I now have one of the Premier Benchmark 16.8 KW 2-axis solar array set-ups!

[Bzzy56]

I am a DIY kind of guy and even though I knew absolutely ZERO about Solar I wasn't intimidated in the least when I stated this quest 2 years ago. I did my homework and the installation myself (Solaris performed the Design for $700) and have now have a completed killer set-up that has most of the local "Professionals" jaws dropping here in Phoenix AZ!

Without further ado, here is the 16.8 KW set-up that has now been fully operational for just over a year:
• Suntracker 2-axis array (Qty 1)
• LG400N2W-V5 panels (Qy 42)
• SE7600A-USS20NHB2 Inverters (Qty 2)
• P505 83V MC4 Optimizers (Qty 42)
• SEAUTOTX5000 Transformer (Qty 1)
• SE-MTR240-0-000-S2 Revenue Meter (Qty 1)
• SEACT0750-20NA-20 200A CT (Qty 6)
• RESU10H 9.8K 400V Battery (Qty 1)
• System Cost: $54,827.33, ~$11K+ of this cost is for the air conditioned solar equipment shack

The system is located approximately 220 feet from my main power panel behind my house and the equipment is all housed in a climate controlled (air conditioned) 10' x 12' stucco/tiled roof shack with a mini-split A/C since I live in the Phoenix AZ area and wanted the equipment maintained within the Mfr's spec temp ranges.

When I did my initial SWAG using PVWATTs it told me that the system should produce in the neighborhood of 44,555 kWh/yr. The first full year of operation through June 30 of this year was 46,490 kWh so I am very pleased with the results! Just not very pleased with the local Utility Company SRP and their paltry $0.028/kWh payout for my excess. This was 46,490kWh generated against a usage baseline of 26,700 kWh or just shy of 20,000 kWh surplus generated.

For comparative purposes I used 2019 as the baseline for monthly consumption and costs since I fired up the System part way through June of 2020 so the dollar/power comparison are July 2020 through June 2021 against the baseline.

The annualized dollar savings of $1377 versus a previous cost of $2816 for 12 months of power consumption is a bit skewed because in the Fall of 2020 we started to use our Pool Heat Pump to maintain our outdoor pool at 90°+ and in 2019 we had neither a pool pump operating nor a pool heat pump.

Our primary motivation for the system was to defray the high cost of operating the pool heat pump which operates part of September through part of May and it did so very nicely plus we got a nice ~$15K tax credit for the system as well bring our net cost down to the $39K range which includes the cost of the air conditioned solar shack!

Aray.jpgArray.jpgArray2.jpgCompl.jpgInsideEquip.jpgMeter.jpgPVWatt.pngMonth.pngMonthly.png

[bcroe]

. When I did my initial SWAG using PVWATTs it told me
that the system should produce in the neighborhood of 44.5 kWh/yr.

Impressive, yes. But your first document mentions 44,500 kWh/yr. Bruce Roe

[azdave]

~$11K+ of this cost is for the air conditioned solar equipment shack

Congrats on completion of the project. We paid $11,250 for our entire system that saves us $1400 a year and you spent that much on just the shack? What is your predicted ROI? Did I read correctly that your NET cost was $39K and the system saves you $1377 per year? That can't be right. Maybe I need my morning coffee. What am I missing?

[J.P.M.]

This is a free country and hail the freedom to choose. But, while doing what you've done for the education value is one thing, if you did it as an investment, I've got some money in some rather conservative, long term bond funds that return about half again as much as what your array produces in terms of % annual return. And, assuming financial Armageddon doesn't occur, I can always get most of my investment out.

I'd have educated myself on paper first. Better, cheaper, easier.

If I was trying to defray the cost of heating pool water, I'd have educated myself about and considered a solar pool water heater for your application. Better, a whole lot cheaper, a lot less maintenance and more production/m^2 to the duty.

Now you're making $0.028/kWh on ~ 20/45 = 44% of your production.

Did you investigate the NEM surplus production rates before you sized the system ?

