Tesla announces low cost batteries for off grid homes


Guest essay by Eric Worrall

Elon Musk has announced the release of a new storage battery for home use. The new battery in principle dramatically reduces the cost of going “off grid” – powering your house entirely from solar or wind, and using the battery to provide backup power, to ensure continuous supply.

According to The Guardian;

The electric car company Tesla has announced its entry into the energy market, unveiling a suite of low-cost solar batteries for homes, businesses and utilities, “the missing piece”, it said, in the transition to a sustainable energy world.

The batteries, which will retail at $3,500 in the US, were launched on Thursday at a Tesla facility in California by the company’s ambitious founder, Elon Musk, who heralded the technology as “a fundamental transformation [in] how energy is delivered across the earth”.

Wall-mounted, with a sleek design, the lithium-ion batteries are designed to capture and store up to 10kWh of energy from wind or solar panel. The reserves can be drawn on when sunlight is low, during grid outages, or at peak demand times, when electricity costs are highest.

The smallest “Powerwall” is 1.3m by 68cm, small enough to be hung inside a garage on or an outside wall. Up to eight batteries can be “stacked” in a home, Musk said, to applause from investors and journalists at the much-anticipated event.

Read more: http://www.theguardian.com/technology/2015/may/01/tesla-announces-low-cost-solar-batteries-elon-musk

I’m excited by this announcement, not because I’m currently considering buying a Tesla battery, but because of the potential this announcement has, for exerting downward pressure on household electricity bills.

Assuming the battery has around 1000 charge / discharge cycles, paying $3500 every 3 years is approaching price parity with some of the more ridiculous electricity utility charges. When you factor in the satisfaction of tearing up your last electricity bill, there is a real chance a significant number of people will be tempted to make the leap.

How will utility companies respond? I suspect they will be forced to cap household bills, to put as much price distance as possible, between the Tesla option, and staying connected to their grid. It will no longer be possible to make electricity rates skyrocket, to treat household electricity consumers as an inelastic revenue source – because now householders have an alternative, to putting up with endless price rises.

The biggest losers from this potential game changer, in my opinion, might be large scale renewable energy providers. Since households now have an alternative to paying ever larger electricity bills, electricity utilities will be forced to keep costs down – they will no longer be able to ignore costs imposed by government mandated renewable schemes. Either the government will be forced to provide higher subsidies, or large scale renewable schemes will have to be scaled back, to keep grid electricity price competitive.

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May 2, 2015 9:06 pm

thank you, Tesla.

Ian W
Reply to  John
May 3, 2015 3:29 am

John you must be invested in Lithium futures.
Have you thought how much Lithium would be needed even for a small town? So you are now thinking this could be done for hundreds of millions?
Get an envelope work out how much Lithium per dwelling, and per car and per every other electronic battery device.
Now check that amount of Lithium against known world wide reserves.

Reply to  Ian W
May 3, 2015 6:22 am

While lithium is fairly common, there is a problem with lithium batteries that greatly reduces their number of charge/discharge cycles. Every time you do on, you cause a dendrite to grow a bit from one of the electrodes. When it hits the other electrode, the battery shorts out. That is ok if you are talking only having the battery for a couple/several years. You will dump the laptop or whatever before the battery quits on you. Not so good with a solar system. You cannot afford to replace the battery every 5 years. Even worse, if the battery shorts out, you have a bomb on your hands. Lead acid also fails eventually due to the sludge at the bottom of the cells, but the fail is less catastrophic and takes longer. My lead acid cells are probably good for 20 years given they are the highest grade industrial cells I could buy and have been shown to have that sort of lifetime. The downside of lead acid is that they are not maintenance free and you have to deal with the hydrogen, etc. that vents out of them. I think my lead acid 100 KWH bank is about the same cost and same total volume as the “musk wonder” with an equivalent amount of storage and will last several times as long as it would.
Musk harvests subsidies, not a lot more. Like P. T. Barnum, people pay to see the show. Nothing against solar or wind properly deployed, but the economics are not what folks think they are.

Reply to  Ian W
May 3, 2015 8:34 am

One can just as easily make Potassium Ion batteries and Magnesium Ion batteries are proven (though not commercial yet). There are dozens of alternative battery chemistries that are show to be about as good as Lithium, or better. As soon as lithium costs too much, the others will substitute. (Already are in some cases).
With that said:
There are also already many battery chemistries that are cheaper than Lithium and work just as well in stationary applications. THE one feature of Lithiums is the light weight in mobile (cars) applications. Not relevant to my garage wall… So (as pointed out below and in the posting I did on this referenced below) simple deep cycle lead acid batteries are about 1/3 the cost, while the old Edison Cell Ni-Fe battery has a multi-decade life span for about the same cost (less in bulk) and are still used in such applications.
This is just a Subsidy Farm for Musk, not a game changer.

