Solar Lease on New Build in Phoenix

[kazpilot25]

Hey everyone,

I am having a new home built in Surprise, AZ (suburb of Phoenix), and was wondering if I could get your input on the system size I might need. Previously, we had lived in a 1200 sq ft. home built in 2001, which was extremely energy inefficient. We are with APS and below is the what we used last year (Kwh):

12/15/2011 1,070
11/15/2011 921
10/14/2011 1,224
09/15/2011 1,756
08/16/2011 1,868
07/18/2011 1,971
06/21/2011 1,551
05/19/2011 879
04/19/2011 850
03/22/2011 850
02/17/2011 938
01/21/2011 944

Now, with that being said, our new house is 2 story and about 2700 sq. ft., and should be super energy efficient. It is Energy Star 3.0 with the radiant barrier roofing, R-30 insulation, 14 SEER AC, etc. My wife works from home with our 2 year old girl, so we keep the house at about 78 all day, and about 76 at night. We are on the 7 to noon plan.

I want the system to offset 100% and then some, so we'll have additional to run a pool in the future. I figured since APS will buy it back, that should be ok. I've been quoted $97 for a 10Kw system, $110 for an 11.7kW system, and $127 for a 13.1kW system. They are all $0 money down, no escalators, and are all SunPower leases.

I appreciate any input as I have no idea how much we will use. If we go with the 13.1kW system, will that be too much that APS won't even buy it all back?

[KRenn]

Hey everyone,

I am having a new home built in Surprise, AZ (suburb of Phoenix), and was wondering if I could get your input on the system size I might need. Previously, we had lived in a 1200 sq ft. home built in 2001, which was extremely energy inefficient. We are with APS and below is the what we used last year (Kwh):

12/15/2011 1,070
11/15/2011 921
10/14/2011 1,224
09/15/2011 1,756
08/16/2011 1,868
07/18/2011 1,971
06/21/2011 1,551
05/19/2011 879
04/19/2011 850
03/22/2011 850
02/17/2011 938
01/21/2011 944

Now, with that being said, our new house is 2 story and about 2700 sq. ft., and should be super energy efficient. It is Energy Star 3.0 with the radiant barrier roofing, R-30 insulation, 14 SEER AC, etc. My wife works from home with our 2 year old girl, so we keep the house at about 78 all day, and about 76 at night. We are on the 7 to noon plan.

I want the system to offset 100% and then some, so we'll have additional to run a pool in the future. I figured since APS will buy it back, that should be ok. I've been quoted $97 for a 10Kw system, $110 for an 11.7kW system, and $127 for a 13.1kW system. They are all $0 money down, no escalators, and are all SunPower leases.

I appreciate any input as I have no idea how much we will use. If we go with the 13.1kW system, will that be too much that APS won't even buy it all back?

APS will buy back up to 125% of the home's use. As far as your home goes, you'd should be around 20,000-22,000 kWh so anywhere from an 11 to 13kW system should work well for you. However depending on when your home is finished your quotations may no longer be valid based on possible incentive changes coming up.

[SoCalsolar]

KRenn methodology?

KRenn I'm not questioning your results but am curious as to your methodology?
Any insight? or is it an industry secret?
thx

[KRenn]

KRenn I'm not questioning your results but am curious as to your methodology?
Any insight? or is it an industry secret?
thx

Standard production values for this region with the panels being used? You can use PVWatts as a base but PVWatts is unusually conservative in that aspect.

[kazpilot25]

I've actually met with the installers and have reserved the incentives with APS, it's now just a matter of determining which is the best system for us.

Question: So if APS buys back 125% of what we use, does that mean they will purchase a max of 5,000 kWh if we use 20,000? Also, If I'm on the 7 to noon plan, and the majority of solar is created "on peak", can that be used to offset "off peak" usage, or is it only used to offset on peak usage and off peak production can only offset off peak usage? I hope that makes sense.

[KRenn]

I've actually met with the installers and have reserved the incentives with APS, it's now just a matter of determining which is the best system for us.

Question: So if APS buys back 125% of what we use, does that mean they will purchase a max of 5,000 kWh if we use 20,000? Also, If I'm on the 7 to noon plan, and the majority of solar is created "on peak", can that be used to offset "off peak" usage, or is it only used to offset on peak usage and off peak production can only offset off peak usage? I hope that makes sense.

To your first question, yes.


APS will credit on-peak usage to on-peak usage, if you have excess on-peak, APS will then apply that to your off-peak credit hours at a blended rate credit...ie....they'll give you back 6.5 cents per kilowatt hour for off-peak hours that you would be paying 4-6 cents per so you still come out ahead.

[kazpilot25]

Gotcha. Thanks for the help.

[SoCalsolar]

KRenn ...

Your are talking to a solar knucklehead here I'm not following you. Standard production values?
Do these project consumption as well as production?
thx

[kazpilot25]

Anybody else have ideas on which system might be best?

[KRenn]

Your are talking to a solar knucklehead here I'm not following you. Standard production values?
Do these project consumption as well as production?
thx

Use PVWatts as your guide, after some time you will figure out what the actual output is in your area.

[KRenn]

Anybody else have ideas on which system might be best?

13kW would be a no-brainer for me personally. You're going to be saving substantial amounts of money and if you plan on adding a pool down the road, that will easily take you beyond 11kW territory.

[kazpilot25]

I think I'm leaning towards the 13kW system for the fact that even if I generate more than APS will buy back, I'll just use more. ha. I'll keep my house a bit cooler in the summer.

[KRenn]

Based on the pricing I think I know which company you're going through.

[kazpilot25]

Supposedly they're one of the topps in Arizona . Are they a good company? Good reputation? They have been very good thus far, but it's only the beginning.

[Ian S]

I want the system to offset 100% and then some, so we'll have additional to run a pool in the future. I figured since APS will buy it back, that should be ok. I've been quoted $97 for a 10Kw system, $110 for an 11.7kW system, and $127 for a 13.1kW system. They are all $0 money down, no escalators, and are all SunPower leases.

I appreciate any input as I have no idea how much we will use. If we go with the 13.1kW system, will that be too much that APS won't even buy it all back?

First of all, a simple calculation yields the following cost/month/kW: $9.69 for the 13.1 kW system, $9.40 for the 11.7kW system, and $9.70 for the 10 kW system. Oddly, that has the midsize system cheapest compared to the largest and smallest. In that respect, the midsize system is the most cost-effective. It also seems to me, that your biggest bang on the 7-noon plan comes from generating enough power to eliminate all your peak charges. After that the returns are diminished as you're only "earning" about $0.06 per kWh. Even if you later add a pool, it's probably possible to have most of the pool's energy draw in the non-peak hours. Also, do you have gas heat or heat pump? I have gas heat in a 2230 sq. ft. home in central Phoenix and used 19,000 kWh last year. However, this is an ca. 1969 block construction home all on one level with minimal insulation apart from a foam roof. It also has a large expanse of floor to ceiling single pane glass along with six slider doors. So pretty energy-inefficient. We also keep the temp about the same as you do. So I wonder if you really would use much more energy than ours.