Why a dual axis tracker ? Have fun with the maintenance.

I'd bet most of the professional's jaws aren't dropping but maybe they're scratching their heads and wondering want you were thinking (or not thinking).

BTW, your numbers quoted in kWh/yr. ? Those should be thousands of kWh/yr. Maybe your education in the fundamentals needs more work.

Take what you want of the above. Scrap the rest.

[Bzzy56]

But your first document mentions 44,500 kWh/yr.

Sorrry, my bad, I was using mWh but used kWh, I went backed and corrected it!

the system saves you $1377 per year? What am I missing?

On the surface yes but the actual number is likely closer to $2K because the baseline cost does not include pool pump running nor the heat pump cost.

Did you investigate the NEM surplus production rates before you sized the system ?

yes

Why a dual axis tracker ? Have fun with the maintenance.

40% additional output and i don't mind spending 10 minutes every six months adding a skirt of grease to the zerk fittings...not really what I'd call a nightmare maintenance scenario lol.

Maybe your education in the fundamentals needs more work.

I don't think so, the system will have a payback of about 10-12 years based on inflation and projected usage and I'm ok with that plus I get to store my outdoor tools, wheelbarrow, etc in an air condtioned shack! The total cost baseline also doesn't include the running of my A/C's in my 40x40 shop where I have 3 mini splits and didn't use them in the baseline cost because I was doing other work outside. We have a total of 8 heat pumps at our residence and in the summer months when I will be working on cars this system will produce plenty of power to defray the cost during daylight hours when my Utility Company charges a WHOPPING $0.24/kWh for power!!! This system may not fit your needs or Financial objectives but it suits my perfectly. Peace!

[sabersix]

This looks like a giant sail. How does the system handle winds? Does it automatically feather out if wind load exceeds a certain amount?

[SunEagle]

This looks like a giant sail. How does the system handle winds? Does it automatically feather out if wind load exceeds a certain amount?

Good question but you should see the giant systems up in Canada. Those things are huge and look pretty much like the one the OP shows.

[Bzzy56]

This looks like a giant sail. How does the system handle winds? Does it automatically feather out if wind load exceeds a certain amount?

With no problems! The system is Engineered for 80 MPH and I have the wind sensor set for 15 MPH

[bcroe]

Any project that meets its design objectives is a success, even if it is not the way
others would do it. I am assuming you have very little issue with clouds and smoke,
clouds, and lately smoke from the west coast fires are the main limiting factors here.
The combination of tracking and clear skies at your latitude is producing great
output for a 15.2KW AC plant. I do not see why you used optimizers though. With
similar dual inverters here, I can spot an operational problem at a glance, looking
for similar output. In 8 years I have had zero panel problems, all issues have been
with the wiring. Those have been easily repaired, with all panels easily reached
from the ground.

A problem with trackers, is they can do nothing about clouds and smoke. With
those limitations and a similar size AC plant here, I have chosen a different approach
which greatly increases output under diminished sun intensity. It also manages
an estimated capability about the same as yours under ideal sun, up to 10.5 sun
hours in a long day. How many kWh have you done on your best day? No moving
parts, but with the not so clear sky in N ILL, it does about 30,000 kWh/year.

And snow can be dumped, if it happens? Any panel cleaning anticipated?

The conversion to mini split heat pumps here started in 2018, now pretty much
settled with 6 maintaining 2 buildings year around. Minis have been selected, and
succeeded in meeting or exceeding all expectations for efficiency, quiet operation,
decentralization of HVAC, and very cold operation to eliminate the need to burn any
fuel for heat. Lowest temp extremes here would not apply to your situation.
Bruce Roe

[bcroe]

Good question but you should see the giant systems up in Canada. Those things are huge and look pretty much like the one the OP shows.

