For a home DC charger more directly connected to an integrated Solar/Powerwall/Inverter/Gateway system, there is "DC Level 1" that ranges 200-450V up to 80A for a maximum 36kW, but Tesla doesn't need to follow that standard and could have their own rate optimized to their hardware. I believe Powerwall currently has internal battery 50V, so maybe it can deliver 5kW @ 100A or 10kW @ 200A which have reasonable wire gauge requirements for home? In any case, the DC voltage doesn't necessarily need to be very high nor amperage either as people generally don't need a personal supercharger in the garage, so whatever is sufficient and safe for an overnight charge is probably good enough.
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Elon tweets: Solar Roof and solar panels will only be sold integrated with Powerwall
- Thread starter willow_hiller
- Start date
With Powerwall/Inverter/Gateway sitting between utility meter and main panel, this seems to place the batteries as close as possible to the grid. Is there enough financial benefit for the utility to have access to the batteries? If so, this value could be shared on a per-kWh basis or in aggregate, e.g., partially subsidized Solar+Powerwall upfront cost.
At least for us, on average we could get an additional ~10¢/kWh for sending electricity to the grid at peak hours instead of off-peak, so if batteries had 14kWh to do this every day, that's around $500/year. If there's another 10¢/kWh utility value available every day, that would have a potential 10-year total value around $10k, which suggests it wouldn't be too unreasonable for subsidization to happen, e.g., Tesla keeps competitive pricing relative to other Solar-only installers because Tesla gets paid by utilities.
At least for us, on average we could get an additional ~10¢/kWh for sending electricity to the grid at peak hours instead of off-peak, so if batteries had 14kWh to do this every day, that's around $500/year. If there's another 10¢/kWh utility value available every day, that would have a potential 10-year total value around $10k, which suggests it wouldn't be too unreasonable for subsidization to happen, e.g., Tesla keeps competitive pricing relative to other Solar-only installers because Tesla gets paid by utilities.
jhn_
Member
Completely rampant speculation built off of other rampant speculation!
That’s what the ConnectedSolutions program in New England is. Power Co. pays to have your battery export to the grid at periods of high demand. You can opt in or out.
CrazyRabbit
Active Member
my guess is a powerwall with a integrated solar inverter is around the corner. DC inputs to PW.
So did I. Reminded me why I ordered my system with 2x powerwalls. Looking forward to the install in two weeks!
No, thats a separate thing (at least from the long discussion thread that is stickied here in this section on it). Some of the people were offered a "free" powerwall to go with their increased price, but it doesnt appear everyone was.
Ah thanks. Looks like there's a few official Tesla pages about virtual power plants that describe the potential benefits.
ConnectedSolutions: "For example, a Powerwall paired with an 8 kW solar system in Massachusetts could create almost $12,000 in value - $3,200 from the federal tax credit, $4,800 from the SMART storage incentive and $3,850 from ConnectedSolutions – more than enough to cover the Powerwall’s price."
South Australia Virtual Power Plant: "A typical customer joining Phase 3 of SA VPP is expected to save between $40 and $406 off their annual electricity bill while providing clean energy to the community and supporting the grid."
The ConnectedSolutions page also points out Powerwall without Solar can still get some benefit, but that gets less than 30% of the value, so Tesla probably wants to have control of more solar-fed Powerwalls directly interfacing with the utility meter, and once they have enough in a region, Tesla can start negotiating with local utilities.
Interestingly and maybe a preview of what might happen if US legislation provides standalone energy storage incentives (i.e., no longer reducing credits based on percentage of solar charging), South Australia Tesla Energy Plan explicitly discusses Energy Arbitrage: "At times, Tesla may charge your Powerwall from the grid and discharge it to the grid for energy arbitrage, taking advantage of low rates to store energy in Powerwall, and then selling it back to the grid when energy costs are higher. Tesla shares this value with customers through grid support bill credits applied monthly and competitive Time of Use rates. This allows you to take full advantage of lower off-peak and solar sponge times to power your home when your Powerwall or solar is being managed, helping to offset any consumption from the grid during peak times when you typically use electricity."
DJVoorhees
Member
Im glad I got my panels already, no way I'd buy those overpriced power walls. My utility offers net metering so the power wall dont have an ROI for me. they were trying to push 4 on me for a total of like 26k, made solar a complete joke when doing the math.