Reply to  John
May 3, 2015 4:01 am

Complete and utter crap

Aynsley Kellow
Reply to  Alex
May 4, 2015 4:52 am

Alas, I tend to agree. They will store ‘up to’ 10kWh of energy for $3500? SO to run a 2kW radiator for 5 hours will cost you $280 at 8% interest – about 15c/kWh just for the storage component. This price will undoubtedly come down, but it is not cheap storage – and there will need to be capacity in excess of demand to charge the battery.

Reply to  John
May 3, 2015 4:40 am

Another company already offers such battery systems , at a significantly lower cost that Tesla. No thanks, Tesla.

Reply to  arthur4563
May 4, 2015 8:09 am

Right. The idea that this is innovative or new is … well, suckered by good PR.
It’s an amazing thing only if he gets the cost down. Hasnt done that yet.

Reply to  John
May 3, 2015 9:00 am

50 years ago I worked summers on the railroad Signal department. Mostly trimming weeds and trees. At that time they had four large lead acid batteries in the bottom of each of the crossing guard control system. There were a rectangular glass jar about 12 inch wide, 18 inch long and two feet high and Each of these had dates of instillation on them. Other than those that were replaced due to cars hitting the control cabinet every one of them I saw was over 20 years old. About every five years we would pump out any sludge from the bottom, like you might do in a fish tank, with a glass – turkey baster – looking device. The Signalman I worked for said that many of these batteries were over 40 years old. On the other hand, I have never had a battery in any power tool of any type last longer than four years – and I am retired and only use these tools as a hobby, Same for all of the LiIon batteries in my many laptops/cellphones.

Reply to  usurbrain
May 3, 2015 10:10 am

I’m off grid and use 6 volt golf cart batteries. Assume 5 years max and that at 20% discharge nightly. Increase that to 50% and figure 3 years and that’s if you don’t screw something up. Sorry but that’s pretty much the facts of life. Solar is great but batteries suck.

Reply to  usurbrain
May 3, 2015 1:17 pm

@EXPAT. These large glass lead acid batteries only use the same type of electrodes and acid. In my 20 years of service in the Nuclear Navy on submarines I only knew of on Battery replacement (Battery meaning the entire set). Yes, occasional an individual cell needed replacement but most of the time there were extenuating circumstances for this replacement. They usually lasted the life of the sub and then some. When the sub was decommissioned the battery (all of the cells)m were salvaged reconditioned and used again. Same for the Emergency batteries that are at every Nuclear Power plant. These cells can be cleaned, and sort of flushed out [like a radiator flus or transmission flush at your local auto repair shop.] I have done this to my car battery and gotten another two years from a standard cheap car battery. Just empty the dirty sludgy acid, flush out with distilled water three or four times, fill with NEW acid, recharge. This has recovered the bad individual cell in a 12 volt battery giving me full power and voltage from the battery. The glass jars in industrial cells just make it easer and let you see the sludge in the bottom.

Janice the Elder
Reply to  John
May 3, 2015 5:38 pm

“Tesla is currently taking orders for the systems, with the first units expected to shift in August.”
You may want to wait, before thanking them, until they actually build and ship a product. In addition, though the company web page says these batteries are warrantied for ten years, I cannot find any specifics about what the warranty covers.

Reply to  Janice the Elder
May 4, 2015 9:21 am

Not to worry Janice, the hype fits the needs for Paris in December and that is what is important right now. After Paris we will start to learn if these batteries change anything very much.

D.J. Hawkins
Reply to  Janice the Elder
May 4, 2015 12:12 pm

Sounds like the return of “vaporware”.

Mark Fraser
May 2, 2015 9:11 pm

So, the on-demand power bank, that holds a buck worth of electricity, costs 100 bucks a month. I imagine each pack comes with a nifty decal for my front door, though.

May 2, 2015 9:11 pm

And I’ll strap a massive heat-sensitive fire hazard to the side of my house? I like the idea of the battery, but I’d never put a giant block of lithium anywhere on my property.

Ted G
Reply to  dangerdad
May 3, 2015 3:59 am

This is potentially good news as Eric Worrall said – How ever your right, lithium-ion batteries have a dark side = fire and explosion potential, a degrading life span. Also ask the people in snow country how the Solar panels stood up to 2 to 6 feet of snow on the roof, Stressing the panels, roof mounting brackets and the roofing material causing stress leaks (shingles /tiles etc…) or the panel performance when they get dirty???
Just asking?

