Why even have batteries?

[bevo]

I don't understand that this statement. I have 3 powerwalls and an 8.16 KW system. I'm on EV2-A. Are you saying I would be better off on a different rate? If so, which one?

The comment is for SCE customers. I don't know enough about PGE plans

 

[MJ_CA_2019]

The comment is for SCE customers. I don't know enough about PGE plans

It still applies to all TOU rate plans. As long as you have enough ESS to never draw at peak rates (and it’s during some solar production so you can export), the higher that rate is, the better for you.

 

[h2ofun]

If you are discussing generators or battery backups then you have to separate convenience vs cost. This isn't a which stock/bond/CD will give me the best rate of return. A major reason a lot of people buy either or both is for backup which can be suffered through (cheapest option) or managed. The other major reason is for TOU arbitrage. That varies depending on where you live and your provider. We purchased for backup. When compared to a generator our 3 walls were roughly $4k cheaper ($12,500 vs $8600). Plus we don't have to spend $ each year maintaining. So far since install in December we have backed up 5 times. They were all minor and we would have certainly just pulled out the candles and been fine if we didn't have batteries. But we didn't have to because we had spent money on them. I'm on a Mercedes forum quite a bit- S class in particular. Every once in a while someone comes on trying to justify the cost. Of course luxury is not something you put to a value proposition. It's like so many things in life- you look at the scale and decide where on the scale you wish to be. Are you buying shoulder, porterhouse, ribeye, filet in choice, prime or waygu? You could buy chicken on sale and save a ton instead. It's one of the hardest conversations to get through my clients heads besides keeping a level head through headwinds (I'm a financial advisor). Deciding where on the scale various purchases and decisions should be...

i have had my whole house generator for a year as and has cost me zero to maintain. main driver to install is i had access to all interior walls to hide wiring and since putting same time as solar the wiring was all done correctly the first time. i did not care about cost since doing it later would have been basically impossible. when the sgip opportunity came along could not pass up. but i sized things so i could try to add more solar with no hw changes. for me spending this money is my fun while others get there fun getting an ev. it sure is fun showing this stuff to folks. they are blown away and say they have never seen a house like mine
worth every penny.

 

[fragchild]

Hurricanes. I've gone 10 days without power. Getting gasoline is almost impossible and it uses 5 gallons per 12 hours to run a window shaker, fridge, and fans. And as with most hurricanes, once they come through it is sunny for days so I can't imagine being without power with perfectly good panels on my roof that I can't use becasue I don't have a PW.

 

[cali8484]

If you are discussing generators or battery backups then you have to separate convenience vs cost. This isn't a which stock/bond/CD will give me the best rate of return. A major reason a lot of people buy either or both is for backup which can be suffered through (cheapest option) or managed. The other major reason is for TOU arbitrage. That varies depending on where you live and your provider. We purchased for backup. When compared to a generator our 3 walls were roughly $4k cheaper ($12,500 vs $8600). Plus we don't have to spend $ each year maintaining. So far since install in December we have backed up 5 times. They were all minor and we would have certainly just pulled out the candles and been fine if we didn't have batteries. But we didn't have to because we had spent money on them. I'm on a Mercedes forum quite a bit- S class in particular. Every once in a while someone comes on trying to justify the cost. Of course luxury is not something you put to a value proposition. It's like so many things in life- you look at the scale and decide where on the scale you wish to be. Are you buying shoulder, porterhouse, ribeye, filet in choice, prime or waygu? You could buy chicken on sale and save a ton instead. It's one of the hardest conversations to get through my clients heads besides keeping a level head through headwinds (I'm a financial advisor). Deciding where on the scale various purchases and decisions should be...

Except I don't think people get government subsidies for S class or Wagyu.

 

[Laketime]

i have had my whole house generator for a year as and has cost me zero to maintain.

You have fuel costs and oil change etc. even if you do it yourself. If you pay a service you pay more (most would pay a service). Few people work or think about their "power supply" a few hours a day like you. It's cool if you are into it, but for many people it's not. I build my own housing, woodwork and furniture, I even mill the lumber sometimes. A lot of people think I'm crazy for putting that time in. But I'd never question their reasoning for hitting the box store for a new bedroom set. We all draw a line where we pay for things or how far down the "luxury" line we go...

