diy solar

diy solar

Does Solar Pay for Itself? Is it worth it?

45 yo. The house I'm putting solar on is in northern California (far enough north to not be part of SF Bay Area). PG&E has my TOU rates at 0.36/kWh off-peak, $0.38/kWh peak. And because it's fire country and they took a 30 year break from maintaining their lines, they can shutoff power on any windy day during the summer (my parents had 5 or 6 days without power not too far from me a year or two ago).

I have a 20 kWh battery Nissan Leaf EV that I'll probably upgrade to a better make with longer range within a couple years.

So, if I lived there full time, payback at ~$0.37/ kWh would be pretty fast, maybe 3 or 4 years after subtracting the 26% (or 30%?) tax credit. Until I can retire (hopefully 5 or 6 years if things go well), I'll only be able to be there 1/4 to 1/3 time.. so probably 6 to 7 years or so to break even.

However, my inverters will have excess solar input capacity beyond what I need. I may add some free / cheap used panels in addition to the new panels I'll buy. If so, with plenty of excess production, I may invite my parents and my neighbors to charge during daylight if they buy an EV. That'll either be a gift or a trade or maybe just honor system at 10 to 15 cents per kWh, but either way, it can push the return of value on my system back down to 3 or 4 years. It just won't necessarily just be me gaining from my system

Note that I'm aiming to be off-grid, potentially with grid only as a backup to charge the batteries at night or after a string of cloudy days
 
yep, and in the netherlands ( my location) its even worse

and to add, initial payback for my system was going to be 5 years, it would have already paid for itself after 2, but got a deal on a pallet 540w panels ( 32 , jinko tiger 545w panels at 0,22 euro cents/w) i took too expand and become even less dependend on the grid, as things seem to completely go hay-wire here atm

i'm 40 going on 41
 
And generalization is dumb.
my comment was neither ,,it was exactly on point …the risky rob OP that you responded to is correct also ..
young folks are not as engaged in solar as many of the older guys today …thats common knowledge.
I do not know how my compliment about Will is in anyway a generalization.
He is an exception and a great inspiration for alot of young men coming up today ,( and older guys ) and unlike the past ,in a world of few young leaders for young men In general.
I feel like we are discussing two different topics or somewhere our wires got crossed...I am somewhat confused.with your reply.
so I will just say , it’s probably just a misunderstanding .

thanks , jim.
 
On a related note, Do panels age out from exposure, or energy usage, or a combination of both? I have always assumed the former, and strive to use everything my panels produce to do something beneficial. I am currently smelting some aluminum with my excess power.
Am I wrong?
 
I would guess it's probably 90+% in the 'exposure' column and very little from actual usage. About the only thing i think actual usage does is slightly exaggerate the heat cycling by getting the panels slightly hotter when they're actually powering something.

But, i sure haven't studied the topic! I'm curious to know. About the only thing i've read/heard is that panels suffer a pretty dramatic dropoff fairly early on (10-20%?) and then decline much slower for the rest of their life. Which, if true, to me just suggests that older panels are even better than i think they are, because a 15y/o panel may not be much more 'degraded' in output than a 3 year old panel is.
 
But, i sure haven't studied the topic! I'm curious to know. About the only thing i've read/heard is that panels suffer a pretty dramatic dropoff fairly early on (10-20%?) and then decline much slower for the rest of their life.
In modern panels there is a ~2% (give or take) degradation in the first minutes/hours of exposure to light. This is normal and is expected.

Thereafter panels decline in performance at less than 0.5% per year. You should expect about 80% of rated capacity after 25 years. Some high quality panels will be 90% or better. This assumes they are not mistreated. Here's an article on the topic:
 
In modern panels there is a ~2% (give or take) degradation in the first minutes/hours of exposure to light. This is normal and is expected.

Thereafter panels decline in performance at less than 0.5% per year. You should expect about 80% of rated capacity after 25 years. Some high quality panels will be 90% or better. This assumes they are not mistreated. Here's an article on the topic:
That article seems to indicate that the degradation is mostly due to exposure and less to energy production.
 
In modern panels there is a ~2% (give or take) degradation in the first minutes/hours of exposure to light. This is normal and is expected.

Thereafter panels decline in performance at less than 0.5% per year. You should expect about 80% of rated capacity after 25 years. Some high quality panels will be 90% or better. This assumes they are not mistreated. Here's an article on the topic:
Great, even less of an issue than i had assumed. I prefer to be a pessimist and assume everything is worse than claimed so i don't get left holding the bag, but so far i have only bought HIGHLY depreciated used panels. If i was paying top dollar for new I'd sure have looked into this before buying, and would actually give a crap about a warranty.

But one thing that article never really mentioned is that for the most part if a company goes under or morphs significantly enough, your warranty is meaningless, and i frankly assume most warranties in excess of 10 yrs are getting into that range. Not to say that the panels SHOULDN'T be warrantied for longer than that, but i wouldn't let the difference between a 20 and a 25 year warranty be much of a factor in my decisions because when you get far enough out into the future, the likelihood of one or the other business entity still existing in a form that will honor a warranty claim, becomes highly dubious. I'd probably take 1% higher efficiency up front, than 5 extra years on a warranty from a company that may not still exist by then.

