NEM 2 PV System Direction per TOU

[Kuma]

My NEM 2 application has been approved and I have been researching best solar direction per PVWatts, SMA Design tool, youtube... and uncertain which direction is best given TOU. South facing provides the highest production. However, if PGE reimburses/credits in dollars, not kwh's, then during Peak Time (5-8pm or 4-9pm) would be the highest dollar payout in credit given this is when PGE charges up to ~50% more compared to day usage. And if that is true, then any grid electricity used during Peak Time could cost ~50% more because the kwh's produced during the daytime are worth less then what PGE charges during Peak Time.

I looked at some local ground mount PV installs and their is not one common direction. These are ground mount installs, some home owner and others professional installs, that face S and SSW and SW. None appear to have shading issues. Perhaps some were installed per magnetic South rather than true South. Just a guess.

Their is also the given that PGE will change its pricing in the future and perhaps even TOU Peak Time hours.

Given that, is the best PV direction South for highest production? Or SSW or SW in an attempt to produce a bit more kw's during Peak Time when the payout is more as compared to day time?

 

[PeteYates]

Hi there, Sorry you received no responses. I am just starting my journey around the exact same goal. In AZ but on APS. Wanting a solar design to cut bill by 50% and as much as possible eliminate peak demand grid usage.

Did you establish optimum direction? Would love to know where you are with this. Thanks

 

[Kuma]

Hi there, Sorry you received no responses. I am just starting my journey around the exact same goal. In AZ but on APS. Wanting a solar design to cut bill by 50% and as much as possible eliminate peak demand grid usage.

Did you establish optimum direction? Would love to know where you are with this. Thanks

Good question. Contacted sources not on this site and read some papers on the subject. After all that research south remains to be the safe choice providing best production yield. Installing some panels south with others ssw or sw was recommended as a good option also. I recently decided to go roof top mount which limits solar direction. But, all things considered such as cost, loss of physical real estate, possible PV damage... and ease of installation I'm good with that decision. The roof mount will provide some panels facing south and other panels west. Now to decide on the ratio of that mix. ie 50/50, 60/40, 70/30... hahaha

 

[OutlawSolar]

Has anyone used batteries to do time shifting export more during peak hours?
And perhaps even after the sun is down. Does PG&E has any restriction on solar+battery systems on exporting after the sun is down?

 

[400bird]

Has anyone used batteries to do time shifting export more during peak hours?
And perhaps even after the sun is down. Does PG&E has any restriction on solar+battery systems on exporting after the sun is down?

Sure, you can but I doubt it makes financial sense to do it if that is your only reason to purchase the battery.

I am with PGE and use my battery to sell through Ohmconnect, I've made something like $900/year the past couple years doing that. PGE credits cover some winter usages. But, still I don't think the battery will ever pay for itself, but that's not why we added it, so the $ from Ohmconnect is a nice bonus.

 

[OutlawSolar]

Sure, you can but I doubt it makes financial sense to do it if that is your only reason to purchase the battery.

I am with PGE and use my battery to sell through Ohmconnect, I've made something like $900/year the past couple years doing that. PGE credits cover some winter usages. But, still I don't think the battery will ever pay for itself, but that's not why we added it, so the $ from Ohmconnect is a nice bonus.

I already have 60KWh batteries for power outage backup. My thought is why not cycling them during the evening peak hours to maximize net metering.

 

[400bird]

I already have 60KWh batteries for power outage backup. My thought is why not cycling them during the evening peak hours to maximize net metering.

Yeah, if you already have them, might as well put them to use. They're probably going to age out before the cycles you are discussing will effect capacity anyways.

Check your battery interconnect paperwork, but from memory, PGE's restrictions revolve around not selling their power back to them (can't buy at night and sell at peak hours, you've got to generate it yourself) and not selling fossil fuel generated energy to them.

 

[OutlawSolar]

I think I can use the morning hour sun to charge the batteries. I hope we can make an argument that we separate sun electrons from PG@E electrons and sell only sun electrons.