But don’t those credits carry through to the winter when, presumably, you are using more power than you produce? Or are you a net producer annually?
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Powerwalls during PG&E PSPS 2020-10-25
- Thread starter bmah
- Start date
But don’t those credits carry through to the winter when, presumably, you are using more power than you produce? Or are you a net producer annually?
Its yearly excess, not monthly excess. during the year you will bank electricity at the rate you would be charged for it when you send it back to the grid. The "wholesale rate" thing only happens at the yearly true up, if you are net producers instead of net consumers.
No, thats not how it works. During summer you are credited for excess at retail rate. You only get 4 cents for any excess on an annual basis. You should get on an EV rate and charge car at night at 14 cents and send solar to grid at 54 cents in the afternoon
Ok. That makes sense. Does this also mean we would not get our current monthly bill?
I will have to decide about the EV rate. Currently, I have been using excess solar and Supercharging to charge. I have free Supercharging for life on my X. But, its lease is up in May. If I buy out the lease the free Supercharging transfer to me as the "original owner". And we bought a Model 3 LR (which mostly just sits (less than 1000 miles since December 2019) because we can't go anywhere) so that has been free to Supercharge. But that free Supercharging has or will expire soon.
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You get a monthly bill for a connection to the grid fee (around $10.) and non bypassable charges (around 4 cents/ kWh). Everything else is loggedd for you annual true up
here's what it looks like. My annual bill was ~$50.
I read from PGE that there is that EV/battery rate for TOU. I am not hearing this in discussions. Are folks using that TOU if one has batteries even if no EV?
Our display of this data does NOT show "Your electricity charges are connected to a solar account". Maybe because we just got PTO is September? We are still on the same TOU plan (E-TOU-B) with a peak rate from 4PM-9PM. Which plan are you on?
I just loved that part of the outage where Bruce had filled up his PWs and dumped excess PV power into an EV
There were a few reasons I did this: First I didn't want the inverter to shut down and waste that solar energy. Second, we all (well mostly?) know about the stupid frequency shifting tricks needed to make that happen, and even though Tesla reconfigured my system to keep the AC line frequency in an acceptable range, I figure why go through that if we don't have to. Third I wanted to see how well the Tesla charging vs. Powerwall interaction worked (tldr: partially).
C'mon, half of you guys and gals would have done the same. Admit it.
Bruce.
There were a few reasons I did this: First I didn't want the inverter to shut down and waste that solar energy. Second, we all (well mostly?) know about the stupid frequency shifting tricks needed to make that happen, and even though Tesla reconfigured my system to keep the AC line frequency in an acceptable range, I figure why go through that if we don't have to. Third I wanted to see how well the Tesla charging vs. Powerwall interaction worked (tldr: partially).
C'mon, half of you guys and gals would have done the same. Admit it.
Bruce.
totally agreed. situation is different when the grid is down
While operating in "off-grid test mode" this summer I did the dump into a car thing at least once a week. But occasionally it did get to 100% and the decreased frequency worked as expected. No excess alarms or drops from the UPSes.There were a few reasons I did this: First I didn't want the inverter to shut down and waste that solar energy. Second, we all (well mostly?) know about the stupid frequency shifting tricks needed to make that happen, and even though Tesla reconfigured my system to keep the AC line frequency in an acceptable range, I figure why go through that if we don't have to. Third I wanted to see how well the Tesla charging vs. Powerwall interaction worked (tldr: partially).
C'mon, half of you guys and gals would have done the same. Admit it.
Bruce.
I think you're mixing up the excess production aspect of net metering with the time of use aspect of net metering.
For the sake of simplicity, let's pretend there's a household without PV or Battery that uses 3,650 kWh per year... and all of that energy is consumed from 4pm to 9pm each day. And for simplicity that means 10 kWh used per day.
