumps, etc.) by connecting to my house's generator input? That generator input is currently a 30A 240V outdoor receptacle and circuit, behind an interlock on the 200A main panel indoors which is connected to the meter outdoors. In this case the FlexBoss18 inverter would act as an off-grid solar generator, and the load it's connected to would be the home's 30A 240V generator circuit, powered from batteries charged by PV.
Seems a little sketchy, sort of an impractically giant sized version of the 240V portable solar generators you can get (I saw EcoFlow Delta Pro can sync two units to act as a 240V household generator). A big downside even if this could work is manual switching required and energy wasted/unutilized due to imbalances in generation vs storage. But at least it would give the backup and renewables option for some household circuits en route to a better setup.

 

[cr0]

Buy all the panels, inverter, and battery you can afford. Lay the panels on the ground, and have it supply power to your home (disconnect from grid). Take a picture of it working (placed in Service).

Then work on a permanent install when you can afford it.

Following up on what I just posted: when you say "have it supply power to your home (disconnect from grid)", is it possible to connect an inverter like FlexBoss18 up to the house's 30A 240V generator input? 'Disconnect from grid' would be true in the sense that the generator's breaker is behind an interlock on the panel's 200A main breakers, which is there so my dirtier gas generator stays off-grid and doesn't backfeed.

Otherwise if getting on-grid by year end doesn't look good, I could just have the setup powering some basic and nearby devices, without any connection to my home's main panel, then once it's on grid can continue building out more solar.

 

[DIYrich]

is it possible to connect an inverter like FlexBoss18 up to the house's 30A 240V generator input?

You could, but make sure you don't overload the connection

 

[Bluedog225]

I think powering a light bulb in the garage is “in service.” Don’t know if the IRS will disagree.

 

[Paul Ebert]

Yes, the GB/FB is able to interact with the grid but not export. There is a tiny bit that will leak out, just simply because of how fast systems can react, but it's less than .1kW a month in my experience.

As an example of how it works, this is the energy graph from home assistant on my system for July. Green (above the 0 line) is the FB using stored battery energy to power loads, orange (above the 0 line) is the FB directly using PV power to power loads, pink (below the 0 line) is the FB storing power in the battery, purple (below the 0 line) is the FB exporting excess power to the grid, blue (above the 0 line) is the FB importing power from the grid to power loads.

Before July 7th, the FB was configured for zero export to the grid. Excess PV generation that couldn't be stored in the battery was simply "lost".

View attachment 324993

In the month prior, I only had 6.4kW of PV installed until the 21st when the rest was installed to bring it to 18.8kW total. You can see how it worked very nicely to supplement the import of grid power, sending nothing back.
View attachment 324998

The GB/FB can't export? Ever and regardless of setup? One of my main goals for my system is to not have to export since my net metering is going away in a few years, but I'd still like to export if the solar output is greater than my load and the batteries are full. It seems to me that a gateway should be able to support exporting when needed.

 

[Verbs]

The GB/FB can't export? Ever and regardless of setup? One of my main goals for my system is to not have to export since my net metering is going away in a few years, but I'd still like to export if the solar output is greater than my load and the batteries are full. It seems to me that a gateway should be able to support exporting when needed.

It can export, if that's what you want it to do. It can also not export, if that's what you want it to do. It supports both.

 

[plympton]

I agree with all that's been said on this thread - buy now, hook up just enough to get the credit, and then go for a 2nd stage install when you can.

BUT!

Don't buy anything that you can't afford to have denied by the IRS. I bought some more battery storage this year after my DIY last year, and I'm not counting getting a 2nd credit when I file next year. If it happens, great. If not, it just extends my ROI a few more years.

 

[DIYrich]

The GB/FB can't export?

@verbsaid "a tiny bit that will leak out". That can cause problems if your utility cares. Asli, it requires an interconnect agreement.

 

[cr0]

An update on this and I'd appreciate a sanity check from others here. How does this sound? We got a couple of quotes from installers, and liked a local one that someone on this forum recommended as working with EG4 products.

