Phoenix Tropicals Gardening

[phoenixtropicals]

I recently purchased a 4.6 kW solar system for my house and was wondering which SRP rate plan would be best. I'm fairly sure I have this figured out now, and it appears that the basic plan with SRP is much better for me than time of use.

Here is the reason:

Time of use allows SRP to group your electricity use into two buckets, onpeak and offpeak. In March of this year I produced way more electricity than I used, but had a bill of $30. I expected a bill more like $15 because that is their flat fee. I didn't expect the excess production to wipe out the flat fee because I am on net metering so they reimburse me for carry over once a year at the end of April. However, since all of my excess production was during offpeak, during the day, they still charged me for onpeak, when it was dark.

In other words, my production during the day does not carry over to the night because its in a different billing bucket. What is particularly bad about this is that my excess off peak production will keep rolling over every month until right before summer, and will be wiped out just before I need it the most. Even worse is the fact that when it is wiped out, they only pay me the wholesale rate, which is about half of what I am paying them for retail rate electricity.

So, to get the most out of your panels you want as much of your production as possible to be applied to the retail rate by reducing what you are billed for. Having two rate buckets gets in the way of that, especially during the winter.

Now, what about summer? Actually, during the summer having two rate buckets hurts you too. It gets light very early in the morning and the air is cool, so your panels will work well. Unfortunately, if you have two rate buckets, none of this morning production can roll over as credit into the afternoon. SRP wins again in that case.

One last question. Will the time of use rate differences potentially make a bigger difference than your solar panel production times? Answer, not likely. The rate differences are actually quite small, about 16%.

So, as far as I can tell, unless you do something that makes the time use plan really significant, like running your pool pump all night, the basic plan is much better.

[Little Luey]

I was thinking about getting solar panels for our home, but that is comming slow.

when I spoke to my provider, APS for me, they talked about buying back the energy I don't use as well. But being on a year round budget plan I don't have those variables you mentioned. I figure I could get some credit from them during the winter and use it up during summer. My thinking is that if we break even, I am good with it.

[jonpcar]

phoenixtropicals...informative post! I have been considering making the plunge into solar as well but the issue you described has been important to me and I haven't been able to find answers...until I saw your post.

I am wondering if you have changed your mind about a fixed-rate plan with the summer rates ? Your description of what happens during winter rates is pretty good. But, unlike summer rates, winter on peak/off peak rates are very close to one another.

The reason that I use the SRP time-of-use plan is the significant savings I get with the summer rates by shifting as much power use to cheap off-peak times. On-peak power costs almost 300% more than off peak rates. (~21 cents vs ~7 cents). The off-peak power rates are obviously very cheap and even much cheaper than fixed rate plans (unlike winter rates, the summer time-of-use off-peak rates are 30%+ cheaper than non-time-of-use rate plans).

I was hoping there would be a big advantage to solar in offsetting those summer peak time rates during the 1:00-8:00 pm slot (I know daylight doesn't last until 8:00, but perhaps until 5-6pm?). Every kw generated in that time period is 3x more valuable than those generated off peak. The result would be cheaper power off-peak (less than 7 cents a kwh due to time-of-use plan) and cheap power on-peak (offset by solar and reduced/minimal use during that period).

Have you given further thought/analysis on this to see if a fixed rate plan is best, even for the summer rates? Thanks

[phoenixtropicals]

The fixed rate is still working very well for me during the summer. My last bill was only $26 (including the $15 minimum fee), whereas usually this time of year I'm around $150. We keep the house at 78 degrees during the day and 77 at night.

Keep in mind that on peak is in the afternoon starting at 1 PM, which means that over half of your most productive solar power hours are already over. Also, the panels are more productive in the morning when the air is cooler. One more thing is that, in the summer, my panels produce very little after 5 PM because the sun swings so far north before setting.

[MKIVRYAN]

Nice panels! Here are mine.

http://i34.photobucket.com/albums/d146/evolust/stuff002.jpg

[phoenixtropicals]

Looking good!

[ManuelBryant]