Powerwalls not connected to grid?

[jacobp]

I had two powerwalls installed in July 2020. I've had solar panels for seven years so at the time the installation of the powerwalls was completed I was told that no ATO was needed. All that was needed was an inspection. That occurred and the system passed. After installation, the Tesla app works as expected showing the battery charging and discharging, providing power to the house. In fact, when we had a couple of power outages the PWs worked to provide power to the house. But, my utility bills didn't show any impact at all. I just shrugged and thought maybe it was just an aberration. But then I received a couple of emails from PEPCO, the electricity supplier, talking about the status of my application for an Energy Storage Only system. I thought this was a bureaucratic error so I ignored it. But then I decided to call Tesla and they told me that they did have to file an application with PEPCO of some sort and that it had been rejected. They are working to resolve this (five months later).

So it appears that while the app was showing me pretty illustrations of how the system is supposed to work, it wasn't doing anything to save money. Now i understand why my bills haven't gone down. This is crazy. Has anyone else experienced this kind of thing?

 

[wjgjr]

I am in PEPCO land, though I don't know about the rules related to PTO for adding PWs (I did it all at once.) That said, what impact were you expecting from adding PWs? PEPCO does not have generally-available TOU rates (particularly ones that are compatible with net metering,) so unless you were able to get in on the pilot program, all PWs would ever do is help you deal with outages. But I would expect no change in your bill as a result of adding PWs to existing solar panels. (In fact, there would be a slight increase due to the small amount of power needed to operate the PWs.) I assume your payments to PEPCO dropped seven years ago when solar was added.

 

[h2ofun]

I am in PEPCO land, though I don't know about the rules related to PTO for adding PWs (I did it all at once.) That said, what impact were you expecting from adding PWs? PEPCO does not have generally-available TOU rates (particularly ones that are compatible with net metering,) so unless you were able to get in on the pilot program, all PWs would ever do is help you deal with outages. But I would expect no change in your bill as a result of adding PWs to existing solar panels. (In fact, there would be a slight increase due to the small amount of power needed to operate the PWs.) I assume your payments to PEPCO dropped seven years ago when solar was added.

This is what I basically have experienced first hand or heard from a friend who installs generators, etc. When I ask them why they installed the battery and what did they expect, I just get a blank stare. For the average person, not on TOU, I agree, I do not see them saving money, just spending a whole bunch to just be able to say, I am cool, I have batteries.

Talking to my installer who put in my solar, heating, and generator, he again told me they had another customer who wanted batteries and they would not do it since they could not show any real cost savings, and they did not want the customer to bad mouth their company when their bill did not go down after spending a ton of money.

I know if I ever get batteries, it will have zero to do with lowering my costs. And as I post, unless they are 100% free, I have no interest based on today's costs. For a power outage, my generator works just fine.

 

[getakey]

If you are on PG&E with TOU rates, they will save you money

 

[jboy210]

I decided to get our SolarRoof and Powerwalls after 2 Power shutoffs for a total of 4 days 2 years ago. And as my friend with solar only pointed out, without batteries it would have made me really upset staring at kW of panels on the roof that provide 0.00 kW during a power outage. Also, during those power shutoffs 2 years ago, we could go inside and eat, and charge phones and computers. In the era of Covid, that is no longer possible.

The additional benefit is the separating Time of Use from Time of Generation. This ensures we never pay the high rate.

 

[wjgjr]

If you are on PG&E with TOU rates, they will save you money

Definitely, and why I mentioned the possibility, but here, there are very few TOU rates. The R-TM rate was closed to new customers in the year 2000, and R-TOU-P is a limited-enrollment pilot program that is full. There are a couple options for EVs (one closed to new customers) but the open one is not compatible with the net metering rider, and the closed one required separate metering of the EV outlet (and also appears to not work with NEM.) So, in most cases, PWs here will not save you money (unless/until they start offering generally-available TOU rates.)

