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Who has solar power at their home? Please chime in....

I've been on the fence for a few years to take the solar power plunge and get a system installed in my home. I've been putting it off for a while because it was my understanding solar power systems generally aren't a good idea if your power bill doesn't exceed $200/month. So here I am in a typical central FL summertime heatwave and now my bills are nearing the $300/month mark. Obviously this is mainly because my home's A/C system is working really hard during the hottest central FL months which is where we're at. Add that plus the recent purchase of my Model 3 and my power consumption has increased quite a bit. This has me thinking about going with a solar setup.

I want to go with a system that charges some battery banks so I can run my home in the evening once the sun goes down. I've heard that charging a Tesla from a solar powered battery bank isn't always a good option. So I'm looking for any advice from any users that are in fact charging their Teslas from any solar powered battery banks.

Please chime in....
 
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I've been on the fence for a few years to take the solar power plunge and get a system installed in my home. I've been putting it off for a while because it was my understanding solar power systems generally aren't a good idea if your power bill doesn't exceed $200/month. So here I am in a typical central FL summertime heatwave and now my bills are nearing the $300/month mark. Obviously this is mainly because my home's A/C system is working really hard during the hottest central FL months which is where we're at. Add that plus the recent purchase of my Model 3 and my power consumption has increased quite a bit. This has me thinking about going with a solar setup.

I want to go with a system that charges some battery banks so I can run my home in the evening once the sun goes down. I've heard that charging a Tesla from a solar powered battery bank isn't always a good option. So I'm looking for any advice from any users that are in fact charging their Teslas from any solar powered battery banks.

Please chime in....
My electricity bill kept climbing until it was over $400 / mo., and that's without running AC very much.

I installed a Tesla 7.93kW system plus a powerwall. So far it's been a great investment.

No out of pocket expense, just a loan payment of $193 / month - 1st installment paid 6 weeks after the system was turned on (been running $100-200 credit against elec bill since).

I'm currently a significant net producer, even with EV charging (though we also charge at work), over the summer months. Based on some rough estimates, I think I will be a slight net consumer when all is said and done, as my winter production will drop significantly (my best days were over 50kwh, but once the days are shorter, the sun's angle less optimal, and we get lots of cloudy days, I expect several months where my average will be as little as 15-20kwh - of course I won't be running AC then, so that will help)

We included the powerwall because PGE (CA) has had some issues and warned of scheduled rolling blackouts. We've had no blackouts so it hasn't been useful to us. We could run it to try to optimize against our Time of Use plan, but it drains more quickly than you might guess and there is efficiency loss in recharging. Still it might be super valuable to us in an emergency - that has not been the case yet. FYI if you want to charge your EV or run your AC off batteries, you'll need at least 2 powerwalls due in part to general power consumption but more specifically to amperage (1 PW won't start anything more than 20 amps or so - the system resets).

So, based on my experience thus far, and my predictive modeling for the year, it is a good decision. There is a good chance it will have been an awesome decision, and some chance that it will be more or less neutral...
 

srs5694

Active Member
Jan 15, 2019
1,545
2,069
Woonsocket, RI
First, be aware that details vary A LOT from one state to another because state-level laws dominate the regulatory landscape for residential solar power. Thus, you may want to ask around for local (Florida) resources, rather than rely on information from this forum, which will largely be information learned from other states. There can also be local (county or city-level) programs or incentives; for instance, some friends of mine in Massachusetts installed solar panels under a program that their city initiated. To that end, one site you might want to visit is Energy Sage, which has information on several states and will help you get the ball rolling by requesting quotes from multiple reputable installers:

