You are correct - I should have said month-to-month they don't issue you a check but carry the credit over. I think - and your cite seems to confirm - that even in April, they carry the credit over, except where your annual production exceeds usage, and they pay that portion at the wholesale rate. This is relevant to me because our solar will only cover ~80% of our use, but we will likely have a credit in April and May based on projections for solar and our typical usage.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Considering solar panels, looking for sizing/financing advice
- Thread starter willow_hiller
- Start date
Reran Watts splitting the roof and assuming all the loss info is about right (I just changed system size, azimuth, and tilt), looks like I will come out around 1.5k higher than Tesla's estimate, which would be great. Still won't power the house fully, especially if we add another electric car, but that'll certainly help decrease the power bills!
After just over 2 weeks of operation, I really do understand the appeal of Powerwalls. My system is generating a ton of watt hours, but there's a fundamental misalignment between my consumption and my production. Highest use times of day are the early morning (hot water, primarily) and the late evening (cooking dinner). If Maryland ever repealed net metering, I would probably jump on a set of Powerwalls in a heartbeat.
Last edited:
It definitely illustrates the challenge with solar as a source of renewables, and why energy storage is really necessary as the fraction of energy derived from solar grows. It also is why places like HI and CA, among others, have shifted their peaks later and disincentivized solar if it doesn't include batteries. Unfortunately, PWs aren't really practical for the seasonal aspect of solar.
It will be interesting to see how MD acts as the requirements for renewable power generation grow and more people get solar. I don't expect that they will repeal net metering any time soon. The real question is what they will do as they hit the NEM cap - as of June, 2019, the state had reached almost exactly half of the cap of 1,500 MW, and they expect to reach the cap in 2025-26. (As a side note, the PSC are overdue publishing their 2020 report on net metering in the state, perhaps due to the pandemic.) At that point, future installs would likely need battery storage as part of the solution to make solar work for them. However, by that time, the assumption would be that the economics for solar and batteries should be better. While the state could make changes, my hope would be that they preserve NEM as it is for existing installs which relied on that, while providing lesser (or perhaps no) incentives depending on the cost of the technology at that time.
The other reason to consider PWs would be if utilities moves forward with the TOU rates they are currently piloting (PEPCO and BGE at least have pilots - not sure about other utilities.) I do think that will happen in the next few years (not mandatory at this point but an option) and that certainly could help with the economics of the PWs.
It's been fascinating watching the CAISO charts, specifically the "Net Demand Trend" which subtracts out renewables like wind and solar. Demand clearly peaks between 7-8pm right as solar production has dropped close to 0. Solar is great for reducing fossil fuel based production during the day but as you note @wjgjr storage is a necessity if you want to avoid the peak problem.
California ISO - Today's Outlook
pdx_m3s
Active Member
At some point it will become financially prudent for utilities to subsidize home battery systems (to a much larger degree than current) to deal with the mismatch between generation and demand.
I totally agree - the irony, though, is that in MD, the state subsidizes buying battery storage (30%, up to $5k) but then offers no incentives (utilities don't have TOU rates generally available to solar net metering customers, but they do have full net metering) to use the batteries to help manage demand. They really should adjust the program to coordinate with utilities and force you to adopt a TOU rate as part of the program.
Demand issues aren't as pressing in MD as CA (this year, for example, I recall no requests to reduce power and no "peak savings days" called for during hot days to incentivize reducing use.) However, not incentivizing battery owners to shift grid demand leads to a less clean fuel mix as peaker plants are called into service more often.
I am happy to report that digital smart meters do indeed overflow when they go negative. Now let's hope PEPCO doesn't try and bill me for this electricity, otherwise at my average rate I'll end up with a $150,000 electricity bill.
Overflow? More like an underflow or rollunder?
I'm really interested in knowing if the billing system interprets this correctly or not.
That would be pretty funny (only because it's not happening to me) but I would hope even PEPCO is competent enough to handle this. The meters may also have hidden digits (or bits) to track this. I suppose you could check that bill to date feature to see if the numbers are crazy.
Got my Peak Energy Savings Credit on my latest bill. We definitely still qualify, but I don't think they allow the measurement can go negative. They listed my baseline as 3 kWh and my measurement as 0 kWh, although I was definitely exporting electricity during that hour.
No $150,000 charge also, thankfully. So they must have some logic for measuring the underflow. Also I missed energy-neutral by 6 kWh. Still, my smallest bill ever. Just under $3.
Can't quite figure out the math though. Even though it says I consumed a net 6 kWh, they gave me a negative electricity supply charge.
No $150,000 charge also, thankfully. So they must have some logic for measuring the underflow. Also I missed energy-neutral by 6 kWh. Still, my smallest bill ever. Just under $3.
Can't quite figure out the math though. Even though it says I consumed a net 6 kWh, they gave me a negative electricity supply charge.
My billing period ends tomorrow night, so I may have something to compare by early next week, but having the generation services charge at -$0.39/kWh makes no sense. On my last bill, the generation charge was $0.0518, which matches what PEPCO publishes for the summer rate. The winter rate (starting 10/1) is $0.06516. Not surprisingly, neither is negative. I am assuming you are on Schedule "R" and the "SOS" rider. If so, I have no idea if it is a bug with the fact you used only 6 kWh for the period or with the rollover to winter rates, or something else I am just missing, but that is strange.
Interesting that you did get the peak savings credit but it did not go negative. That would be the only other odd thing that I could guess is that somehow the amount you exported during that hour was credited to you in the generation services area and that is how you ended up getting a negative number when everything was blended together.
