Aps (arizona) solar calculator accuracy

[josefaz]

I'm new here and I'm considering solar at our home. I spent a few hours in this forum getting information on how to get started but suddenly became overwhelmed with all the choices. As an Arizona residence, I checked the APS website and played with the solar calculations based on my usage. I was a little disappointed that ROI results are around 16 years but from the threads I read here that came from Arizona residence, the ROI is around 5-6 years the most (some even less). What am I missing? I realize the calculations are just rough estimates but since APS promotes the solar power, I would think the calculations would be more attractive if I was in the market to convert to solar energy.
My APS calculation for a 50% annual usage (I use 15500 kWh/year) net cost is $14,540 and annual savings of $890. Payback is 16.4 years. Now tell me if you're in the market for solar, would'nt this figure discourage you? With all the incentives deducted from the net cost, I can only assume this is a lease estimate which I'm interested in.

[russ]

What system cost did you assume for cost per DC kW?

What rate plan did you consider - that seems to make a huge difference there.

The APS calculator seems to oversize the panel requirement substantially. Might try Sharp's calculator http://sharpusa.cleanpowerestimator.com/default.aspx

It looks closer to 10 years from what I saw.

[Ian S]

I'm new here and I'm considering solar at our home. I spent a few hours in this forum getting information on how to get started but suddenly became overwhelmed with all the choices. As an Arizona residence, I checked the APS website and played with the solar calculations based on my usage. I was a little disappointed that ROI results are around 16 years but from the threads I read here that came from Arizona residence, the ROI is around 5-6 years the most (some even less). What am I missing? I realize the calculations are just rough estimates but since APS promotes the solar power, I would think the calculations would be more attractive if I was in the market to convert to solar energy.
My APS calculation for a 50% annual usage (I use 15500 kWh/year) net cost is $14,540 and annual savings of $890. Payback is 16.4 years. Now tell me if you're in the market for solar, would'nt this figure discourage you? With all the incentives deducted from the net cost, I can only assume this is a lease estimate which I'm interested in.

You will do better with a prepaid lease. Price the Sunpower lease which I have even though it took over six months from signing to installation. Bear in mind though that APS has reduced its rebate by 45% from last year so those of us who got in then got a better deal. Also the calculation of savings is not that trivial especially if you'll be switching to a different rate plan when you go on solar like I did - combined demand TOA to TOA alone. I don't know if the APS calculator is sophisticated enough to take the nuances of that into consideration. When I did a calculation, I originally estimated that on the noon to 7 pm plan, about half my production would be peak power time. That worked out over a year that I would have excess peak time production and insufficient off-peak. But the credit at the end of the year for my on-peak excess would pretty much amount to 1 for 1 offset of some of my off peak deficit. That would leave some additional off peak to pay for but at about $.06/kWh, the total electric cost is really reduced from before the solar. You may want to look at a somewhat higher production and see how that works.

[russ]

Ian is the resident expert on APS after all his studying prior to signing a lease.

[josefaz]

With the Sharp calculations, I still think that is too long.
Ian, I'm on the 7 p.m.-12 a.m. (off-peak) plan with APS. You mentioned in some of your threads that APS credits off and on-peak separately, since no one is home during the day at our household, will a solar system still benefit us? My understanding from your threads that during on-peak in my case will create a surplus at the end of the year and I don't get anything from it because the house use less electricity during the day. We typically consume 80% of our electric during the off-peaks hours. Of course I can tailor my plan when I'm commited to solar but at this point of my research I'm not totally convinced especially when APS reduced there incentive by 45% from last year as you mentioned.
I also think no other way to get solar but pre-paid lease but with ROI of 10 years is a little too long for me. I can always revisit the solar options a couple of years down the road when hopefully a better technology, lower panel cost and better incentive could possibly become available. Your deal Perfect Power seems what I would consider but that was last year and I doubt I'll get that. I still intend to get an estimate from a couple of installers to get an idea of the actual pre-paid cost.

