New Powerwall Advanced Options [Toggles for charging from and discharging to grid from powerwalls]

[miimura]

Also, for the 8 month long Winter season on EV2-A, Part-Peak ($0.41/kWh) and Peak ($0.43/kWh) are not that different in price. So, if you can run on PW power from 3pm-12mid, you're much better off.

 

[aesculus]

Assuming winter means limited solar production, you'll likely be heating your home with the peak time energy rates from 4pm to 11pm.

Luckily, for a few more years, I am on EV1-A that has 2-9 peak weekdays and 3-7 on weekends. Plus I back off the heating during peak for a double benefit. But with the PWs they protect me from these peak periods unless I don't get any production during the day. That happens but not often. That off peak grid charge could help here.

Now in three more years come and talk to me about what plan PG&E sticks me with.

 

[jboy210]

Sorry I meant the shoulder times. I didn't mean peak. The EV2A plan I'm on is peak 4pm to 9pm. Shoulder starts at 3pm and ends at 11pm.

But this is still kind of crazy with so many folks having EVs (but no solar or powerwalls) on this rate plan. They get absolutely KILLED by this, especially in the summertime when they run ACs.

I had a neighbor tell me that after getting an EV and switching to EV2A, her monthly expenses went up ~$100 compared to what they were paying before under E-1 and paying for gasoline. She was like "I don't understand why people get EVs, gasoline was way cheaper". I told her she should just switch back to E-1 or go to E-TOU-C, since her home energy use (excluding car charging) was so focused during partial/peak time that it didn't make economic sense for her. But all this started go confuse her.

She insisted PG&E told her the EV2A rate plan was best for EVs as long as she charged her car at night, so going to those other plans would be worse. She wasn't going to take my advice. I guess the other reason her utility bill shot up was simply the cost of electricity/gas went up like 33%... so maybe the $100 had nothing to do with the EV and everything to do with energy costs.

Also, a $100 does not buy a month's worth of gasoline unless you don't drive very much.

 

[getakey]

Sorry I meant the shoulder times. I didn't mean peak. The EV2A plan I'm on is peak 4pm to 9pm. Shoulder starts at 3pm and ends at 11pm.

But this is still kind of crazy with so many folks having EVs (but no solar or powerwalls) on this rate plan. They get absolutely KILLED by this, especially in the summertime when they run ACs.

I had a neighbor tell me that after getting an EV and switching to EV2A, her monthly expenses went up ~$100 compared to what they were paying before under E-1 and paying for gasoline. She was like "I don't understand why people get EVs, gasoline was way cheaper". I told her she should just switch back to E-1 or go to E-TOU-C, since her home energy use (excluding car charging) was so focused during partial/peak time that it didn't make economic sense for her. But all this started go confuse her.

She insisted PG&E told her the EV2A rate plan was best for EVs as long as she charged her car at night, so going to those other plans would be worse. She wasn't going to take my advice. I guess the other reason her utility bill shot up was simply the cost of electricity/gas went up like 33%... so maybe the $100 had nothing to do with the EV and everything to do with energy costs.

If she was charging after 11pm, hard to believe her EV cost exceeded her ICE gas costs

 

[holeydonut]

If she was charging after 11pm, hard to believe her EV cost exceeded her ICE gas costs

While she paid less for charging her EV, I suspect she was paying much more for normal in-home stuff. But to her, it was all commingled. She was used to a PG&E energy bill + stopping off at Chevron. She knew what she was spending before. Afterwards, her Chevron costs went to zero, but the PG&E costs went sky high.

When she complained to PG&E, they told her she probably underestimated how much it'd cost to charge an EV. Easy "mistake on her part" har har?

 

[holeydonut]

Also, a $100 does not buy a month's worth of gasoline unless you don't drive very much.

She didn't drive much. That's why she was annoyed that PG&E + ICE/Gasoline cost her less than PG&E + EV (but under EV2A).

I'm not saying she's right... I'm saying it's too easy for a homeowner who isn't a TMC-nerd to be confused by all this TOU stuff.

 

[miimura]

The recent rate hikes probably didn't help either.

 

[h2ofun]

Yeah, people with electric heating under EV rate plans get hosed unless they can use their Powerwalls to grid-export some solar during peak to balance things out over their annual NEM.

Assuming winter means limited solar production, you'll likely be heating your home with the peak time energy rates from 4pm to 11pm. That's insanely expensive and could easily make you have a credit deficit even if your NEM kWh exports and imports are 100% offset.

This is why I run my house off the batteries when no solar, since I do use like 60 to 80 kwh per day, like now with it cold again

 

[cwied]

Sorry I meant the shoulder times. I didn't mean peak. The EV2A plan I'm on is peak 4pm to 9pm. Shoulder starts at 3pm and ends at 11pm.