Interesting that you did get the peak savings credit but it did not go negative. That would be the only other odd thing that I could guess is that somehow the amount you exported during that hour was credited to you in the generation services area and that is how you ended up getting a negative number when everything was blended together.
To follow up on this, the shock is my PEPCO bill was actually available this morning on their website (sometimes it seems to take a couple of days.)
Our bill this month ended up being very simple. Our net usage for the month was -10 kWh. That does not offset the $8.50 monthly charge but is banked as a credit towards next month. Additionally, our peak savings credit was 1 kWh, so they also did not credit us for going negative (and since we had solar the whole prior month, we rarely were net users during that time, so 1 kWh is accurate.) So, our final bill was $7.25.
Because we had negative usage, PEPCO completely eliminated the "Supply Charges" section and the only rates they included in the "Demand Charges" section were the peak credit and - for some reason - the administrative credit (which, with 0 kWh used is $0.) Mildly annoying that they don't list all of the sections and lines with "0 kWh" since I still want to calculate the amount I saved, and it is sometimes difficult to find all of the amounts on PEPCO's website.
Our bill this month ended up being very simple. Our net usage for the month was -10 kWh. That does not offset the $8.50 monthly charge but is banked as a credit towards next month. Additionally, our peak savings credit was 1 kWh, so they also did not credit us for going negative (and since we had solar the whole prior month, we rarely were net users during that time, so 1 kWh is accurate.) So, our final bill was $7.25.
Because we had negative usage, PEPCO completely eliminated the "Supply Charges" section and the only rates they included in the "Demand Charges" section were the peak credit and - for some reason - the administrative credit (which, with 0 kWh used is $0.) Mildly annoying that they don't list all of the sections and lines with "0 kWh" since I still want to calculate the amount I saved, and it is sometimes difficult to find all of the amounts on PEPCO's website.
One other amusing item on the bill - it includes a section titled "Your daily electricity use for this bill period", which is a bar chart for each day. However, despite having -10kWh used for the period, every day is positive. It appears they are adding up the hourly data for each day but excluding any hour that was negative (net production.) So the graph is really "daily net usage for those hours where net solar and/or PW was less than home use." (And it has been mentioned elsewhere, but PEPCO net meters do not track use and production separately - they only store the net number, so PEPCO does not know our home load, just our net.)
They point you to their website for hourly breakdowns, and the website does appear to properly account for solar, so its graph does show us as negative on many of the days.
They point you to their website for hourly breakdowns, and the website does appear to properly account for solar, so its graph does show us as negative on many of the days.
I have found somewhat similar results from Duke. I have a fixed monthly charge of $10.63 and I need to pay that no matter what, whether I am net positive or net negative.
I have also found that the graphs and such on the bill and website are not very helpful. My meter does measure the power that I use and the power that I feed back to the grid separately. And last month the bill shows that I used 869kWh and fed back 687kWh, for a net use of 245kWh. It has a little graph that shows my average daily usage and the graph shows a daily average of 29kWh (869kWh/30 days), however in the text under the graph it states that my average daily usage was 8kWh (245kWh/30days).
Additionally, on their web site I can see my daily power usage, but it only shows the power that I have drawn from the grid. There is no way to see the power I have sent back to the grid on the web site at all.
I have also found that the graphs and such on the bill and website are not very helpful. My meter does measure the power that I use and the power that I feed back to the grid separately. And last month the bill shows that I used 869kWh and fed back 687kWh, for a net use of 245kWh. It has a little graph that shows my average daily usage and the graph shows a daily average of 29kWh (869kWh/30 days), however in the text under the graph it states that my average daily usage was 8kWh (245kWh/30days).
Additionally, on their web site I can see my daily power usage, but it only shows the power that I have drawn from the grid. There is no way to see the power I have sent back to the grid on the web site at all.
Well, he'd dead, Jim.
No lights and no response from the inverter this morning. I've heard these units can have high infant mortality, but I wasn't expecting a death within the first month!
Waiting for Tesla business hours before giving them a call.
No lights and no response from the inverter this morning. I've heard these units can have high infant mortality, but I wasn't expecting a death within the first month!
Waiting for Tesla business hours before giving them a call.
Well, Tesla tech support is amazing. They were able to troubleshoot over the phone and now I'm back up and running!
Good to hear you’re back up and running
. It’s my understanding that the high failure rate of the solaredge inverters was due to a bad batch of capacitors and was resolved a year or so ago, so new inverters shouldn’t have that problem.
Just out of curiosity though, what was the problem and solution for you?
. It’s my understanding that the high failure rate of the solaredge inverters was due to a bad batch of capacitors and was resolved a year or so ago, so new inverters shouldn’t have that problem. Just out of curiosity though, what was the problem and solution for you?
Good to hear you’re back up and running
Just out of curiosity though, what was the problem and solution for you?
We're having some dense fog that's settling in the morning. I think it must have tripped something inside of the inverter. I had tried power-cycling just the inverter and the DC disconnect (Inverter dial off > DC disconnect off > Wait > DC disconnect on > Inverter dial on), but that didn't have any effect. On the phone the technician walked me though:
Inverter dial Off > DC disconnect Off > Main panel solar breaker Off > Wait 1 minute > Breaker on > DC disconnect On > Inverter dial on
And that did the trick!
Glad that they could get it working and it wasn't a hardware failure. Odd that the fog would cause it - other than the annoyance of losing out on production in the morning (which we have seen here too) it seem like it shouldn't affect things to the point of requiring manual intervention to reset the system.
