New Info on Solar

[JoshPlumSE]

So, I was recently informed by my homeowner's insurance that our insurance would not be renewed next year unless we replaced our existing roof.

That put me down a fairly "deep dive" on energy efficiency related to roofs and also the idea of installing solar on our roof. Eventually deciding to go full solar. There were a few things that I learned as part of this process that I though I would share:

a) The price for solar for our roof (2 story house with less than 2000sf) is approximately $35k. That includes materials, construction and everything. No discounts from the government that I know of in that cost.

b) When the solar panels are switched on (probably 2023 for me), we will get a $11k tax rebate when we file our taxes. Essentially 33% of the cost of the solar project. Which is the big "incentive" to go green.

c) We chose not to do the "battery backup" type of thing. Which would have added 10 to 20 thousand to the project. Therefore, if the grid goes down in the summer, we still won't have any power to our house (because of how the system works).

d) Because of the high cost of the "battery walls", one of the guys was talking about how it sounds like the "future" is to include the ability to use an electric car's battery as the battery backup. So, no "battery wall" would have to be purchased. But, we would have to redo the panel or such before we could do that. But, it would be much cheaper than the battery wall.

e) Electric companies are considering a "grid connection" fee for houses to recoup some of the loses they are incurring from all these homeowners who now have solar.

 

[rb1957]

sounds like "provision for future battery installations" ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[JoshPlumSE]

Yes. But, I believe it takes some changes from whatever they would put in now. But, it sounds like a really cool option for the future.

 

[TugboatEng]

It's the inverter. There are a wide range of options and changing an option typically requires complete replacement of the inverter $$$. The basic inverters require grid power to function. If you want batteries to run at night your inverter will require more inputs and a change controller. If you want to backup in the case of power failure you're going to need to get one that can run islanded.

 

[JoshPlumSE]

It's probably related to that... a change controller that dictates when the system can be disconnected from the grid and such. As it works now (or when the installation is complete) if the grid goes down we go down too.

However, it's not the inverter. I believe we've got inverters on all of our panels instead of a single inverter for the whole system. Makes the system more reliable, but slightly more expensive.

 

[GregLocock]

35k is big bucks for a solar only system (although prices have increased since I bought mine). How many watts of panels?

In Australia batteries make little financial sense for houses that are on the grid, for the most part, although some companies are finally introducing time of day electricity prices, which encourage you to have full batteries by 3pm, and then use that through to midnight. Whether they'll start introducing timed feed in tariffs is yet to be seen.

The difference in cost between a self-islanding system with a battery, and a non self islanding system is $200 in components and $2000 in practice.

Cheers

Greg Locock


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[JoshPlumSE]

Keep in mind this is Southern California. Everything is more expensive here. I gave you the average price of the three quotes. It's a little tricky because I'm getting my roof replaced as well and that costs between $14k and $20k. I chose a company that quoted a lower solar cost $31k, but a higher roof cost $20k.

We're getting 21 panels. Each panel is 400 watts. To produce an expected 963 kWh per month on average.

Keep in mind that I work from home. So, the AC is running much more often in the Summer than it was when I worked at an office. Also, my wife was home this summer. Which meant the AC was set 2 or 4 degrees F lower than it would have been if I'd been alone in the house. To top it off, this was a very hot year. They base the number of panels and such off of your past year's utility bill.

If Southern California starts getting cooler, then maybe we'll have an over abundance of panels. But, if it continues to get warmer then we'll be sitting cool and pretty compared to our neighbors.

 

[GregLocock]

About 1400 hours per year, same as where I am. To be honest given all the other costs I base my sizing on the worst month, then in summer the a/c can let rip.



Cheers

Greg Locock


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[EdStainless]

So your house won't run as an 'island'?
Charging an EV from your solar is easy, drawing power back into the house is the hard part.
Yes, houses with solar are a burden on the utilities.
They have to manage their generation along with yours.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[LionelHutz]

However, it's not the inverter. I believe we've got inverters on all of our panels instead of a single inverter for the whole system.

I believe the per panel inverters are still all grid tied and they are certified to island on loss of utility. You don't have a separate module between the panels and the grid performing this function.

Those make it harder to add batteries, each inverter is outputting AC synchronized to the grid. Having the panels all go to a central inverter means DC is available there and that can be used to do battery charging or the batteries can be used as the power input to the inverter instead of the panels.

 

[IRstuff]

On the solar system we had installed on a previous house, the panels ran into a single box that was connected to the grid.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[JoshPlumSE]

I know our electrical panel is being upgraded. But, only to be able to accept or give out 200 amps. The house is 1973 construction so, it would not be capable of supporting some newer appliances (or EV charging). That being said, I'm certain the panel is not to the level that would be required to live off grid.

 

[IRstuff]

That being said, I'm certain the panel is not to the level that would be required to live off grid.

Not sure that's relevant; the solar panel box we got sat between our electrical panel and the meter, so the panel could feed directly into the meter, although the meter was upgraded to a "smart" meter about 3 years prior. If the grid went down, the box would send power to our electrical panel, as if it were the grid.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[itsmoked]

When you come to your senses and decide you need battery backup in the future you surely do NOT want to have a completely incompatible micro-inverter system.

PG&E is currently militating to give a massive discount to house solar that includes batteries as that will allow them to drop all the battery based customers during the three hour peaks on hot summer days.

I see the future as having a lot of Aussie like black-outs from a lack of storage. That's one reason why I'm in the process of going off-grid in-town.

At the very least your system should have a hybrid all-in-one installed that will take in the utility, a generator, and provide battery charging and on-grid charging and grid-tie. It may cost a little more but opens up all possibilities in the future. Then when you want to add batteries or a generator or an EV you just do it instead of it being a huge decision to pitch the current inverter or a truckload of overpriced micro-inverters.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[TugboatEng]

Would it be possible for the micro-inverter system to synch up with a battery driven inverter or generator once the system is islanded?

 

[GregLocock]

Well I've just been contacted by a battery company who claim they can fit a 10 kWh battery for $3000, after subsidies, to my grid connected house that has solar already. I expect there's a catch, but it's a reputable battery at least.

A complete 5 kW system for my off grid house comes in at at least $25000, plus genny.

Cheers

Greg Locock


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[itsmoked]

Would it be possible for the micro-inverter system to synch up with a battery driven inverter or generator once the system is islanded?

I have not seen that, besides grid inverters now are only allowed to send into the grid after being told by the grid owner "it's allowed now". After an inverter as been booted due to a power outage I can't see the utility saying go ahead and try while the grid is still down. Inverters no longer autonomously sync and connect to a live grid.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[itsmoked]

A complete 5 kW system for my off grid house comes in at at least $25000, plus genny.

The materials for an off-grid 5kWhr system is only about $4k. Shows how gougy solar installers are! If you can do your own work you will come in far, FAR lower than any subsidized commercially installed system. That or you can build three times the capacity yourself staying under the commercial cost.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[GregLocock]

Sorry, that's 5 kW solar, 10 kWh battery, and all the electronic gubbins, cabinet and wiring, installed.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[hokie66]

DIY solar, and all electrics for that matter is illegal in Australia. A surefire way of voiding your homeowner’s insurance.