Hector Pascal
Reply to  Ted G
May 3, 2015 5:06 am

Snow country here. We have a metre of snow on the roof from end of December to early March. No solar panels here. Nope, not going to happen.

Reply to  dangerdad
May 3, 2015 5:15 am

Lower electric bills, higher insurance premiums. Yeah, sounds like a GREAT idea.

Reply to  dangerdad
May 3, 2015 2:30 pm

Especially if the lithium container is breached and water gets introduced to the lithium. Water on lithium makes a fire much bigger and spectacular.
I don’t think the firemen would be amused when chunks of molten lithium are blown out of the battery and lands on the firemen (& fireladies).
I would expect that new building codes would require lithium batteries located in a separate building built out of reinforced concrete or cinderblock open to the sky.
So much for off the grid.
Anyway the batteries are still far to expensive for me.

Reply to  ATheoK
May 4, 2015 12:51 pm

There have been several reports lately of the problems caused by solar panels during a fire.
I’ve been reading about some fire depts. talking about creating a standing policy of only fighting fires in building with such panels from the outside.
Between the danger of the inside wiring still being energized, to the additional weight causing roof collapses to be more likely, and more deadly, to the problems of trying to ventilate a roof covered by such panels, it just isn’t worth the risk to them.

May 2, 2015 9:12 pm

More importantly, coal and gas power stations won’t have to keep burning to have back up power for erratic energy demand from “renewable” sources, if everyone who installs it also installs a battery.
However, from an environmental perspective,” renewables” just became more detrimental than fossil fuels (which are still needed to dig the toxic cocktails out of the ground, transport them, smelt them, manufacture them, install them, maintain them, repair them and eventually dispose of them)

Reply to  wickedwenchfan
May 2, 2015 10:15 pm

The “hower ever, from an environmental perspective”…. that has been my biggest opposition against the so called renewables for years, there has never been that part of the equation talked about on the so called “green” side.

Reply to  wickedwenchfan
May 2, 2015 11:34 pm

coal and gas power stations won’t have to keep burning to have back up power …“.
Regrettably, that won’t be true for a long time yet. There will still be enforced unreliables on the grid. A big move off-grid simply means higher costs for retail consumers. Another “regrettably” is that the only reason this off-grid stuff can even remotely compete is the high power price created by the mandated unreliables. It’s a double whammy for the long suffering ordinary citizen.
Here in Oz there’s a battle going on in govt circles about whether to increase or cut the RET (renewable energy target) . Hopefully sanity will prevail, i.e. a cut.

Reply to  wickedwenchfan
May 3, 2015 2:56 am

And, then, there are taxes. Energy is highly taxed. It might be “political” to look the other way in some cases but, if this sort of thing takes off, it will be heavily taxed too.

Reply to  wickedwenchfan
May 3, 2015 3:20 am

Sorry wickedwenchfan, coal and gas stations run at their most efficient at rated power. They have to keep going.

Reply to  johnmarshall
May 3, 2015 6:26 am

However, combined cycle ng plants do not have to run continuously, they can start up and shut down quickly. Coal is another matter all together.

Reply to  johnmarshall
May 3, 2015 12:28 pm

Where did you get that information? 40 Years experience in the electrical utility generation and I have never heard that. Yes, it does have a faster startup/shutdown time HOWEVER, the efficiency comes from the combined cycle part – that is steam generation from the waste heat, then the steam driving another generator. How long does it take for you to get heat out of you car heater on a cold day. 15 minutes, more? that would be great but it is longer. By the time the CCTG is at peak efficiency the storm cloud has passed or the wind is blowing and you don’t need it any more. Meanwhile you are using the power of just the gas turbine part of the generator and you need two to get the power of one working at full efficiency. Thus you are pumping just as much CO2 into the air as the dirty coal plants that the Envirowhacos want to get rid of. No net reduction in CO2 just double, triple the cost for electricity. Don call me nuts do some research and discover the FACGTS, not the propaganda.

Third Party
May 2, 2015 9:13 pm

Storage near $100/kWh is no big deal. We want <$10/kWh….

Reply to  Third Party
May 2, 2015 9:21 pm

And this is about $350/kWh.

Mario lento
Reply to  PabloNH
May 3, 2015 12:25 am

Some perspective here. The 10kWh can be used daily for solar and intermittently for wind power.