Vaguely relevant:
8yfvgnv6b3631.jpg
 
Great, even less of an issue than i had assumed. I prefer to be a pessimist and assume everything is worse than claimed so i don't get left holding the bag, but so far i have only bought HIGHLY depreciated used panels. If i was paying top dollar for new I'd sure have looked into this before buying, and would actually give a crap about a warranty.

But one thing that article never really mentioned is that for the most part if a company goes under or morphs significantly enough, your warranty is meaningless, and i frankly assume most warranties in excess of 10 yrs are getting into that range. Not to say that the panels SHOULDN'T be warrantied for longer than that, but i wouldn't let the difference between a 20 and a 25 year warranty be much of a factor in my decisions because when you get far enough out into the future, the likelihood of one or the other business entity still existing in a form that will honor a warranty claim, becomes highly dubious. I'd probably take 1% higher efficiency up front, than 5 extra years on a warranty from a company that may not still exist by then.

Vaguely relevant:
8yfvgnv6b3631.jpg
This is on point. It is HIGHLY likely (especially in today's economic environment) that your panel manufacturer will not exist in 2047. I recently did an 8Kw panel upgrade with used panels for around 25% of new panels and producing around 70% of rated power. It keeps my charge controllers running cool. If you have the "real estate", used panels are the way to go for a DIYer.
 
But one thing that article never really mentioned is that for the most part if a company goes under or morphs significantly enough, your warranty is meaningless, and i frankly assume most warranties in excess of 10 yrs are getting into that range.
Most solar panel warranties are useless anyway.

If you read them you'll see they exclude coverage for panels are not installed exactly as per the installation manual, and this includes avoiding shade. Anyone bodging up a DIY array / rack, not using the correct clamping zones, lying them on the ground etc etc are likely in breach of the warranty terms and conditions.

Also, warranty depends on where you are.

In Australia, consumer law cannot be superseded by the warranty (it must be fit for purpose and be reasonably durable) and the warranty is first and foremost to be managed by the installer. The manufacturer only comes into play if the installer is no longer in business. It is illegal for an installer (or retailer) here to fob you off to the manufacturer for warranty claims but of course if neither are in business then sure, you are SOL.

Which is why you make a balanced assessment of risk when purchasing panels. If you go with a well known brand who has been operating for many years and have panels which consistently test well (they are all performance tested), then you reduce the risk of needing to make warranty claim but also if you do then the chances of them being able to process it are better. And there are brands who do stand by their panels and will provide replacements. In Australia we do have consumer rankings for PV panels which is helpful as it gives a sense of not only which are quality but also which are supported should something go wrong.

When you buy old / used panels, then you get what you pay for. It might be a bargain, or it might tun out to be a massive PITA.

Stealing this chart from here as it's a pretty decent indictor for the panel brands you can find here. All the panel brands listed on the chart are recommended here. If the panels are not shown, then it's probably best to look elsewhere or do your own due diligence:

Link:

Screen Shot 2022-09-21 at 7.21.04 am.png
 
But one thing that article never really mentioned is that for the most part if a company goes under or morphs significantly enough, your warranty is meaningless, and i frankly assume most warranties in excess of 10 yrs are getting into that range.
Well I should also point out that I was providing an article specifically about the question of panel degradation, not warranties.

If you search that site you'll find a series of articles which discuss panel warranties specifically, and most articles are pretty critical of them. Still, a lot of the companies do stand by them and provide good support here, but the risks with solar PV panels and long term warranty support are not really any different to the risks you can expect from any comparable long-life products you might buy.
 
.315 euro per KWH wholesale if my math is right.

If operating cost is twice generation / Purchase cost then consumers are paying .63 Euro per KWH..
Fuel costs have risen significantly, but nowhere near the ~20x that wholesale rates have. And delivery costs have probably risen very little. So they have a lot of profiteering.
 
On to panel aging and usage. I'm going to guess that most of the degradation is from thermal cycling. If I'm taking electrical energy from that panels that's sunlight that isn't getting turned into heat in the panels, causing even higher temps.
 
On to panel aging and usage. I'm going to guess that most of the degradation is from thermal cycling. If I'm taking electrical energy from that panels that's sunlight that isn't getting turned into heat in the panels, causing even higher temps.
I stayed at a Holiday Inn Express last night, so I'm qualified to argue the inverse. Converting light energy to electrical energy will produce heat.
 
The light is hitting the panel regardless of loaded or not. If you're taking energy out in the form of electricity that energy is NOT heating the panel.
 
The light is hitting the panel regardless of loaded or not. If you're taking energy out in the form of electricity that energy is NOT heating the panel.
Good point. In a closed system matrix, that would give around 20% energy transfer to electricity less whatever energy transfer coefficient exists. Seems like a net gain. I'll check into the Motel 6 and get back to you.
 
Well I should also point out that I was providing an article specifically about the question of panel degradation, not warranties.
Absolutely. None of my skepticism was directed at you and it was admittedly a tangent for me to bring it up.

As far as electricity not heating the panels.. i dont know even close to enough to quantify any of it, but i think big picture if all of us had to actually convert all the potential energy hitting us into either heat or something else we'd all be dead, and it's only by the fact that lot of the potential energy of 'sunlight' actually reflects off of things, that we continue to survive. Maybe i'm wrong there. But a solar panel definitely doesn't convert all the energy that hits it to heat when it is electrically not connected to anything. Whether it reflects less when producing electricity, and less of what, at what wavelengths etc, is far beyond me. :ROFLMAO:
 
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