Has the OB discussed this before? I did a search but nothing relevant popped up.

I've just started looking into it and was wondering if anybody had any thoughts. Has the technology and pricing come to a point where it is worth considering yet?

I am being quoted anywhere from $1.75 to $2.05 per watt. My consumption has been about 20,000KWh per year for the last several years. My co-op has net metering capabilities and credits the retail rate for any excess that goes to the grid. The solar companies are claiming a 7 year break even at current electricity pricing plus an assumed 2.5% inflation rate on energy prices. 30 year panel warranties, with 25 year installation warranties, 10 years on the batteries ( I plan to have battery backup enough for 3 days with no power and no/limited sun). I'm hoping there might be away to just use a regular gas generator to charge the batteries in case of extended outages?

Anybody have any strong convictions one way or the other on solar being a good idea or not. I'm in Grimes County and sun exposure is not a problem. They claim the financial ROI is 13.5%, if true I've done worse before.

If energy prices hold firm for the next 25 years, I'll pay out between $95K-$100K to the electric company. If you assume any sort of inflation, I'm guessing it could be as high as $125K (maybe more if China attacks our grid ). So for a $35K cash initial outlay plus another $20K or so for batteries and maintenance over the next 25 years, it seems like you'd come out on top. But I'm assuming that's not the whole story, which is why I started the post. What are they not telling me?

Just know, when the grid goes down, you go to battery power. No matter how sunny it is. Your panels are off when the grid is off. Not sure if this is a deal breaker for you, but it is for me. I want to be able to use panels after a storm and the current setup doesn't really allow for that.

This is what I found on a website, I will have to bump my insurance up a little. Currently have $100K, co-op is requiring $250K

That is cool that they actually pay that. That last paragraph scares me just a little, to me it screams "this is expensive and/or a gigantic pain".

Milwaukees Best Light said:

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Just know, when the grid goes down, you go to battery power. No matter how sunny it is. Your panels are off when the grid is off. Not sure if this is a deal breaker for you, but it is for me. I want to be able to use panels after a storm and the current setup doesn't really allow for that.

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Well that doesn't make sense, and would definitely be a deal breaker. What is the purpose of a solar power system if you need grid power? My understanding is the solar panels are generating DC power, that DC power is charging the batteries, and then you need a DC-to-AC converter to power the house. What am I missing, why does it need grid power to operate?

If I had to guess it is more of safety issue for them. If the grid is down it is likely due to a power line issue. You are a producer connected to the grid and they don't want the risk of you back feeding while they work on the lines.
ETA: Above is purely a guess on my part. I have however seen an instance where the power company had shut down a circuit at the transformer, yet somehow the house with solar was feeding the line. The linemen were less than happy.

That makes sense, but I don't understand how it would be any different than a gas generator. I assume there would be an interconnect switch that you have to flip when the power is out, similar to a generator setup. Maybe they aren't designed that way? That would stink...

Milwaukees Best Light said:

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Just know, when the grid goes down, you go to battery power. No matter how sunny it is. Your panels are off when the grid is off. Not sure if this is a deal breaker for you, but it is for me. I want to be able to use panels after a storm and the current setup doesn't really allow for that.

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I agree, this is a real issue!

Bronco6Gen said:

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This is what I found on a website, I will have to bump my insurance up a little. Currently have $100K, co-op is requiring $250K

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Is this the retail energy rate or total retail rate (including transmission and delivery charges)?

Bronco6Gen said:

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That makes sense, but I don't understand how it would be any different than a gas generator. I assume there would be an interconnect switch that you have to flip when the power is out, similar to a generator setup. Maybe they aren't designed that way? That would stink...

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The panels are on the "utility side", when utility power trips off, solar panels are disconnected. If you have an automatic backup source, it's separated from the utility side by an automatic transfer switch. Only one side of the automatic transfer switch can provide power at a given time. This is as technical as I get.....

Hmmm, I see…so the panels are feeding the house OR the batteries? They don't design it where everything flows through the batteries? My assumption was the solar panels charge the batteries, the house uses the batteries for power and when their isn't enough power from the panels to charge the batteries the grid supplements the power needed to charge the batteries.

That not being the case, I guess if you got enough battery storage, and an alternative way to charge the batteries ( like a gas generator) it could work as long as you could be charging and using the batteries at the same time. If you had enough battery storage to last you 5 days with no external charging source, could you run a generator and stretch that out to 8-10 days?

