Tesla Powerwall

[kingocat]

I have an 8KW system and I was wondering if it would make sense to install 2 powerwalls. We get power outage a few times a year here in Southern California. Im currently paying about $15 a month for SCE for the "delivery" fees. If install the Powerwall, will i save about 15/month since I will be storing my own power off grid?
Any Powerwall owners have any thoughts?
is it worth it?

thanks

[RichardCullip]

I have an 8KW system and I was wondering if it would make sense to install 2 powerwalls. We get power outage a few times a year here in Southern California. Im currently paying about $15 a month for SCE for the "delivery" fees. If install the Powerwall, will i save about 15/month since I will be storing my own power off grid?
Any Powerwall owners have any thoughts?
is it worth it?

thanks

$15/month for power delivery is a whole lot cheaper than paying for 2 Powerwalls. With your monthly bill so low it makes no financial sense to get the Powerwalls. Now, handling power outages is a different story but a generator is better suited for covering infrequent power outages than the Powerwalls.

[SunEagle]

$15/month for power delivery is a whole lot cheaper than paying for 2 Powerwalls. With your monthly bill so low it makes no financial sense to get the Powerwalls. Now, handling power outages is a different story but a generator is better suited for covering infrequent power outages than the Powerwalls.

I agree that a battery system will never pay for itself for just emergency outages. I would also just get a generator.

Now if the OP had TOU rate and could reduce the cost of power consumption using the battery at the higher rate times it may be cost effective. But to just try to eliminate that $15 connection fee, as they say up in NJ "Forget about it".

[solardreamer]

I have an 8KW system and I was wondering if it would make sense to install 2 powerwalls. We get power outage a few times a year here in Southern California. Im currently paying about $15 a month for SCE for the "delivery" fees. If install the Powerwall, will i save about 15/month since I will be storing my own power off grid?
Any Powerwall owners have any thoughts?
is it worth it?

thanks

Since you already have 8kW of PV I suspect your $15/month "delivery" is a non-bypassable charge so getting Powerwalls or any other home battery system would not eliminate that charge. Is it "worth" it? As others have pointed out, it's not worthwhile financially. The payback period for outage usage is far longer than the warranty or lifespan of the Powerwall. Some people try to cover the Powerwall cost with virtual power plant program incentives but most results are disappointing. However, if you value the Powerwall for convenience, comfort, hobby or any other non-financial reasons then it could be worthwhile. But be aware of some important limitations of the Powerwall (compared to other home battery systems) for backup power usage including having no control to charge from the grid as needed (e.g. in preparation for outage) and no support for charging from a generator (e.g. black start a drained Powerwall during extended cloudy outages).

[peakbagger]

Some utilities are subsidizing battery installs, basically taking money out of the ratepayers pockets via system benefit fees (called different things in different markets). They then have the rights to remotely dispatch the batteries to help with grid loading conditions. I know that in Mass the battery is basically free but its very dependent on lot of very utility specific conditions.

[chrisski]

At $11k for a powerwall holding somewhere around 13 kWh of power, I can't ever see a real situation it'd pay for itself. I do see it being very useful for power outages, but would not run my air conditioners except a few hours.

[solardreamer]

At $11k for a powerwall holding somewhere around 13 kWh of power, I can't ever see a real situation it'd pay for itself. I do see it being very useful for power outages, but would not run my air conditioners except a few hours.

$11K for a standalone Powerwall installed would be quite a find now that Tesla only sell Powerwall bundled with their PV systems. I've only seen ~$15K quotes for standalone Powerwalls installed from third-party installers.

[chrisski]

$11K for a standalone Powerwall installed would be quite a find now that Tesla only sell Powerwall bundled with their PV systems. I've only seen ~$15K quotes for standalone Powerwalls installed from third-party installers.

Last month I walked into the Tesla Sales shop in Glendale AZ, and the price they gave me for a standalone powerwall is $11k. I do not know if there were any other fees attached, but the sales rep said you could add on only a Powerwall even to an installation done by a different contractor. Another guy I work with said exactly what you're saying that Tesla does not install. I was there to buy a Tesla EV, not a Powerwall.

