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Understanding PGE/SVCE electricity bills/TrueUP
- Thread starter SMAlset
- Start date
I realized there's possibly a big correction to the ROI calcs I posted yesterday - I said the before my numbers should be the same both slightly below and above 100% of annual production. But if you overgenerate, while it is true you get 100% full retail credit from SVCE - but that is only on the SVCE generation portion of your overproduction. I think on the PG&E true-up, you'll only get I believe about $0.02 or so of the PG&E portion, and since that's more than half the total bundled rates, it's essentially nothing. So I think that may cut the benefit of overproduction by about 50%. So if the last 4.25kwh is all overproduction, the payback periods would nearly double, about 15 years for E-TOU-C, 20 years for EV2-A.
Regarding 3rd Powerwall, I did do follow-up ROI calcs on Powerwall, but didn't share because this is highly dependent on individual household usage patterns across seasons and daily TOU. What I would say is, if you're looking at "worth" strictly from an ROI persective, then you're talking about using it to load-shift peak to off-peak, and not for outages (which has a valuable but intangible ROI). I believe it is the case still that you cannot just push the stored energy out to the grid to get peak credits, it's banked solar energy from earlier in the day that you can only offset what you self-consume during those peak hours.
So I think some guidelines:
-you're basically load-shifting peak rates to off-peak rates by self-consuming during peak periods, so for each kwh, the benefit is largely the difference between the peak and off-peak rate for each kwh.
-you're also avoiding the $0.02-0.03 NBC's per kwh by not importing from the grid.
-if you're self-consuming after midnight you're just load-shifting off-peak to off-peak, you're thus only avoiding NBC's, but not getting any peak->off-peak gains.
-so it's basically how much daily and annual peak usage can you shift to off-peak. If 2 Powerwall's will already take you to self-consume through the 4-9 or 4-midnight peaks, the 3rd Powerwall only saves NBC's and provides additional outage capacity.
-E-TOU-C is almost a flat rate these days, load-shifting in winter is only $0.02 difference, summer is more like $0.08. I don't have summer A/C usage so I only net consumed 200 summer peak kwh per year, so wasn't worth it. 700 winter peak kwh, but at $0.02 also not worth it, the NBC avoidance would provide the most benefit in my case, but still was 30+ year payback on a powerwall.
-EV2-A has a significant difference between peak and off-peak, esp in summer like $0.32 /kwh. That is where to find incremental ROI for the 3rd Powerwall. So assume EV2-A.
Roughly then, if you have significant summer AC usage from 4-9 (and maybe 9-11), and the 2 Powerwalls don't take you to full self-consumption during peak, the 3rd Powerwall would get you $0.32/kwh (+$0.02/kwh NBC) for each additional kwh you can self-consume during summer evenings. (The new pool probably won't factor, since you'll probably want to run pumps and heaters during off-peak earlier in the day at off-peak rates.)
Nobody can advise you well on how many Powerwalls you really need or which rate plan you should choose without detailed information about your usage pattern. If you are truly only generating 40% of the kWh that you consume over the course of a year, then you will have a substantial bill due at true-up and any TOU shifting that you can do will save you real cash. If you are a significant net energy consumer with solar and Powerwalls, you should evaluate how many unavoidable kWh you consume during Peak and Part-Peak hours. Unavoidable usage is things like lighting and cooking and air conditioning that are not practical (or popular with the family) to shift to other hours. Things like pool pumps, EV charging, laundry, and dishwasher usage can be shifted out of the Peak hours with relative convenience. You want the Powerwalls to have enough energy capacity in kWh to supply your unavoidable Peak usage. If it can cover the Part-Peak usage then that is even better. You should also consider how much energy you need to reserve for backup in case of grid outage too.
As long as your Powerwalls can routinely supply your peak usage so you normally don't pay the Peak rate and you are a significant net consumer, you should choose the rate plan with the cheapest Off-Peak price. I believe that is the EV2-A rate.
My current annual usage is 16500 kWh, by adding a pool which comes with its own solar system and electrical features (fountains etc) I am expecting my usage to go up, no idea what to but I am guessing upto 20000 kWh.
The Tesla 12k System should still cover my needs (21000 kWh) however I am opting for the 17k system (27000 kWh) based on the advice received on this forum.
As for the Powerwalls, I was thinking purchase two to obtain better economies of scale (install fees, gateway etc).
From the sounds of it I am better of going with the 12K system and 2PW rather than that 17K system with 2PW due to the ROI. Or to add another PW (3 total) to 17K system.
Is my thinking correct?
