TOU for SCE in Southern California analysis

[J.P.M.]

Perhaps the solution could be 2 set points for the thermostat. Set the desired temp
high for the time you want it to run, and drop it 10 degrees when you don't. That will
provide "hot water" at all times; perhaps you'll need to turn up the HOT knob some if
all the prime time heated water is used up. And give a hint you're past "optimum time".
Bruce Roe

I'm sure there are a number of ways to handle the situation. While what you suggest is certainly logical and possible, given the current arrangement(s) and rather primitive controls in common use for DHW applications, I doubt if the added expense and complication with the attendant likelihood of increased maint. or other problems make it likely.

Most current thermostats for DHW applications are cheap and not very precise. However, they have the advantage of low cost, simplicity and because of the simplicity, some measure of reliability.

Before declaring something a problem, an understanding of what's happening (inside the tank for one example) and why may be helpful to see if a solution or a better mousetrap is needed.

Evolution has made DHW systems quite reliable and mostly stupid proof.

Current water heating tech. in the U.S. evolved when the cost of the energy was cheap - cheaper than more insulation or use reduction. Them days are gone and probably ain't coming back.

[bcroe]

Point is, when the thermostat calls for heat is usually not well understood, thought of, controlled, or very predictable. Couple that with the fact that common water heater thermostats are not very precise ( my experience after playing around with a few is that if they claim a deadband range of 5 deg. F., that's more likely something like 5 deg. F., -2/+5 deg. for a tolerance.

One solution to this is to put the water heater on a timer. That can cause some problems if the consequences are not understood, but in the case of storage of electrically heated H2O, it will control when power is used.delet will help

Perhaps the solution could be 2 set points for the thermostat. Set the desired temp
high for the time you want it to run, and drop it 10 degrees when you don't. That will
provide "hot water" at all times; perhaps you'll need to turn up the HOT knob some if
all the prime time heated water is used up. And give a hint you're past "optimum time".
Bruce Roe

[J.P.M.]

Probably should just let this thread die, but I had a TOU epiphany tonight. My chosen TOU plan costs me:
$0.11/kWh during "super-off peak" from 10pm to 8am
$0.30/kWh during regular "off peak" from both 8pm to 10pm and 8am to 2pm
$0.46/kWh for "peak" from 2pm to 8pm

Tonight the dishwasher was not full, there was enough room for breakfast dishes. My standard procedure would have been to conserve energy and water and not prematurely run the dishwasher until after breakfast the next day. BUT, now that I'm thinking of TOU costing, my tendency is to run the dishwasher at night when energy is cheapest. Mathematically, it's a no-brainer to run the dishwasher tonight at partial load, because I can afford to run the dishwasher FOUR times from 10pm until 8am for LESS than one time time during peak hours. It's almost 3 times vs regular off peak. Wow, it's great for me financially, but it encourages me to be more wasteful. Obviously, I'm not considering the extra cost of water, but still. Wow.

Good heads' up thinking. However, if you heat your water with electricity and have a standard set up w/storage tank, depending on things like tank temp. other H2O draws, etc. the tank thermostat may call for heat (power) at times different than the appliance draw. Depending on use/draw pattern, there is a lag between when the draw takes place and when the thermostat comes on. Sometimes minutes, sometimes much longer, maybe hours.

VERY approximately, between standby tank and piping losses, a tank might lose between .3 to 1.0 deg. F./hr., say .5 deg. F. If the thermostat has, say, a 5 deg. F. "float" or "deadband", several hours may elapse between calls for heat.

For example (only), if the (say 80 gal. ?) tank temp. is say, 140 F. and the dishwasher use reduces the H2O temp. so that the thermostat "thinks" the (local- around the thermostat) temp. drops to say, 136 F., the thermostat may not call for heat. However, the tank losses to the ambient will continue through the night. At some point, maybe before or maybe after 0500 hrs. when semi peak rates come on. Or, it might be that the 2 deg. F. decrease from the dishes will cause the tank to get to the thermostat "on" point sooner (before 0500 hrs.).

Point is, when the thermostat calls for heat is usually not well understood, thought of, controlled, or very predictable. Couple that with the fact that common water heater thermostats are not very precise ( my experience after playing around with a few is that if they claim a deadband range of 5 deg. F., that's more likely something like 5 deg. F., -2/+5 deg. for a tolerance.

One solution to this is to put the water heater on a timer. That can cause some problems if the consequences are not understood, but in the case of storage of electrically heated H2O, it will control when power is used.delet will help

[silversaver]

Thats the beauty of TOU if the plan works for you. You might be at net 0 kWh, but you get credit on your account.

Green botton download 2014 net usage after solar from SCE, looks like TOU-D-A is a winner.

