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What is your Reserve for Power Outages setting?

What is your Reserve % on your Powerwall?


  • Total voters
    44

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
7,261
8,040
Riverside Co. CA
odd that Net Metering means different things with different utilities

It means the same thing for each utility (giving generating facilities credit for the energy they export to be used against energy they use). What changes is the amount of credit they give for export, and the non bypassable charges they impose on whatever plan you are on.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
7,261
8,040
Riverside Co. CA
then why would someone put it on backup only with net metering?

Because they dont suffer the roughly 10% losses in and out, and if they have 1:1 net meeting (meaning paid the same credit putting it in as taking it out) then they lose 10% by running it through the battery.

Net metering means the same thing, but some get more or less credit from the utility as I said.
 

Zythryn

Model Y custom Warming Stripes wrap.
Mar 18, 2009
2,168
1,189
Minnesota
In the summer about 25%.
In the winter 80%, typically 100% during the coldest weeks of the winter.
Our heat is electric only, we have no secondary source of heat. Thus power outages in winter are much more critical than outages in the summer.
 

wjgjr

Member
May 11, 2020
980
741
Silver Spring, MD
odd that Net Metering means different things with different utilities
Yes, there is a whole spectrum of net metering arrangements - that is why I try to remember to say "full net metering" to describe what my utility does. Essentially, every kW I send back into the grid, the utility pays me at the full, retail price - the same price I pay for each kW I take from the grid. I know others get only a wholesale or generation rate, and there are a large number of different rules about how credits for net metering can be used or paid out. So about all net metering really means is the utility gives you some sort of credit for energy you send back to the grid, and most (but not all - I know at least one poster said their utility gives you nothing) have some form of it.
 
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getakey

Member
Jan 28, 2020
992
307
95762
Yes, there is a whole spectrum of net metering arrangements - that is why I try to remember to say "full net metering" to describe what my utility does. Essentially, every kW I send back into the grid, the utility pays me at the full, retail price - the same price I pay for each kW I take from the grid. I know others get only a wholesale or generation rate, and there are a large number of different rules about how credits for net metering can be used or paid out. So about all net metering really means is the utility gives you some sort of credit for energy you send back to the grid, and most (but not all - I know at least one poster said their utility gives you nothing) have some form of it.

Went back and read your other post. Missed the point about you having no TOU. now it makes sense for backup only
 

wjgjr

Member
May 11, 2020
980
741
Silver Spring, MD
Went back and read your other post. Missed the point about you having no TOU. now it makes sense for backup only
Yes, TOU would change things, and I tend to expect we will see that here soon (they have some pilot rates for testing TOU and actually do have an EV TOU plan, but that cannot be combined with NEM.) And the state oddly has a great battery storage credit despite not incentivizing its actual use. But for now, same price, 24/7.

And as a note, in addition to having the same rate for usage we actually don't pay a different monthly fee for NEM than regular customers ($8.50/month for all flat fees.)
 

GaitherBill

Member
Jun 10, 2020
83
54
Maryland/DMV
Is that really all you pay? I need to run a line from your place. Next utility over, and our kWh charge last month was 14.9565 cents (and I expect a lot of people would be happy with that rate.)

:eek:

Really?

Wow.

Yeah, the rate stated for us up here in the "country" is even going down slightly October 1st to 6.016 cents.

We do have one downside, they only read our meter every other month, and sending in a reading is not an option with a net meter.

The alternating month reading is an estimate based on last years usage.So it's going to take a full calendar year for our billing to really straighten itself out.
 

wjgjr

Member
May 11, 2020
980
741
Silver Spring, MD
:eek:

Really?

Wow.

Yeah, the rate stated for us up here in the "country" is even going down slightly October 1st to 6.016 cents.

We do have one downside, they only read our meter every other month, and sending in a reading is not an option with a net meter.

The alternating month reading is an estimate based on last years usage.So it's going to take a full calendar year for our billing to really straighten itself out.
Just the generation component of our electricity is more than that ($0.06714). I guess all that extra money went into buying the smart meters that report in their data automatically.

If we ever get V2G, you could setup an underground business filling up cars to smuggle bootlegged electrons across utility lines.
 

jboy210

Supporting Member
Dec 2, 2016
4,673
2,902
Northern California
Yes, there is a whole spectrum of net metering arrangements - that is why I try to remember to say "full net metering" to describe what my utility does. Essentially, every kW I send back into the grid, the utility pays me at the full, retail price - the same price I pay for each kW I take from the grid. I know others get only a wholesale or generation rate, and there are a large number of different rules about how credits for net metering can be used or paid out. So about all net metering really means is the utility gives you some sort of credit for energy you send back to the grid, and most (but not all - I know at least one poster said their utility gives you nothing) have some form of it.
A good point of pointing out the difference. Here in California, they credit you kW for kW, but any excess you produce is bought from you at wholesale. So you buy at $0.20 or $0.40 and sell at approximately $0.04.
 

wjgjr

Member
May 11, 2020
980
741
Silver Spring, MD
A good point of pointing out the difference. Here in California, they credit you kW for kW, but any excess you produce is bought from you at wholesale. So you buy at $0.20 or $0.40 and sell at approximately $0.04.
As I understand it here (and I haven't gotten into great detail since my system does not cover my annual usage) the only time you will get money back from a utility in MD (and I believe these rules cover all utilities in the state as they are set by the state's public services commission) is if you over-produce for a year. I think this is somewhat like the "true-up" bills you get in CA (in cases of a refund,) but it appears to be fixed to April for all customers in MD (so I actually hope if you have a surplus for the first time in March/April after running deficits the rest of the year, they don't pay it out instead of banking for the summer.) At that point, excess usage is paid out at the generation rate. Otherwise, any credits roll over from month to month at the full retail (generation+transmission+distribution) rate. So I probably should be clear that it is full net metering up to your usage.

Our utility also covers DC, and in DC they apparently never pay out. Credits remain forever, at the retail rate, but you can never convert them into cash. So I guess if you overproduce there really is an incentive to find ways to use those credits, including getting an EV or charging others' EVs.
 

getakey

Member
Jan 28, 2020
992
307
95762
A good point of pointing out the difference. Here in California, they credit you kW for kW, but any excess you produce is bought from you at wholesale. So you buy at $0.20 or $0.40 and sell at approximately $0.04.

To be clear, if you are sending to grid at Peak, you are credited on paper at the peak rate. So with PWs its possible to never buy at Peak. You only sell at wholesale if your annual production is over what you use.
 

Doom Man

Member
Jan 22, 2020
37
33
New Orleans, LA
Does anyone make their selection with cycles or longevity of the PW in mind?

Yes, but I don't know if what I do is optimal. I'm in south Louisiana, where we have frequent summer outages. Lately I've kept the reserve at 70%, to be sure I've got power if a thunderstorm knocks the neighborhood out for 8-10 hours and I'm not able to change the thermostats to conserve energy.

My thinking is that I don't want to keep the reserve at 100% / backup-only, because it shortens battery life to keep a lithium battery fully charged in hot conditions. By setting the reserve at 70%, my battery remains mostly below 100% when it's hot. Any lower and I could run the battery down with an overnight outage. It could be that 80% or 90% would be adequate to preserve the battery life; I just don't know. I have 1:1 net metering, so I'd like to keep the reserve as high as possible to extend battery life.
 

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