Looking for Advice - PV installation in Mesa, AZ

[oilerlord]

It's been a minute since my first post Fun to be back chatting with the experts again.

To update, we have a 9.2kW SunPower system we installed back in 2015 at our home in Canada going strong. No issues.

We're now about to closing on a home in Mesa and as luck would have it - it has a massive south facing roof. I'm looking into loading it up with solar. I've been doing some searches here but haven't found what SRP (local POCO) handles grid-tie in terms of credits for exports, or really, if it makes financial sense to install a 12+ kW PV setup in this state. However, given how much solar we see here - I'm guessing the math makes sense.

I'm looking to do the normal stuff others do - run the AC, charge the EV, and basically eliminate the power bill. PVwatts still looks good for sizing this install. Does it make sense to oversupply to the grid, is there a limit? If anyone has advice on how the state / city handles solar export credits, current available subsidies and/or finance plans, and an installer you trust, I'd like to hear from you.

Also...gear. I still like the look or our old SunPower 225's, and want that same attractiveness for this new array. There is no obstructions or trees but I still prefer micro inverters. We've had zero issues with our ABB 0.25's, and I'm happy to pay for that kind of reliability again.

[solar pete]

Hi oilerlord,

Welcome back, it probably only makes sense to oversize if you have a feed in tariff in your area OR you plan on adding battery's at some stage, if so you need to think about charging the battery in winter. As always google is your friend in this department, not sure if www.solarreviews.com has much info for Canada but it wouldn't hurt to have a look, good luck with it, cheers

[oilerlord]

Good to be back.

As mentioned, the system would be installed in Mesa, AZ (USA). I did look at the solarreviews link but at this point I really don't want a dozen solar installers showing up at the door pressuring to close a deal.

At this point I'm just looking at how Arizona (particularly - Mesa) handles grid tied systems, particularly exporting kWH's.

I'll just give SRP (the local POCO) a call tomorrow and ask some questions.

[azdave]

SRP really doesn't want your excess energy unless it is between 2-8PM and I can see that becoming 3-8 PM in the future as more and more residential solar capacity is added. West facing arrays are more favorable to their plans for sure. They pay very little for excess energy during off-peak periods. You really need to study their E-27 contact for RE customers. Last I checked, every RE customer bill includes a higher monthly base connection fee ($13-$24 more than non-solar user). They settle any exported energy as an account credit at the end of each month instead of at an annual renewal date. They also have a demand fee that penalizes you for the entire month's energy use based upon the single highest peak demand that occurs during any 30-minute period in that month. Good luck figuring out in advance what the demand fees might add to your monthly bill. I honestly would never install solar if given the choice today. The ROI is too far in the future to be of benefit to me. I was very lucky to get under contract with SRP before all of the changes they made back in 2015. Their next rate increase is scheduled for November and includes a change to the base rate too so I'll be included in that, even under my old contract.

https://www.srpnet.com/price-plans/residential-electric/solar/customer-generation

[oilerlord]

Dave, thank you for your candor. From experience, it took 10 years to ROI on our system at home, and that was mostly DIY with used gear. It's crazy that some firms are still quoting 25-year ROI's and sell it with a straight face.

Do they credit excess kWh's exported at the end of each month, or just an arbitrary dollar amount?

The way it works back at home, I only get credited base rate per kWh - which is about 1/3 of what we pay when you factor in fees & taxes.

I'll look into that contract to find out more.

[oilerlord]

I read that E-27 contract. It brings up more questions than it answers.

Why power companies write regulations with the intent to obfuscate and confuse the reader, I'll never know.

[azdave]

Do they credit excess kWh's exported at the end of each month, or just an arbitrary dollar amount?
The way it works back at home, I only get credited base rate per kWh - which is about 1/3 of what we pay when you factor in fees & taxes.

I'm on an older SRP contract with no TOU plan required. I bank excess kWhs all but two months of the year which I can use at a 1-1 rate up until my anniversary date. At the anniversary date, I get an account credit at wholesale prices and the bank resets to zero. In the last few years, the wholesale account credit has paid all of our connection fees for the upcoming year so we have literally paid nothing for electricity the last several years.

Under the newer E-27 contracts, I believe they issue a monthly, retail account credit with the value determined by which TOU period you were in when the excess was banked. Receiving retail credit for your excess production sounds better than me getting wholesale for mine but with all the TOU hassles, demand fees and higher base fees of the new RE contracts, I'm getting a better deal for sure. I still have 9 years remaining under that contract before I'll be forced into a new agreement.

You really need a DIY install these days to get a decent ROI in my opinion. SRP used to have limits on residential system size but not sure if they still do. You might have to limit your export if you don't self-consume enough on a larger system.