Author Topic: EEVblog #724 - Home Solar Power System Analysis & Update  (Read 43485 times)

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Offline EEVblog

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EEVblog #724 - Home Solar Power System Analysis & Update
« on: March 16, 2015, 09:26:40 am »
Dave looks at his 3kW home solar power system after being in operation for 18 months and analyses the results.
How much energy was produced?
How does net and gross metering work?
What is the payback period?
What is solar insolation?
The 3kW system uses 12 x 250W LG MonoX panels
http://www.solarclarity.nl/wp-content/uploads/2011/09/Data-Sheet-LG-Mono-and-Multi-X-ENG.pdf
and an SMA Sunnyboy 3000TL inverter.
http://files.sma.de/dl/15330/SB5000TL-21-DAU131211W.pdf
Uploading data to PVoutput.org using PVbeancounter and bluetooth from the Sunnyboy inverter.

 

Offline nixfu

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #1 on: March 16, 2015, 09:51:27 am »
Dave...side question.  What is the aerial mast for?  Do you need to raise your TV antenna that high in the area you live?  Or is it used to capture the lightning you need for the 1.21 gigawatts to power your flux capacitor?

Glad you covered what kind of AC you use.  I imagine that is a large percentage of your energy cost being in Sydney.
« Last Edit: March 16, 2015, 10:01:11 am by nixfu »
 

Offline tecman

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #2 on: March 16, 2015, 10:03:07 am »
Here in USA-USA-USA I installed a 9.2 KW rated system, that is just over 3 years since the install.  I am in PA which is in the northeast.  I generate 12 MWH/year.  That accounts for 60% of our total usage.  Nice thing is we have net-metering which has unity pay for use-sell back (approx $0.13/KWH at this time).  It uses just one meter which subtracts the solar excess generation from the used power.  We have little to negative usage from May through October, and consume the most power over winter.  Gray days, snow covered panels and heating costs (geo-thermal heat pumps) are the cause of the greater winter usage.  This winter was very cold (last month average temp was 22 deg F !).  I had to go out and clean snow off the panels several times.  It is a ground array, so cleaning is easy, but several times I was unable to get to the panels and had to wait for improved conditions to clean off the panels.

Paul
« Last Edit: March 16, 2015, 10:14:05 am by tecman »
 

Offline EEVblog

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #3 on: March 16, 2015, 10:08:39 am »
Dave...side question.  What is the aerial mast for?  Do you need to raise your TV antenna that high in the area you live?

I live in the Hills District and I'm down the bottom of a gully...
Although the mast came with the house, so I'm not sure if it's 100% necessary in my case.
 

Offline EEVblog

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #4 on: March 16, 2015, 10:09:50 am »
I had to go out and clean snow off the panels several times.

Snow? What's that? I don't understand...
 

Offline nixfu

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #5 on: March 16, 2015, 10:17:11 am »
Have you thought of adding battery storage?  It seems it would pay for itself based on how little you get for net-metering credit. 

 

Offline Kohanbash

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #6 on: March 16, 2015, 10:23:38 am »
Hi
Nice video.

- You can get a pyronometer for about $200 (at least in the US) with an analog output.
Ex. http://www.apogeeinstruments.com/pyranometer-sp-110/

tecman- I am also in PA (Pittsburgh) I am surprised how much you generate. In Pittsburgh we only have about 60 sunny days a year. How large is the area of your system?

Cheers!
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Offline LaurenceW

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #7 on: March 16, 2015, 10:34:24 am »
Dave, here in the "Old Dart" (wtf?), I have a 4kWpk system. We are further from the equator that you are, so longer summer days mean I am able to beat your figures for 2 (maybe 3) months of the year, in high summer. But you've got me beat, the rest! Check out how much your solar power waxes and waynes through the seasons, and compare it to mine (PVoutput user Wilkins_watts). Very low power in the short, cold winter days!

