TOU for APS in AZ

MikeSus

getting ready to get our system running and totally confused as to what plan makes sense for us. As most of our usage is off peak, does it make sense to switch off a TOU plan?

With thermal loading (precooling the house) during peak our 3200sqft McMansion idles at 800w as measured with effigy monitor.

solar_dave

Re: TOU for APS in AZ

Do you have solar? If so you might want to move some loads to on-peak and use the TOU plan.

MikeSus

Re: TOU for APS in AZ

solar_dave wrote: »

Do you have solar? If so you might want to move some loads to on-peak and use the TOU plan.

11.5kw

Currently we have reduced our peak by using the thermal mass method, are you suggesting stopping that? (precooling house and "coasting" during peak)

solar_dave

Re: TOU for APS in AZ

MikeSus wrote: »

11.5kw

Currently we have reduced our peak by using the thermal mass method, are you suggesting stopping that? (precooling house and "coasting" during peak)

I tried the solar mass method too, but could just not see any advantage when solar is in play.

Well if you can move some loads to the on-peak portion then your solar can cover those. I run my 12.5KW and still pay a fair amount for off peak this time of year(last 3 months have been over $100), mostly to cover night time AC usage, I still have excess on-peak built up from earlier in the year. I charge my Chevy Volts mostly with on-peak, and we run laundry mostly in the day time. We don't heat water with electric so that is not a contributor. We are on the old 9AM to 9PM TOU that is frozen and not available to you if you are just now changing over. The thing about TOU is the power you generate can only offset the consumption in that TOU period. SO day time generation will not help your night time consumption. Now with the noon to 7PM TOU you might do alright because your morning production would all be off peak, that would help the overnight consumption. The other option, just staying on the standard tier rate makes no distinction on time but does make a distinction on amount of consumption, I have heard from a couple of people that this can make sense. I have a bunch of consumption data from the last year of so, I just need to write a bit of Perl to make the needed calculation to determine that best options. With the new rates on EPR6 having anything leftover at year end is just counter productive. It used to be we could build up enough in the fall to cover all our bill until like April, but with less than a 3 cent a kWh credit for end of year excess, I don't see much of a credit in the works this year. Like I said in the other post a 57% reduction in $$$ credited.

Now with that being said you might want to just ride out your new system a month or 2 just to see what the bill looks like.

BTW we didn't pay any transmission costs until August this year, and that cost more than the generation. APS is trying to make it as difficult as they can now to get to near net zero.

MikeSus

Re: TOU for APS in AZ

Ah another Volt owner!

I ran the numbers using the tiered and it doesn't look like a very good option

I am thinking I will stick on the noon to seven, and stop the thermal mass. It appears that I save $$$ by doing so and not kWh using this method. With solar you really want to save the kWh.

With that low return on buyback, it really is looking like I will need to find a way to use peak tho, I think you are correct in that analysis.

Another thing I have been looking at is adding a whole house fan. By not having to run AC when its cool outside, that should help keep the kWh down.

solar_dave

Re: TOU for APS in AZ

MikeSus wrote: »

Ah another Volt owner!

Yep a pair of them.

If you can collect the data for both your consumption and your production by hour over time it starts to look pretty easy to determine your best course of action if you can get a years worth of data. The biggest problem in AZ is that the consumption swings are pretty large summer vs "winter". I know we consume about double our production in summer months.

Don't forget that if you go TOU you are stuck there for a year.

MikeSus

Re: TOU for APS in AZ

solar_dave wrote: »

Yep a pair of them.

If you can collect the data for both your consumption and your production by hour over time it starts to look pretty easy to determine your best course of action if you can get a years worth of data. The biggest problem in AZ is that the consumption swings are pretty large summer vs "winter". I know we consume about double our production in summer months.

Don't forget that if you go TOU you are stuck there for a year.

We have only been here for a few months, but in looking at the previous owners usage I can see they went from a low of about 1200kwh in Feb to a breathtaking 4400 in Aug. Using a pair of Nest thermostats and changing out pool pump, lights to cfl or led I was about to knock that down by about 800kwh per month.

My goal is to be at 90% or better of usage, and I *think* if I go whole house fan and maybe supplant the AC with swamp cooling for the months it will work, I could get a bit higher.

I calculated that the previous owner had to be getter 500-700 electric bills in the summer :-o

solar_dave

Re: TOU for APS in AZ

MikeSus wrote: »

We have only been here for a few months, but in looking at the previous owners usage I can see they went from a low of about 1200kwh in Feb to a breathtaking 4400 in Aug. Using a pair of Nest thermostats and changing out pool pump, lights to cfl or led I was about to knock that down by about 800kwh per month.