We wanted ground-mount but they insisted on roof-mount and quoted ground-mounted as costing $10-20K more. Our roof was re-shingled about 4 years ago and the sheathing underneath is easy to see from the attic, looks fine. Their roofer thought it was good to go.

Our goal: A PV system to cover all our energy needs is out of our budget for now. We're aiming to have at least a day or two of backup power, that would automatically transfer and would supplement grid power while that was available. Also wanted to continue having use of a 5.5kWH gas generator that came with our house.

The system we signed up for will cover 50-60% of our energy use over the course of a year. 9660W PV array with (21) Aptos 460W panels on the sturdier and easier to access roof of our house (not over garage or an attic-less addition). Mounted with Iron Ridge Flashfoot2 mounts and XR100 mounting rails. Roof has a gentle slope, 14 panels on the SE-facing side and 7 more on the NW-facing side. Includes Tigo TS4-A-O optimizers for the panels which I was not familiar with.

Inverter is FlexBoss18 and one 14.3kWH EG4 indoor wall-mount battery. They said I'm the last customer they're signing up to get this in service by year end, and that to have a true backup system I'll need additional work in 2026 having a gateway installed. For now, battery is in service, but battery cannot run when grid is down - they said the permitting and work for that could delay getting it all in this year. I'm a little unclear how the generator interlock fits into all this to begin with, but when a Gateway is installed in 2026 I understand that can hook up then. They estimated $1.5-4K more for that 2026 work.

By my estimate, 14KWH would last us a day of relatively heavy use and not much energy conservation. So having that energy storage in one battery feels good, especially since we could probably trim it down further, hopefully get some sunshine, and could add another battery in the future. In the meantime, offsetting 50%+ of our annual energy use sounds good and gets us to a break even of 10-15yrs (longer if we use less power, shorter if power costs increase more than 5% per year). Given this equipment should last 25 years+, breaking even before halfway through its lifespan sounds good to me, plus I understand the panels and many components could last longer being kept in dry, cool conditions.

Overall price per watt of entire system, battery storage included, is about $4. Another quote that would cover all our power needs was $3.37/W with slightly smaller Tesla battery, but the scale of that system was out of our budget to start. This is before federal tax credit and state incentives, which after all that should get our out-of-pocket cost closer to $25K.

This makes sense in my mind, though I am nervous about getting it in service by year end. I've asked a few installers if there's a way to just get things setup and powering up before grid connection to ensure it's in by end of year but it seems like the permitting and all that needs to come first, and they want to just bang it out in a day not drag it out over a partial installation.

 

[DIYrich]

If I were you, I would drop the battery, upgrade to Flexboss21, install the Gridboss now and as much additional solar as you can.
Easy to install the battery later yourself. Consider using 5kWh rack batteries to make it easy to handle.

With battery prices continuing to decline, you might be able to breakeven next year (lower price next year offsets tax credit this year).

 

[cr0]

If I were you, I would drop the battery, upgrade to Flexboss21, install the Gridboss now and as much additional solar as you can.
Easy to install the battery later yourself. Consider using 5kWh rack batteries to make it easy to handle.

With battery prices continuing to decline, you might be able to breakeven next year (lower price next year offsets tax credit this year).

Interesting idea, thanks. I'll ask the company's solar engineer about that possibility. They seemed to think getting the battery setup in backup mode was what would delay the whole install until next year, but it seemed like the GridBoss installation was the key factor there not the battery. I say that since they were up to install the battery to start but couldn't say they'd be able to get the GB installed by end of the year. They also thought there would be better, cheaper gateways (MIDS) available next year.

 

[plympton]

Curious how you arrived at “14kWh is good for a single heavy day”. In that assuming there’s good sunshine and the 14 would cover what you’d have to pull from the grid to cover? Also assuming you’d be at 100% when you go off-grid?

Was going over my numbers and it seems like a harder number to calculate than I figured - sun and battery SOC come into play. Curious - what is the right way to calculate this?

I have 20 kWh battery, 3.6 kW solar, and use about 14kWh just at idle a day (no stove, dryer, etc).

