TOU Rates/Tesla and Solar

TOU Rates/Tesla and Solar

I am looking at installing solar at my house in South OC and am trying to make sense of how the TOU rates and SDGE come into play. On a non EVTOU rate, it is pretty simple, but it becomes much more complicated now and no one seems able to give me a straight answer. I also must admit, my energy usage is pretty low in peak rates (350 KW/mo), off peak (1100 KW) and super off peak (1200kw). I am not sure solar gives me as much of an economic incentive now, and it is hard to justify the cost of a 6-7kW array.

Looking for any good feedback as well as I would take good referrals in the south OC area.



tashbrook | July 11, 2013

My email is above if you need more info. I live in SoCal and installed solar a couple of years ago. I delayed for a long time. Here is what made me do a 6.4kW array on the house:

I have a pool and a decent sized house.
Was constantly in Tier 5.
Cost of electricity annualized was about $330/month. So lower in the winter and peak summer could hit $650. (post install I run about $85 a month on average)
Read a study for the last 20 years in SoCal that housed that installed solar post builder received a premium about equal to 85% of the capital outlay if they sold the house. That took my ROI down from 7.4 years to under 2.

The company knocked on my door one day after I decided to pull the trigger. I looked at the kid and told him his day was about to be the easiest day he’s had in a long time. He gave me his speil and just told him to send someone to do the analysis and two hours later I was signing up. Now, the guy was very reputable. Configured the size of the system for the best ROI and not for his best sale. Lets just say I had all the analysis and detail in a spreadsheet so he knew I had some inkling of what I was talking about.

TOU made a huge difference as well as the solar. I generate at a higher rate and pull off at night at a lower rate. We did make some changes in the house. We don’t use major appliances until off-peak hours like the pool pumps and laundry unless we need to.

This was all prior to the Tesla. Still have not seen much extra usage but it’s been a pretty mild summer so far.

Have been very happy with the install process and system and would do it again in a heartbeat.

As a side note, if comfort is a concern I would get a whole house fan. We had one installed about 4 years ago. Man it can cool the house down in a matter of minutes at night. It probably saved me $100/month in the summer. I would highly recommend on for So Cal. They seem to be popular in the Midwest. Not sure why we don’t have more here in California.

ChrisPDX | July 11, 2013

I had the same question too with my provider (Portland General Electric). I have an PV system that provided 100% of my total electricity (the past year I only had to pay $10 per month in billing/account fees). However, my MS will about double my usage. According to PGE, it's similar to how it works now, except instead of a single in/out meter, I have 3 (logically, not physically). For each billing period, if I have surplus kWh credit during peak time (most likely as I'm producing the most and using the least), it goes to the next lower cost tier. Then if there's surplus for that tier, then I get credit for the lowest cost tier. Keep in mind the credit is simply kilowatt hours, not dollars from the higher rate tiers (at least with my provider).

For example, say I produced a net surplus 500kWh during the high period, used a net 320kWh during mid and used another 400kWh off peak, I would only pay for 220kWh at off-peak rates for that month.

Get a few quotes from different installers and see if they can calculate your net savings based on your current TOU rates and usage.

jasonsc | July 11, 2013

@tashbrook. Thanks for the info. I used to live in the midwest and was actually looking at whole house fans right now. They aren't real big and I used to live by them at night back in Missouri.

Who did you end up going with on solar?

sia | July 11, 2013

We live in San Diego county and installed an 8kW solar panel system in January, with enough excess production to support an EV. We got the Tesla 6 weeks ago and are now using all of our solar production: Driving on Sunshine!
I just signed up for SDG&E TOU-2 program, in case we use more than we produce; it certainly doesn’t hurt. | July 11, 2013

I live in NorCal and had SolarCity install a system that covers my Tier 2 and higher usage--still buy Tier 1 from SMUD. My daytime usage if pretty modest, unless the AC is running so most of the PV . SMUD also has a ToU plan for EV owners with a rate of $0.06/kWh.

The plan is to charge the MS off the solar during the day and flip over and charge of the TOU if I need to charge at night--say after a full day on the road. Basically, I will have my HPWC connected to a switch box that lets me switch between the solar and ToU feeds.


wolfpv | July 12, 2013

(nor-cal PG&E customer) I did a careful analysis AFTER I got the Tesla, and found that at my flat rate tier 3 electricity was costing the same as gas - approx $0.15/mile, all in. Quickly changed to E9a (EV) Time of Use rate, but realized solar was the answer. 6.5kW system was installed and running two weeks later (another story).

Because of the peculiarities of CA law and PUC rulings, you can sell electricity at ~ $0.30/kWh (daytime) and buy it back at ~$0.10/kWh (off-peak), so you don't even need to produce your full needs in order to drive your bill to zero. Incidentally, my roof faces E and W, and I had all panels installed on the W side, as the TofU rates (and therefore my electricity "selling price") are highest in the afternoon.

After fed rebate, my system cost $14K and returns about $3600/year in reduced electricity costs. Quite a bit better return than the $140/year or so it was making at the bank - not to mention making the car's environmental promise more of a reality.


Colasec | July 12, 2013

wolfpv, I want to hear this other story. How in the heck did you get a system installed and running in two weeks? Everything I've heard from every single company is 3-6 months!

And how did you get 6.5kW for $14K? I'm shopping right now and that's better by far than anything I've seen....

Feel free to email me at colasec.tesla -at- gmail if you don't want to share publicly. Any help/advice you could provide would be much appreciated.

simplesolarinc | July 12, 2013

Hi jasonsc, i am a tesla owner and install solar as well in oc. Email me at my username @ gmail,com and I can explain to you how how you works. You can generate most of the power in the peak time and offset up to 4x of the usage at super off peak rates.

Docrob | July 12, 2013
US solar systems, not including installation or Tax breaks. They have 11 systems between 6 and 7kw for prices ranging from $9,243 to $12,835. The 30% rebate will take ~$3,000 off that cost and Installation will add $3-4,000, $14,000 for 6.5K is in the ballpark. There are a lot of people who are significantly overcharging as people are used to high prices from only 2-3 years ago however module costs have fallen substantially since then so shop around. Also remember, if you choose to go with a Solar lease to avoid the upfront cost in the end those companies wouldn't offer the service if there wasn't a cut in it for them, if you can stomach the upfront cost and shop around it will ALWAYS be cheaper in the long run to buy yourself.

Brian H | July 12, 2013

Solar came up with the leasing option when it proved to be so hard to get people to do the financially rational thing with an upfront purchase.

keichhor | July 13, 2013

I have been looking all over for an installation for $3k! Can you drop any names? I had a 3.2KWH system installed just over 3 years ago, but I wanted to double my system.

I know the website you listed and another bluepacficsolar also sell the complete systems for great prices, but both of them suggested I install the system on my own. :( Not going to happen.