Solar production. Panel ratings/claim vs reality

[Carl_NH]

NortracNY - we on TBN analyze stuff (to death sometimes) and make decisions based on facts and real world user experience - initial cost, ROI, quality, maintenance etc. Then typically use spreadsheets and input these variables to look at all the options and costs and benefits associated

So the more information gathered from the community of like or similar applications, or issues is invaluable when one is buying, acquiring or just trying to fix something that is broken.

Granted there are opinions too - why we did x or y, or buy x brand, but most of us are aware enough to read beyond that.

 

[NorTracNY]

Sorry, I'm an engineer. I'll pass since you're ignoring site assessment and the information I tried to help with was so well received. Best of luck.

 

[ning]

Sorry, I'm an engineer. I'll pass since you're ignoring site assessment and the information I tried to help with was so well received. Best of luck.

You mean this "information"?

Sorry, but I only read the first 15-20post. My system was sized by a distributor of SunPower. They slightly oversized it and it has produced more than I use about 30% of the time. Call your energy company, but I'd be shocked if they true up each month. It's yearly for me and I've never heard otherwise. Keep in mind that the panels will produce less over time. SunPower says 0.5% loss each year. I went with leasing with SunPower, so they guarantee production and send me a check the years the panels don't produce the minimum.

Let's see all the helpful information...

• "only read the first 15-20post" [sic] -- ok, so you're probably missing a lot of context. Glad you're willing to spend a minute to help
• "My system was sized by a distributor of SunPower" -- this contains zero useful information
• "they slightly oversized it" -- what are the parameters which went into this "slightly oversized"? what was the usage, what was the desired output, what panels & inverters were used that make it "slightly oversized"? -- information not provided, useless
• "has produced more than I use about 30% of the time" -- again, what size (panels & inverters) is it, and how much do you use that it produces more "about 30% of the time"? is that 30% of the time like the peak sun days in the summer, or what -- no useful information

Glad you're an engineer, but I hope I don't use anything that's made to a spec you've written if this is what you consider "useful information".

Facts and figures, buddy. Not vague notions.

 

[MAX-24-Dean]

deleted

 

[LD1]

You mean this "information"?



Let's see all the helpful information...

• "only read the first 15-20post" [sic] -- ok, so you're probably missing a lot of context. Glad you're willing to spend a minute to help
• "My system was sized by a distributor of SunPower" -- this contains zero useful information
• "they slightly oversized it" -- what are the parameters which went into this "slightly oversized"? what was the usage, what was the desired output, what panels & inverters were used that make it "slightly oversized"? -- information not provided, useless
• "has produced more than I use about 30% of the time" -- again, what size (panels & inverters) is it, and how much do you use that it produces more "about 30% of the time"? is that 30% of the time like the peak sun days in the summer, or what -- no useful information

Glad you're an engineer, but I hope I don't use anything that's made to a spec you've written if this is what you consider "useful information".

Facts and figures, buddy. Not vague notions.

Thank you. You beat me to it.

I though it was just me being cranky as I get older.....but I guess it wasnt just me.

Must be some huge secret to his system, size, usage, production, etc??? Either that....or as an engineer he is totally clueless about any of it. Which is the direction I am leaning since he didnt size his own system, and doesnt even own it (lease). So there really is nothing useful he is capable of adding to this post

 

[ultrarunner]

Hi LD,

December 2014 Installed 24 LG Mono Panels 300 W with Solar Edge inverters for 7,2KW
Garage Roof Mount – 38* angle, 190* south facing, Latitude 42*
Cost installed $26K, State credit $4000 Federal Credit $8500 net cost $13,500
ROI was 8.5 years – electric cost .18 KWH when we installed then rose to .22 then to .33 last year. We are grandfathered into true net metering where they pay us for excess at the same price we pay for electricity so if we over generate they send us a check that month.
Annual use – 10-11,000 KWH vs annual generation 8100-8600 KWH average
Q1 – 15-1800 KWH
Q2 2700 KWN
Q3 2600 KWH
Q4 15-1800 KWH
The lowest generation months are December, January and February mostly due to sun angle and snow, but they shed snow pretty fast.
View attachment 879587

I like your idea for doing the tilting ground mount, and really I think you need to keep it simple with one adjustment for summer and one for winter – makes it easier?
Also you should factor in some increase in electricity rates – they never go down, and then the cost for delivery (poles lines etc) is going up everywhere.

I have 3 arrays on tilting ground mounts and changing the the tilt is a minute per array… a single bolt to pull and move to the next slot.

15 years now with 160 W panels and a SunnyBoy inverter.

Each year I receive a small check around $300 at true up for my 6kW system although with new increased monthly charges approved who is to say?

 

[tradosaurus]

I don't understand much of the solar panel jargon but I do know that the $30K investment it would cost for panels and installation, with the panel having to be installed 500 ft from the house, just didn't make financial sense.
If Texas had a generous solar program to subsidize most of the cost I would consider it. Also my electric company doesn't work with solar generation.

 

[ponytug]

I don't understand much of the solar panel jargon but I do know that the $30K investment it would cost for panels and installation, with the panel having to be installed 500 ft from the house, just didn't make financial sense.
If Texas had a generous solar program to subsidize most of the cost I would consider it. Also my electric company doesn't work with solar generation.

I think that's pretty normal.

I ran numbers for solar off and on for a decade or so before the factors aligned to make it reasonable.

Solar go /no go decisions are very, very local in my experience. Shade, wire costs, installation costs, rebates, and the extent of net metering have significant effects on the return on investment.

Different strokes for different folks...

I have found PVWatts and excel to be very helpful.

All the best,

Peter

 

[LD1]

I have 3 arrays on tilting ground mounts and changing the the tilt is a minute per array… a single bolt to pull and move to the next slot.

15 years now with 160 W panels and a SunnyBoy inverter.

Each year I receive a small check around $300 at true up for my 6kW system although with new increased monthly charges approved who is to say?

What are those mounts/racking

Right now thats what I am analyzing. I am leaning toward eg4 brightmount

EG4® BrightMount Solar Panel Ground Mount Rack

Durable EG4® BrightMount solar panel ground mount rack, easy to install, withstands 105 mph winds, and backed by a 10-year warranty for lasting performance.

eg4electronics.com

They seem pretty cheap (affordabe) way to mount 4 panels at a time. I just gotta do concrete piers. And they offer limited adjustment 25-30-35 angles.

Watched alot of videos and read some reviews on them....and people seem to like em, but they arent UL listed and as with most cheap stuff, it comes from china. But I literally cannot come up with any other solution remotely close to being able to mount 20 500w panels for ~$1200

All the other racking I am looking at quite pricey and usually not even adjustable.

With the EG4 I can auger holes and do concrete. Concrete would be the only added expense.

One vendor I was communicating with was suggesting integra-rack IR35....but even it seems pricey.

 

[LD1]

I think that's pretty normal.

I ran numbers for solar off and on for a decade or so before the factors aligned to make it reasonable.

Solar go /no go decisions are very, very local in my experience. Shade, wire costs, installation costs, rebates, and the extent of net metering have significant effects on the return on investment.

Different strokes for different folks...

I have found PVWatts and excel to be very helpful.

All the best,

Peter

BAsically same thing I have done over the last 10 years. About once every 2-3 years I get a renewed interest in solar, start crunching numbers, communicating with electric company, and pricing materials. Never could pencil out to better than a ~20yr payback.

Equipment getting cheaper, panels getting cheaper and better, rates going up, and my power company doing a more favorable net metering plan have aligned everything for sub 10-year ROI