The way I understand it, the panels are connected to the grid on the utility side, sans batteries. You're producing electricity for them technically and offsetting your usage, not for yourself and selling excess back.

Are you sure the utility will let you have batteries on the system?

You should be able to set up your system so you can isolate the solar from the grid and still charge your batteries if the grid is down.

Otherwise you are correct, it makes no sense to have solar if it needs the grid to be on to work.

My big fear with solar is needed to get a new roof after the panels are in place. It's not cheap to have a contractor remove then reinstall the panels. My guess is that the cost of that alone would exceed any savings that you expect.

Absolutely was one of my biggest concerns as my roof is 18 years old, however, I have plenty of space on the ground so I'm getting ground systems quoted. Plus, maybe it's not a concern in practice, but the thought of several penetrations into my roof doesn't sit well with me.

It my understanding that roof installation most vendors require a fairly new roofs to be eligible. But long term it is still a concern.

They definitely do, every single one of them has asked how old my roof is. That's why the conversation switched to a ground system.

My current roof is 18 years old, I'm 50 years old...I only want to get 1 more new roof in my lifetime so I don't want to prematurely get a new roof now to accommodate a solar installation and have to go through it again when I'm 75-80, I need another 7-10 years out of this one.

Just thought I'd pop back in to clear up a couple of common misconceptions. I purchased a system that will be installed within the next 4-5 weeks.

First, you can get a system that is both tied to the grid, and works when the grid is down. You have to have the right equipment (like a Hybrid inverter), but it is possible, and common, you just have to work with a company that knows what they are doing. So there are systems suitable for both generating everyday power, and work as whole home backup power when the grid is down. In fact, you can have a regular gas or propane generator backup tied in as well. So you can have grid, solar, and generator power all tied to a single system that auto-senses which power source to be using. In my case, if the grid is down and there is little to no sun for several days then my generator will kick on to recharge the batteries. The nice thing about that is 100% of the generator power is being consumed and not wasted, so it is extremely efficient. For example, if you have a 10,000 watt generator, but you are only using 8000 watts at any given time as your backup power in a traditional generator backup scenario, those 2000 watts that you burned fuel to get are wasted in a "use it or lose it" power generation system. Versus having the generator charge the batteries that the solar system also uses, 100% of the power being generated by the gas generator is used, so you're much more efficient and the generator won't need to run 24/7.

Second, in talking to them about roof conditions, they warranty leaks with any roof penetrations for 10-15 years depending on which company you are talking to. So they are hesitant to install on an older roof that may develop problems unrelated to their installation. If you want to waive that warranty they'll install it on any roof you want. What that does with your home insurance is unknown, I'm not installing on my roof.

My system works when the grid is down. I specifically sought this solution after so many people had problems during the winter storm. I can cut the power from the grid and my house will be powered by my panels.

Generators have voltage regulators that control the output of electricity. They mainly do this by controlling the throttle. You cannot shoot more electricity than the draw. Not saying using the genny to charge batteries isn't more efficient, just saying that using a 10k genny on an 8k demand isn't wasting 2k of juice.

Please keep us updated on this. I am still really curious about this and want to follow your story.

This is true of inverter generators, but unless things have changed, the generators I grew up with turned at a certain RPM regardless of load. Admittedly, these days, most people have inverter type generators, so it is a very fair point.

Bronco6Gen said:

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Just thought I'd pop back in to clear up a couple of common misconceptions. I purchased a system that will be installed within the next 4-5 weeks.

First, you can get a system that is both tied to the grid, and works when the grid is down. You have to have the right equipment (like a Hybrid inverter), but it is possible, and common, you just have to work with a company that knows what they are doing. So there are systems suitable for both generating everyday power, and work as whole home backup power when the grid is down. In fact, you can have a regular gas or propane generator backup tied in as well. So you can have grid, solar, and generator power all tied to a single system that auto-senses which power source to be using. In my case, if the grid is down and there is little to no sun for several days then my generator will kick on to recharge the batteries. The nice thing about that is 100% of the generator power is being consumed and not wasted, so it is extremely efficient. For example, if you have a 10,000 watt generator, but you are only using 8000 watts at any given time as your backup power in a traditional generator backup scenario, those 2000 watts that you burned fuel to get are wasted in a "use it or lose it" power generation system. Versus having the generator charge the batteries that the solar system also uses, 100% of the power being generated by the gas generator is used, so you're much more efficient and the generator won't need to run 24/7.