Just a quick heads-up: EV2-A shoulder ends at midnight, not 11pm:

https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_EV2%20(Sch).pdf

 

[cwied]

But if you have very little afternoon production (in my case due to shading), it won't help much? I do get about 2 kwh of production from 4-6 pm in the summer months, but I'm also consuming about the 2 kwh during that time. There's no way to configure "ok, let me consume the 2 kwh from the Powerwall during this time, while the 2 kwh of solar gets pushed to the grid" - as that not truly excess solar?

As mentioned before, the "all solar" export is a main feature of the original time-based control. One thing that's been added in the latest release is the "export everything" option that can export stored solar from the Powerwalls. When this is turned on, the Powerwalls will export solar stored from earlier in the day during peak hours. This greatly increases the potential ROI for Powerwalls, especially in cases like yours where you don't produce much solar during peak hours.

The caveat here is that the return is all just NEM credits that can be used to offset your electricity usage during the year (i.e., between true-ups). This limits your potential gain to the amount you pay at true-up, excluding non-bypassable charges.

 

[cwied]

If you have a $ deficit, you pay the $ deficit.
If you have a $ surplus, but a kWh deficit, you pay nothing and get nothing.
If you have a $ surplus and a kWh surplus, you get reimbursed for the kWh surplus at the $0.02-$0.03/kWh rate.

Do you know if there is any provision for the unlikely, but theoretically possible case where you have a kWh surplus, but a $ deficit? It seems like you might get paid out for the kWh surplus and owe the $ deficit. That is, I think the two might actually be completely independent calculations.

 

[wwhitney]

Do you know if there is any provision for the unlikely, but theoretically possible case where you have a kWh surplus, but a $ deficit? It seems like you might get paid out for the kWh surplus and owe the $ deficit. That is, I think the two might actually be completely independent calculations.

The logic tree I posted covers this case, and applies as written. You have a $ deficit, so you pay the $ deficit. The kWh surplus is immaterial.

Cheers, Wayne

 

[Redhill_qik]

Do you know if there is any provision for the unlikely, but theoretically possible case where you have a kWh surplus, but a $ deficit? It seems like you might get paid out for the kWh surplus and owe the $ deficit. That is, I think the two might actually be completely independent calculations.

I don't think that it is possible as for most of the time that PV is generating and exporting the TOU is in off-peak which is the lowest for each tariff. But, if this did occur then you pay the deficit which is the first condition.

 

[sunwarriors]

She didn't drive much. That's why she was annoyed that PG&E + ICE/Gasoline cost her less than PG&E + EV (but under EV2A).

I'm not saying she's right... I'm saying it's too easy for a homeowner who isn't a TMC-nerd to be confused by all this TOU stuff.

This can't be stated more. I was going to get the EV plan which has a very low $0.09/kWh off hours (compared to $0.60 peak), but since it has a higher minimum $16, I decided not to do that since I already have a $10 power bill already and barely charge the EV anyways (WFH). People need to know their energy usage patterns and plan for it and even shift energy usage, but that's probably asking too much from the typical home owner.

 

[SoundDaTrumpet]

Thanks for the post! (Page 5) @wwhitney Called Tesla Energy Help Line, and under 12 minutes, L1 support updated my configuration to allow the App to show Energy Exports = Everything. This feature will boost more cost savings. [NEM 1, EVA, 2xPW, 6.8kWh annual solar production, 6.0/3.0kWh home/EV consumption, $700 annual true-up, $1400 anticipated under EV2.]

 

[RKCRLR]

I believe you're correct in that your credits are balanced based on $$ first, then if there is extra, is paid out at $0.02-$0.03 (no matter when it was banked). This makes exporting during peak better like you say since you build up a $$ credit faster (export 1 hour of peak is worth maybe 2-3 hours of off-peak).

My wonder/debate is whether the increased cycling of the battery is worth forcing your PWs to export when it's night time at all. I've been debating mentally whether I should raise my reserve so I start drawing power from the grid after peak periods (4pm-9pm) rather than use the battery overnight at all to minimize cycling the batteries even more. Does having a reserve of 80% allow the battery to last much longer vs. say, 20% or 40%?

I'm not sure how much degradation really appears from normal use. I assume with 10 year warranties, that's about full drains daily for 10 years. If it was 50% of that, maybe that's 20 years before it gets to the possible usual 70% degradation.

I pretty much stuck as many panels as I could and with more sun in So Cal, should end up net exporting anyways, but still not sure if it's worth it vs. using the battery more. I'll probably wait for my tru-up to see how the year went, but since we're already passed the winter months, assume it'll be more net exported for the rest of the year.

