North facing Panels

[SunEagle]

Turns out when it is cloudy the north facing panels generate about 50% of the south facing panels (usually in the morning in S.Calif). So it does add something. Obviously if I had a larger South Facing roof more Southern facing panels would have been better.

When it is cloudy I would expect the South facing would not produce much of anything.

So if the North is 50% of the South then IMO 1/2 of "a little bit" is next to nothing and might not have been worth the extra expense for those North panels.

[littleharbor]

If the north facing array could be tilted up to something like level you would at least get some benefit from the summer season. Not too aesthetically pleasing and would require manual cleaning regimen.

[compchat]

Turns out when it is cloudy the north facing panels generate about 50% of the south facing panels (usually in the morning in S.Calif). So it does add something. Obviously if I had a larger South Facing roof more Southern facing panels would have been better.

[J.P.M.]

OMG, One of their people told me that they don't care how you mount them as long as they are right side up! This is the kind of thing that gives solar installers a bad rep.

Kind of like making sure turf installers aren't color blind ? (As in:"Remember guys - green side up !")

[TurkeyBob]

The moon?
After 15 years of work in the RV solar world I have say something. I have had people tell me they were getting charging under a full moon. The foot candles on the ground from full sun is over 20,000. A full moon on a clear night can do about 2/10 of a fc. You do the math, but people have argued. The same thing was said about parking an RV with solar panels on the roof under a parking lot light at Wallyworld. People are generally pretty gullible and will believe the things they hear if repeated a few times.

When I told professionals in this business that I could run my house on a 2KW array I was told that is impossible. How else can they sell big systems? I am doing exactly that, but figuring out which of the solar charge controller manufacturers had a clue was key. Many of the people on this forum have drunk the Koolaid and bought the wrong things, but I won't go into the details here because they won't believe me. I use Morningstar now with Crown batteries.

[solarix]

OMG, North facing array! might as well point them at the moon.... Our utility here used to check on array orientation as art of their red-tape process and dock your rebates depending on how far from South the array was. Then they killed the rebates and the orientation check. One of their people told me that they don't care how you mount them as long as they are right side up! This is the kind of thing that gives solar installers a bad rep.

[DanKegel]

I have often wondered why the federal solar tax credit is 30% without regard to efficiency. A production tax credit wouldn't have the problem you describe, but for some reason that's used more for wind than for solar. (And PTCs can also have perverse effects, like how wind farms are incentivized to produce even when the price for power goes negative.)

This underscores how tricky regulation is to get right. A carbon fee & dividend would be much simpler, and wouldn't suffer from either of those problems.

[inetdog]

This simply proves that the grid tie solar world is full of crooks. The government should be basing any tax credits on net metering, not the wattage of the panels. Seeing pics of panels on north facing roofs, panels in shade and even one system where panels were installed in shade made by an adjacent house all add up to this conclusion.

State subsidies tend to have an efficiency condition in their terms that would disallow subsidy for North facing panels unless the installer lied when filling out the forms.

[TurkeyBob]

This simply proves that the grid tie solar world is full of crooks. The government should be basing any tax credits on net metering, not the wattage of the panels. Seeing pics of panels on north facing roofs, panels in shade and even one system where panels were installed in shade made by an adjacent house all add up to this conclusion.

[J.P.M.]

While I am working on ROI analysis, I do believe that $/W is one part of the story. I have limited space on my roof on SW and SE. The most open space is NW. I got quotes from several companies. In some cases, they recommended a higher nameplate wattage panel and $/W is higher. I took advice from JPM and other members and started using PVWatts and SAM.

The ROI on the system w/ higher $ per DC Watts is better than the one with lower $ per DC Watts for same total system output. The reason being, I can fit 12 panels on SW & SE. With higher output panels, I just need to use SE & SW panels. On lower wattage panels, additional panels go NE. Performance of NE facing panels (one of major brand-name company wants to put 6 panels there) is pretty bad.

Just my 2 watts

And you're having fun I bet.

What you're finding is certainly possible, but I'd also look at LOCE's for all orientations. Different orientations of the same array size will indeed produce different ROI's with the optimum orientation usually producing the greatest simple ROI and the lowest LOCE.

Commonly with tiered rates, but not always, and separate from % total offset, a smaller array will be more cost effective per nameplate Watt than a larger array in the same orientation and duty. So, fewer panels in one orientation due to space constraints may be more cost effective due to smaller size, mostly but not entirely separate from orientation, even if a different orientation with a larger size produces more annual output per nameplate Watt. It can get tricky.
A larger possible area for a bigger array facing away from the equator as your NW orientation for example, will have at least two strikes against it vs. a smaller equator facing array: Less resource availability/area, and perhaps replacing more of the lower tier electricity to some degree, depending on how much power is offset.

[VGdublin]

I think the best time to raise the red flag is when comparing dollars per watt before signing the contract. That would have caught the unproductive north-facing panels.

What brand & model panels, and how much are you paying (without subsidies)?

Can you post pictures?

I'm using reverse-tilt mounts for a couple panels on the north side of my house so they face the sun better, but I can't swear that it's a good idea.

While I am working on ROI analysis, I do believe that $/W is one part of the story. I have limited space on my roof on SW and SE. The most open space is NW. I got quotes from several companies. In some cases, they recommended a higher nameplate wattage panel and $/W is higher. I took advice from JPM and other members and started using PVWatts and SAM.

The ROI on the system w/ higher $ per DC Watts is better than the one with lower $ per DC Watts for same total system output. The reason being, I can fit 12 panels on SW & SE. With higher output panels, I just need to use SE & SW panels. On lower wattage panels, additional panels go NE. Performance of NE facing panels (one of major brand-name company wants to put 6 panels there) is pretty bad.

Just my 2 watts

[J.P.M.]

To perhaps clear up one point: It is not necessarily the orientation of what the panels sit on, it's the orientation of the panels themselves.

Often and commonly, solar arrays are parallel to the roof they sit on. That's probably best for a lot of reasons. But, because that's the usual and common arrangement, does not mean other support arrangements are not possible.

[DanKegel]

I think the best time to raise the red flag is when comparing dollars per watt before signing the contract. That would have caught the unproductive north-facing panels.

What brand & model panels, and how much are you paying (without subsidies)?

Can you post pictures?

I'm using reverse-tilt mounts for a couple panels on the north side of my house so they face the sun better, but I can't swear that it's a good idea.

[J.P.M.]

One more time: Check PVWatts estimates for different orientations for your location.

[solarix]

Ditto on Emartin00