[Ian S]

With the Sharp calculations, I still think that is too long.
Ian, I'm on the 7 p.m.-12 a.m. (off-peak) plan with APS. You mentioned in some of your threads that APS credits off and on-peak separately, since no one is home during the day at our household, will a solar system still benefit us? My understanding from your threads that during on-peak in my case will create a surplus at the end of the year and I don't get anything from it because the house use less electricity during the day.

Well, you don't actually lose the surplus at the end of the year, rather you get a credit for it and the amount of that credit is about $.06 per kWh according to the net metering rate schedule EPR6 which is tacked onto your noon to 7 pm pricing plan. In effect then, that credit will offset some or all of the cost of the off-peak deficit. When I was first talking to Perfect Power, the sales guy suggested the standard rate plan so all the solar production would be offsetting all your usage. However, one of his colleagues had gone with the noon til 7 pm plan and I simply could not see where the standard plan would be better than that even when one of us is home during the day. So I have opted for the noon to 7 pm plan. I can always change after a year. They have a super peak plan as well that would work well for someone away during the day but my partner works out of the home and needs AC all day. I would also say that although you generate roughly half your energy between noon and 7, weekends and holidays are off-peak so if you do the calculation, keep that in mind.

[KRenn]

I'm new here and I'm considering solar at our home. I spent a few hours in this forum getting information on how to get started but suddenly became overwhelmed with all the choices. As an Arizona residence, I checked the APS website and played with the solar calculations based on my usage. I was a little disappointed that ROI results are around 16 years but from the threads I read here that came from Arizona residence, the ROI is around 5-6 years the most (some even less). What am I missing? I realize the calculations are just rough estimates but since APS promotes the solar power, I would think the calculations would be more attractive if I was in the market to convert to solar energy.
My APS calculation for a 50% annual usage (I use 15500 kWh/year) net cost is $14,540 and annual savings of $890. Payback is 16.4 years. Now tell me if you're in the market for solar, would'nt this figure discourage you? With all the incentives deducted from the net cost, I can only assume this is a lease estimate which I'm interested in.

Don't rely on the utility calculators, most of them are out-dated, which shouldn't be all that shocking. Most people nowadays are leasing either through a prepaid or a monthly lease, financially it seems to be a much better option than purchase as long as your credit is decent.

[KRenn]

With the Sharp calculations, I still think that is too long.
Ian, I'm on the 7 p.m.-12 a.m. (off-peak) plan with APS. You mentioned in some of your threads that APS credits off and on-peak separately, since no one is home during the day at our household, will a solar system still benefit us? My understanding from your threads that during on-peak in my case will create a surplus at the end of the year and I don't get anything from it because the house use less electricity during the day. We typically consume 80% of our electric during the off-peaks hours. Of course I can tailor my plan when I'm commited to solar but at this point of my research I'm not totally convinced especially when APS reduced there incentive by 45% from last year as you mentioned.
I also think no other way to get solar but pre-paid lease but with ROI of 10 years is a little too long for me. I can always revisit the solar options a couple of years down the road when hopefully a better technology, lower panel cost and better incentive could possibly become available. Your deal Perfect Power seems what I would consider but that was last year and I doubt I'll get that. I still intend to get an estimate from a couple of installers to get an idea of the actual pre-paid cost.

ROI seems to be running about 4-8 years currently for APS customers, it just all depends on who you talk to, the difference now between one company and another is greater than ever in terms of pricing. You could have two quotes that are $5000 or $6000 apart for the same exact size system. I also wouldn't count on a better incentive happening, they are predicting that APS will hit $0.10 a watt at the end of the year and once that is out, utility rebates will be done as solar will still be moving and self-sustaining although more than a few installers will have to find a new line of work at that point in time.

[pfp]

Well, you don't actually lose the surplus at the end of the year, rather you get a credit for it and the amount of that credit is about $.06 per kWh according to the net metering rate schedule EPR6 which is tacked onto your noon to 7 pm pricing plan. In effect then, that credit will offset some or all of the cost of the off-peak deficit. When I was first talking to Perfect Power, the sales guy suggested the standard rate plan so all the solar production would be offsetting all your usage. However, one of his colleagues had gone with the noon til 7 pm plan and I simply could not see where the standard plan would be better than that even when one of us is home during the day. So I have opted for the noon to 7 pm plan. I can always change after a year. They have a super peak plan as well that would work well for someone away during the day but my partner works out of the home and needs AC all day. I would also say that although you generate roughly half your energy between noon and 7, weekends and holidays are off-peak so if you do the calculation, keep that in mind.