Reply to  PabloNH
May 4, 2015 8:14 am

So if can handle 1,000 cycles, then the battery cost is $350/1000 or 35cent / KWh ???
Huh, only 3x my utility bill cost for electricity for the battery alone. The math doesnt add up.

May 2, 2015 9:15 pm

Could be a big opportunity to save power company costs if the batteries can be optimized for load shifting to pull power from grid during low demand periods and running on battery during high demand periods, perhaps the integrated power management of the battery can be controlled by power companies as to when to draw power from grid or to run on stored power. Power companies may include these a premise equipment complementing the power meter, or provide a special rate for consumers who use load-shifting versions. Load shifting at premises could reduce the cost peak load requirements on power plants and distribution systems and thus save everyone money.

son of mulder
Reply to  kenneumeister
May 3, 2015 2:43 am

If everyone is charging their battery from the grid during the low demand period, when will the low demand period be?

Reply to  son of mulder
May 3, 2015 4:48 am

“when will the low demand period be”
Exactly. Trim the peak, raise the valley, it’s for load leveling. I suspect they’ll only be economical in areas that have really high rates. I haven’t looked into what power they can output, but they probably can’t run your home without the grid either.
Is an Inverter included?

Ann Banisher
Reply to  son of mulder
May 3, 2015 7:23 am

“You can go to the Tesla website – wwwDOTtelsamotorsDOTcom/powerwall…..and see some of the limitations. There are several, but the important ones in my view are the “Power” rating of 2.0 kW continuous 3.3 kW peak and the “Installation” where it says AC-DC inverter not included.
What the “Power” limitation means, is if you want air conditioning….it better be a room air conditioner because that will take 1.1 kW. Central Air is more like 5 kW and way too big for one Tesla unit. You also probably do not want to cook anything, wash, iron, heat, dry your hair or a whole other list of things we take for granted. Google “household power requirements.” 2 KW….2000 watts…is not a lot of power.
The other big limitation is the “AC-DC inverter not included.” Since the battery is DC….and everything in your house is typically AC…..you need something to convert that power. You can buy a decent inverter built for solar panel systems for around $2000….so now your basic Tesla battery / inverter system that will run (1) hair dryer, a TV and your electric toothbrush costs you $5000….before paying for installation.”
If you are connected to PG&E in Southern CA, you can save 4 cents per kWh by charging at off peak times. A 10 kwh daily use Tesla battery will cost you $7000 installed with the required AC/DC inverter and will save you 40 cents per day. (10 kWh x 4 cents savings per kW)

son of mulder
Reply to  son of mulder
May 3, 2015 7:38 am

And when should I charge my electric car?

Reply to  son of mulder
May 3, 2015 8:38 am

@Ann Banisher
Yes I’m aware of residential power and energy requirements. And that this wouldn’t allow you to go off-grid, even with a massive lifestyle change. But I don’t expect rates to remain stable in the future, at some point this concept might be effective?
I’m not in CA so I’m guessing here. I pulled up the PG&E TOU rates March 2015. The basic energy charge Schedule E-7 Tier 1 off=peak – peak: $0.11129 – $0.35944 (yikes!) That’s ~$0.25 delta for summer. And you are correct on the $0.04 delta for the winter rate.
Assuming net metering, the investment would be better spent on PV.
BTW, I find the idea of the California Climate Credit amusing.

Ann Banisher
Reply to  son of mulder
May 3, 2015 10:12 am

Yeah, net metering would wipe out any benefit of peak offpeak saving.
I already have solar here is SoCal to insulate myself from future Ca Climate stupidity.
Unless I was off grid and wanted to piggyback 3 of these packs together, I can’t see the retail use of this.
As for utility scale use, if one $3500 wall pack of batteries will get you 3 hr of peak use of an average household, how big a facility would your average utility need to house that mountain of batteries?
And we haven’t even addressed lifespan and storage loss.
BTW, my rates for net metering are $.19/kWh base, $.29 tier 2, $.43 tier 3 & $.46 tier 4 (tier 2 kicks in at 150, 3 at 300, & 4 at 400/kWh per mo) talk about yikes!