Except I don't think people get government subsidies for S class or Wagyu.

Expense accounts pay for much more than they should. But the argument still stands, this is a luxury for most...

 

[jboy210]

Hurricanes. I've gone 10 days without power. Getting gasoline is almost impossible and it uses 5 gallons per 12 hours to run a window shaker, fridge, and fans. And as with most hurricanes, once they come through it is sunny for days so I can't imagine being without power with perfectly good panels on my roof that I can't use becasue I don't have a PW.

A friend of mine bought 3 powerwalls after staring at his 16kW of solar panels bathed in sun producing 0 power. He was pissed at eating cold food, while his freezers thawed for 2 sunny days during a power outage.

 

[Puma2020]

While we do get the occasional hurricanes, blizzards and ice storms are more of an issue up here in the north. Went through one ice storm many years ago where it took down over 3,000 HV transmission lines in Quebec. The favorite wedding present after that was a generator for the house.
The ROI for a battery system is NOT just the cost. The OP is correct that the ROI will never be reached, unless you count the generator costs and the fuel/maint costs and the other issues of not having grid power. With a solar system, the battery system becomes useful if you have any significant outages. Doesn't even have to be a major storm. A car slipping on an icy road and takes out a power pole and line, can leave you in the cold for several hours or even days depending where it occurred.

 

[skepticcyclist]

I also have many gas appliances for heat and sounds like we have same SCE rate choices ... I was orig in Prime TOU due to no pv /no pw and charging a model 3 at super off peak or off peak (rate was same??) anyway with pv/pw ...I recently switched to TOU 4-9 since it appears I may be a NET producer for the year and as such tou 4-9 has slightly lower base charges than prime ?? ..not 100% sure on this though haha

Prime has the lowest off peak rates of all the plans.
Winter $0.16
Summer $0.17

TOU 4-9 off peak rates are:
Winter $0.26
Summer $0.27

Link

 

[skepticcyclist]

I also have many gas appliances for heat and sounds like we have same SCE rate choices ... I was orig in Prime TOU due to no pv /no pw and charging a model 3 at super off peak or off peak (rate was same??) anyway with pv/pw ...I recently switched to TOU 4-9 since it appears I may be a NET producer for the year and as such tou 4-9 has slightly lower base charges than prime ?? ..not 100% sure on this though haha

Baseline credit is a usage allowance. It is an allowance they give you at a fix rate up to a certain determine kWh usage. They currently give you $0.07/kWh towards your use in the TOU 4-9. But there is a $0.10 difference in rates between the TOU 4-9 and Prime. So would still pay $0.20/kWh for your usage in the TOU 4-9 and then $0.27 for any usage over your allotment. With Prime you are only paying $0.17/kWh. So Prime is still less money.

Where it can save you or make you more money is they do pay you an additional $0.07 kWh over your allowance. So some people can make more money or pay less over the year with the TOU 4-9 plan. So you would have to do your own calculations to see what is best for you. For me, Prime was the best

What you overproduced is credited at wholesale rates for all plans. You do not "make" more money on higher rate plans over baseline credit

 

[skepticcyclist]

SCE Prime TOU is great for people with EV and no solar. Generally, if you have solar, you would be better off with the TOU 4-9 plan for 2 reasons.
1. The mandatory daily charge will add ~$10/month to the bill. This is on top of NBC. Your monthly bill is likely $18-$24. Monthly bill on TOU 4-9 is ~$13. This is assuming system was sized properly and generation exceeds consumption.
2. You actually want the off peak rate to be higher if you send more energy to the grid than consume during off peak. Again, if the system was sized properly, this is likely the case. Instead of getting $0.16/kWh credit, you'll get $0.27/kWh credit.

Do the math. I think you'll find you are better off without the Prime plan.

You are partially correct.

I did do the math which is why I switched and why I end up paying less each month and get more back at the end of the year with Prime.

SCE pays wholesale for what is sent back over what you consume. It is the same wholesale price for all TOU plans once you are over you baseline credit kWh allocation.

I run my pool pump and appliances at night during the off peak time. Lower off peak rates saves money on those days where we do not produce more than we use.

