CA drivers with solar

[ucmndd]

PGE EV-A TOU and a 7.5kw solar system works well for us. I drive a lot (35k/year) and charge exclusively during off-peak at night. Most months we break even or slightly over-produce during peak and part-peak times, then charge from the grid overnight at 12c/kwh.

During the really sunny months we overproduce during the day, sell the excess to PGE for 45 cents/kwh and buy it back at night for 12 cents/kwh.

 

[Foxtrotter]

The SCE website has a calculator that will take your own usage hour by hour for the last year and show you what the charges would have been for each of the rate plans. I found that with our 3.4kw system we had been paying on the tiered system about $600 more than we would have on TOU-D-A. It really makes a big difference to sell the electricity at the highest rate and buy it at the lowest. TOU-D-A also subsidizes the baseline consumption, around 300 kWh in our case, by $0.08 per kWh.

I highly recommend running the calculator in any case just to see how the plans compare. If you change to the TOU you can watch how its working day by day using the displays on the SCE site to see if its working for you. On the site you can watch each months monetary and Kwh balances as they develop and look at the consumption for each day hour by hour with the rates that are being applied.

 

[derkan]

I don't have solar but have suffered from SCE's plans quite a bit. After 2 years with my MX I finally paid $3k to get a dedicated EV Panel (and meter) installed, so that I could get the TOU-EV-1 rate for charging. Based on my math it pays for itself in 2 years. Plus I can't afford to go into the high-usage tier in my home bill. I don't like any of the TOU plans for my main power because I work from home and need A/C like other posters here.

 

[therealmrmike]

I have a S and 5.8kW solar but am on NEM 2.0 we are on tou-d-a. Our PV is South facing and we also replaced all our windows with dual glazed. It works out great we end up using 100kw a month avg. but we only charge super off peak @.12-.13 or bill for the month is -650 @ month 11

 

[dethman]

called SCE to switch from tiered to TOU-D-A and they recommended TOU-D-B as they thought my usage would be too high. i have a 5kw PV system and am net neutral before the EV, using about 600-650kwh per month that the solar essentially covers. i'm not sure if they count how the peak rates would be credited on the PV system.

trying to figure out the difference between the two, not sure about this credit vs daily charge thing.

any thoughts on TOU-D-A vs TOU-D-B on edison?

 

[Mokuzai]

Been trying to figure this out myself so I created a spreadsheet to analyze the hourly data from the SCE site. If you enter your hourly data into the spreadsheet it'll tell you what rate is best for that day. The formulas can be copied down for additional rows, for the hourly data I download spreadsheets from the old hourly usage page (they changed this recently so it's a bit harder to find now) then transpose the values only to retain the highlighting. It looks at the date and figures out if it's weekday vs weekend and summer vs winter to pull the appropriate rate from the Rates tab.

This is assuming that the credits are the same rate as the charges. This also doesn't consider any baseline credits and doesn't consider going up in tiers. According to this I should be going with D-A with the solar production hitting the higher rate times.

SCE Rate Compare.xlsx

 

[Foxtrotter]

The credits are the same rates as the charges so you can sell it to them at the max rates and buy it at night at the lowest rates. The baseline adds to the benefits.

For example,
June 2017 we produced 150 kWh more (one partially electric car, volt) than we used and the credit was $36.
This June we consumed 380 kWh (with two electric cars) more than we used and the credit was $41.

TOU D A is crazily beneficial if you don't have much daytime consumption and lots of 10pm to 8AM along with your solar.
To save a few more bucks we even run the laundry machines and the dishwasher at night.

The day rates are lower in winter and that is where our big non-auto consumption is for the heat pump. But even that is predominantly night consumption so I'm hopeful it will work out better than hitting the high usage tier in two or three months.

 

[dethman]

Been trying to figure this out myself so I created a spreadsheet to analyze the hourly data from the SCE site. If you enter your hourly data into the spreadsheet it'll tell you what rate is best for that day. The formulas can be copied down for additional rows, for the hourly data I download spreadsheets from the old hourly usage page (they changed this recently so it's a bit harder to find now) then transpose the values only to retain the highlighting. It looks at the date and figures out if it's weekday vs weekend and summer vs winter to pull the appropriate rate from the Rates tab.

This is assuming that the credits are the same rate as the charges. This also doesn't consider any baseline credits and doesn't consider going up in tiers. According to this I should be going with D-A with the solar production hitting the higher rate times.

SCE Rate Compare.xlsx

Wow that is hardcore! Looks awesome ill try plugging stuff in when i get home.

Re: the sce site changing, i used to see the positive/negative energy flow during the day when i was producing but dont see it on daily usage any more on the new site. Annoying.

