Im guessing we will know slightly more after the earnings call.
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Elon tweets: Solar Roof and solar panels will only be sold integrated with Powerwall
- Thread starter willow_hiller
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Im guessing we will know slightly more after the earnings call.
Not necessarily. Plenty of current Solar + Powerwall installs that still use the Tesla Inverter. All of the talk in this thread about removing the inverter has just been speculation based upon Elon's tweet working of solar feeding directly into the Powerwall.
The only part I know for sure that bundling Solar + Powerwall will eliminate will be the home consumption monitor (Powerblaster/neurio), as the Tesla Gateway required for the Powerwall fully replaces the monitor.
I think you will still need an inverter somewhere to convert DC from the solar panel to AC for immediate home use and pushing back to the grid. And you still need a switch aka the PW Gateway (or replacement) to make decisions about how to route the power around.
pilotSteve
Active Member
not Generac (I looked at those and they have good specs) but we went with four LG Chem Resu batteries. They are DC in and DC out so lower losses then DC>AC>DC>AC architecture in current PowerWalls. (LG/SolarEdge architecture is single conversion solar or storage DC to AC)
From the 2021-Q1 earnings report, this is the explanation for not installing Powerwalls alone, at least:
"Energy storage deployments grew 71% YoY in Q1, mainly driven by the popularity of Powerwall. Demand for Powerwall continues to far exceed our production rate. As a result, we recently shifted Powerwall deliveries to solar customers only. As we increase our production rate, we may make it available once again as a stand-alone product. The recent snowstorm in Texas and other blackout events continue to drive customers toward home energy storage solutions."
"Energy storage deployments grew 71% YoY in Q1, mainly driven by the popularity of Powerwall. Demand for Powerwall continues to far exceed our production rate. As a result, we recently shifted Powerwall deliveries to solar customers only. As we increase our production rate, we may make it available once again as a stand-alone product. The recent snowstorm in Texas and other blackout events continue to drive customers toward home energy storage solutions."
Yeah I agree there isn't enough attention around educating PV+ESS customers why they may want a DC coupled ESS instead of AC. I feel like installers just throw AC coupled in there for simplicity, but the DC coupled should be cheaper and more efficient.
For my install, I have the following AC coupled approach which results in ~10% efficiency loss for energy to make its round trip through the PV+ESS towhere it ultimately becomes useful for powering home loads (inverters highlighted in bold).
DC (production) >>(1. Enphase Micro Inverters)>> AC (home microgrid) >>(2. PW Inverter)>> DC (ESS Storage at rest) >>(3. PW Inverter)>> AC (home microgrid)
Contrast that with some DC-coupled ESS where it looks more like...
DC (production) >>(1. DC controller)>> DC (ESS Storage at rest) >>(2. Home Inverters)>> AC (home microgrid)
The problem I see with the second option is that the simpler design places enormous pressure on the (1. DC controller) and (2. Home Inverters) to perform their task reliably. They are each single points of failure. And so far, I haven't seen evidence to suggest any single company makes a reliable residential DC gateway and also a inverter(s) for the task of dealing with the entire system for years. SolarEdge may have improved their failure rate, but the frequency of failure still feels high. Plus the turnaround time to get a replacement seems awfully high.
The counter arguments one installer used to address my "single point of failure" concern was that homes are served by the PoCo through a single "point of failure" as well. But to me, the PoCos have one thing going for them which is they employ a lot of rapid response T-men (or women) who can be dispatched and can get a block or subdivision back up and running relatively quickly. A homeowner doesn't have that type of rapid response or resources to obtain replacement parts.
The installer also said the likelihood of failure of a large residential inverter still didn't offset 10% efficiency losses during the lifetime of the system. But my hatred of PG&E is why I ultimately went with a AC coupled system.
But it's good to hear your installer actually got you to consider why you'd want AC or DC coupled.
pdx_m3s
Active Member
I read this as, "Powerwalls are only available to Tesla Solar customers for the time being," rather than, "Powerwalls are mandatory for every Tesla Solar purchase."
Time will tell.
Looking at the tesla website or PW, it says Available for purchase with solar. I see nothing on the solar side that says you have to buy a PW, at the moment.
Hmm... So no mention of a DC Powerwall on the call. He does call the recent crop of Powerwalls "2 plus" since they have almost double the kW output (same kWh) as officially rated (on twitter I think he said 1.5x, but on the call he said double).
But Elon says that the wiring of these new systems coupled with Powerwall will be fundamentally different (solar only to Powerwall, wired directly in-between the main panel and the grid, so that no main panel rewiring will need to be done). Again, it's not clear why a Powerwall is a necessary component in this new configuration. Or whether excess solar generation could be sold back to the grid when the battery is full.
But he did then go on how critical virtual power plants will be to stabilizing the future grid.
I'm afraid we'll just have to wait and see until the website updates or the first installs happen.
But Elon says that the wiring of these new systems coupled with Powerwall will be fundamentally different (solar only to Powerwall, wired directly in-between the main panel and the grid, so that no main panel rewiring will need to be done). Again, it's not clear why a Powerwall is a necessary component in this new configuration. Or whether excess solar generation could be sold back to the grid when the battery is full.
But he did then go on how critical virtual power plants will be to stabilizing the future grid.
I'm afraid we'll just have to wait and see until the website updates or the first installs happen.