The Tesla 12k System should still cover my needs (21000 kWh) however I am opting for the 17k system (27000 kWh) based on the advice received on this forum.
As for the Powerwalls, I was thinking purchase two to obtain better economies of scale (install fees, gateway etc).
From the sounds of it I am better of going with the 12K system and 2PW rather than that 17K system with 2PW due to the ROI. Or to add another PW (3 total) to 17K system.
Is my thinking correct?
You should ask Tesla about the off-grid performance of the 17kW solar system with 2 Powerwalls. If they clearly tell you that it will gracefully modulate the solar when the grid is down, then that is a reasonable way to go.
However, if you have the financial means to do the 17kW + 3 PW system, but go with a smaller system, you will probably regret it down the road. Doing any expansion of solar or adding PW is a massive hassle, if possible at all.
Nah, if you have the money, I would do the 17K system and 3 PW's. Adding the stuff after is basically impossible. And as codes change, you may not be even able to do it at all. And once folks have solar, batteries, it is amazing how we end up finding ways to use more electricity.
Personally, ROI was the most important to me so I ended up going with 8kW (already had existing 3kW) and 2PW. ROI on powerwalls isn’t great and the warranty is only good for 10 years, so something I took into consideration. I would have went with just a single PW but wanted whole house backup so had to go with two. In the rare event that I have an outage I can easily manage my loads to last a day with just batteries. I am also assuming that solar and batteries will get cheaper over time and appliances/EV will become more efficient, but I agree it will probably be harder to get more installed in the future. With the system I purchased I think it will take 10+ years for me to break even, but there is some value knowing that my house will have power if there is an outage.
For @cciesingh and others looking to oversize in SVCE/PGE territory, I just received a mailer from SVCE this week - starting May 2022, they will no longer be paying full retail rates for excess generation. Instead, they'll be paying 2X "net surplus compensation" rate, which they said works out to about $0.06/kwh. Significantly reduces the benefit of oversizing and overproducing, esp if you were counting on any banking summer peak overproduction on EV-2A or E-TOU-C. "Only" a 30-40% hit if overproducing primarily during non-Summer off-peak though.
It was probably too generous for SVCE to sustain NEM full retail credits, good while it lasted for those who could take advantage...
It was probably too generous for SVCE to sustain NEM full retail credits, good while it lasted for those who could take advantage...
I received the same letter an posted about it in the SVCE thread in the California sub-forum.
They will continue paying retail rates for true-ups through April 2022.
Yeah SVCE's policy on excess generation being credited at Retail is one of the most generous plans I've ever heard of... it basically would be something NEM 1.0 folks experienced many years ago. To have it last until 2022 is like free money for a lot of folks hah.
If having power during a storm is the most important factor for you (normal house loads and laptop, computer etc), then keep in mind that most I think power outages occur, at least in northern Calif and SF Bay area, during the Fall/Winter season when we get red flag days, dry lightning strikes, storms. In other words when our morning/daytime skies can be overcast and yield poor solar generation for your PW/PWs. If power goes out over a few days, will you be able to make it through as long as you want then?
Just a few years ago we had one month, think maybe February, where almost every day produced rain. Also don’t forget to factor in this seasonal time for your water heater/furnance heating usage. Nothing like cold showers or cold air during the winter. There’s also the risk of pipes freezing and bursting if you’re in an area that gets freezing/sub-freezing temps. If you think you’ll be changing out equipment down the road from gas to electric or adding EV charging (get this installed BEFORE getting your solar/PWs installed so it’s already factored into your main panel load and gets transferred), just another point to contemplate maybe having an extra PW to store extra solar energy. If StormWatch kicks in you’ll be storing all that extra PW energy during that time even if your solar panels can’t “fill them” on some winter days.
As others have mentioned above, it’s not always easy to just call up and add more solar panels or PWs for various reasons listed. Does make it challenging to project out needs sometimes especially if you have a growing family and stay in the house long-term.
Just a few years ago we had one month, think maybe February, where almost every day produced rain. Also don’t forget to factor in this seasonal time for your water heater/furnance heating usage. Nothing like cold showers or cold air during the winter. There’s also the risk of pipes freezing and bursting if you’re in an area that gets freezing/sub-freezing temps. If you think you’ll be changing out equipment down the road from gas to electric or adding EV charging (get this installed BEFORE getting your solar/PWs installed so it’s already factored into your main panel load and gets transferred), just another point to contemplate maybe having an extra PW to store extra solar energy. If StormWatch kicks in you’ll be storing all that extra PW energy during that time even if your solar panels can’t “fill them” on some winter days.