Bill Parsons
Reply to  son of mulder
May 3, 2015 11:15 am

A typical American household uses about 10,000 kWh yearly*, which would average out to about 27 kWh per day.
“…designed to capture and store up to 10kWh of energy from wind or solar panel. The reserves can be drawn on when sunlight is low, during grid outages, or at peak demand times, when electricity costs are highest.”
So, would you need three of these things to go “off grid”? That would be about $10,500 for independence… replaced every HOW often?!
I also wonder about whether his cost is based on the projections of what Musk’s “gigafactory” will do once it hits full stride, which may take years; and finally, whether, some of that production cost is factoring in start-up subsidies still being handed out for solar enterprises. Solar still looks like one of the most expensive energy sources, considering panels, converters, maintenance, batteries, and costs to the environment.
* Organization of American States Office of Sustainable Development

Reply to  son of mulder
May 4, 2015 12:55 pm

Ann, presumably you already have a DC to AC converter that came with the solar panel.

Reply to  kenneumeister
May 3, 2015 12:37 pm

How will the power company save costs when they have to pay homeowners that are giving them electricity 5 times as much as it costs them to make electricity? And provide all the power distribution costs on top of that. Nuclear and Mine-mouth coal plants can make electricity for about $0.03 to $0.05 per kwh. Net meter programs make the utility pay the home owner $0.12 to $0.20 per kwh how does that save money. How long could you sell donuts if you sold donuts for $6.00 BUT had to by back any donuts the costumer brought back during the same day for $0.50 each?

May 2, 2015 9:17 pm

There are other companies producing similar technologies. There is a company in Calgary, Alberta supplying control systems for LG systems. This is a potential winner for all parties – off grid, solar PV storage, wind storage, peaking storage in home, and someday, industrial, load balancing, remote site and developing nations, etc.
Elon Musk is a super promoter but this is an emerging technology that could help in a lot of areas once all the issues are worked out. But all technologies are like that.
150 years ago, who would have guessed that something as simple as reinventing Roman sewer and water systems would increase our life spans and reduce death and disease … and that we are still working on providing these services in the developing world.

Harry Buttle
May 2, 2015 9:18 pm

Their website says a 10 year warranty – http://www.teslamotors.com/powerwall

Reply to  Harry Buttle
May 2, 2015 9:26 pm

… as long as you never charge them.

Martin Audley
Reply to  Harry Buttle
May 3, 2015 2:40 am

OK – So it costs $1 per day within its 10 year warranty. Double that to £2 to include a similarly-priced inverter (that likewise is likely to fail in that time) and installation costs.
Soooo, can anyone save $2 per day just on the difference between peak and low electricity costs now?
It’s certainly not a slam-dunk money saver.

Reply to  Martin Audley
May 3, 2015 5:02 am

“can anyone save $2 per day just on the difference between peak and low electricity costs now”
IF you peak rate is $0.30 kWh, and charged it with PV, your 10kWh battery potentially contains $3 worth of electrons, no?
IF they made system controls for a home battery, the PV inverter would become a DC/DC converter that feeds into the battery, and then use the battery’s inverter (DC/AC) to push power to the grid. That inverter would need to be bi-directional to pull power from the grid to charge the battery at night. It’s the same topology as a fuel cell vehicle.

Reply to  Martin Audley
May 4, 2015 9:01 am

You’ve also got to make the electricity to go in them: add the cost of the solar panels.

May 2, 2015 9:22 pm

Tax Credit?

May 2, 2015 9:24 pm

Re-election money.
Renewable energy Tax Credit.
Sure as the sun not shinning on a rainy day.

Reply to  fobdangerclose
May 3, 2015 2:16 am

The quoted price for off the shelf technology i. e. Li-On batteries is waaay below the real-world cost. One can only assume the mug punter musk shareholder is the real loser, a regular Pt Barnum for the new millennium, Is that apple juice i whiff in your always half full glass?

May 2, 2015 9:25 pm

The developing world may be the biggest beneficiaries. An entire village could share one.

Ian W
Reply to  gymnosperm
May 3, 2015 4:49 am

It would cost the entire village’s annual income.
When you are living hand to mouth using dung for fuel and ox carts for transport, with the nearest power line a few hundred miles away, being offered a garage wall battery is way up in the ‘let them eat cake’ level of understanding.

Reply to  Ian W
May 3, 2015 8:20 am

Certainly true right now, but on a national level compared with the costs of developing high voltage generation, distribution and transformer substations; a solar array and a really good battery could be a cheap way to light up a village.

Ian W
Reply to  Ian W
May 3, 2015 8:39 am

Re gymnosperm
May 3, 2015 at 8:20 am
If you wish to keep that village a village and the people in poverty and in hoc to whoever paid for the batteries, PV cells, inverters etc., That of course is the current approach try to keep the poor in poverty and prevent development that reliable power could bring. Reliable real power would provide 24/7 refrigeration for medicines and veterinary supplies, as well as lights power for cooking, perhaps televisions for the entire village. No…… “pat villager patronizingly on the head’ it’s cheaper for us just to give you enough for lights at night and, as we gave it to you we expect your vote in exchange for our largesse.

