Tesla Powerwall

[OCJ]

If your goal is ROI then no it's not worth it.

However, if you value the Powerwall for convenience, comfort, hobby or any other non-financial reasons then it could be worthwhile.

This is why I got a Powerwall+. The ROI is still there, but a bit longer.

I'm not too concerned about outages, but it's nice knowing I do have that whole house backup.

I like having control over how I send to grid. Pre-PTO I was Self-Powered of course. When I got PTO I switched to Time-Based Control, after a month I switched back to Self-Powered, and next month I'm going to try a combination of Time-Based Control and Self-Powered by creating my own TOU schedule.

I guess you could call that a hobby (around $100 a month), but my monthly system cost is still less than what my average monthly bill would have been. Now had my electric rates been reasonable, I would have had to evaluate the cost of this hobby differently.

[dglavin96]

I have a quote from Tesla for a 14.8 kW system which they estimate will cover 90% of my electricity usage. The quote includes 2 powerwalls, which would supposedly provide 7+ days of whole home backup. Are the powerwalls worth the extra cost, assuming that the system will overproduce at times during the day and the powerwalls will provide some or all of our electrical usage overnight and on cloudy days? The net cost for the 2 is $18500, after a $1500 bundling discount.

[solardreamer]

I have a quote from Tesla for a 14.8 kW system which they estimate will cover 90% of my electricity usage. The quote includes 2 powerwalls, which would supposedly provide 7+ days of whole home backup. Are the powerwalls worth the extra cost, assuming that the system will overproduce at times during the day and the powerwalls will provide some or all of our electrical usage overnight and on cloudy days? The net cost for the 2 is $18500, after a $1500 bundling discount.

It all depends on what you care about. If it's purely financial then it's not worth it. You can get similar power capacity portable generator with much longer run time at < 20% of the discounted cost of 2 PW's. Remember each PW only stores about the same amount energy as one 20 lb propane tank.

[Ampster]

The cost the OP quoted was just for the Powerwalls not the 14.8kW solar system. I agree it all depends on what you care about and I would add, what the rates are. Any battery system can help reduce the impact of high TOU rates. The payback is longer but it may also be a hedge against further erosion of NEM benefits.
In addition, in some markets, Tesla has been able to aggregate Powerwalls in a Virtual Power Plant (VPP) which allows owners to receive additional compensation for helping the grid.

[Will792]

I have a quote from Tesla for a 14.8 kW system which they estimate will cover 90% of my electricity usage. The quote includes 2 powerwalls, which would supposedly provide 7+ days of whole home backup. Are the powerwalls worth the extra cost, assuming that the system will overproduce at times during the day and the powerwalls will provide some or all of our electrical usage overnight and on cloudy days? The net cost for the 2 is $18500, after a $1500 bundling discount.

I would challenge this 7+ days backup. Each PW is 14KWh so 28KWh for two. If your house uses electricity for cooling or heating it won’t last long and you cannot make assumption that daytime PV production would be sufficient to handle all consumption and battery recharging.

[J.P.M.]

I would challenge this 7+ days backup. Each PW is 14KWh so 28KWh for two. If your house uses electricity for cooling or heating it won’t last long and you cannot make assumption that daytime PV production would be sufficient to handle all consumption and battery recharging.

I agree. Unless dglavin 96 is able to get by on 3-4 kWh/day - a highly unlikely daily load, 28 kWh will not, by itself, carry the home for 7 days. Sounds to me like the usual Tesla B.S. from their droid incompetents.

[Will792]

In addition, in some markets, Tesla has been able to aggregate Powerwalls in a Virtual Power Plant (VPP) which allows owners to receive additional compensation for helping the grid.

In my market (CT) payments from this program roughly cover cost of PWs in 4-5 years. This assumes that the program stays the same in the future.

[Ampster]

In my market (CT) payments from this program roughly cover cost of PWs in 4-5 years. This assumes that the program stays the same in the future.

That is a better payback on batteries than most people get in other markets. Which is why some of the previous comments about economics of batteries may very well be different. That may also be one thing that adds to grid stability.

[Calsun]

We lose power many times during the year and after looking at the $7,000 price in 2012 for the Tesla battery pack I decided to put the money into a natural gas powered standby generator instead. The problem with battery packs is that they would have provided at most a 48 hour power supply and we have outages that can last for 3-6 days in Central California. The natural gas powered generator can run indefinitely. Also no fire worries with the outside generator and there was a Tesla battery at the local power plant that caught fire and fortunately could vent to the outdoors so no workers were injured. If it happened at a house it could have burned it to the ground.

[SunEagle]

We lose power many times during the year and after looking at the $7,000 price in 2012 for the Tesla battery pack I decided to put the money into a natural gas powered standby generator instead. The problem with battery packs is that they would have provided at most a 48 hour power supply and we have outages that can last for 3-6 days in Central California. The natural gas powered generator can run indefinitely. Also no fire worries with the outside generator and there was a Tesla battery at the local power plant that caught fire and fortunately could vent to the outdoors so no workers were injured. If it happened at a house it could have burned it to the ground.

So in another post you mentioned batteries that are charged from the grid via a 100amp panel. What type of batteries do you own?

[Calsun]

The local dealer for Tesla power wall units has had it take 16 months to get replacements for ones that have failed.