I will note that, due to the generous incentives MD has, plus the ITC, plus the bundle discount offered at the time when installing with solar, 2 PWs came out under $6k total. So, while not money-makers, they become a much more competitive option for backup power.

 

[jacobp]

I am in PEPCO land, though I don't know about the rules related to PTO for adding PWs (I did it all at once.) That said, what impact were you expecting from adding PWs? PEPCO does not have generally-available TOU rates (particularly ones that are compatible with net metering,) so unless you were able to get in on the pilot program, all PWs would ever do is help you deal with outages. But I would expect no change in your bill as a result of adding PWs to existing solar panels. (In fact, there would be a slight increase due to the small amount of power needed to operate the PWs.) I assume your payments to PEPCO dropped seven years ago when solar was added.

I was involved in the pilot program, so I do have TOU rates.

 

[jacobp]

If you are on PG&E with TOU rates, they will save you money

I am on PEPCO in the DC area and I have TOU rates.

 

[jacobp]

Definitely, and why I mentioned the possibility, but here, there are very few TOU rates. The R-TM rate was closed to new customers in the year 2000, and R-TOU-P is a limited-enrollment pilot program that is full. There are a couple options for EVs (one closed to new customers) but the open one is not compatible with the net metering rider, and the closed one required separate metering of the EV outlet (and also appears to not work with NEM.) So, in most cases, PWs here will not save you money (unless/until they start offering generally-available TOU rates.)

I will note that, due to the generous incentives MD has, plus the ITC, plus the bundle discount offered at the time when installing with solar, 2 PWs came out under $6k total. So, while not money-makers, they become a much more competitive option for backup power.

I guess I'm lucky. I have net metering, TOU rates, and a separate meter (and much lower rates) for my EV chargers. Under those conditions should I expect to see a cost savings from the Powerwalls?

 

[getakey]

I guess I'm lucky. I have net metering, TOU rates, and a separate meter (and much lower rates) for my EV chargers. Under those conditions should I expect to see a cost savings from the Powerwalls?

What are the rates and during what time periods?

 

[wjgjr]

I guess I'm lucky. I have net metering, TOU rates, and a separate meter (and much lower rates) for my EV chargers. Under those conditions should I expect to see a cost savings from the Powerwalls?

Yes, assuming you are on the R-TOU-P rate, you should see savings. However, as I understand it, in winter, the peak period is 6-9 AM (excluding weekends,) which means you are generating very little solar to export, so the savings will mostly be based on discharging from the PWs during the 6-9 AM timeframe. In general, the savings will be less dramatic than the summer, when peak is 2-7 PM.

I am assuming you have configured the app to set the peak to 6-9 AM. Can you confirm that you see the PWs discharging during that time and then charging back up after 9?

On the PEPCO side, you should be able to download the Green Dot data. Does it show 0 or negative usage for 6-9 AM? I would also assume your bill should show how much usage was at peak and how much off-peak.

(The above assumes you are on R-TOU-P, since you mentioned you were in the pilot - if you are in R-TM, that has different times.)

 

[jacobp]

For my house, my on peak (Noon to 8pm) rate is 8.16 cents. Off peak (Midnight to 8am; and all day Saturday and Sunday) is 6.3 cents. Intermediate rate is 6.7 cents. For the EV chargers my rate is 2.3 cents (8pm to noon).

 

[jacobp]

Yes, assuming you are on the R-TOU-P rate, you should see savings. However, as I understand it, in winter, the peak period is 6-9 AM (excluding weekends,) which means you are generating very little solar to export, so the savings will mostly be based on discharging from the PWs during the 6-9 AM timeframe. In general, the savings will be less dramatic than the summer, when peak is 2-7 PM.

I am assuming you have configured the app to set the peak to 6-9 AM. Can you confirm that you see the PWs discharging during that time and then charging back up after 9?

On the PEPCO side, you should be able to download the Green Dot data. Does it show 0 or negative usage for 6-9 AM? I would also assume your bill should show how much usage was at peak and how much off-peak.

(The above assumes you are on R-TOU-P, since you mentioned you were in the pilot - if you are in R-TM, that has different times.)

