Advice needed for system install

[dcchapman7]

What was the annual harvest (not the daily) ? That's the deciding factor. If they are close, then go with the easiest, which I suspect is the patio

Sorry, the annual production west facing patio cover installation is 5,738 Kwh, the annual production on the east facing roof installation is 5,590 Kwh. I'd prefer installing on the patio cover to maintain a better aesthetic on the east facing roof (front of the house) as far as avoiding any negative impact on resale value... but solar pete mentioned above possible wind issue with tilt frames on the cover... but seems like we don't get a real windy day very often here in the central valley....thoughts on a minimum tilt if installed on the patio cover?... had one reply 10 degree tilt, again for some reason PV watts has higher production with lower tilt for west facing install...

[dcchapman7]

In addition to my why the 20 % losses, and going back to your original post with respect to T.O.U. rates and orientation, another question I'd have is : How much of a difference in annual revenue will the two different orientations produce ? My guess is under current and probably (at least for a while) T.O.U. tariffs, that the west orientation will produce more annual revenue (or off set more of an annual bill, same thing). You can get the hourly output estimates from PVWatts, but you'll need information on what your POCO charges for each of 8,760 hours for the year. Getting that info sounds like a daunting task and a PITA, but while it's a pain, it'll be necessary if you want a better estimate. On the other hand, if it takes, say, 4 hours and saves a couple hundred $$/yr., it might be worth it. Your money, your choice. Whatever you decide, it'll still need to account for shading.

That sounds a bit daunting... I was just thinking simplistically on this one, that with TOU rates, the energy that I produce from west facing panels during peak hours would make for greater annual revenue... but looking at the hourly for east and west facing systems - it looks like the for east facing highest production is roughly 10:00 a.m. - 1:00 p.m., and west facing highest production is roughly 11:00-2:00 p.m. - peak rates M-F here are currently 3:00 - 8:00 p.m. and will change to 4:00 - 9:00 p.m. eventually, so don't know how significant west facing panels would actually be in terms of value of electricity produced, however on the hourly PV watts excel sheet it only shows production up through 4:00 p.m. through all the months (unless I'm reading it wrong?), but I see the west facing portions of our roof getting sun until at least 7:00 p.m. in the summer and would think there should be production in the PV watts hourly calculations showing this?

[J.P.M.]

That sounds a bit daunting... I was just thinking simplistically on this one, that with TOU rates, the energy that I produce from west facing panels during peak hours would make for greater annual revenue... but looking at the hourly for east and west facing systems - it looks like the for east facing highest production is roughly 10:00 a.m. - 1:00 p.m., and west facing highest production is roughly 11:00-2:00 p.m. - peak rates M-F here are currently 3:00 - 8:00 p.m. and will change to 4:00 - 9:00 p.m. eventually, so don't know how significant west facing panels would actually be in terms of value of electricity produced, however on the hourly PV watts excel sheet it only shows production up through 4:00 p.m. through all the months (unless I'm reading it wrong?), but I see the west facing portions of our roof getting sun until at least 7:00 p.m. in the summer and would think there should be production in the PV watts hourly calculations showing this?

Something is amiss. My PVWatts hourly output for Fresno shows lots of output at 1600 hrs. and later.

Your logic seems sound to me. The task looks daunting and not made any easier by the POCO. But it is possible and some form of at least quasi-detailed analysis seems warranted if you want more insight into which orientation has the higher probability of producing greater annual output. I've done it for my POCO. A detailed wade into the way your bill, or how a T. O.U. tariff works is necessary. As I suggested, it takes a few hours, but persistence and patience will pay off. Whether it's worth it to you is something only you can determine.

FWIW, my experience with canned promises of an easy fix for this and similar situations are worthless B.S. You can get reasonably accurate numbers on your own for some effort and learn a lot in the process. In light of the fact that PVWatts model estimates are long term and based mostly on modeled (not actual) data, and that T.O.U. times as well as rates are sure to vary in the future, are among the many things to consider for this particular situation, as well as the bigger picture of whether to invest in PV at all.

In spite of all the hype and hoopla, PV may not always be, and as a matter of fact usually isn't the most cost effective way to reduce an electric bill. Lots of other use reduction methods have a better ROI and/or shorter payback.