Compare solar quotes from pre-screened solar installers | EnergySage

That said, I live in Rhode Island, and I had solar panels installed on my house about a year ago. I'm not an expert on Florida laws with respect to solar, but my impression is that they aren't nearly as good as they are in Rhode Island. Here, there are two main ways to hook up solar panels: Using net metering, where the panels are "behind" the electric meter, which can spin both forwards and backwards, and excess power generation one month can be credited to subsequent months' bills; and under the Rhode Island Renewable Energy Growth (RI-REG) program, where the solar panels have their own meter, and the utility pays a ridiculously high price for solar power, but you continue to officially buy electricity from them. Neither system requires battery storage. AFAIK, there's no law against installing batteries, but there's no financial incentive to install them. The main reason I can think of is to serve as a backup in case of a power outage, but the power is fairly reliable here, so that's not a compelling argument for me personally. Of course, your laws in Florida are different from the ones here, so it may be different for you. In any event, I can't comment on the battery storage issue. I don't know if batteries are really worthwhile in Florida. If so, that'll raise your costs and increase the payout period -- but OTOH, you'll probably get more sunlight in Florida than I do in Rhode Island, so your payout period might not be higher than mine. (It was estimated at 8 years for me, on the RI-REG program.)
 
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Rocky_H

Well-Known Member
Feb 19, 2015
8,620
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Boise, ID
I've been putting it off for a while because it was my understanding solar power systems generally aren't a good idea if your power bill doesn't exceed $200/month. So here I am in a typical central FL summertime heatwave and now my bills are nearing the $300/month mark.
Yeah, that's kind of in the ballpark. There are a few factors to balance with that. Since you are replacing kilowatt hours that you would normally buy with kilowatt hours that you are producing, the payback time is very related to how expensive your rates are where you live. And how long a payback time are you willing to tolerate with how long you expect to live there. I kept watching and waiting for 10-15 years because I live in Idaho, where we have some of the cheapest electricity in the country, so I couldn't get the payback time to get under about 15-20 years. But in most of California, it's a no brainer since it pays for itself in about 3-4 years. Panel prices kept coming down, and it finally got to about a decade payback, so we went for it a couple years ago.

I want to go with a system that charges some battery banks so I can run my home in the evening once the sun goes down.
Uh...wow. That's not how that works. I do remember our illustrious "president" thinking that's how renewable energy works, saying people couldn't watch TV if the wind wasn't blowing or the sun wasn't shining, but it's not true. You don't have your house connected only to the solar panels and have to light candles and kerosene lamps to deal with your nightly blackout.

Almost every state has what is called "net metering" for customers who get solar panels on their houses. (I just looked up Florida, and they do too.) Basically the electric grid that already goes to your house acts as your battery storage. The panels provide energy directly to your house AND drive excess back into the neighborhood grid during the day, while your panels are producing a lot, and then you draw electricity from the grid during the nights or if you are consuming more than your panels are producing. It's all completely behind-the-scenes transparent to you. They just have to put in a different kind of electric meter that tracks the input and output, so they can know how many credits of excess energy you have produced and stored, and then how much you later use. You generally build up a credit balance from about May through September, when there is a lot of excess sun, and then you draw down those credits through the winter when there is less sun.

Getting a battery system with your solar panel installation is waaaay more expensive, easily doubling or tripling the cost, and is usually not worth it. There is usually just the one advantage to it, which is that it can be an uninterruptible power supply for your house, in case you live in an area that has grid power failures pretty frequently. Other than that, it's generally a waste of money.

The other maybe possibility of it being worth it would be if you live in a state where the electric utility company has insane price differences between electricity at different times of the day. So then you might be able to set up a battery back to charge up from nearly free grid electricity at night to avoid paying the painful gouging rates during the afternoons. But that's very dependent on where you live if that's a thing or worthwhile.
 
I put solar on the house in 2016 (California). I added 3 extra panels (280 watt ea) over what I actually needed for a future electric car. Did not know at the time it would be a model 3. I'll be ok this year because of net metering over the calander year. Not sure what I'll be paying in 2020. Right now I pay the minimum of $10 per month for electric. Current system produced about 110% of my needs for all prior years.
 
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I've been on the fence for a few years to take the solar power plunge and get a system installed in my home. I've been putting it off for a while because it was my understanding solar power systems generally aren't a good idea if your power bill doesn't exceed $200/month. So here I am in a typical central FL summertime heatwave and now my bills are nearing the $300/month mark. Obviously this is mainly because my home's A/C system is working really hard during the hottest central FL months which is where we're at. Add that plus the recent purchase of my Model 3 and my power consumption has increased quite a bit. This has me thinking about going with a solar setup.