As others have mentioned above, it’s not always easy to just call up and add more solar panels or PWs for various reasons listed. Does make it challenging to project out needs sometimes especially if you have a growing family and stay in the house long-term.
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GenSao
Member
Perhaps. IMHO it makes sense to include EV charging as part of your usage.
Here is another way to look at it. You are pre-paying for electricity with solar. Consider the total cost of the solar system (exclude Powerwalls) divided by the expected production over time. For me, I anticipate my solar will cost me $0.07-0.09/kWh over the life of the system.
Unfortunately utility TOU rates will increase over time. Over 18 years (2001-2019) the PG&E E1 Average rate has increased annually by 3.75%. Even the EV-A off peak rate increased from $0.1223 in 2017 to $0.1443 in 2021. Supercharging in CA costs more ($0.28) and will vary based on TOU and subject to rate increased over time.
As a standalone consideration, Powerwalls provide limited (if any) ROI. Get as many as you desire for backup as that is the true reason to consider them.
Do consider they consume power (approx 0.5-1.0kWh/day) with a higher value for outdoors. Also take into account the 90% round trip efficiently (or 10% loss). For reference, 20% (or 3,000 kWH) of my home use was supplied by the battery. Combined I estimate an added load of 1,000 kWh (3,000 x 10% + 350 x 2) used for my 2 Powerwalls.
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PG&E wants to increase natural gas rates by 50% over the next half-decade. I'm afraid anyone relying on gas for heating is about to get a swift kick in the nuts. The only pro-active solution TMC has discovered (at normal income levels) is to up-size the solar a ton; install electric heat pump units; and get in under NEM 2.0 with some batteries to boot. Basically run @h2ofun's playbook.
Yep, thats exactly what I have done. Will find out if I was super smart, or super dumb soon.
Nah you're good. There is like zero push to abolish grandfathering under NEM 1.0 or 2.0 now. I think that abolishment was just bluster so it seems like the IOU's gave up on something in the negotiation. But removing grandfathering never should have been in scope anyway.
But, when your NEM 2.0 does expire, your solar array is going to get super duper expensive. Not sure how long you plan on owning the house haha.
Actually this raises an interesting point. If Janet sells a house to Bob that has solar on it, does Bob inherit Janet's NEM grandfathering, or does Bob automatically get pushed to a new NEM and reset the clock?
Because under NEM 3.0, Janet's solar system could easily become a liability if it were mis-sized.
I thought I heard that the grandfathering stays with the system and house, not person owning.
Yeah, I asked my real estate agent (he's used to my stupid questions by now) and he says for his clients that buy homes with solar, they inherit whatever the house had. So I guess it's what you're saying... Grandfathering stays with the house. He says so far I'm still the only person to have asked him about the 36" inch MSP to Gas Riser thing.
This is a good outcome since it would suck if the "NEM Asset" goes away during sale. But can you imagine if you had to pay a flat fee for solar export, but PG&E only gave you the wholesale rate (or less) for that generation? You'd need more batteries or you'd have to just turn off the array.
And I cannot fathom how a homeowner being incentivized to turn off their solar is a "reasonable outcome" from an effective NEM policy.
Do you really think any energy source isn’t going to increase rates greatly down the road under current companies? It will be like water rates in EBMD from what I’ve heard over last few years: everyone conserve water and we’re increasing rates as a deterent; done great job conserving but now due to lower billing revenue (less water sold) we need to increase rates again. On top of the already raised rates.
They’re going to get you regardless. I’m sure if they can they will raise the monthly $10 rate for solar accounts to some exorbitant amount and you’ll be using more electricity switching over everything (plus people only have so much roof to place panels on). So EVs will be a growing electrical load on the system as well as all home heating, water heater and cooking. NEM is only for 10-years right? And they have other ways to increase fees. Loretta Lynch was saying right now all the gas line checks at people’s homes aren’t billed to them, instead we all pay for it through some other means. But if you’re in an area that has old houses the cost to replace those gas lines will be very costly and its going to come from someone, rate payers. While different utility, replacing aging water/sewer systems will be the same.
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Well, I think things are going up, but there isn't much that will likely shoot up the ~50% in just a short number of years like in all the proposals being tossed around. And based on where we're seeing the NG prices move on the future contracts it could be even more than 50% rate increase for NG.
Interestingly enough, gasoline prices aren't really going up much for the rest of the USA (California is another animal)... may actually come down as EV adoption goes up.
I remember back in 2008 some USA automakers were actually selling cars with the option for customers to take cash incentives, or "lock in" gas prices where they were given a gas card good for X number of gallons over 3 years. Some customers actually took the gas card instead of the cash. They got worked over so bad hah.