My goal is to be at 90% or better of usage, and I *think* if I go whole house fan and maybe supplant the AC with swamp cooling for the months it will work, I could get a bit higher.

I calculated that the previous owner had to be getter 500-700 electric bills in the summer :-o

2500 Sq ft house here
700 sq ft office/shop/man-cave with 3 ton mini-split AC unit.
2 Chevy Volts
20,000 gallon pool

June 3382 kWh consumed and 2031 kWh produced with solar. But we purchase 985 kWH off peak for a cost of $77, that was the last month we got out of MOST of our service delivery charge. The rest was on-peak bank that APS owed us back. In July the bill went up to $173. This month we are back down to $121. And next month I assume we will be back under $50. Still our annual bill pre-solar was like $5500 annually, and post solar ~ $500 annually. We have yet to buy any on-peak generation and still have 723 kWh in on-peak reserve that will never get consumed. I to am thinking about noon to 7PM plans.

Next year will be slightly more with the reduced buy back. We are pretty efficient with 17+ seer AC units and lots of insulation, a VFD pool pump, a mix of CFL and LED lighting. All the computers here are Mac mini's which draw really low watts on standby.

MikeSus

Re: TOU for APS in AZ

solar_dave wrote: »

2500 Sq ft house here
700 sq ft office/shop/man-cave with 3 ton mini-split AC unit.
2 Chevy Volts
20,000 gallon pool

June 3382 kWh consumed and 2031 kWh produced with solar. But we purchase 985 kWH off peak for a cost of $77, that was the last month we got out of MOST of our service delivery charge. The rest was on-peak bank that APS owed us back. In July the bill went up to $173. This month we are back down to $121. And next month I assume we will be back under $50. Still our annual bill pre-solar was like $5500 annually, and post solar ~ $500 annually. We have yet to buy any on-peak generation and still have 723 kWh in on-peak reserve that will never get consumed. I to am thinking about noon to 7PM plans.

Next year will be slightly more with the reduced buy back. We are pretty efficient with 17+ seer AC units and lots of insulation, a VFD pool pump, a mix of CFL and LED lighting. All the computers here are Mac mini's which draw really low watts on standby.

Did the Pool Pump too! Amazing watching the pump turn 750rpm using 98w!!

I don't have TED but I am using a Efirgy monitor to assist us in watching the peak loads. I think the hardest part for me will be not knowing our true baseline, but I at least have the previous owners to go off of. Between the Nests, cfl's, leds, and the pool pump, we are about 12% less usage than the previous owner.

What is your total system size to gen > 2000kWh?

From PVWatts I am looking closer to 1600kWh.

My plant has 39 LG 290w panels into 2 SunnyBoy Inverters (1 5000, 1 4000)

It would be nice to be closer to 2000kWh

solar_dave

Re: TOU for APS in AZ

MikeSus wrote: »

Did the Pool Pump too! Amazing watching the pump turn 750rpm using 98w!!

I don't have TED but I am using a Efirgy monitor to assist us in watching the peak loads. I think the hardest part for me will be not knowing our true baseline, but I at least have the previous owners to go off of. Between the Nests, cfl's, leds, and the pool pump, we are about 12% less usage than the previous owner.

What is your total system size to gen > 2000kWh?

From PVWatts I am looking closer to 1600kWh.

My plant has 39 LG 290w panels into 2 SunnyBoy Inverters (1 5000, 1 4000)

It would be nice to be closer to 2000kWh

Our peak months all over 2000 kWH this year were April, May, and June with May being the leader at 2148 kWh. The system is 12.5 Kw and described in my signature. I have been contemplating a 2.5-3.0 Kw addition since most of the low hanging fruit here have been hit in the conservation arena. But in reality the numbers don't play out well with the current rate tariff, if I did it it would be more because I can rather than strict financial results.

Ian S

Re: TOU for APS in AZ

solar_dave wrote: »

With the new rates on EPR6 having anything leftover at year end is just counter productive. It used to be we could build up enough in the fall to cover all our bill until like April, but with less than a 3 cent a kWh credit for end of year excess, I don't see much of a credit in the works this year. Like I said in the other post a 57% reduction in $$$ credited.

Wow, I'd missed that. Not a huge concern to me but just another way APS is chipping away at solar. I think if you are close to producing as much as you use, the standard rate plan is best. For me though, I only produce about 2/3 of what I use although if I replace my A/C unit next year, that percentage may go up.

This will be my first full year of solar and the benefit of banking peak credits early in the year has really paid off: I won't have paid for any peak usage all year. Still have paid quite a bit for off peak. $$ savings look like they'll wind up at $120/mo. That means my prepaid lease investment will be paid back in less than 5 years. Assuming of course, that APS doesn't figure out more ways to screw us!