 

[Mokuzai]

Ya I'm not a fan of the new site. To get to the old downloadable graph I click on something to get to the old interface like "Device Management" then you can access the "My Account" tab which has the "View Recent Usage" button to the old graph.

 

[dethman]

Ya I'm not a fan of the new site. To get to the old downloadable graph I click on something to get to the old interface like "Device Management" then you can access the "My Account" tab which has the "View Recent Usage" button to the old graph.

hot damn you rock. thanks.

 

[Mokuzai]

Switched over to TOU-D-A and so far looks like my little spreadsheet is pretty close.

 

[dethman]

Switched over to TOU-D-A and so far looks like my little spreadsheet is pretty close.

View attachment 313140

that's a pretty awesome spreadsheet! punching in my numbers now. in the charges column, for example 'tiered' and 'tou-d-a' columns, what does the red and green mean?

for example in tiered -5.25 is red, but in TOU-D-A -5.43 is green.

 

[Mokuzai]

It's a gradient from most expensive to cheapest on a per day basis. That's a pretty small range but the max expensive will be the most red and the max cheapest will be the most green.

For the hourly data, it's the same thing but it looks at the whole set across all days.

 

[Mokuzai]

So on July 6th a heat wave started. Interesting to see how things shifted on higher usage.

 

[dethman]

So on July 6th a heat wave started. Interesting to see how things shifted on higher usage.

View attachment 319032

Those late evening peak rates are killer.

 

[Need]

So we finally decided to go Solar after we ordered a 2nd Tesla. The solar company guy kept raving about how great TOU-D-T is as it shifted the peak hours 2 hours early so the panels could generated more $. But I remember this thread where everyone is doing TOU-D-A because of the low Super Off Peak rate when charging the cars. So I created a spreadsheet to show him that for EV peeps, we are better off with TOU-D-A. As you can see, with TOU-D-T, I will need 56 panels (16.8kW system) which is what he recommended. But with TOU-D-A, I only needed 40 panels (12kW system). That's a saving of almost $15K!

 

[golfpilot]

I have a small solar system on my current house. With the special PGE pricing my average cost per KWh is .20 (concord,ca). Just bought a new house in the valley, the electric company there has charges based on usage only. .14 a KW is the highest tier, most expenisve it gets. At that price I don't think it makes sense to add solar...

 

[miimura]

I have a small solar system on my current house. With the special PGE pricing my average cost per KWh is .20 (concord,ca). Just bought a new house in the valley, the electric company there has charges based on usage only. .14 a KW is the highest tier, most expenisve it gets. At that price I don't think it makes sense to add solar...

What is the utility at the new place? If I could get unlimited kWh for less than $0.15/kWh all-in, I would not have bothered with solar or Powerwalls.

 

[golfpilot]

What is the utility at the new place? If I could get unlimited kWh for less than $0.15/kWh all-in, I would not have bothered with solar or Powerwalls.

Turlock Irrigation... Schedule de 2015 . Prices haven't changed, this is what is posted on website. Benefit of living where nobody else wants to live I guess

 

[brucet999]

what rate plan do you use?

I'll be getting my MX soon, looking for the most efficient plan. Currently i'm with southern california edison, have a 5kW PV system and am on NEM 1.0. My electricity bill for the last 12 months was $35 for the year (plus the mandatory $10/mo connection fee.)

Will prob drive 15000 miles/yr, so that's probably an additional 400-500 kWh per month charging.

Was looking at time of use rates so i could charge cheaper at night, but for these the daytime rates seem kind of exorbitant. currently i pay or get credited 16 cents/kwh for tier 1 across the board whether day or night. The TOU EV-1 plan is 13 cents at night but 37cents/kwh during the day! seems high. not even sure if i can do TOU with NEM 1.0.

anyway just wanted input as to what other tesla owners with solar do. thanks.

Call SCE customer service and request a comparative cost. I was on tiered rates but when I bought the Tesla, I enquired about how TOU would affect me. They can take a few representative weeks in the past year and compare what you would have paid under TOU vs your existing tiered rates plan. I chose an August week, a March week and a December week (highest usage, due to Christmas lights, etc.) and the result was that annually, I would have paid $25 less under TOU.

TOU-D-A is best for PV and for EV charging. You are paid for your PV production on the basis of the rate in effect at the time of delivery onto the Grid, so you get paid at $0.48/kWh for late afternoon production (assuming you have west-facing panels that are producing then) but pay only $0.12/kWh for your super off peak charging between 10pm and 8am. I calculated that off-setting only 70% of kWh usage would nevertheless result in a fiscal overage in our favor (which you don't get back at end of period, BTW) but opted for a calculated 95% off-set for environmental reasons and as insurance against future rate changes or increased usage.