A bit minor but one thing to consider, especially when sizing a system for 100% usage, is that APS has charges based on the number of days as well as the kWh used. A solar system can only take care of the kWh - you will still be paying APS the amount based on days. On the standard rate plan the days charge comes out to approx $9/mo while on any other rate plan it comes to about $17. No sense paying this extra amount every month if you are generating all the power you use.

[KRenn]

A bit minor but one thing to consider, especially when sizing a system for 100% usage, is that APS has charges based on the number of days as well as the kWh used. A solar system can only take care of the kWh - you will still be paying APS the amount based on days. On the standard rate plan the days charge comes out to approx $9/mo while on any other rate plan it comes to about $17. No sense paying this extra amount every month if you are generating all the power you use.

That breaks down into a variety of things, billing, APS says they still have to send you a bill, even if you owe nothing, metering, their meter is on your property, even if you can't help it and of course the environmental surcharge that will now be passed on at a cost of $3 a month for a grand total of $10-16 left over monthly.

[pfp]

That breaks down into a variety of things, billing, APS says they still have to send you a bill, even if you owe nothing, metering, their meter is on your property, even if you can't help it and of course the environmental surcharge that will now be passed on at a cost of $3 a month for a grand total of $10-16 left over monthly.

I understand. I'm Just pointing out that is roughly 2x more on anything but the standard rate plan.

[KRenn]

I understand. I'm Just pointing out that is roughly 2x more on anything but the standard rate plan.

True but you get better compensated on the TOU for the most part.

[pfp]

True but you get better compensated on the TOU for the most part.

At the end of the year you get a credit to your account for unused generated power at the following rates:
Peak = 0.0659
Off-Peak = 0.05963
The difference between them is 0.00627 (6/10 of a cent)

This difference definitely can be used to your advantage but you would have to do some very serious number crunching to verify the payoff vs using the standard rate plan which guarantees a $8 monthly savings over any other rate plan.

Something else to keep in mind if you opt for the TOU plans is that all accumulated (kWh) credits on your account are reset to zero at the beginning of the year. You need to be sure that you are generating and banking enough peak power to cover what you will need once A/C season arrives. On the 7-noon plan this might be tricky since approximately 40% of generation should occur before noon.

[Ian S]

At the end of the year you get a credit to your account for unused generated power at the following rates:
Peak = 0.0659
Off-Peak = 0.05963
The difference between them is 0.00627 (6/10 of a cent)

This difference definitely can be used to your advantage but you would have to do some very serious number crunching to verify the payoff vs using the standard rate plan which guarantees a $8 monthly savings over any other rate plan.

Something else to keep in mind if you opt for the TOU plans is that all accumulated (kWh) credits on your account are reset to zero at the beginning of the year. You need to be sure that you are generating and banking enough peak power to cover what you will need once A/C season arrives. On the 7-noon plan this might be tricky since approximately 40% of generation should occur before noon.

I certainly agree that if you are planning to produce more than you use, the standard rate plan would be best for the reason you indicate. However, my system is insufficient to cover more than about 60-70% of my needs. I did a spreadsheet calculation last year using a local friend's Sunpower data adjusted for my system size and compared the TOU and the standard rate plans. The TOU wound up saving several hundred $$ more in kWh costs than the standard rate plan. Interestingly, the calculation indicated that I would have excess peak credits at the end of the year which at the APS credit rate, would wind up offsetting about 1-to-1 some of my off-peak deficit. Unfortunately, with my late startup (mid-May), I won't have the benefit of all the winter and spring credit buildup.

The one thing I've noticed on the smart meter is that it also seems to track my peak power fed back to the grid - presumably analogous to the Demand kW feature used on the Combination TOU/Demand plan. Does that mean I could go on that type of a plan and have my Demand component reduced by the value of the peak power I feed back to the grid?