Second, in talking to them about roof conditions, they warranty leaks with any roof penetrations for 10-15 years depending on which company you are talking to. So they are hesitant to install on an older roof that may develop problems unrelated to their installation. If you want to waive that warranty they'll install it on any roof you want. What that does with your home insurance is unknown, I'm not installing on my roof.

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Sounds like you are doing something similar to my FIL. He has had a ground based solar system for years that was back feeding enough into the grid for most of the year that all he paid the electric company was an $8/month line connection charge. He recently added a battery wall, propane tank, and a propane powered generator. So now, instead of backfeeding the grid, he charges his batteries and then runs the house off of the batteries overnight. When the batteries are topped off, then the rest produced by the solar panels goes back to the grid. If the grid goes down, when he runs out of battery power, the generator kicks on to run the house and charge the batteries (when the sun isn't shining).

Yep, sounds like the same setup...when I first starting doing research the internet was telling me the solar panels wouldn't work when the grid is down for fear of harming people working on the grid, just have to get the right system

What is the price difference for what you are describing vs the system that shuts down with the grid?

What size did you install? It seems like it makes sense to go all the way up to 30kW. The return on the excess (30 less what you would have installed without net metering) should be a little higher than your base kW.

About $7500 on the low side, just depends on how much storage you want. My system is about $18K more. I'm future proofing it, so I have more inverter than I need and can easily expand, and I wanted extra storage.

Right at 28, I sized it where I'd still be producing 25 after 30 years. The panels degrade in efficiency at a rate of .25% every year. I've got enough inverter capacity for 30, so it's just a matter of purchasing more panels if I need to. Panels are about $500/ea for a 450 watt panel.

Great approach. Are those numbers AC?

Anyone know how a Tesla powerwall relates to this set up? It (powerwall) sounds like it costs about as much as a whole home generator. But I'm thinking it would save on electricity bill and without the oil and noise. I guess downside is battery life, how long it would supply house w/o a ton of sun ie ice agedon part 2 and possible damage to panels with weather. My house has wo a pretty large flat area that's not visible so no eye sore.

Bronco6Gen said:

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Right at 28, I sized it where I'd still be producing 25 after 30 years. The panels degrade in efficiency at a rate of .25% every year. I've got enough inverter capacity for 30, so it's just a matter of purchasing more panels if I need to. Panels are about $500/ea for a 450 watt panel.

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Is your quoted panel price from an installer because you can get them much cheaper than that nowadays. Signature Solar in N. Tx has them for around $0.36 per watt.

-What are they telling you about the useful life of the equipment?
-What literature did they provide to prove their number?
-How long do they warranty the panels and batteries?
-When should you reasonably expect output to start being reduced due to age or normal wear of the equipment ?

oklaunion said:

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Bronco6Gen said:

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Right at 28, I sized it where I'd still be producing 25 after 30 years. The panels degrade in efficiency at a rate of .25% every year. I've got enough inverter capacity for 30, so it's just a matter of purchasing more panels if I need to. Panels are about $500/ea for a 450 watt panel.

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Is your quoted panel price from an installer because you can get them much cheaper than that nowadays. Signature Solar in N. Tx has them for around $0.36 per watt.

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Yeah, that's installed price with an external optimizer added onto each panel. The panels themselves are around th3 $.40 per watt price.

Something to check into with your local co-op.

I know that one in North Texas (north of DFW) is planning to support this :

https://microgridresources.org/what-is-microgrid/

rme said:

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Great approach. Are those numbers AC?

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Sorry for the shorthand...the industry talks in watts, kilowatts (KW), and kilowatt hours (KWh). When talking about your monthly or yearly output they're mainly talking about KWH. So for me, for my yearly consumption, I use between 20,000KWh and 22,000KWh in total. The system I'm installing produces 28,000KWh per year, and a little over 20KW of continuous power at any given time when the sun is shining.

BTW, I learned that another myth is that it doesn't work on cloudy days. Even on completely thick overcast days they still produce about 25% power, something to keep in mine when sizing your system. They have online solar calculators that figure all this stuff out for you