 

[plympton]

Also curious if you can get in-country batteries (tariff included) with the 30% tax credit and hook them up minimally to qualify. As far as I know they just have to supply energy to the house, not be fully integrated ideal configuration.

They could go down next year (economic slump + credit goes away), but it’s such a wildcard. I’m tempted to buy another battery off Amazon, but since it’s shipped 3rd party worried about getting a surprise tariff.

 

[cr0]

Curious how you arrived at “14kWh is good for a single heavy day”. In that assuming there’s good sunshine and the 14 would cover what you’d have to pull from the grid to cover? Also assuming you’d be at 100% when you go off-grid?

Was going over my numbers and it seems like a harder number to calculate than I figured - sun and battery SOC come into play. Curious - what is the right way to calculate this?

I have 20 kWh battery, 3.6 kW solar, and use about 14kWh just at idle a day (no stove, dryer, etc).

It was tricky to estimate and I have some uncertainty about it. I'm comforted by the potential to add another battery down the line.

Here's my process. I listed all the loads I would want to run on a power outage day. I'm picture a hurricane or wildfire (we have small ones in our area, rarely) as a grid-down scenario.

• Cooking: In that kind of emergency I'd probably not run an electric range, I'd use microwave and hot water, wood stove, propane camp stove, etc. Or I'd use the range but sacrifice something else. So I allotted 1500W*0.5hrs=750Wh to that.
• Using cloth diapers, we may need to run a couple of washes nowadays. 710W machine rating * 2hrs = 3000Wh. Note that this is probably an over-estimate, because the machine is not constantly drawing that much power. Using a kill-o-watt meter I found that 3 laundry cycles (2 for diapers, 1 regular load - more than I'd do on an emergency day!) only used 0.37kWH=370Wh! So my 3000Wh is way overestimated.
• Well pump was a big uncertainty. I have a continuous pressure pump and have not measured its running current. I know it runs on my 5/5.5kW gas generator. I have reason to think it uses 2kW continuous, and roughly estimating how much I'd run our taps on an emergency day, I put that at 2kW*4hrs=8000Wh.
• Hot water is the other big uncertainty. Its elements are rated to peak at 4500W. I've read it probably uses something like 1500W continuously, but I'm really not sure. I did 1500W * 2 hrs of actively running = 3000Wh. I suspect this is where I'd come up short, and if I find that hot water only comes with grid power, sunny daytime, or gas generator, we could live with that (and maybe add more batteries in the future).
• Fridge and chest freezer I ran a few numbers for but settled on total of 1600Wh to get a day of running both of those. Again I'm pretty sure that is an over-estimate.

Tally that up and it leaves me with about 14kWH needed for a day of laundry, some minimalist electric cooking, some frugal hot water use, and cold storage. This assumes battery starts fully charged (at least ahead of a hurricane I'd plan ahead for that). Also assumes no PV generation, gas power, or ability to run off our electric vehicle's 66+kWH battery. My sump pump is on a separate battery backup so we didn't count that.

This seemed like a good starting point, and conveniently, one EG4 wall-mount battery is sized just over 14kWH and is integrated with safety features making me more comfortable having it in a basement beneath bedrooms.

 

[OhYou_]

does the solar equipment have to actually power a "real" home to meet this credits?

 

[cr0]

does the solar equipment have to actually power a "real" home to meet this credits?

It has to be in service, but it is not any more specific than that. So it doesn't need to power a home. The thing is, when hiring a professional installer, I cannot have them get things 'in service' prior to getting all the permitting and grid connection work done. They want to do all the installation work in one day, and make sure it is only installed when the permitting and all that is worked out.

If I was doing an off-grid system, with no planned grid-tie, I think it would be easier to qualify for the tax credit. You could just get all the components and rig them up to be 'in service' powering a lightbulb or something, then rearrange later. It seems like that flexibility is not realistic if installing hybrid systems ultimately.

 

[DIYrich]

does the solar equipment have to actually power a "real" home to meet this credits?

Does not have to power "All" the home. "Critical Loads Panel" is enough.

@cr0 idea could work. Main Panel -> Off Grid Inverter -> Sub Panel (Critical Loads Panel).