Powerwall

[GrayHare]

Finally, a standardized solution for spanning power outages, or even going off grid for someone with solar panels. The fire hazard of lithium ion masses in or near my home is a concern.

 

[jimnjana]

I will consider this for future purchase. For me, this may make sense as I do live in FL and power outages are something we plan for during hurricane season. We have a small gas generator that is enough for basic life support (room ac, refrigerator, lights). Currently if the power goes out, our PV system will go offline. So, if the battery back up will keep my PV system up and running DW would be very happy.

 

[tgotch]

Here is Musk's presentation.

 

[M Paquette]

This looks like a good design. 7 or 10 KW/Hour capacities, and capable of delivering 2 KW steady and 3.5 KW peak. The cells are liquid cooled, and in that large flat package, won't be as prone to thermal runaway as those dense, more cubical packages that hold heat in the center cells.

Our electric power use is pretty light, so one of the 10KW/Hour packs and a modest solar array could let us run 'off the grid' for an indefinite period, as long as we don't use the whole-house air conditioner or electric dryer. (Those would need multiple packs and a pretty expensive inverter.)


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[GrayHare]

Every thunderstorm brings momentaries and brief outages here. Having something to fill in those gaps would be very nice, though I see complexities that translate into additional installation costs. For example, the thermostat needs to not turn on the heat/cool system if supply is exclusively from the Powerwall.

 

[ERD50]

Agree with others that this might make sense for people off-grid (3rd world countries or vacation homes, etc) or in an area with lots of power outages. But how does it compare with other solutions? For non-mobile applications, aren't lead-acid much cheaper?

I guess lithium would be less maintenance than lead-acid, but I think cost will be a bigger factor for many. For the price delta, you might be able to have a 'battery guy' come out a few times a year to check the lead-acid?

But if you have a decent grid, I don't see how this would add anything. Solar panels are producing during peak rate times, so why store any kw-hrs?


Tech question: How does something like this, which is designed to both absorb and feed power, deal with a line outage and transfer switch? The typical backup generator sees the power goes down, and disconnects, starts up and powers the house. It can monitor the line, and shut the generator down and switch back in when the line comes up.

But in normal mode, this could be feeding the line in off-peak times. So how can it tell not to feed the line? Would it need to disconnect for a short time every few seconds, and disconnect if the line is down?
-ERD50

 

[Lakewood90712]

Lead acid storage batteries are a fraction of the cost. IIRC lead acid losses in charging/ discharging are about 30% , don't know if the lithium batteries are more efficient.

Tesla's plan all along was to replace Tesla elec. car cells that have become too week for the car under warranty, and re-purpose them in stationary storage devices like Powerwall.

Some elec. car lithium batteries can be degraded fairly quickly in hard use. An acquaintance with a Nissan Leaf lost 20% of range in just one year, thru hard use ( 70 mph in the car pool lane every day) Tesla has been tweaking software for model S owners to try and prevent range / capacity loss.

 

[candrew]

An interesting article on Tesla's Powerwall that addresses issues related to cost, safety, grid tie vs. off - grid, lead acid vs. L-ion.

Will The Tesla PowerWall let you go off grid for $3500 ? - Solar Quotes Blog

I'm impressed that Tesla offers a 10 year warranty on the Powerwall. I'm interested to learn more about inverter compatibility.

 

[ls99]

The system is 400 volts, from what I scanned. And will only sell to installers. I could possibly consider it for my camp, which has no commercial power. I would have to cough up more $$$ for solar panels to feed a 400 volt system. Plus install of the tesla stuff. Muchoo Drachma, no thanks.
As it is proposed I'll pass. Simply not cost effective for me.

 

[pb4uski]

On our local news it indicated that it would supply power for about 6 ours in event of an outage. Not long enough for me to be interested, but I'm sure it will get better/more interesting over time.

 

[ERD50]

An interesting article on Tesla's Powerwall that addresses issues related to cost, safety, grid tie vs. off - grid, lead acid vs. L-ion.