I want to go with a system that charges some battery banks so I can run my home in the evening once the sun goes down. I've heard that charging a Tesla from a solar powered battery bank isn't always a good option. So I'm looking for any advice from any users that are in fact charging their Teslas from any solar powered battery banks.

Please chime in....

You want to ask around here
Tesla Energy

More specifically, this fellow I received my proposal summary today (central Florida)

I reside in Los Angeles, where my local municipality (Los Angeles Department of Water and Power) has NEM (net energy metering) and I pay around $0.17/kWh for first 1,000 and i have peak hours, normal hours and off-peak. what i am getting too, as other implied, it all depends since State by state and even cities is different. If you have NEM, its worth getting solar and if you get tons of sunshine in your area and if your house roof is new and if it faces South at certain degrees will produce good amount of energy.

Getting a battery is very expensive, form Tesla is around $10k before 30% ITC and from what i read there is no ROI on it. You buy only if you do not have NEM, or you are in the area where there is a lot of blackouts due to weather, fires, or whatever else.

Start with this to see what you can get based on your house and how much energy you will get
PVWatts Calculator

Read and get quotes from here to see what it will take. As you might be aware, 30% credit will decrease after this year, so if you are serious about it, start looking into it now before the rush and holidays
Compare solar quotes from pre-screened solar installers | EnergySage

BZ
 
Okay. So say I average 1700 kWh/month on my usage. Now let's say I get a 15 kW system that according to the link mentioned earlier produces on average 1800-1900 kWh/month. Now let's say my house uses 1000 kWh in the daytime and the rest is used either early morning or after the sun goes down. Would I still be buying power from the electric company even though I'd be pretty much producing the same amount of power I'd technically use in the entire day?

Not really sure how that works.
 
I am in central Florida too, and I have a 14.7 kW system. FPL allows net metering, so for each kWh you overproduce during the day and send to the grid, you get one kWh back for free at night. So if you had a big enough system that produced 100% of your usage, on average, your bill would be 0, plus taxes and fees. At our electricity rates, if you can get a system installed at around $2 per watt, the payback period would be around 9 years.
 

Zaxxon

Active Member
Supporting Member
Dec 11, 2012
4,705
22,083
Colorado
Okay. So say I average 1700 kWh/month on my usage. Now let's say I get a 15 kW system that according to the link mentioned earlier produces on average 1800-1900 kWh/month. Now let's say my house uses 1000 kWh in the daytime and the rest is used either early morning or after the sun goes down. Would I still be buying power from the electric company even though I'd be pretty much producing the same amount of power I'd technically use in the entire day?

Not really sure how that works.

Florida is a net metering at retail pricing state if the internet is not misleading me, so think of your electricity like water. When your house is using more than your panels are producing, the electricity flows into your house from the grid, and you rack up a bill for that energy. But when your panels are producing more than your house needs, the electricity flows out to your neighbors, and you earn credit for that energy.

Your house will use a certain amount of power each day, and your panels will produce a certain amount. Over the course of the month, all that matters is the total at the end of the billing period. You don't have to care about when you're using vs producing. Therefore you only need to consider Powerwalls if you either want to protect against grid outages or you want your home to be 'truly' solar-powered at all times rather than just on a net basis. But beware that adding Powerwalls will drastically increase the total system price and likely extend the payback period. That's not to say don't do it--I think it'd be awesome if money were no object for me.

The specifics of how long it'll take before the system 'pays for itself' will depend significantly on what you pay currently for power, whether your utility actually does pay retail rates for net-metered power, and whether you can get on a time-of-use power plan (where you pay more at 'peak' times during the day, and less at night--these tend to work out spectacularly well for EV owners with solar, since you produce at the peak times and can easily schedule your biggest power consumer-your cars-to charge at the cheapest time overnight).

So let us know those specifics. I would also put in an order with Tesla, as it's a refundable $100 that will get you an actual design on your actual roof's specifics and a consultation with someone who knows your local situation. My experience with the solar folks at Tesla was quite good. Make sure to use someone's (or your own!) referral code if you do move forward, as they're offering 2k Supercharger miles.