Samuel C Cogar
Reply to  Ian W
May 3, 2015 10:29 am

How about a 12V DC system, a little windmill with a 90A altenator, a couple solar panels and a few 12V car batteries or equivalents …… and the villagers could live in their non-mobile RV with many of the comforts of home.
Wiring a structure (house) for 12VDC is a lot cheaper than wiring it for 110VAC. And just about every RV Dealer can sell you just about any type of appliance you want.

Reply to  Ian W
May 4, 2015 9:13 am

Samuel C Cogar says “How about a 12V DC system, a little windmill with a 90A altenator,(…).
90 Amps is for arc-welding – it’ll find any poor joint and make a fire. A 48V DC system is better
because it quarters the current (22.5A), so smaller switches, thinner wires and reasonably safe to handle. Above 50V DC you get into shock-hazard territory.

Reply to  gymnosperm
May 3, 2015 12:43 pm

The best thing those villages could use has existed for more than 150 years – a windmill water pump with a tank at the top of the platform. Just like many plains state farms had before the Rural Electric Power act. Two of my great uncles had them.

Just an engineer
Reply to  usurbrain
May 4, 2015 5:34 am
Reply to  Just an engineer
May 4, 2015 6:22 am

Thanks! Had the Aeromotor pump on top of a 25ft wooden tower on the farm I grew up on. As I remember only had to replace a shear-pin that did its job, worked forever!

May 2, 2015 9:27 pm

Wouldn’t it make as much sense to charge the battery from the grid during low cost power between midnight and dawn and draw on it during the high cost afternoon?
If it will store 10KWhr and take 1000 charge cycles (probably at 75% draw down) that is 7,500 KWhr per $3,500 battery. That means you need at least $0.47 / KWhr rate differential between the high cost afternoon and the midnight recharge. You would need to get 5000 cycles (14 years) out of the battery to bring the differential down below $0.10/KWhr
In Houston, TX, our electricity rates are in the neighborhood of $0.09 to $0.11 / KWhr – flat rate.

Reply to  Stephen Rasey
May 2, 2015 9:47 pm

Stephen Rasey May 2, 2015 at 9:27 pm
Wouldn’t it make as much sense to charge the battery from the grid during low cost power between midnight and dawn and draw on it during the high cost afternoon?

My understanding is that’s one of the use cases being suggested. Two problems with that. The first, as your numbers show, is that you need a whopping difference in peak versus off peak costs to make that viable. The second problem is that widespread adoption would quite potentially be self defeating. If everybody tries to charge at midnight in order to use the electricity the next day, the peak (and hence any surcharges associated with the peak) then moves to…. midnight. Of course you wouldn’t get full adoption, nor would this be a solution for industry, so you may get some net benefit out of it. Too early to tell, and the things that could potentially go wrong with that much energy stored on the wall of your garage are pretty lengthy. As good as it sounds, just generating the stuff inexpensively in the first place seems much more rational.

Ian W
Reply to  davidmhoffer
May 3, 2015 4:52 am

Just when would the household be charging their electric cars?
This is not just a case of moving peaks, this is a case of rewiring entire neighborhoods.

Reply to  Stephen Rasey
May 2, 2015 9:48 pm

The website says that the daily cycle model is only 7 KWhr at $3000 each, guaranteed for 10 years.
On that basis, you would get 3650 cycles for a total of 25,550 KWhr of storage. That gives a $0.12 / KWhr storage cost.
I wonder what those devices will do to your homeowners insurance (fire) cost? Probably minimal. If even as bad as 1 in 10,000 batteries catches fire over its life to put a $500K home at risk, that is only a $5 / yr / home surcharge.

Reply to  Stephen Rasey
May 2, 2015 10:00 pm

That gives a $0.12 / KWhr storage cost.
+ shipping +mounting +integration into existing electrical system +inspection…,
This easily gets to double that.
And I expect the insurance companies will demand a much higher premium until there’s enough track record to assemble some meaningful statistics.
I can see some jurisdictions even regulating against them. First fire fighter that gets fried fighting a fire because of one of these things and look for serious push back…

Reply to  Stephen Rasey
May 3, 2015 1:50 am

David, the inverter alone for a solar system of the size to make this a viable proposition costs around £2,600 ($4,000).

Reply to  Stephen Rasey
May 3, 2015 5:11 am

” the inverter alone for a solar system of the size to make this a viable proposition costs around £2,600 ($4,000).”
I didn’t see where they gave power output, so it MIGHT only output 500-1,000 Watts.