So does this imply the V2.1's are ready for something? But, new systems. Just tell us what is going on
At the very least, this seems to confirm that they're wiring their systems for VPP now.
It technically probably isn't. What they are doing is putting the Energy/Powerwall Gateway in every install. (Between the meter and main panel.) And maybe the gateway won't work without at least one Powerwall.
My home has the utility meter on the left side of the box and the main panel on the right side. The underground service line feeds up to the meter socket, then wires from the load side of the meter socket feed straight through the center divider of the box to the main breaker. The main breaker and all of the home circuit breakers are on the same bus bars. How can the powerwall be interposed between the meter and the main panel in this case? Are most homes wired differently with a separate meter box?
I've been waiting since placing my order on Thanksgiving 2020 for Tesla to come back with a proposal. I've done a bunch of design work on my own to try to figure out a practical way to follow @Vines suggestion to gut the main panel and move all the home circuits to a separate subpanel in order to put the gateway in between them. The physical constraints are tricky, but I think I found one panel that would work. So given the constraints that I see, I wonder what Elon's statement really means. I was always intending to have whole-house backup, if that's all he means. But he emphasized not needing to modify the main panel, and I don't see how that's possible for my installation.
(Plus, I already have solar panels + inverter + batteries installed in 2000 that I would be replacing with the solar roof and powerwalls, and the existing system includes a subpanel to back up a subset of the circuits, so those circuits would have to move back into the main panel.)
I've been waiting since placing my order on Thanksgiving 2020 for Tesla to come back with a proposal. I've done a bunch of design work on my own to try to figure out a practical way to follow @Vines suggestion to gut the main panel and move all the home circuits to a separate subpanel in order to put the gateway in between them. The physical constraints are tricky, but I think I found one panel that would work. So given the constraints that I see, I wonder what Elon's statement really means. I was always intending to have whole-house backup, if that's all he means. But he emphasized not needing to modify the main panel, and I don't see how that's possible for my installation.
(Plus, I already have solar panels + inverter + batteries installed in 2000 that I would be replacing with the solar roof and powerwalls, and the existing system includes a subpanel to back up a subset of the circuits, so those circuits would have to move back into the main panel.)
pdx_m3s
Active Member
Well, Elon made it very clear on the call:
"We will not sell a house with solar without a Powerwall. That solar can either be solar retrofit, in other words conventional panels put on a roof, or it can be the Tesla solar glass roof. In all cases, it will have the Powerwall 2."
"All installations will have Powerwall. The difficulty of installation will be much less/easier, because the power from the solar roof will only ever go directly into the Powerwall, and the Powerwall will only every go between the [meter] and the main panel. You never need to touch the main electrical/circuit breakers (main panel). Effectively almost every house looks the same electrically, instead of being a unique work of art (needing to re-wire the main panel)."
Elon then goes on to say they are effecictively creating a distributed virtual utility. From a business case, this is quite substantial.
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Thanks for listening to the Q2 earnings and getting this info for us!
As much as I want to agree with Elon that his approach would magically simplify everything (EDIT, I said "load side" but meant "line side" intercept that forces the TEG2 to be the first thing that comes in after the meter socket in all instances), I cannot imagine this working in practice given how diverse every home is, how different AHJs interpret everything, and PG&E getting to do PG&E things whenever they feel like it.
I would have loved it if someone used the main service panel as a simple raceway to shove a TEG2 in between the meter socket and service disconnect of my MSP. Hell, if they let the TEG2 be the MSP, that would have been cool (like if there was a meter socket add-on for the TEG2 that made the total enclosure fit in the same size as your average 200A main service panel).
Then I would have a much cleaner and simpler install. But alas, the technology and rule enforcers don't allow this awesomeness. And PG&E definitely would not have approved it.
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Well, shows what months of reading this board show. I still don't understand electricity. 
I thought that solar only was always the most simple install.
Followed by whole home back up with as many Powerwalls as Needed.
Followed by the nightmare which is partial home back up.
Unless he means the plan is only "full" systems, like mine if you will, which have the capability of full autonomy plus being part of a "distributed virtual utility".
I thought that solar only was always the most simple install.
Followed by whole home back up with as many Powerwalls as Needed.
Followed by the nightmare which is partial home back up.
Unless he means the plan is only "full" systems, like mine if you will, which have the capability of full autonomy plus being part of a "distributed virtual utility".
I think in a lot of cases the current main panel isn't capable of having solar added. So you have to replace the main panel. Adding a Gateway is apparently easier than replacing the main panel.
Thanks for listening in on the earnings call. You have added a lot of great data points here.
I can see where he might be coming from, trying to simplify installations. However, electrons move from high potential to low, so it doesn't matter if the plan is meter - Powerwall- load /solar or meter - load / solar - Powerwall, except from the rewiring main panels. It seems like many people here have had real issues around main service panels. If the new system can take 225 Amp feed throughs in their internal busbars, it would simplify those installations where the meter isn't integrated into the main panel. You could make a Tesla "combiner box" be the high current center of a system.
Much as it is fun to speculate, the devil is in the details about what problems the proposed changes might fix, and what they might induce. Tesla certainly now has the benefit of living through a large number of installs, so that data is probably being put to good use, or at least I hope that it is being put to good use.
We shall see...
All the best,
BG
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