SDG&E Introduces New EV Rate Sept. 1, 2011

The total rate page which Drees has cited is quite helpful because it gives you the historical charges so you can compare the new and the old rates quite easily.

The short story is that EV-TOU rates all went up a couple of cents. If you have solar you'll notice the increase less because your peak production will be paid out at a couple of cents more and you'll pay a couple of cents more for off-peak and super off-peak. On the basic DR rate the higher usage levels went up quite a bit, more like seven cents. That would be noticeable. The solar companies have reported record interest and you can see why -- customers now have more reason to use solar to get out of the highest usage bands.

FWIW I think SDG&E has a very favorable plan for solar given the peak period is noon to six. If you have a solar system that's about as good as you can get other than something like 11 AM - 6 PM. Moving the peak period back during the day would not be very helpful. If SDG&E did that I think I'd just add another kW of panels and move back to the DR plan.

SanDust said:

The total rate page which Drees has cited is quite helpful because it gives you the historical charges so you can compare the new and the old rates quite easily.

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It is quite useful - here's the link again since it's easy to miss: http://www.sdge.com/total-residential-electric-rates" onclick="window.open(this.href);return false;

SanDust said:

The short story is that EV-TOU rates all went up a couple of cents.

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Yep, pretty much 2c/kWh across the board for the EV-TOU rate. This actually reduces the spread between peak/off-peak as a percentage.

SanDust said:

If you have solar you'll notice the increase less because your peak production will be paid out at a couple of cents more and you'll pay a couple of cents more for off-peak and super off-peak.

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Yep, DR-SES (the solar TOU rate) is also up about 2c/kWh across the board.

SanDust said:

On the basic DR rate the higher usage levels went up quite a bit, more like seven cents. That would be noticeable. The solar companies have reported record interest and you can see why -- customers now have more reason to use solar to get out of the highest usage bands.

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Yeah, I didn't notice earlier that the baseline / tier-1 rates stayed the same, but tier-2 and tier-3 are each up about 7c/kWh. Solar which knocks off your top-tiers really becomes more cost effective now (which is ironic since SDG&E seems to be fighting distributed solar).

SanDust said:

FWIW I think SDG&E has a very favorable plan for solar given the peak period is noon to six. If you have a solar system that's about as good as you can get other than something like 11 AM - 6 PM. Moving the peak period back during the day would not be very helpful. If SDG&E did that I think I'd just add another kW of panels and move back to the DR plan.

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Yes, something I'm considering is moving from DR to DR-SES. I originally stayed on DR since it's very easy to predict what your bill will be. It's much more difficult to predict what your bill will be on a TOU plan. If I look at my net usage month from last year (January) my average electricity cost was about 17c/kWh - lower than the DR-SES rate. So the question would be - would I generate enough credits during the summer months to offset that? It almost seems like a no-brainer, but I still hesitate without running some actual calculations based on real data.

I really wish that the smartmeter data was easier to download/analyze. Ideally you'd download your import/export data over the last year in hourly increments and then simply plug it in to a calculator which tells you which rate plan gives you the lowest cost. But solar customers only recently got access to smart-meter data and the dumb "smart button" download is only in a lame XML format. Maybe I'll have to write a tool which takes that XML data and does the work for you and put it on a website for others to use.

drees said:

Yes, something I'm considering is moving from DR to DR-SES. I originally stayed on DR since it's very easy to predict what your bill will be. It's much more difficult to predict what your bill will be on a TOU plan.

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Why would you not use EV-TOU? That seems far more favorable than DR-SES.

SanDust said:

drees said:

Yes, something I'm considering is moving from DR to DR-SES. I originally stayed on DR since it's very easy to predict what your bill will be. It's much more difficult to predict what your bill will be on a TOU plan.

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Why would you not use EV-TOU? That seems far more favorable than DR-SES.

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Definitely a possibility:

DR Summer/Winter:
0.14764 / 0.14764 Baseline
0.17077 / 0.17077 101-130%
0.34590 / 0.32737 131-200%
0.36590 / 0.34737 200%+

DR-SES Summer/Winter:
0.19537 / 0.19720 Off-Peak
0.21246 / 0.20628 Semi-Peak
0.30078 / 0.20628 On-Peak

EV-TOU Summer/Winter:
0.16012 / 0.16225 Super Off-Peak
0.18556 / 0.18799 Off-Peak
0.29003 / 0.19534 On-Peak

On the surface EV-TOU appears better since in any period it's never more expensive than DR-SES. But the difference lies in the definition of the on/off peak periods:

DR-SES:
Summer On-Peak: 11am - 6pm weekdays excluding holidays
Summer Semi-Peak: 6am - 11am, 6pm - 10pm weekdays excluding holidays
Summer Off-Peak: 10pm - 6am weekdays and all hours weekdays/holidays
Winter Semi-Peak: 6am - 6pm weekdays excluding holidays
Winter Off-Peak: 6pm - 6am weekdays and all hours weekdays/holidays

EV-TOU:
On-Peak: 12pm - 8pm
Off-Peak: 5am - 12pm, 8pm - 12am
Super Off-Peak: 12am - 5 am

The EV-TOU rate has the disadvantage of running well after the sun goes down along with starting 1 hour later.
The DR-SES rate has either the advantage or disadvantage of no peak rates on weekends / holidays depending on how you look at it. If you are at home doing laundry, running AC it's a positive.

Anyway, the question ends up being whether you can generate more summer on-peak energy on DR-SES than you use off-peak to make up for the lower off-peak rates of the EV-TOU rates. I suspect it ends up being fairly close either way if you are also charging an EV. But since I have an EV meter, I can simply keep the EV on EV-TOU (since I don't use much electricity off-peak except for car charging) and then put the house on DR-SES.

My thinking has been that since your excess production is greatest during Peak, the greater spread between Peak and Super Off-Peak makes EV-TOU more appealing. However, since they've added a couple of cents to both Peak and Off-Peak so the spread is less and, as you've mentioned, having an extra hour in the morning helps since during that period you should be producing more than you're using. Because of the spread having Peak/Super Off-Peak on the weekends and holidays works for me.

If you have people home during the day or if you use a lot of power during the day then a TOU isn't a good choice.