Like you, I went for a premium system of Sanyo/Panasoinc panels and SMA TL4000 inverter. It just all works. The system has been in 3 1/2 years. I paid TOP DOLLAR (about USD $16000 equivalent - ouch, yes), as did many other "early adopters." Yes we, too, saw something of a GOLD RUSH, until the government turned down the Feed In Tariff scheme, somewhat. Still, my system will also pay for itself in around 6 years, then I can sit back and enjoy the overly generous gov't susbsidy, which continues for a further 18 years after break even WOOOOOO-HOOOOO.

Most Brits move house, on average every seven years. There are just over 500,000 solar PV systems in the UK. When doing the payback calcs, a major and hard-to-quantify factor in all calculations is "how does the housing market value a solar installation?" The jury is still out on that one in the UK, but I think attitudes are changing, as people slowly "get it".

There is another side benefit, of course, in that it makes you THINK about every kWhr! "The cheapest KWhr is the one you never burned."
« Last Edit: March 16, 2015, 10:38:28 am by LaurenceW »
If you don't measure, you don't get.
 

Offline EEVblog

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #8 on: March 16, 2015, 10:51:39 am »
Have you thought of adding battery storage?  It seems it would pay for itself based on how little you get for net-metering credit.

Thought about it, but not really looked into it. We have limited space to put such a system.
 

Offline EEVblog

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #9 on: March 16, 2015, 10:53:28 am »
Dave, here in the "Old Dart" (wtf?), I have a 4kWpk system. We are further from the equator that you are, so longer summer days mean I am able to beat your figures for 2 (maybe 3) months of the year, in high summer. But you've got me beat, the rest! Check out how much your solar power waxes and waynes through the seasons, and compare it to mine (PVoutput user Wilkins_watts). Very low power in the short, cold winter days!

Our system does not have ideal tilt or angle. It is what it is unfortunately.
Our solar insolation would be higher than the old dart, so if conditions were the same ours would produce more.
 

Offline EEVblog

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #10 on: March 16, 2015, 10:54:16 am »
How large is the area of your system?

No idea. You can read the panel datasheet and calculate.
 

Offline rs20

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #11 on: March 16, 2015, 10:58:53 am »
I had to go out and clean snow off the panels several times.

Why not put heaters under the panels, and melt the snow away? #SolarRoadways
 

Online dr.diesel

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #12 on: March 16, 2015, 11:01:58 am »
Damn!  Here in Indiana I pay $0.09/kWh USD.  (Pricing is tiered, but my average)

Offline number33

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #13 on: March 16, 2015, 11:11:56 am »
Just to rub salt in the wound, the UK system isn't a net or a gross method, it pays a FIT for every kWhr generated regardless of whether or not you use it and then an additional amount for each kWhr exported to the grid.  It's currently 13.9p (26.7 Aus cents) per kWhr generated plus 4.9p (9.2 Aus cent) per kWhr exported.  This is for domestic (<4kW) installations.

Early adopters get an even better deal, just from memory something like 43p/kWhr generated plus 3p/kWhr exported and fixed for 25 years.  Of course they did pay much more for their installations, perhaps two to three times the current rate. Payback times were about ten years then and are probably about the same now.
Malvern - Worcestershire - England
 

Offline tecman

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #14 on: March 16, 2015, 11:20:14 am »
I had to go out and clean snow off the panels several times.

Snow? What's that? I don't understand...


You don't know what you are missing !
 

Offline tecman

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #15 on: March 16, 2015, 11:26:03 am »
I had to go out and clean snow off the panels several times.

Why not put heaters under the panels, and melt the snow away? #SolarRoadways

An area  20m long by 3.5m would require a major investment for heaters an the power to run them.  It also would need to work in the teens (F) to help.

paul
 

Offline tecman

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #16 on: March 16, 2015, 11:29:22 am »
tecman- I am also in PA (Pittsburgh) I am surprised how much you generate. In Pittsburgh we only have about 60 sunny days a year. How large is the area of your system?

Cheers!

I have 40 panels, nameplate rating is 9.2 kw.

