Smart Meters and Net Metering?

[bcroe]

^^^ It seems like it shouldn't be too big of a deal to manually brush the snow off the panels since they're at ground level, no?

We get some snow here, if the drifts get too deep, I might take the AWD tractor back
there and do some snow blowing. But clearing 1200 square feet of panels standing
nearly 12' high, every time it snows, is WAAAYYY too much maintenance.

For those not living in sunny CA or FL, what is even available for clearing panels? The
signs say "DANGER 400 VDC", I am not too anxious to stand in wet stuff and mess with
them. We need a long pole with good insulation for the job, anything available off the shelf?

Bruce Roe

[SunEagle]

Been busy with other winter prep, the "panel platform lifter" is still in the design stage. Looking
at the snow on the low angle surface, I'm sure raising them would clear them faster & increase
power. Power is holding at 2 KW, but I have some panels near vertical, nearly clear. My clamp
on ammeter says those are doing about 3 times the output per string of those with snow cover.

This pic pretty much shows the snow advantage of near vertical angle. When the sun comes back,
I expect the snow to slide off the lower angle panels, but meantime I lost much of their days'
production. Learning more as I go... Bruce Roe

I presume the vertical panels are the ones facing South? I would expect them to generate more than the West facing panels.

There may be another way to get your panels cleared quicker. When I was auditing a 1 MW system out in Carson City back in February I found out that the Inverter had a circuit that would send some energy back to the panels to help with melting the snow so it would slide off faster. It had snowed the day before and there was small piles of snow on the ground in front of the panels.

[Volusiano]

We get some snow here, if the drifts get too deep, I might take the AWD tractor back
there and do some snow blowing. But clearing 1200 square feet of panels standing
nearly 12' high, every time it snows, is WAAAYYY too much maintenance.

For those not living in sunny CA or FL, what is even available for clearing panels? The
signs say "DANGER 400 VDC", I am not too anxious to stand in wet stuff and mess with
them. We need a long pole with good insulation for the job, anything available off the shelf?

Bruce Roe

Being from AZ, clearly I didn't consider everything you said here which makes a lot of sense, LOL.

[SunEagle]

Being from AZ, clearly I didn't consider everything you said here which makes a lot of sense, LOL.

Didn't it snow in Phoenix last year which canceled a golf tournament.

[Volusiano]

It was a terrible winter last year and it did snow but just for a little bit and by the time it hit the ground, the snow melted away very quickly anyway. But we had a pretty cold winter which drove up heating bills significantly and several nights of freezing temperature which killed a lot of plants that could not withstand the freezing weather.

[bcroe]

Panel Defroser

I presume the vertical panels are the ones facing South? I would expect them to generate more than the West facing panels.

There may be another way to get your panels cleared quicker. When I was auditing a 1 MW system out in Carson City back in February I found out that the Inverter had a circuit that would send some energy back to the panels to help with melting the snow so it would slide off faster. It had snowed the day before and there were small piles of snow on the ground in front of the panels.

Can you describe in some detail , how back power is applied to melt the snow? Is the turn on/turn off
automatic, or a manual operation. I could build something for a tested method. Just found another reason
to put a video camera out there, with a radio link.

Actually, the snow covered panels are facing south. The clear array is double sided, facing east & west (see
pic). The general idea is, the east facing work the best early morning. As the sun approaches noon, the south
facing panels do best. Approaching sunset, the west facing do the best. So the power is brought up overall,
without raising the noontime peak. A given size plant can support a lot more panels. The PV WATTS Calculator
suggested this version would increase harvest 30%. My observations are, that that is true for good sun. But
when sun is poor (clouded), light is dispersed, this low level is boosted by 50%. So 50% of much reduced is
still much reduced, but I'll take it.

The extra panels may seem inefficient, but they cost a lot less per KWH harvested. I figured only 60% as
much per KWH harvested (which is different from peak KW). If you already have the panels, its more like
20%. More energy without increasing plant size (inverters & wiring). The support mounts more panels
because it is 2 sided. No elevation changes. And today I see it does better with snow. Bruce Roe

[Volusiano]

In your first picture, I see some pretty tall trees facing the west facing panels, although it's hard to gauge the distance between the panels and the trees. Just wondering, won't those tall trees cause premature shading on your west panels as the sun sets?

[bcroe]

In your first picture, I see some pretty tall trees facing the west facing
panels, although it's hard to gauge the distance between the panels and the trees. Just wondering,
won't those tall trees cause premature shading on your west panels as the sun sets?