Are those dual axis? There have been proposed commercial trackers here, the axis running
N-S to track time of day. I suspect they have in mind the idea of dumping snow, though some
proposed were not high enough to clear any snow accumulation (which I was quick to point
out at a zoning review). The problem with them, is at such latitude the axis wants to be tilted
up very substantially. Bruce Roe

[SunEagle]

Are those dual axis? There have been proposed commercial trackers here, the axis running
N-S to track time of day. I suspect they have in mind the idea of dumping snow, though some
proposed were not high enough to clear any snow accumulation (which I was quick to point
out at a zoning review). The problem with them, is at such latitude the axis wants to be tilted
up very substantially. Bruce Roe

From what I know they are dual axis and as big as a house. I use to have their coordinates on my business computer but they got wiped when it was upgraded to windows 10. From what I remember they are commercial type with maybe 4 or 5 of them in a very small area along a highway.

[Bzzy56]

How many kWh have you done on your best day?

185 kWh

And snow can be dumped, if it happens?

The array had a "snow" setting to tilt the array at full 60 degrees at night to dump the snow.


Any panel cleaning anticipated?

I typically use Windex 2 story window cleaner on the end of a hose about every 3 months or so.

Please say Screenshot_20210824-083407.png more about why you wouldn't use Optimizers....

Are those dual axis?

Yes!

[bcroe]

How many kWh have you done on your best day?

185 kWh

Please say Screenshot_20210824-083407.png more about why you wouldn't use Optimizers....

That is excellent performance. The primary performance reason to use optimizers is
to allow each panel to deliver the most power at any time. That is important if partial
shading can happen, apparently not for you. It can be to optimize individual panels,
but that is negligible improvement from a string of a matched set of panels, each panel
has a somewhat broad point for almost optimum operating point. My expectation is
the optimizers (which are not 100% efficient) would waste as much power as they
saved in your environment, we are talking small single digit percentages.

Optimizers could be used with rather badly matched strings of panels, not typical practice.
Some owners want to know what every panel is doing, for the same reasons as above
it is simpler, more efficient, and more reliable to just look at the totals.

Some owners are concerned with locating panel failures. The optimizers are far more
likely to fail than the panels, and they are hard to service. Over 8 years I have had
zero panel failures (I have over a hundred), the issues have been wiring problems,
which optimizers cannot help with.

Your info gives me an opportunity to compare my fixed PV system with an optimum
tracker PV system, on a perfect sunny day. Your collected energy is about 8% more
than my fixed system, which I would attribute mostly to my latitude and a bit of shading.
Here is a power curve over one of my best days. This is achieved basically by putting
a second set of panels on the other side of the supports, building them to face E-W.

We rarely have such sunny days here, it is a range of clouds and lately smoke from
fires. As a consequence my annual energy collected is only about 2/3 of yours. It
would be even less than that if the panels were not doubled up to maintain some
output on even the worst days (rain and snow storms). That is the reason for this
arrangement, and optimizing sunny days is somewhat secondary. If the tracker
were located here, it would put out less energy than mine, since a tracker cannot
compensate for clouds. Bruce Roe

NScurJn17.jpg

[Bzzy56]

Over 8 years I have had
zero panel failures (I have over a hundred)

Wow, interesting!

I've already had two panel failures within 6 months of start-up so I'm very thankful that with a quick glance at my Optimizer's data it revealed that I had a bad panel and the Mfgr (LG) requested optimizer data from the adjacent panels before they would authorize replacement panels under warranty.

If the tracker were located here, it would put out less energy than mine, since a tracker cannot compensate for clouds

Fortunately I have a lot of sun and VERY few cloudy days! Looks like you've got the right set-up for your conditions, that's awesome!

[foo1bar]

From what I know they are dual axis and as big as a house. I use to have their coordinates on my business computer but they got wiped when it was upgraded to windows 10. From what I remember they are commercial type with maybe 4 or 5 of them in a very small area along a highway.

There's the single-axis ones that are larger than a house.
Like this:

https://www.google.com/maps/@45.1757...z244nQ!2e0!7i1 6384!8i8192

And this one that looks more houselike from the outside:
https://www.google.com/maps/@44.8081...ofkHUQ!2e0!7i1 3312!8i6656?hl=en

Both sites are near Ottawa.