TOU for SCE in Southern California analysis

[rhedayi]

Alisobob
thanks for the charts. Let me ask a couple of questions to everyone....
say I stay in the current standard plan, say I use 12k power and generate 9k power.....the 3k excess I use will cost what ?? is it 3000/12 which is roughly 250 kw and I pay that as if it is a monthly thing , that is pretty cheap, 250kw of power would be like a $40 bill I guess......

considering TOUDT which is attached below, if I use a/c in the early afternoon I think my panels will make more energy than the a/c will use. A/c is only used when the baby is sleeping (typically) a/c is then used at night around 8pm......midnight etc....

tou.jpg

[Alisobob]

solar62.JPGsolar60.JPGsolar59.JPG

The RED bars are On Peak generation. ( Noon until 5pm.)

If you can Generate and not Consume during these hours... TOU-D-T could work for you.

[rhedayi]

Alisobob
this is the next thing I need to figure out with my new SP 5.2kw system, tou or not with SCE, your uploaded statement clips have me confused...here is my worse month in 2014 with the hourly usage ?? Is there a quick way to look and decide if TOU makes sense for a particular usage pattern ?

sep14.jpgsep16.jpg

[Alisobob]

Heres my first TOU-D-T statement, and how it all shook out. I also included 3 snapshots , Total use, Peak, and Off Peak.

Hope it sheds some light on how you can save money, combining solar generation, with TOU billing.

solar75.JPGsolar72.JPGsolar73.JPGsolar74.JPG

[SunEagle]

Energy conservation is FIRST here too, its been pursued & improved here for years. But
it is a game you can't win, because zero is never attained.

So then there is SECOND. Here that means find an energy source that eliminates
that frustration of never reaching zero, perhaps at a more comfortable level. With
solar, its a lot easier to build big first, than to try and find a way to expand later.

Another approach used here on many things, is try something small scale first, get
real world experience, then use that background to get a powerful solution.

Obviously these ideas will not appeal to all. Bruce Roe

When I get the chance to retire and move to my property in North Florida I will look into First lowering my electrical footprint and then take advantage of solar.

Right now its "stay the line" with a wife and mother in law that have slightly different ideas what energy conservation should involve.

[gvl]

Since you ask:

Right strategy ? - Who knows, opinions vary. Just one of many. Unwise : ?? Not a word I'd choose.

This being a free country the short answer is it depends on what you want and how you see your options.

If it was me, I'd do the most cost effective stuff first, if not done already, change the pool pumping schedule to only operate at super off peak times , and see what effect that has on the bill. Changing out a pump may not save that much more elec. vs. simply changing the # of hrs. the pump runs and when. Is it possible to only run it only at super off peak times ? Use your head first instead of your wallet if/when at all possible. That's called the smart money way. See what a schedule change does, and then get a new pump if you figure that will add to the savings over the current pump when both are operated only at super off peak, while at the same time paying for itself sooner than some other use reduction/bill reduction (solar) measure.

The 2 kW reduction in array size will reduce annual output by VERY ~ 3,000 kWh/yr, +/- some, and reduce array cost by ~~ $4,500 after tax credit. So, what's the marginal cost of the last 3,000 kWh of power you buy at say, 1/3,1/3,1/3, peak, off peak, super off, while keeping one corner of one eye on the best SWAG of what costs are likely to do in the future (as in who knows ? - but being too pessimistic can be as bad as too optimistic).

My current pump is very noisy, yes running it at super-off-peak would produce a big impact but I wouldn't want to run it at night for my own comfort and the comfort of my neighbors. Variable speed ones are quiet, so not only are they more efficient but you can also run them super-off-peak without annoying living things around you. I have LED lights everywhere and constantly fighting with my family to keep them off when not needed. Energy star washer/dryer/fridge. I suppose there is room for improvement in the attic by adding better insulation, etc. but the net effect is difficult to predict. I have an EV that I charge at night. My installer is willing to add 2kW to to the project for about $5k for the overall cost of about $3.1/W, so I would be getting it at $2.5 per watt before the tax credit, which is a good deal I suppose.

[J.P.M.]

Energy conservation is FIRST here too, its been pursued & improved here for years. But
it is a game you can't win, because zero is never attained.

So then there is SECOND. Here that means find an energy source that eliminates
that frustration of never reaching zero, perhaps at a more comfortable level. With
solar, its a lot easier to build big first, than to try and find a way to expand later.

Another approach used here on many things, is try something small scale first, get
real world experience, then use that background to get a powerful solution.

Obviously these ideas will not appeal to all. Bruce Roe

Hey Bruce: On getting to zero:

"Ah, but a man's reach should exceed his grasp, or what's a heaven for ?"