Now let's pretend this household adds a PV only system that generates 3,650 kWh per year. And let's use PG&E's
E-TOU-C times and E6 rates (see below)
When the sun is up, and the household isn't using anything, all that PV energy is sent to the grid at the TOU rate of energy at that time. On this rate plan, the house would be banking kWh at the "off peak rate" up until 4pm. So let's pretend the house banked 7 kWh from 6am to 4pm at $0.18 ($1.26)
But then at 4pm, the house starts to use consume energy toward that fake 10 kWh. From 4pm until 9pm, the PV produces 3 kWh but now the house needs to withdraw from the grid that 7 kWh it banked earlier. And that becomes the problem. The energy was banked with the off-peak rate, but is withdrawn at the peak rate of $0.37. So the cost of the 7 kWh used from the grid is $2.59. The homeowner owes the net difference of $1.33 (plus all the fees and overhang that PG&E charges the customer).
I know my example is extreme, but keep in mind there's nothing stopping PG&E from making it so that "peak" is 5pm to 10pm and then turn the peak rate to $0.50. The utilities have said they think rooftop solar needs to "pay its fair share" and they believe homeowners who install solar have unfairly raised costs for normal customers.
The $0.04 comes in if the PV generates 4,000 in a year but the home only uses 3,650. That 350 kWh is sold to PG&E at the wholesale rate with no overhead reimbursement for the homeowner's infrastructure investment.
It's not as bad as always banking at $0.04; but it's still a problem for most PV-only home since it's not an ideal net metering for the household even though the net generation vs consumption is likely zero for the year. And that's why installing batteries is so important. The customer isn't going to gouge themselves on energy rates so they get "true net metering" for the cost of their batteries. And the homeowner gains resiliency.
I'm sure someone has done the math and determined that the cost of batteries doesn't actually offset the delta between the peak/off-peak rates. But as I told my sales rep... if I'm going to get f*cked, I'd rather pay a clean energy company than pay PG&E.
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SageBrush
REJECT Fascism
Excellent example, and so far as I can tell exactly right. I also absolutely agree with you about spending money where it does good and with companies that are socially responsible.
Bruce is obviously delighted with his setup during a power outage and it might be worth the price of admission in CA.
Power outages aside though, an example where a TOU schedule has peak electricity costing 2x as much as during PV generation hours pencils out to simply putting up more PV to offset the more expensive peak use. I say this because PV is ~ $2 a watt to have installed (and less on the margin) so PV to offset peak use would be double at $4 a watt which works out to ~ 8 cents a peak kWh over the PV system lifetime before financing is considered. If off-peak energy consumption is 2x peak energy consumption then the PV installation would cost
2x + 1x*2 = 4x/3 = 33% more to install than one without a TOU schedule. Still *really* cheap. The moral to this story is that abundant, cheap home PV cures a lot of consumer angst towards the utility.
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I am fortunate to live a 1:1 net metering state with a stable power grid (for now anyway) but if things were to become CA like I would install one powerwall as insurance against a fridge full of rotten food and to have enough energy for lights and vampires. That works out to ~ 2 -3 kWh a day. Everything else is pretty negotiable in my house for a day or two.
Thanks, although the pretty part isn't really my doing.
The code that polls the Powerwall gateway is in Github (link was in another post, but it's bmah888/gotesla). It writes to InfluxDB, an open-source timeseries database. Grafana, an open-source visualization system, is the thing that draws the graphs with a Web interface. You can basically get everything going for free, but it might take a little know-how and time to put the pieces together.
Bruce.
On the subject of Grafana, there are also a few other example setups in github. I based mine off of this: mihailescu2m/powerwall_monitor. It's relatively easy to get this up and running if you have basic linux administration knowledge, although I did end up tweaking some parts where I preferred different queries to what was configured.
This setup uses telegraf to grab the data.
This setup uses telegraf to grab the data.
Getting back to the Price Schedule settings, I'm curious how the Northern CA/PGE folks handle the partial peak period. I too, live in Northern CA, Oakland to be exact, and I entered the exact times for Peak (4 - 9) and Off-peak (12 - 3). Although you can't directly enter the time for partial peak, it appears that it still calculates it and shows it in the diagram. What I don't know is how it handles the partial peak time in terms of decisions about charging or sending back to the grid. Does it treat it like Peak, Off-peak, or some combination? I know some people just set Peak to include the partial peak time. How do others with PGE approach that?