Yes, I don't live in the desert. There are trees, and some shading happens in every direction.
The closest ones got trimmed, hence the firewood pile. Peak times are pretty much in the clear,
on days we can see the sun. Premature shading, well, lets see this winter how bad it gets.
When the south facing get shade near sunset, the west facing are putting out. Some trees are
over 100' away & off my property, I haven't messed with them (yet). Bruce

[dmacioce]

Have you tried going online to SCE and see what kind of information they have about how to read the smart meters? I tried briefly and saw them post some short info on how to read the smart meters for NEM customers on the FAQ (with the 001 and 071 codes, etc).

My utility company provides online information on how to read our smart meters, and even displays day-by-day charts showing our on-peak and off-peak consumption. After our solar turn-on date, we can start to see the net on-peak and off peak consumption going negative on days that we over produce.

Yeah, I went online, and all the documentation says that there should be a display "071" which shows the net energy usage. The problem is that I don't have display "071" -- just "001" and "082".

However, I called SCE this morning, and the representative in the NEM department told me that it looked like when the guy installed the meter, he didn't program the meter to display the information on the "071" display. SO, she put in a request to update the programming. But, she assured me that it is a display issue only. The net usage info is being sent to SCE.

However, she also said that I won't be able to access any of the data online until after the first billing cycle on the new meter, which is in a couple of weeks.

Anyway, thanks for the help/info!

[SunEagle]

Can you describe in some detail , how back power is applied to melt the snow? Is the turn on/turn off
automatic, or a manual operation. I could build something for a tested method. Just found another reason
to put a video camera out there, with a radio link.

Actually, the snow covered panels are facing south. The clear array is double sided, facing east & west (see
pic). The general idea is, the east facing work the best early morning. As the sun approaches noon, the south
facing panels do best. Approaching sunset, the west facing do the best. So the power is brought up overall,
without raising the noontime peak. A given size plant can support a lot more panels. The PV WATTS Calculator
suggested this version would increase harvest 30%. My observations are, that that is true for good sun. But
when sun is poor (clouded), light is dispersed, this low level is boosted by 50%. So 50% of much reduced is
still much reduced, but I'll take it.

The extra panels may seem inefficient, but they cost a lot less per KWH harvested. I figured only 60% as
much per KWH harvested (which is different from peak KW). If you already have the panels, its more like
20%. More energy without increasing plant size (inverters & wiring). The support mounts more panels
because it is 2 sided. No elevation changes. And today I see it does better with snow. Bruce Roe

I now understand your panel arrangement better. Seems it is set up to capture some sunlight depending on the time of day and has saved you some money on the mounting. Pretty nice.

As for the "snow melting" system. I could not find any specific information or circuit details on how the inverters pumped back power to the panels to melt the snow. I now believe that the guy I was talking to about it was either pulling my leg or assumed that is how it was working since the snow always slipped off the panels by early morning.

The inverter is a utility scale 500 kw Solaron manufactured by Advanced Energy Industries. It can take in 600VDC and sends out 480VAC. There are two that handle the 1MW system. Definitely something most people will not be using.

[bcroe]

I now understand your panel arrangement better. Seems it is set up to capture some sunlight depending on the time of day and has saved you some money on the mounting. Pretty nice.

As for the "snow melting" system. I could not find any specific information or circuit details on how the inverters pumped back power to the panels to melt the snow. I now believe that the guy I was talking to about it was either pulling my leg or assumed that is how it was working since the snow always slipped off the panels by early morning.

The inverter is a utility scale 500 kw Solaron manufactured by Advanced Energy Industries. It can take in 600VDC and sends out 480VAC. There are two that handle the 1MW system. Definitely something most people will not be using.

A year ago Rockford put up a claimed 3 MW plant by the airport. It is so far behind the "NO TRESPASSING"
signs, its hard to see it at all, let alone get a good look. The panel factory (Wanxiang) is close by, they
hope to make it a lot bigger some day. Might eat up all the power co solar obligations, and shut out any
more of us little guys.

Been very overcast yesterday & today, but I see 2/3 of the south facing array has melted clean.
Expecting more snow momentarily, but got 12 KWH anyway. Melting clean would not take long I
suspect, once the sun comes out. But I'd like to elevate to keep it off, and keep getting that
12 KWH on days before the sun is back. Bruce

[inetdog]

Melting clean would not take long I
suspect, once the sun comes out. But I'd like to elevate to keep it off, and keep getting that
12 KWH on days before the sun is back. Bruce

If the panel is facing a large area of clean snow, the albedo effect from the snow could be giving you more power than aiming the panels directly at the sun on those days.
(And no, panels will not go snow blind.)

[bcroe]

If the panel is facing a large area of clean snow, the albedo effect from the snow could be giving you more power than aiming the panels directly at the sun on those days.
(And no, panels will not go snow blind.

Right, but that also likes the panels more toward vertical. Need to work on that. Sun came
out today, 75 KWH. Bruce