Will The Tesla PowerWall let you go off grid for $3500 ? - Solar Quotes Blog

I'm impressed that Tesla offers a 10 year warranty on the Powerwall. I'm interested to learn more about inverter compatibility.

Interesting - according to his figures, the long term cost is much lower than lead-acid. Sounds like this would have applications for the RV crowd, maybe if scaled down?

-ERD50

 

[M Paquette]

Next, what we need to get in North America is something like THIS, so we can sell the accumulated power in that battery automatically on the spot market instead of at whatever rate the utility decides to offer or the local PUC sets.

 

[Lakewood90712]

Next, what we need to get in North America is something like THIS, so we can sell the accumulated power in that battery automatically on the spot market instead of at whatever rate the utility decides to offer or the local PUC sets.

Just hold the phone a minute. My ER is partially funded by electric utility company dividends, so I need things to continue as is, rigged in favor of the utility , not the power customer

 

[candrew]

Next, what we need to get in North America is something like THIS, so we can sell the accumulated power in that battery automatically on the spot market instead of at whatever rate the utility decides to offer or the local PUC sets.

+1

We have a grid-tied array on our home in the Phoenix area. Excess power we feed back into the grid during high demand, high cost on-peak hours is reimbursed to us by our local utility at the wholesale rate while power we pull during off peak is charged to us at retail (that includes power generation charges). And yet there are still complaints from the utility and others about solar customers not paying their share of the freight for use of the grid.

 

[ERD50]

Next, what we need to get in North America is something like THIS, so we can sell the accumulated power in that battery automatically on the spot market instead of at whatever rate the utility decides to offer or the local PUC sets.

Have you seen any case studies? I'm curious what people on average are able to get for their stored kWh. I have read that peak rates can go very high for utility, but haven't seen any real numbers, $ and hours/day averages.

If it is very profitable, I gotta wonder why the utilities wouldn't just do this themselves, at commercial scale, which would have better economies of scale?

+1

We have a grid-tied array on our home in the Phoenix area. Excess power we feed back into the grid during high demand, high cost on-peak hours is reimbursed to us by our local utility at the wholesale rate while power we pull during off peak is charged to us at retail (that includes power generation charges). And yet there are still complaints from the utility and others about solar customers not paying their share of the freight for use of the grid.

Well, it pretty much makes sense for the utility to pay you wholesale rates - that's what they pay other suppliers, so why should you be different? Though I could understand some premium for 'green' energy, if that is built into their rates.

But then there should be no issues about not paying for the cost of the grid (assuming you pay a basic connection fee), I don't think other wholesalers pay any grid costs. And you are effectively lowering distribution losses for them, your excess electricity will be absorbed by your nearby neighbors, rather than traveling many miles from a power plant.

One more thought on this - if someone is using the Tesla battery to store/sell electricity, then what are the chances they will have much power during a blackout? What if they just sold most of it hours before the blackout? What if that happens in the evening, and we are 12 hours away from getting any significant solar?

It seems like you do pretty much one or the other, or take your chances - but who wants to take a chance of being w/o power after spending this kind of money? I guess buy two systems, only sell from one? More $$$.

-ERD50

 

[jimnjana]

+1

We have a grid-tied array on our home in the Phoenix area. Excess power we feed back into the grid during high demand, high cost on-peak hours is reimbursed to us by our local utility at the wholesale rate while power we pull during off peak is charged to us at retail (that includes power generation charges). And yet there are still complaints from the utility and others about solar customers not paying their share of the freight for use of the grid.

With FPL we get a credit and build a Reserve with excess generated. It works out well enough for us. During the summer months the reserve is drained and we start all over again in the fall.

 

[Mulligan]

Just hold the phone a minute. My ER is partially funded by electric utility company dividends, so I need things to continue as is, rigged in favor of the utility , not the power customer

+1! Electric utility preferred stocks are about the only thing I am willing to invest in. A sure thing.... Don't be coming up with some invention to upset my applecart. My electric bill was in the $40s this month. I gladly will pay that to get my thousands in yearly preferred dividend payments back from them.