I generate almost exactly what PVWatts indicated.

paul
 

Offline rs20

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #17 on: March 16, 2015, 11:32:31 am »
An area  20m long by 3.5m would require a major investment for heaters an the power to run them.  It also would need to work in the teens (F) to help.

paul

It wouldn't require a major investment on the power to run the heaters; the solar panels make their own electricity for free! #SolarRoadways

[ Edit: Just to be clear, #SolarRoadways is synonymous with #Joke  ;) ]
« Last Edit: March 16, 2015, 11:38:24 am by rs20 »
 

Offline KTP

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #18 on: March 16, 2015, 11:40:51 am »
I love those Mono-X panels.  I just put four 270 watt LG panels on our homebuilt truck camper and am already seeing over 600 watts flat mounted during March in Seattle.  I am using a Midnite Classic 150 since their factory and engineers are about 20 miles from me.


 

Offline EEVblog

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #19 on: March 16, 2015, 11:43:35 am »
I love those Mono-X panels.  I just put four 270 watt LG panels on our homebuilt truck camper and am already seeing over 600 watts flat mounted during March in Seattle.

Nice. I assume you have storage in that?
 

Offline rolycat

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #20 on: March 16, 2015, 11:47:04 am »
My PV installation is curiously similar to Dave's - 12 LG MonoX panels and an SMA Sunny Boy inverter.

The main difference is that the panels are the 300W NeON type giving a 3.6kWp system. These were chosen due to limited roof space.

It was installed in November 2014 and generation so far has been very good, generally outperforming expectations each month based on a projected annual output of 3,337 kWh. Predicted payback time should be around six to seven years.

(EDIT)
Maximum observed output so far was 3,513W on 25th February. It seems improbably high for the middle of winter - awaiting summer figures with interest.
« Last Edit: March 16, 2015, 12:20:50 pm by rolycat »
 

Offline jolshefsky

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #21 on: March 16, 2015, 12:46:47 pm »
For what it's worth, I wrote a blog about my own solar system. I'm in upstate New York, U.S. (the western part of the state at around 43°N latitude).

My system was a lot lot more per watt installed—perhaps Dave did a lot of the work himself. Subsidies and tax rebates brought the cost down to reasonable levels, my payback is much longer—more like 20 years. Checking my work, our net metering works differently where I'm at (it's more like a virtual "energy bank" which I feed excess into the grid and draw from it until it's gone each year) my system produces around 4,000 KWh/year for around US$600/year (at US$0.15/KWh) which is around double the $363 figure I got ... hmm ... I better check my work there.
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Offline reagle

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #22 on: March 16, 2015, 01:23:50 pm »
Dave, loved the timelapse. What material is your roof made of- is that metal tiles? It looked like they just sit in place with no mounting?!

What a coincidence- my system  is also an Upstate NY system. (See the year end update on it  in http://kuzyatech.com/solar-a-year-later)
It's 22 Sunpower ACPV panels rated 5.5kW total, but only managed around 4.3kWh last year. Too much damn snow with my low slope roof.
This year will be even worse- my microinverters were not talking for 39 days in a row due to three feet of snow on top of the panels!
I fought with it for a bit, but then ran the numbers and realized I better spend the energy digging out my driveway vs clearing the panels on the roof ;)
It's now mid March, and I still have a few panels slowly defrosting.
On a positive note, getting data from it is very nice- each microinverter talks to a central gateway over powerline link, and that talks to the net. So I get individual panel stats



Offline EEVblog

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #23 on: March 16, 2015, 01:46:11 pm »
Dave, loved the timelapse. What material is your roof made of- is that metal tiles? It looked like they just sit in place with no mounting?!

Terracotta.
Every 2nd row has a nail to hold down, so can remove the other rows.
 

Offline Poe

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Re: EEVblog #724 - Home Solar Power System Analysis & Update
« Reply #24 on: March 16, 2015, 02:05:58 pm »
I've never had any money to invest, so maybe I'm way off base here.....
But I get the impression that it would make more financial sense to invest that $5k in the stock market.
Eight years of compounding savings versus just getting your money back (Does this equipment retain its value on the second-hand market or would people be silly to buy used?) then hoping you can turn a profit near the end or after the warranty has expired.
Dunno.  Just thinking out loud.

 


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