Reply to  Stephen Rasey
May 4, 2015 1:05 pm

It’s not just the fire you have to worry about. If the fire causes the case to crack or melt, and some water gets into those batteries, the possibility of explosion then exists, putting the lives of fire fighters at risk.
I’ve read that some fire departments are talking about possibly only fighting fires from the outside if they see solar panels on the roof.

Reply to  Stephen Rasey
May 2, 2015 10:09 pm

And then there is the cost of the required inverter. That $1,200 – $2,000 for a 3.3 KW to 7 KW inverter system.
Forbes: Why Tesla’s Powerwall Is Just Another Toy For Rich Green People
by Christopher Helman

Reply to  Stephen Rasey
May 3, 2015 12:05 am

From what I have been reading about inverters it is recommended that to purchase a premium inverter. Prices for top line inverters start close to $2,000 and go up from there.

Reply to  Stephen Rasey
May 3, 2015 1:09 am

I’m off-grid. I paid £0.99 (yes, 99p!!!) for my inverter, off of eBay.
It’s 3KW pure sine wave.
It has been working reliably for over 8 years.
It’s powering my house now.
Here’s the trick – you just shop around for redundant UPS systems.
Problem solved.
Huge numbers of these units are scrapped, simply because people widely do not appreciate that they can be operated as stand alone inverters.

Reply to  Stephen Rasey
May 3, 2015 1:18 am

That article from Forbes has a very large misstatement of how much power an American home uses on average. The article says “The average American home draws an average of 1,200 watts of power around-the-clock, according to the U.S. Department of Energy.” but even the site cited says the average use is 909kwh per month which (if my math is correct) is 30 kwh per DAY and more to what my experience has been.
With those kinds of errors, one might wonder what else Mr. Helman got wrong in his article.

Reply to  Stephen Rasey
May 3, 2015 2:26 am

Jake check YOUR arrithmetic

Reply to  Stephen Rasey
May 3, 2015 2:26 am

1200 watt, 24 hours => 28.8 kWh. This is about 30 kWh as by your calculation. Where is the error?

Reply to  Stephen Rasey
May 4, 2015 1:13 pm

Frog, your solution would only work so long as only a tiny fraction of the population was doing it. More than that and the supply of surplus parts dries up.

Bob Diaz
May 2, 2015 9:29 pm

Business should be very good in Hawaii where the cost per kWh is 34 to 46 cents depending on which island you’re on. I’m not sure of the laws about living off the grid, but it would make sense considering the high price of electricity:

May 2, 2015 9:43 pm

Sorry, Eric, but this is just more Tesla hype. 10 kilowatt hours of storage for $3,500? Not impressed. I can purchase today, off the shelf, a 12 kilowatt-hour battery designed for 20 years of solar storage use for $2,750.
Tesla’s battery is just another rich man’s toy, backed by lots of hype and publicity. Folks, you can buy more storage for less money, no problem, trucked to your door. Here’s one of many batteries on the market that give you more for less.

Reply to  Willis Eschenbach
May 2, 2015 9:53 pm

It is only 12 volts in the link. Dryer use 220 volts 30 amps power.
Need an inverter ?
What am I missing here?

Reply to  sunsettommy
May 2, 2015 10:05 pm

A clothes line.

Reply to  sunsettommy
May 2, 2015 10:07 pm

Near as I can tell, both the battery I listed and the Tesla system would require an inverter.

Bill Parsons
Reply to  sunsettommy
May 3, 2015 11:30 am

Max Photon
May 2, 2015 at 10:05 pm
A clothes line.
So, you DO have stock in solar then?

Reply to  sunsettommy
May 3, 2015 12:35 pm

I AM solar.

John MR
Reply to  Willis Eschenbach
May 2, 2015 10:54 pm

Whenever I read stories like this, I’m reminded of the scene from the movie Dumb and Dumber, when Jim Carrey’s character exclaims, “We landed on the moon”.!
Just a battery folks. No quantum leaps here.
Move along.

Reply to  John MR
May 3, 2015 6:53 am

But it’s a fancy, sexy battery. Cool people will buy them. Made by Tesla.And gets great press (free publicity) because “green energy“.