When we purchased our 2012 S P85, Tesla was recommending 90% as the normal max charge, and charging above that only when needed - and not keeping the battery above 90% for long before driving.
We have 4 PW on a "Free Nights" plan using the Cost Savings mode. Overnight, the system appears to predict how much solar power will be generated the next day, and will discharge the PowerWalls during the free night period (even though our grid power is free).
While we'd prefer not to use any PowerWall energy overnight - and keep as much as possible for unplanned outages or for days with cloud cover, it's very possible the system uses the PowerWalls overnight to avoid having them sit fully charged.
The only time (in Cost Savngs) that the batteries will sit at 100% for long periods is when Storm Watch is activated. Otherwise our batteries do a charge/discharge cycle each day - which is covered for unlimited cycles for 10 years, as long as we (normally) charge only from the solar panels.
Yeah I agree with the general theme that Powerwalls and battery backup is probably a thing that Californians will be able to rationalize a lot better than folks in other states with normal utilities that don’t shut down services en masse multiple times a year. So it doesn’t make much rational sense for Tesla to force Powerwalls on everybody.
But from a business perspective it makes perfect sense. Tesla did their plan of bargain basement solar installs in the last two years to put themselves on the map. While sunrun/vivint keep spending on advertising, Tesla got word of mouth and priority inquiries on name brand and price.
So now Tesla needs to unlock some path to actually making profit, and they do that integrating energy sources and storage into one system and leave antiquated low-margin solar-only for the other guys. This keeps Tesla at the forefront of residential energy while also leverages their strength with inverters and storage.
But from a business perspective it makes perfect sense. Tesla did their plan of bargain basement solar installs in the last two years to put themselves on the map. While sunrun/vivint keep spending on advertising, Tesla got word of mouth and priority inquiries on name brand and price.
So now Tesla needs to unlock some path to actually making profit, and they do that integrating energy sources and storage into one system and leave antiquated low-margin solar-only for the other guys. This keeps Tesla at the forefront of residential energy while also leverages their strength with inverters and storage.
Were they not already "on the map" in solar when they bought one of the largest, if not THE largest solar installer nationwide? Though that business seemed like an unprofitable, unsustainable high-volume business model - every time I walked into a Home Depot there was a SolarCity salesperson roaming the aisles, the amount spent on sales and commissions plus advertising...
I think I get what you mean though, the bargain installs was also not going to be profitable as a low overhead, high-volume model, but a loss leader to prime leads to upsell batteries and swing towards profitability.
pdx_m3s
Active Member
This
Appropriate for some, and not for others. I still cant figure out why so many people seem to think "the right choice for me is the right choice for everyone" for stuff like this. Im not trying to tell you that powerwalls are right for you, why are you trying to tell everyone that powerwalls are not right for them?
DJVoorhees
Member
It's simple math, if you are considering Solar for anything other than simple savings which you can calculate on the back of a napkin, then nothing here matters.
Solar and power walls meant we could work and bill throughout some outages. The solar Roof was more than panels but looked better to us. It was definitely not all about money for us.
This is one of those "soapbox" type issues for me... I have written and erased this response like 5 times because I find myself ranting. Lets just say that I feel "very strongly" that peoples individual circumstances, wants, desires etc drive these kind of decisions, and just because purchasing some item or other is right (or wrong) for one person does not mean it is automatically right (or wrong) for everyone.
So, I fully support everyones individual decision, and reject strongly any notion that one persons "lack of ROI" has anything to do with anyone but that person.
DJVoorhees
Member
Nobody said it was, it's an assumption you made based on someone agreeing with someone else.
I think it’s safe to say that initial SolarCity attempt didn’t go so well. But the rebooted Tesla Energy business model seems poised to be the leading solution for homeowners who want green energy tech plus bells and whistles from Tesla.
I think Powerwalls are great, and I couldn’t care less if someone else doesn’t want them in their house. I’m pretty sure everyone here has a unique reason to buy what they want to buy.
I also hate PG&E out of spite since they’re so poorly operated. so I’m on board with the notion of everyone possible getting solar plus batteries in NorCal. Yay for Elon in making pv+ESS more common. this setup is the most any homeowner is legally allowed to gain some distance from PG&E (100% grid defection is illegal). The ROI doesn’t work from a pure financial perspective, but the spite makes it worth it to me.
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