Robert Browning

[bcroe]

Good advice. Keep it simple. If you want to spend less on your electric
bill find ways to use less. Conservation first is my motto.

Energy conservation is FIRST here too, its been pursued & improved here for years. But
it is a game you can't win, because zero is never attained.

So then there is SECOND. Here that means find an energy source that eliminates
that frustration of never reaching zero, perhaps at a more comfortable level. With
solar, its a lot easier to build big first, than to try and find a way to expand later.

Another approach used here on many things, is try something small scale first, get
real world experience, then use that background to get a powerful solution.

Obviously these ideas will not appeal to all. Bruce Roe

[J.P.M.]

It is the right strategy I suppose. I'm currently facing a dilemma whether or not to do what you say or delay the payback period for a year or so and get a larger system that should give me more comfort and flexibility in the long run. About the only sensible approach to minimize my usage right now is to install a variable speed pool pump which will cost about $1000 after rebates, then a 8kW solar should be enough to 0-out or close my monthly bill under the current TOU rate schedule. Or I can install 10kW solar for $5k more before the tax credit and not worry about the pump for the moment with the same effect on my monthly bill. So the pump becomes a ballast I can throw out in the future should my solar install out become insufficient for whatever reason be it rate changes, degradation, or buying an EV. Would you say that getting a 10kW system is unwise in this situation?

Since you ask:

Right strategy ? - Who knows, opinions vary. Just one of many. Unwise : ?? Not a word I'd choose.

This being a free country the short answer is it depends on what you want and how you see your options.

If it was me, I'd do the most cost effective stuff first, if not done already, change the pool pumping schedule to only operate at super off peak times , and see what effect that has on the bill. Changing out a pump may not save that much more elec. vs. simply changing the # of hrs. the pump runs and when. Is it possible to only run it only at super off peak times ? Use your head first instead of your wallet if/when at all possible. That's called the smart money way. See what a schedule change does, and then get a new pump if you figure that will add to the savings over the current pump when both are operated only at super off peak, while at the same time paying for itself sooner than some other use reduction/bill reduction (solar) measure.

The 2 kW reduction in array size will reduce annual output by VERY ~ 3,000 kWh/yr, +/- some, and reduce array cost by ~~ $4,500 after tax credit. So, what's the marginal cost of the last 3,000 kWh of power you buy at say, 1/3,1/3,1/3, peak, off peak, super off, while keeping one corner of one eye on the best SWAG of what costs are likely to do in the future (as in who knows ? - but being too pessimistic can be as bad as too optimistic).

[SunEagle]

In the bigger scheme of things, the less electricity used, the less the bill. I'll put more effort into load reduction within the limits of a lifestyle that worrying about the future direction of POCO rates, using the logic I'll work on things I may have some measure of control over.

Since things will change in the future in ways that are unpredictable, and for me uncontrolable - as in $4.00/gal. 12 months ago to ~ $2.50/gal a few months back, to about $3.00/gal. now - T.O.U. rates may or may not be attractive in the future. Example: Someone may solve the energy storage situation in a scalable way for both residential up to district and utility considerations, perhaps making residential utility hookup an anachronism. I'm not betting the farm on that happening in my lifetime, but the lower the load (something I can do something about) the less POCO and rate payer shenanigans can affect me, and that's about as much future planning about where rates are going as I deem worthy of thinking about.

Thought about in a certain way, T.O.U. pricing MAY be best used in the planning stages of any residential solar project, both for system sizing and array orientation, but my guess is that will best work with a pretty hard load/use profile as f(time). It may be that an array can be oriented to best maximize revenue according to a current T.O.U. time schedule and rates, with the full knowledge that the time schedule and rate(s) used will change - that's life - so take your best shot. That sizing can then be matched to the expense side - what is used, how much and when after gerrymandered the load profile to minimize expense by attention to both how much and when power is used as seen fit. Basically, size and orient the system to match the expense of the electricity, after getting that expense as low as possible by managing when and how much electricity is used.

Good advice. Keep it simple. If you want to spend less on your electric bill find ways to use less. Conservation first is my motto.

[gvl]

... Basically, size and orient the system to match the expense of the electricity, after getting that expense as low as possible by managing when and how much electricity is used.

It is the right strategy I suppose. I'm currently facing a dilemma whether or not to do what you say or delay the payback period for a year or so and get a larger system that should give me more comfort and flexibility in the long run. About the only sensible approach to minimize my usage right now is to install a variable speed pool pump which will cost about $1000 after rebates, then a 8kW solar should be enough to 0-out or close my monthly bill under the current TOU rate schedule. Or I can install 10kW solar for $5k more before the tax credit and not worry about the pump for the moment with the same effect on my monthly bill. So the pump becomes a ballast I can throw out in the future should my solar install out become insufficient for whatever reason be it rate changes, degradation, or buying an EV. Would you say that getting a 10kW system is unwise in this situation?