[insaneoctane]

Probably should just let this thread die, but I had a TOU epiphany tonight. My chosen TOU plan costs me:
$0.11/kWh during "super-off peak" from 10pm to 8am
$0.30/kWh during regular "off peak" from both 8pm to 10pm and 8am to 2pm
$0.46/kWh for "peak" from 2pm to 8pm

Tonight the dishwasher was not full, there was enough room for breakfast dishes. My standard procedure would have been to conserve energy and water and not prematurely run the dishwasher until after breakfast the next day. BUT, now that I'm thinking of TOU costing, my tendency is to run the dishwasher at night when energy is cheapest. Mathematically, it's a no-brainer to run the dishwasher tonight at partial load, because I can afford to run the dishwasher FOUR times from 10pm until 8am for LESS than one time time during peak hours. It's almost 3 times vs regular off peak. Wow, it's great for me financially, but it encourages me to be more wasteful. Obviously, I'm not considering the extra cost of water, but still. Wow.

[silversaver]

Here is good example of allocation 10 cents credit/debit:



Residential Time-of-Use (TOU-D) NEM Customer FAQs
How is the Baseline Credit included in TOU-D, Option A applied to a customer’s bill?
TOU-D, Option A includes a Baseline Credit, which is applicable to up to 100 percent of a customer’s standard Baseline Allocation, as found in Preliminary Statement, Part H. (Click here for further information: https://www.sce.com/NR/sc3/tm2/pdf/ce07-12.pdf) This results in a lower energy charge for Baseline usage.
Net Consumer of Electricity
When you are a net consumer for the month (i.e., you consume more electricity from SCE than you export to the grid), a portion of your energy charges will be lowered through the baseline credit applied monthly on a $per kWh basis. For example:
• If a customer has a Baseline Allocation of 500 kWh/month and their net kWh (consumption from SCE minus exported generation) for the month is 750 kWh, the customer will receive 10 cents per kWh credit up to the 500 kWh Baseline amount, equal to a $50 credit.
• If a customer has a Baseline Allocation of 500 kWh/month and their net kWh for the month is 250 kWh, the customer will receive 10 cents per kWh credit up to the net 250 kWh, equal to a $25 credit.
Net Generator of Electricity
When you are a net generator for the month (i.e., you export more electricity than you consume from SCE that month), the Baseline Credit will appear as a monthly charge since you are multiplying a negative kWh amount by a negative billing factor. This is necessary to ensure that you receive the same rate for the exported kWh that you would have received if you had consumed that same kWh from SCE.
For example, if a customer has a Baseline Allocation of 500 kWh/month, and their net kWh for the month is -100 kWh (exported generation is greater than consumption from SCE), the customer’s bill will reflect a 10 cents per kWh charge up to the net -100 kWh of generation, which results in a $10 charge.
Note: The Baseline Allocation varies by Baseline Region. You can learn your specific region and allocation by calling us at 1-800-655-4555 and asking an SCE representative.

How does the TOU-D rate On-Peak hours impact my bill?
If you generate excess electricity (i.e., export more electricity than you consume from SCE) during the hours of 2 PM to 8 PM, your NEM credits will be calculated using the TOU-D on-peak rate for the applicable season, meaning that the kWh exported between these hours will receive the highest credit amount.
If you do not generate enough electricity to offset your on-site load during the hours of 2 PM to 8 PM, it is important to try to shift as much of your electric load (e.g., PEV charging, clothes and dish washing or pool pump operation) as you can to Off-Peak and Super Off-Peak hours to reduce your electric costs since kWh consumed in the On-Peak hours are charged at a higher rate than kWh consumed in the Off-Peak and Super Off-Peak hours
What is the Basic Charge on both Options A and B of Schedule TOU-D and why are they different?
The Basic Charge is a mechanism approved by the California Public Utilities
Commission’s (CPUC) that allows SCE to recover some of the costs associated with ensuring the grid can provide safe and reliable power to all customers. This charge ensures that all SCE residential customers, regardless of their monthly use, contribute toward the recovery of these costs.
• Customers choosing Option A are generally lower usage customers who will pay a basic charge corresponding to the customer charge in place for customers taking service on Schedule D.
• Customers choosing Option B are generally higher usage customers who will pay a higher basic charge but lower energy charges (cents/kWh).

[silversaver]

I would not say which plan is better than others, choose whatever is best for you.

[insaneoctane]

I'm not sure how much more you guys care about this thread anymore, but I've sort of committed to myself to complete a few more hooks in the spreadsheet to make it more general and manipulate-able. So, I'm making it easy to scale both usage and production based off a matrix of 0-23 (hours) by 1-12 (months). This helps have enough control to do some high level what-if analysis. Anyway, I just looked at my newly selected TOU-D-A plan vs generation and it's quite sensitive. For my baseline usage, I have to generate at least 8,000 kWh/year to break even and at least 6,500 kWh/year to beat RATE-D. Without knowing my systems output, it's interesting; we'll see where I end up. Anyway here's that graph for those interested.

I figured the scaling array would make it easy to adjust for the light months I had in July and November because I wasn't home. I can scale those months up if I didn't think that was normal.

tou-graph_gen_2015.03.15.JPG

[insaneoctane]

You can see my consumption data here... the PV production data will be added soon.

I'm impressed with how low you have your always on/baseline rate. I can't seem to get there with 2 refrigerators, 2 DVRs (24/7), my Dell i3 server (24/7), and all my network equipment (24/7). There is probably more work for me to do against my always on usage, but likely with some compromise. I also have a family of 5. Anyway, good job.