No my monthly bill isn't that high. And is never that high. My last bill was negative and the bill before that was $15

 

[skepticcyclist]

It still applies to all TOU rate plans. As long as you have enough ESS to never draw at peak rates (and it’s during some solar production so you can export), the higher that rate is, the better for you.

Not when you are only paid the same wholesale rate on all plans for what you produce over what you consume

 

[Electrph]

But it isn't 100% accurate.

Off peak rates for consumption and production don't matter when usage and production match 1:1. Then when you produce more than you use you are only paid wholesale for every kWh over regardless of the plan you're on. So that too is a wash. It is when you use more than you produce where prime saves money.

Energy producers to not make more with higher rate plans

So if I am a net producer for year (zero net usage) then would tou 4-9 not be less in my case when looking at only basis charges vs prime ? ( I meant basic charges in previous post not the baseline credit or the off peak rate which I assumed did not benefit me if I am a net producer ?)

 

[skepticcyclist]

So if I am a net producer for year (zero net usage) then would tou 4-9 not be less in my case when looking at only basis charges vs prime ? ( I meant basic charges in previous post not the baseline credit which I assumed did not benefit me if I am a net producer ?)

It could be. The 4-9 plan may be better for some over the Prime. It depends on how much you use, when you use it, and many other variables. The best thing to do is look at your history of usage and compare it to your solar production.

I was on the 4-9 plan originally. But because of the morning marine layer and when we run our pool pump, the prime ended up saving me money in the long run. For you the 4-9 may be better.

I was just clarifying that the 4-9 is not always the best for all people, as well as the misconception that higher rate plans pays you higher rate for production (which it doesn't.) Net metering is only 1:1 for production matching usage. Any net over production is wholesale and is paid at the same wholesale rates for all plans. The baseline credit does give you additional production money based on what your allocation is.

For anyone new to this, they should try to the 4-9 plan first since that is what they automatically sent you up with anyway. Monitor you usage and see what it would be if you went to the Prime. Then determine which is better

 

[GJones]

I assume you have gas heating?

A bit of a split - I have gas central heat for 70% of the house, heat pump for the the other 30%. Unless the days are exceptionally cold (under 30F), the heat pump can service the entire house. I also have gas water heating. I would like to replace both gas appliances with heat pumps so that I could plug the gas entirely, but would have to up the solar and battery to 12 kW and 3 batteries to do it. Maybe next year.

 

[Electrph]

It could be. The 4-9 plan may be better for some over the Prime. It depends on how much you use, when you use it, and many other variables. The best thing to do is look at your history of usage and compare it to your solar production.

I was on the 4-9 plan originally. But because of the morning marine layer and when we run our pool pump, the prime ended up saving me money in the long run. For you the 4-9 may be better.

I was just clarifying that the 4-9 is not always the best for all people, as well as the misconception that higher rate plans pays you higher rate for production (which it doesn't.) Net metering is only 1:1 for production matching usage. Any net over production is wholesale and is paid at the same wholesale rates for all plans. The baseline credit does give you additional production money based on what your allocation is.

For anyone new to this, they should try to the 4-9 plan first since that is what they automatically sent you up with anyway. Monitor you usage and see what it would be if you went to the Prime. Then determine which is better

Basic question just so I understand correctly ... with SCE TOU prime or 4-9 and 1:1 net metering the cost per kWh only comes into effect if you are a net consumer correct (ignoring any non- bypassable charges) ? In other words say I produce (made up to make easy) 100 KWh per month excess 80 during off peak 20 during peak ... now I have 80 credits to use during off peak and 20 credits to use during peak correct? And there is no price per kWH attached to these so in this case plan rate prime vs 4-9 makes no difference correct? And at end of year true up I am paid same wholesale rate for any excess again irrespective of prime vs 4-9

 

[skepticcyclist]

Basic question just so I understand correctly ... with SCE TOU prime or 4-9 and 1:1 net metering the cost per kWh only comes into effect if you are a net consumer correct (ignoring any non- bypassable charges) ? In other words say I produce (made up to make easy) 100 KWh per month excess 80 during off peak 20 during peak ... now I have 80 credits to use during off peak and 20 credits to use during peak correct? And there is no price per kWH attached to these so in this case plan rate prime vs 4-9 makes no difference correct? And at end of year true up I am paid same wholesale rate for any excess again irrespective of prime vs 4-9

Yes. Correct. Except there is a slight advantage with the 4-9 plan with the additional $0.07 kWh net production up to your baseline allowance.