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[Lakewood90712]

This product is a baby step, but it's real. It's going to take time, like 15-20 years, distributed generation on the grid is going to happen. The vested interests , like my electric utility companies will fight , eventually they will have to adapt.

 

[ERD50]

This product is a baby step, but it's real. It's going to take time, like 15-20 years, distributed generation on the grid is going to happen. The vested interests , like my electric utility companies will fight , eventually they will have to adapt.

Actually, if something like the earlier link, Reposit Power , comes to pass, why would the utilities fight it? More people supplying energy for the peaks means more competition and lower spot prices. The utilities have to buy/produce that peak power to sell to you (at average rates) - the more suppliers the merrier.

But as I also said, if this is cost effective, it sure would seem like the utilities would jump on it themselves. One large installation versus hundreds of homes makes a lot more sense. And those installations can still be small enough to be distributed around a populated area, to reduce distribution losses.

When solar/wind become big sources on the grid (w/o storage), it is a problem for the utilities - they may have to ramp up their peaker plants as these supplies vary, and they don't have any control over it. So at some point they will (and are) fighting that. But if people are connecting batteries, that helps to smooth out the variance - it's all good (if it is affordable).

-ERD50

 

[imoldernu]

A little off-topic, but a true story about living off the grid, back in 1976.
My BIL and SIL moved from New York to Prince Edward Island to oceanfront property about a 3/4 mile from power lines. Even then, the cost to bring electricity in was about $20K... steep for my relatives who were starting a new business on a shoestring and living in a very old trailer.
Heat from a wood stove, and water from a shallow well and propane for cooking. They bought and installed a small windmill and a 12 battery power supply. House wiring for lights, small appliances, well pump, washer and refrigeration varied from 12V to 36V... A small generator for emergency power was hardly ever used. They lived there for two years while building their home.

Am not sure of the details, but recall that during that time, they felt no stress or hardship. He later went on to incorporating windmill sales as part of his expanding business. As I recall, the entire project... wind power, batteries, specialty appliances, wiring and the trailer itself came to about 12K... allowing them cash to build their new business...

The Tesla technology maybe new, but living off the grid has been around for a long time.

 

[Lakewood90712]

Actually, if something like the earlier link, Reposit Power , comes to pass, why would the utilities fight it? More people supplying energy for the peaks means more competition and lower spot prices. The utilities have to buy/produce that peak power to sell to you (at average rates) - the more suppliers the merrier.

But as I also said, if this is cost effective, it sure would seem like the utilities would jump on it themselves. One large installation versus hundreds of homes makes a lot more sense. And those installations can still be small enough to be distributed around a populated area, to reduce distribution losses.

When solar/wind become big sources on the grid (w/o storage), it is a problem for the utilities - they may have to ramp up their peaker plants as these supplies vary, and they don't have any control over it. So at some point they will (and are) fighting that. But if people are connecting batteries, that helps to smooth out the variance - it's all good (if it is affordable).

-ERD50

Large scale , it has been done in Japan, even before the Fukashima disaster, using Sodium sulfur battery tech. I don't know id li-on is scaleable on an economic basis. The sodium sulfur tech has low losses in charge/discharge (under 10 %) but I wouldn't want it near my house.

 

[ERD50]

Large scale , it has been done in Japan, even before the Fukashima disaster, using Sodium sulfur battery tech. I don't know id li-on is scaleable on an economic basis. The sodium sulfur tech has low losses in charge/discharge (under 10 %) but I wouldn't want it near my house.

Right, some utilities are looking into this, a few pilot programs are out there. But I do think they use batteries that are much cheaper than Lithium (the sodium sulfur you mention, some kind of iron something or other, probably a few others). Lithium is the choice for portable power because it has the best energy density, but size/weight isn't that important for a stationary application like a utility would be using. Same with safety, not nearly as important when you don't carry it in your pocket, or drive it around a public road.

-ERD50