I am on the pilot rates. My understanding is that for that program, peak is noon to 8pm. Off peak is midnight to 8am and intermediate is everything else. It is also my understanding that those time periods are the same for winter and summer. But to be honest, I have not checked on that in quite a while.

As far as acutal usage, in the summer, i almost never incur on peak charges as the solar panels take care of that. In the winter, I am beginning to see more on peak charges, but so far they have been offset by the carryover credits from the summer solar generation being fed back to the grid.

 

[getakey]

For my house, my on peak (Noon to 8pm) rate is 8.16 cents. Off peak (Midnight to 8am; and all day Saturday and Sunday) is 6.3 cents. Intermediate rate is 6.7 cents. For the EV chargers my rate is 2.3 cents (8pm to noon).

you will only be able to save on the delta between Peak and Off/Intermediate. Charge PWs during Intermediate (assuming that is 8am to noon). Then discharge during Peak. You will save (8.16-6.7) x kWhs used from PWs. Not very much because of your low rates. If you have Non by-passable charges may not be worth it.

Jealous of your rates though. My Off Peak rate is higher than your Peak

 

[wjgjr]

I am on the pilot rates. My understanding is that for that program, peak is noon to 8pm. Off peak is midnight to 8am and intermediate is everything else.

Peak Savers | Pepco - An Exelon Company and https://www.pepco.com/SafetyCommunity/Community/Documents/Updated 092619 - R-TOU-P.pdf both indicate the summer peak is 2-7 PM and the winter peak is 6-9 AM.

RTM is the legacy time-metered rate. That sounds like what you are describing. That rate was closed in the year 2000 according to PEPCO, so if you are on that rate, I am assuming you have been on it for at least 20 years. That rate also seems to have less than a penny difference between peak and off-peak. (Also, intermediate rates are higher than peak - https://www.pepco.com/MyAccount/MyBillUsage/Documents/Updated 060120 - RTM.pdf.) However, the above still applies as to how you can check your usage and confirm whether energy is being shifted to off-peak

Can you confirm which rate plan you are actually on? I am not aware of any other PEPCO residential rate plans in MD other than the five listed:

Current Tariffs (Maryland) | Pepco - An Exelon Company

PIV and R-PIV are both listed as not being compatible with net metering. I am assuming your EV charging is on the older EV rate since you mentioned the separate meter.

 

[h2ofun]

you will only be able to save on the delta between Peak and Off/Intermediate. Charge PWs during Intermediate (assuming that is 8am to noon). Then discharge during Peak. You will save (8.16-6.7) x kWhs used from PWs. Not very much because of your low rates. If you have Non by-passable charges may not be worth it.

Jealous of your rates though. My Off Peak rate is higher than your Peak

I never thought about this way cheaper electricity rates outside Calif. These would make ROI on solar, let alone batteries, even much worse.

 

[Oceanwolf]

For my house, my on peak (Noon to 8pm) rate is 8.16 cents. Off peak (Midnight to 8am; and all day Saturday and Sunday) is 6.3 cents. Intermediate rate is 6.7 cents. For the EV chargers my rate is 2.3 cents (8pm to noon).

Wow... my off-peak is 14 cents and Peak is 40 cents. I thought my off-peak was great.

 

[h2ofun]

Wow... my off-peak is 14 cents and Peak is 40 cents. I thought my off-peak was great.

One reason so many leave Calif is the energy costs are off the scale, and even then, we still get 3rd world blackouts.

 

[AxlxA]

@h2ofun hence the saying "we pay for the sunshine"
This is electric cost, state income tax, sales tax, whatever else there is, housing prices, rent prices, whatever else

 

[h2ofun]

@h2ofun hence the saying "we pay for the sunshine"
This is electric cost, state income tax, sales tax, whatever else there is, housing prices, rent prices, whatever else

So true! Lived here my entire life and I realize I have to put up with all the junk which gives me such great weather. Now, this rain we are just getting has to stop, should never rain or be cold here.