Walk in the Tesla shop and see what they say. Tesla has a number to call also. I'd be interested to see if it truly is $11k.

[Ampster]

Some utilities are subsidizing battery installs, basically taking money out of the ratepayers pockets via system benefit fees (called different things in different markets). They then have the rights to remotely dispatch the batteries to help with grid loading conditions. I know that in Mass the battery is basically free but its very dependent on lot of very utility specific conditions.

In California those grants are provided by the California Energy Commission. The SGIP grants are funded by taxpayers, not rate payors. The processing is done by the power companies so it may look like ratepayor funds Yes the grants have very specific conditions including limits on discharging batteries into the grid. However during times when grid is over stressed by demand that could be a good thing.

[Ampster]

Since you already have 8kW of PV I suspect your $15/month "delivery" is a non-bypassable charge so getting Powerwalls or any other home battery system would not eliminate that charge. Is it "worth" it? As others have pointed out, it's not worthwhile financially. The payback period for outage usage is far longer than the warranty or lifespan of the Powerwall. Some people try to cover the Powerwall cost with virtual power plant program incentives but most results are disappointing. However, if you value the Powerwall for convenience, comfort, hobby or any other non-financial reasons then it could be worthwhile..

A battery could reduce NBCs but not MDCs. That is not enough to created reasonable payback. However reducing peak charges, having backup and getting Virtual Power Plant payments all can add up to reduce payback.

[EverAzure]

PowerWall is NMC. It is a short-life system. The same is Generac. LFP is better, 10+ years life.

[Ampster]

PowerWall is NMC. It is a short-life system. The same is Generac. LFP is better, 10+ years life.

Are there any UL listed LFP packs available in the market?
LFPs big advantage is safety. No thermal runaway. I think in either case battery life is determined more by how it is managed. I have not seen any emperical data that shows why LFP will last longer than NMC.

I have both, and not reached a conclusion yet.

[EverAzure]

Are there any UL listed LFP packs available in the market?
LFPs big advantage is safety. No thermal runaway. I think in either case battery life is determined more by how it is managed. I have not seen any emperical data that shows why LFP will last longer than NMC.

I have both, and not reached a conclusion yet.

You can find a battery with UL certification. But it takes time. If the battery cell and solar system have UL at the same time, it is the best. I still insist on my point of view, LFP has a longer life than NMC. This is determined by two different chemical components. And I don't like a battery that may explode.

[Ampster]

You can find a battery with UL certification. But it takes time. If the battery cell and solar system have UL at the same time, it is the best. I still insist on my point of view, LFP has a longer life than NMC. This is determined by two different chemical components. And I don't like a battery that may explode.

I agree with your point of view in terms of the life of LFP but have not found anything that scientifically supports that view. I was only taking issue with your earlier statement that it was a scientific fact. I also wholeheartedly agree LFP is safer and that is factual.
My 42 kWh LFP pack has two years and probably 300 full cycles on it and I hope to get another fifteen years out of it. The 150 kWhs of NMC in my two EVs range from three to six years old and will be replaced sooner. The range degradation on the EVs has been minimal but the safety and convenience features on the older one have been surpassed on newer models. By the time we replace the second EV, LFP may be an option. We drive over 25,000 miles a year collectively on the two EVs.

[EverAzure]

i agree with your point of view in terms of the life of lfp but have not found anything that scientifically supports that view. I was only taking issue with yourvearlier statement that it was a scientific fact. I also wholeheartedly agree lfp is safer and that is factual.
My 42 kwh pack has two years and probably 300 full cycles on it and i hope to get another fifteen years out of it. The 150 kwhs in my two evs range from three to six years old and will be replaced sooner. The range degradation on the evs has been minimal but the safety and convenience features on the older one have been surpassed on newer models. By the time we replace the second one, lfp may be an option. We drive over 25,000 miles a year collectively on the two evs.

amazing!! Great!!