Tesla's site shows their 'large' system in FL at $30k before incentives, $21k after. That's for an 11.4 kW system producing on average about 45 kWh/day--well under $2/W after tax credit. I think you'd want a system a bit bigger than that if you want to zero out your usage. Even tho Tesla offers those three sizes on their site, they will work with you if you want or need something a bit bigger or smaller than any given tier. (The tiers are 12/24/36 panels, and I just had 15 installed last month, for example.)

Also keep in mind that barring any speedy action by the federal government, the ITC that grants the 30% federal tax credit on panel installs begins to sunset on 1/1/20, so if you are going to make the move to solar, doing so this year makes sense.

Good luck, whatever you decide.
 
Another concern I have is my roof is roughly 15 years old and it's still in pretty good condition. I wonder if I'd be recommended to have a new roof installed prior to getting solar panels installed? That'd easily be an extra $8K that would be pretty hard for me to swallow.
 
It's normal asphalt shingle style roof. No idea what the expected life left is.

Usually when you get your solar quotes, company will come out to assess your roof and underlayment and such, they will let you know. A reputable solar installer willl also have roof license (at least in CA) and warranty against leaks for 25 years.
 
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I designed and installed my own system, live in South Carolina. I chose to do this because the cost of paying for a “professional install” is about double and therefore doubles the payback.

South Carolina has 25% tax credit and then the Federal 30% as mentioned above.

What others have said is good info. You need to determine how much energy you use each month/ annual both in kWh and in $. Then determine what length of payback you want to have. These two data points will help you understand how much you can “afford” to spend on a system. Once you do that, get a professional quote from a reputable company. Now you will have three key data points to help you understand the total cost of doing this. If you’d like detailed help with understanding the ins and outs, I would be happy to discuss with you by phone; typing it all out isn’t efficient.

I will make some very general statements to try and give some basic boundaries (most or all of this is covered by others already)

1) if you pay a company to do the install and pay out of pocket for it, and you are in a net metering setup with the utility, expect about a 9 year payback.

2) only install the system in such a size that offers “optimal” solar usage. What I mean is don’t add a bunch of panels and hardware to grab sunlight from the north or east (potentially west) facing roof. It just adds cost/watt. You don’t need to install a system to cover 100% of usage to get a specific ROI. But the system you install does need to be optimized / efficient.

3) as others say- in a net metering scenario, batteries are nothing more than a very expensive emergency backup. The will basically double the initial cost of your install and provide zero ROI UNLESS you have peak and off peak rate schedules. I chose not add batteries for now. If/when net metering ends, it might be worth it later. I have a small gas (sorry!!) generator for emergencies. In Florida, perhaps hurricanes and other weather makes a battery backup worth the cost for you- however keep in mind that you could do battery backup anyway, without solar if that’s what you wanted.

Pm if you want to review your specifics. I am not in the solar business. I am an engineer that took the solar idea too far because I could. Payback is trending to 4 years, 7 months.
 

srs5694

Active Member
Jan 15, 2019
1,545
2,069
Woonsocket, RI
My understanding is that asphalt roofs generally last 15-30 years. You'll definitely need to have yours assessed before installing solar panels on it; if you only have, say, five years of useful life left, then installing solar panels now makes no sense unless you replace the shingles (and maybe other stuff), too.

One more point: There's a Federal tax credit worth 30% of the cost of solar panels that expires (or maybe just gets cut in half; I don't recall the details) at the end of this year, IIRC. It can easily take a couple months between ordering solar panels and having them fully installed, so if you're serious about this, you should act very soon. That said, the cost of solar panels has been dropping for years, so if that trend continues, waiting another few years might result in a cost reduction comparable to the Federal tax credit. This might make sense if your roof is old enough to make a solar installation a dubious proposition but not yet old enough that you want to replace/repair/maintain it now.

Bottom line: You should be talking to local contractors about all of this. They're familiar with Florida laws and can inspect your roof. Check out the EnergySage link I posted earlier and/or ask any friends or neighbors who have solar panels for references.
 

Zaxxon

Active Member
Supporting Member
Dec 11, 2012
4,705
22,083
Colorado
Also note that if you have to replace the roof in order to install panels, that replacement or part of it may also qualify for the 30% tax credit. This is ambiguous and depends on your specific situation from what I've seen elsewhere, so you should consult a CPA to make that determination.
 

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