North-facing panels?!

[DanKegel]

Today in LA I saw a house with panels on all four slopes- north, east, west, and south. Never seen that before, always thought north would cut power by half, too much to be worth it.

But heck, panels are getting cheap, and if the installer's on the roof anyway, maybe it's worth it. So I tried to fire up pvwatts to check output. Alas, pvwatts seems down today. But I did see a couple pages on the topic:

http://www.businessspectator.com.au/article/2015/1/22/solar-energy/south-facing-solar-panels-time-has-come

http://www.solstats.com/blog/solar-energy/solar-roof-angle-roof-orientation-and-solar-power/

So, yeah, panels facing towards the pole probably only produce about half as much around here.
My payback period is 8 years with south and west facing panels, and adding north facing panels would just make that worse.

So I'm back to "What were they thinking?". Makes me wonder who their installer was.

If electric rates double, well, that might be another matter.

[lkruper]

Today in LA I saw a house with panels on all four slopes- north, east, west, and south. Never seen that before, always thought north would cut power by half, too much to be worth it.

But heck, panels are getting cheap, and if the installer's on the roof anyway, maybe it's worth it. So I tried to fire up pvwatts to check output. Alas, pvwatts seems down today. But I did see a couple pages on the topic:

http://www.businessspectator.com.au/article/2015/1/22/solar-energy/south-facing-solar-panels-time-has-come

http://www.solstats.com/blog/solar-energy/solar-roof-angle-roof-orientation-and-solar-power/

So, yeah, panels facing towards the pole probably only produce about half as much around here.
My payback period is 8 years with south and west facing panels, and adding north facing panels would just make that worse.

So I'm back to "What were they thinking?". Makes me wonder who their installer was.

If electric rates double, well, that might be another matter.

One site is from Australia and the other one says: "if you live in Australia then you want a North-facing roof"

[DanKegel]

Yep. But there was no confusion on my end; the question is whether it ever makes sense to put panels on a roof that faces not east, not west, and not towards the equator.

And I think the answer is "yeah, but not in Los Angeles today for most folks". But I could be wrong.

[inetdog]

Yep. But there was no confusion on my end; the question is whether it ever makes sense to put panels on a roof that faces not east, not west, and not towards the equator.

And I think the answer is "yeah, but not in Los Angeles today for most folks". But I could be wrong.

If you are short of space and really need the additional panel area, one option is to put the panels on the North roof, but not mount them flat to the roof. Even getting them horizontal (and with spacing to prevent shading) can help.

[HX_Guy]

PVWatts seems to be working for me...put in a 5kW system for testing, 8% system losses and 22º tilt in Phoenix, AZ area.

90º: 7,708 kWh production
180º: 8,907 kWh production
270º: 7,731 kWh production
359º: 5,990 kWh production

Not as bad as I thought it would be...

[DanKegel]

one option is to put the panels on the North roof, but not mount them flat to the roof. Even getting them horizontal (and with spacing to prevent shading) can help.

Good point. BTW, I think searching for "reverse tilt" is a good way to find relate discussions (well, that probably refers to tilting them up past horizontal, but it's the same idea).
I hear some installers won't do it, and it probably takes a bit more care and engineering.

[solarfrank]

A 6 kw solar system in LA on a 4/12 roof will produce on south 9600 kwh and facing north will produce 7000 kwh, you will loose 37%. Reverse tilt and compound tilt looks ugly and are few projects installed around LA when solar panels has been expensive and looks horrible. I saw couple of systems around LA with modules facing north and also in shade.

[J.P.M.]

For 92026: Same system, 0 deg, 6,093 kWh
90 deg, 7,480 kWh
180 deg, 8445 kWh
270 deg, 7,867 kWh

Horiz. : 7,851 kWh

FWIW, looks like horiz. beats 90 deg. az. and about dead heat w/ 270 deg. az. @ 22 deg. tilt, at least in my neighborhood.

System size, 5 kW.

[DanKegel]

pvwatts is still busted here; it won't accept any address I give it, it tells me to try a different one
It always says "Please enter a different location. Sometimes a more specific location works better, but other times a more general location is best."

Is it a better deal than upgrading a few of your better-aimed panels to SunPower?

[foo1bar]

Is it a better deal than upgrading a few of your better-aimed panels to SunPower?

Maybe - depends on how much each option costs.

$900 for 280W that produces 60% (~170W) is better deal than going from 4@280 to 4@320 (160W more) for an extra $1800.
(estimating an extra $1/watt on the existing watts, PLUS the extra wattage)

Of course the actual costs could also be $1100 on the north facing 170W equivalent, while only $512 for extra 160W facing south.

It really really depends on the particulars.