This is from SCE website. It is the last question on the page. The current plans are now $0.07 not $0.10 like what is stated here.

As a Residential Net Energy Metering customer, if your recommended rate is TOU-D-A, the calculation for the baseline credit is based on your monthly baseline kilowatt-hour electricity allowance and if you are a net consumer or net generator (for the month). Net Consumer: 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 of $0.10 per kWh (up to the baseline allowance limit). Net Generator - 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 of $0.10 per excess generated kWh (up to the baseline allowance limit). 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.

The daily charges are the same for both, except Prime can have a slight advantage as it is always $0.40. With the 4-9 there is a daily basic charge of $0.05 and a minimum daily charge of $0.35. These add up to be the same $0.40 per day, but since it is minimum it can be higher. So the prime is always $0.40 where the 4-9 can be higher than $0.40

 

[bevo]

Basic question just so I understand correctly ... with SCE TOU prime or 4-9 and 1:1 net metering the cost per kWh only comes into effect if you are a net consumer correct (ignoring any non- bypassable charges) ? In other words say I produce (made up to make easy) 100 KWh per month excess 80 during off peak 20 during peak ... now I have 80 credits to use during off peak and 20 credits to use during peak correct? And there is no price per kWH attached to these so in this case plan rate prime vs 4-9 makes no difference correct? And at end of year true up I am paid same wholesale rate for any excess again irrespective of prime vs 4-9

If you are a net producer for the full year, and by that I mean if after the 12 month period, you have a credit and not a bill, then it is almost assuredly true that you should be on the TOU 4-9 and not the Prime plan.
Take a look at the two monthly bills below. The firs is the Prime and second is TOU 4-9. Both bills consist of delivery charges plus NBC. Ignore the CA Climate Credit which occurs about 3 times a year regardless of the plan.
The reason TOU 4-9 is better is because NBC counts towards the daily minimum whereas it does not for Prime. Prime is a fixed daily charge.
Consider the May bill (second bill). If I were on Prime, the total bill would be $23.47 ($11.46 delivery charge + $12.01 NBC) or $10.02 more. There's really no math possible that would make Prime be less than TOU 4-9 in terms of the monthly bill, which consists of delivery charges + NBC.

Bringing this back to Powerwall to semi stay on topic, Powerwall would provide little to no financial savings (being a net producer that I am). That's because Powerwall could reduce NBC, but then those charges would simply move to daily minimum charge, thus gaining me nothing.

 

[skepticcyclist]

If you are a net producer for the full year, and by that I mean if after the 12 month period, you have a credit and not a bill, then it is almost assuredly true that you should be on the TOU 4-9 and not the Prime plan.
Take a look at the two monthly bills below. The firs is the Prime and second is TOU 4-9. Both bills consist of delivery charges plus NBC. Ignore the CA Climate Credit which occurs about 3 times a year regardless of the plan.
The reason TOU 4-9 is better is because NBC counts towards the daily minimum whereas it does not for Prime. Prime is a fixed daily charge.
Consider the May bill (second bill). If I were on Prime, the total bill would be $23.47 ($11.46 delivery charge + $12.01 NBC) or $10.02 more. There's really no math possible that would make Prime be less than TOU 4-9 in terms of the monthly bill, which consists of delivery charges + NBC.

Bringing this back to Powerwall to semi stay on topic, Powerwall would provide little to no financial savings (being a net producer that I am). That's because Powerwall could reduce NBC, but then those charges would simply move to daily minimum charge, thus gaining me nothing.


View attachment 663001


View attachment 663002

As I showed with my bill, I constantly pay $10-$15 per month with prime. I switched from the 4-9 and my monthly bill is less. I don’t know where people are getting the $20+ per month info.

 

[Roy2001]

I think 5% is unusually low. My solar still produces about 25% in the winter of what it does in summer.

It really depends.

In central valley of CA, summer means sunny every day and my 6.5kw system generates about 45kWh/day. During winter when it is raining whole day, it generates as little as 2kWh. So during December/January/February time frame, monthly output varies from 350-600kWh, depending on weather.