[J.P.M.]

I'm basically thinking along the same lines and it makes me believe that sizing your solar system to the today's TOU realities is not the right approach and it may bite you back some time down the road as higher bills. Adding more panels may become more difficult in the future, amongst other things it will likely nullify your grandfathered net-metering agreement that guarantees the same price for usage/export.

In the bigger scheme of things, the less electricity used, the less the bill. I'll put more effort into load reduction within the limits of a lifestyle than worrying about the future direction of POCO rates, using the logic I'll work on things I may have some measure of control over.

Since things will change in the future in ways that are unpredictable, and for me uncontrolable - as in $4.00/gal. 12 months ago to ~ $2.50/gal a few months back, to about $3.00/gal. now - T.O.U. rates may or may not be attractive in the future. Example: Someone may solve the energy storage situation in a scalable way for both residential up to district and utility considerations, perhaps making residential utility hookup an anachronism. I'm not betting the farm on that happening in my lifetime, but the lower the load (something I can do something about) the less POCO and rate payer shenanigans can affect me, and that's about as much future planning about where rates are going as I deem worthy of thinking about.

Thought about in a certain way, T.O.U. pricing MAY be best used in the planning stages of any residential solar project, both for system sizing and array orientation, but my guess is that will best work with a pretty hard load/use profile as f(time). It may be that an array can be oriented to best maximize revenue according to a current T.O.U. time schedule and rates, with the full knowledge that the time schedule and rate(s) used will change - that's life - so take your best shot. That sizing can then be matched to the expense side - what is used, how much and when after gerrymandering the load profile to minimize expense by attention to both how much and when power is used as seen fit. Basically, size and orient the system to match the expense of the electricity, after getting that expense as low as possible by managing when and how much electricity is used.

[gvl]

Very likely, but probably not as a gesture of good will or humanitarianism. One big reason TOU rates exist is to help the POCOs manage peak loads. They often refer to time variant pricing such as T.O.U as a way of "sending rate signals" to the users to disincentivize/discourage using power at peak times such as weekdays, mid to late afternoon. Initially, the idea itself had little to do with solar production, and actually still doesn't.

T.O.U. plans will continue to change as they have in the past in response to changes in load patterns. It may be that in the future, POCOs will uncouple T.O.U. use pattern pricing from Solar time variant generation reimbursement. There's not much reasoning I can think of why they MUST be joined at the hip. Even now, peak solar generation and peak load are out of sync by a few hrs. in CA, and probably other sunny markets with peak load occurring about 2-3 hrs. later, which BTW is probably why peak T.O.U. hrs. for CA POCO's have been shifting later for the has couple/3 years or so - that change adding some backup to the belief that T.O.U. rate policies and purposes are mostly about load management.

I'm basically thinking along the same lines and it makes me believe that sizing your solar system to the today's TOU realities is not the right approach and it may bite you back some time down the road as higher bills. Adding more panels may become more difficult in the future, amongst other things it will likely nullify your grandfathered net-metering agreement that guarantees the same price for usage/export.

[J.P.M.]

Slightly OT, but considering the steadily growing solar install base I'd like to hear some opinions on how likely SCE is to change the TOU plans over time to minimize the cost gap between the on-peak and off-peak rates.

Very likely, but probably not as a gesture of good will or humanitarianism. One big reason TOU rates exist is to help the POCOs manage peak loads. They often refer to time variant pricing such as T.O.U as a way of "sending rate signals" to the users to disincentivize/discourage using power at peak times such as weekdays, mid to late afternoon. Initially, the idea itself had little to do with solar production, and actually still doesn't.

T.O.U. plans will continue to change as they have in the past in response to changes in load patterns. It may be that in the future, POCOs will uncouple T.O.U. use pattern pricing from Solar time variant generation reimbursement. There's not much reasoning I can think of why they MUST be joined at the hip. Even now, peak solar generation and peak load are out of sync by a few hrs. in CA, and probably other sunny markets with peak load occurring about 2-3 hrs. later, which BTW is probably why peak T.O.U. hrs. for CA POCO's have been shifting later for the has couple/3 years or so - that change adding some backup to the belief that T.O.U. rate policies and purposes are mostly about load management.

[gvl]

Slightly OT, but considering the steadily growing solar install base I'd like to hear some opinions on how likely SCE is to change the TOU plans over time to minimize the cost gap between the on-peak and off-peak rates.