...the PV production data will be added soon.

What will provide this data?

[J.P.M.]

I installed the TED5000 once I decided to go solar, but prior to solar installation because I was unsatisfied with only knowing my net usage. While it's true my PUCO can supply me hourly data, net usage would have me running outside to my inverter to figure actual consumption vs generation. Not to mention trying to do any analysis afterwards, when I couldn't see what the inverter output *was*. Anyway I really love my TED5000 data. I admit I am a data head, so although I feel totally justified in considering it a need for me, others might think differently. If my PUCO could have differentiated between consumption, generation, and net I might have thought of doing without.

I originally considered micro inverters almost solely for the data gateway options. I feel this valuable forum offered more level headed advice. The TED5000 was my compromise and I feel a great one at that!

The (IMO) wise observation about having 2 watches as thus not knowing what time it is notwithstanding, how about both, Eagle and Ted ?

[insaneoctane]

I installed the TED5000 once I decided to go solar, but prior to solar installation because I was unsatisfied with only knowing my net usage. While it's true my PUCO can supply me hourly data, net usage would have me running outside to my inverter to figure actual consumption vs generation. Not to mention trying to do any analysis afterwards, when I couldn't see what the inverter output *was*. Anyway I really love my TED5000 data. I admit I am a data head, so although I feel totally justified in considering it a need for me, others might think differently. If my PUCO could have differentiated between consumption, generation, and net I might have thought of doing without.

I originally considered micro inverters almost solely for the data gateway options. I feel this valuable forum offered more level headed advice. The TED5000 was my compromise and I feel a great one at that!

[bcroe]

The Kill-A-Watt is great for matching usage patterns in the chart to actual devices and appliances, when disaggregation from chart patterns alone is difficult. It is not possible to access the power supply for every electricity consuming device, so there are some questions the Kill-A-Watt alone can't answer.

5 minutes is fast enough to detect short loads (like the microwave), and whether I collect at 5 min or 60 min the cost to me is the same.

As J.P.M. suggests, the more data I can collect, the more understanding I will have of how TOU pricing might affect me. Based on what the utilities are saying, sometime in the next few years, I think TOU pricing will become much more common, and I want to be prepared for it.

I find that by looking at the chart, it helps build a connection between my lifestyle choices and the energy it takes to support them. Whether that results in changes or not is too soon to say, but I like the feeling of being a conscious consumer of energy. I suspect that changes will creep in as a result of that awareness, whether I intend to make them or not.

Yes I keep forgetting about that T.O.U. billing on the left coast. I was able to access
any 120VAC device, including wired in devices like motion detectors and GFI
outlets. I installed a special outlet on the main box for the Kill-A-Watt and fed each
circuit through it. For the 240VAC range I used a regular revenue (disc) meter.

Awareness and understanding are the first step. The first thing I noticed was how
much was just waste, and how much improvement could be made without any
lifestyle change. The microwave oven used more KWH a year in standby than in
operation; now modified the standby is zero. And so on. Bruce Roe

[sensij]

The Kill-A-Watt is great for matching usage patterns in the chart to actual devices and appliances, when disaggregation from chart patterns alone is difficult. It is not possible to access the power supply for every electricity consuming device, so there are some questions the Kill-A-Watt alone can't answer.

5 minutes is fast enough to detect short loads (like the microwave), and whether I collect at 5 min or 60 min the cost to me is the same.

As J.P.M. suggests, the more data I can collect, the more understanding I will have of how TOU pricing might affect me. Based on what the utilities are saying, sometime in the next few years, I think TOU pricing will become much more common, and I want to be prepared for it.

I find that by looking at the chart, it helps build a connection between my lifestyle choices and the energy it takes to support them. Whether that results in changes or not is too soon to say, but I like the feeling of being a conscious consumer of energy. I suspect that changes will creep in as a result of that awareness, whether I intend to make them or not.

[J.P.M.]

That Kill-A-Watt can help you figure exactly where and how much energy you are using. With
that knowledge what will you change? How will the 5 minute monitoring help? Bruce Roe

It can be a big help in the quest to get a representative pattern of usage as f(time). That can be very helpful in determining whether T.O.U. billing may be beneficial to a user.

[bcroe]

The Eagle device (~$100), made by Rainforest Automation, talks directly to a smart meter and makes your usage data available for logging... either directly into csv, or uploading to the cloud. No calibration problems since it is getting data from the meter itself. It is compatible with most SDG&E, SCE, and PG&E meters. I transfer my data to PVOutput.org at 5 minute intervals, although it is capable of reporting much faster. You can see my consumption data here... the PV production data will be added soon. Click a date to see the detail... the defauly view is intended for production data, which I don't have yet.

It is pretty easy to see by looking at the chart when the fridges, heater and other cyclic loads come on. Loads like the microwave, electric oven, and humidifier are also easy to spot. I've started using a Kill-A-Watt to mapping out my baseline usage, usually around 170 W, or over 200 when the fountain is running, and have accounted for around 100 W of it so far.

That Kill-A-Watt can help you figure exactly where and how much energy you are using. With
that knowledge what will you change? How will the 5 minute monitoring help? Bruce Roe