Powerwalls are warrantied for 37.8 MWh of aggregate throughput when not used for solar or backup. That gives you an idea of the design life of a Powerwall.

 

[SailorDave]

I love this grid charging feature. If I follow i Could sign up for a free nights program here in Texas. My battery would top up starting at 8pm ( start of nights) run off grid all night and then start to discharge at 6am (night ends) until my solar starts to top it up again and I would never have a power bill again. Does this sound right?

 

[ptdusn]

Well, my PWs updated to 22.9.2 and no PW charge from the grid feature.

 

[ZBB]

I love this grid charging feature. If I follow i Could sign up for a free nights program here in Texas. My battery would top up starting at 8pm ( start of nights) run off grid all night and then start to discharge at 6am (night ends) until my solar starts to top it up again and I would never have a power bill again. Does this sound right?

You'll still have a minimal bill. I'm on the Houston area and on a free nights plan since last June (our plan was up a few weeks before our install, and we didn't have PTO until Sept 1, so we had a couple months of bills where we had limited solar use).

Even without the grid charging feature, our monthly electric bills have been in the $6-8 range per month since Sept. Our TDU charges a monthly min fee to connect of $4.39 -- we've had a little bit of random grid draw during the day (balancing), a couple Storm Watch activations that pulled from the grid during peak, and a couple of daytime car charges that hit the Powerwall charge limit. But all of that adds up to $2-4 per month. We had one bill for $14 -- but that was a billing error where I think the meter info was delayed (the additional was all for one day; I chose not to dispute it since I don't want to call attention to how we are using the free nights plan -- just not worth the risk for $7!). Since Sept, 98% of our grid draw has been off-peak!

We did have one day just after Thanksgiving last year where we pulled a bit from the grid -- it had been cloudy all week and the PW % at end of day was lower each day (and I kept dropping the reserve -- stopping at 10%). But even then, that only cost ~$2 and that was the last cloudy day. The grid charging feature would have been helpful that week.

For now, I'm not turning grid charging on. But once we get past the tax audit window for 2021, I'll consider it. Our free nights plan is up for renewal on June 15, and our current supplier's offer is for a 2 year contract at a slightly higher peak rate. I modeled it out and expect to pay about 50 cents more per month (the peak rate goes up about 4-5 cents per kWh)... I also compared some of the other free nights plans from other providers as well as some net metering plans. The one we're on results in the lowest total bill for our usage -- about $8/month estimated electric bills , vs ~$39 monthly average for the best of the net metering plans. Even though we "sell" excess solar back to the grid at $0 on the free nights plan, being able to pull at $0 at night is a better deal (and we mostly charge the cars at night)...

 

[ptdusn]

You'll still have a minimal bill. I'm on the Houston area and on a free nights plan since last June (our plan was up a few weeks before our install, and we didn't have PTO until Sept 1, so we had a couple months of bills where we had limited solar use).

Even without the grid charging feature, our monthly electric bills have been in the $6-8 range per month since Sept. Our TDU charges a monthly min fee to connect of $4.39 -- we've had a little bit of random grid draw during the day (balancing), a couple Storm Watch activations that pulled from the grid during peak, and a couple of daytime car charges that hit the Powerwall charge limit. But all of that adds up to $2-4 per month. We had one bill for $14 -- but that was a billing error where I think the meter info was delayed (the additional was all for one day; I chose not to dispute it since I don't want to call attention to how we are using the free nights plan -- just not worth the risk for $7!). Since Sept, 98% of our grid draw has been off-peak!

We did have one day just after Thanksgiving last year where we pulled a bit from the grid -- it had been cloudy all week and the PW % at end of day was lower each day (and I kept dropping the reserve -- stopping at 10%). But even then, that only cost ~$2 and that was the last cloudy day. The grid charging feature would have been helpful that week.

For now, I'm not turning grid charging on. But once we get past the tax audit window for 2021, I'll consider it. Our free nights plan is up for renewal on June 15, and our current supplier's offer is for a 2 year contract at a slightly higher peak rate. I modeled it out and expect to pay about 50 cents more per month (the peak rate goes up about 4-5 cents per kWh)... I also compared some of the other free nights plans from other providers as well as some net metering plans. The one we're on results in the lowest total bill for our usage -- about $8/month estimated electric bills , vs ~$39 monthly average for the best of the net metering plans. Even though we "sell" excess solar back to the grid at $0 on the free nights plan, being able to pull at $0 at night is a better deal (and we mostly charge the cars at night)...

Are you with SRP, or APS? SRP doesn't have the free nights plan.