Reply to  John MR
May 3, 2015 12:57 pm

Very funny. You hit the nail on the head.
By the way, love him or hate him, Alex Jones is pretty darn funny when he imitates chicken-neck trendies.
Alex’s Bill Gates Chicken-Neck Bastard Rant

Reply to  Willis Eschenbach
May 3, 2015 12:16 am

I have been thinking about going with this company,s products for a solar/battery setup….http://www.rollsbattery.com/
They sound like they are durable easily maintained batteries with a good track record for longevity. I was thinking of going with their 3 of their 4 volt batteries which are rated at 1350 AH/20 hr each.

Reply to  Eric Worrall
May 3, 2015 12:16 pm

Thanks for your comments, Eric.
The difficulty I have with Tesla is that it’s all hype. Their batteries are not cheaper. They are not new and improved. They are not even as good as any of a dozen other batteries.
In a previous post I discussed the oddity that the only technology from the 1800s that is almost entirely unchanged is the automobile battery. Nothing has ever beaten it … and as my example from above shows, that includes the Tesla battery. Technology from the eighteen hundreds still beats Tesla’s finest. Go figure
You claim that this represents some kind of milestone, viz:

Either the government will be forced to provide higher subsidies, or large scale renewable schemes will have to be scaled back, to keep grid electricity price competitive.

But since what Tesla offers has been on offer for over a century, I find it hard to believe that Tesla changes anything. Even with cheaper technology, it hasn’t made inroads even in Hawaii unless it is subsidized.
You also say:

… around 1000 charge / discharge cycles, paying $3500 every 3 years is approaching price parity with some of the more ridiculous electricity utility charges …

The problem with your numbers reminds me of the old sailor’s lament, which is “Yes, the wind is free … but everything else costs money”. In the same way, yes, the sun is free but everything else costs money.
And in this case, you’ve only included the money for the battery. You haven’t included the cost of the panels, or of the inverter, or of the wiring, or of the battery-to-grid phase-locking, or of the safety interlocks, or of the frames to mount the panels, or the skilled labor costs of the installation of all of the above, or of the maintenance of the same. You also haven’t included the costs of power for those times when your battery goes flat, which a 10 kWh battery will do in short order in the winter … unsubsidized solar is a great solution for niche markets. I lived off of the grid for a couple of years, and solar was my salvation. I ran a 24-volt system using a dozen of the big phone company 2-volt batteries, and it kept my lights going and my computer in operation.
But for replacing grid power? The only solar making inroads there is subsidized solar, and as someone who is paying the subsidies, I’m not impressed in the slightest.
Thanks for your post,

Erik Magnuson
Reply to  Eric Worrall
May 3, 2015 1:44 pm

If the batteries can last 10 years while cycling 7KWh per day, then the $3,000 price is looking like a good deal if the electric utilities are allowed to do net metering on a time of day basis. That works out to about 14 cents per KWh, which will likely be less than the difference in rates between 11am and 7pm.
My understanding is that the cycle life of Li-ion batteries is much longer if the batteries are cycled between 40 and 60% depth of discharge. This suggests that stabilizing the grid for wind generation may be even more cost effective than for solar as the batteries would potentially be cycled several times a day. This would require some sort of interaction with the utility, with Tesla’s business model is providing the signalling infrastructure for a fee.
In regards to Willis’s comments about lead acid batteries: The initial price per KWh of storage capacity is cheaper with the lead acid than Li-ion, but not quite so sure if cycle life-time energy storage is cheaper. The graph on the Trojan website indicated that the cycle lifetime was inversely proportional to depth of discharge (i.e. 25% DOD gives 2X the number of cycles as 50% DOD). One other knock against lead acid is the charge discharge efficiency is significantly poorer than Li-ion.

Just an engineer
Reply to  Eric Worrall
May 4, 2015 5:55 am

Seems to me that the next charge that the residential customer is going to see is the “electrical demand charge” (businesses are charged this to cap their electrical draw). So the upshot is that despite not “using” any grid energy most of the time, you will pay a substantial monthly fee to “reserve” backup power, unless you want to go dark.

Walt D.
Reply to  Willis Eschenbach
May 3, 2015 5:40 am

If this technology was cost effective, Southern California Edison and Pacific Gas and Electric would be using it.. Also you don’t need an Al Gore mansion to burn through 10KWh quickly. If you need the air conditioning on and you cook dinner and breakfast you will blow through 10KWh in no time. Your solar panels only work from 10am to 5pm at full power. You need to be specially located in California for wind to work in your back yard.

Reply to  Willis Eschenbach
May 3, 2015 7:08 am

These are 12V lead-acid. While cheaper and generally safer than Li-Ion, they are larger and much heavier. Wouldn’t be thatmuch of a detriment for home use though.
I agree, there is nothing earth-shuttering about Tesla’s batteries. It is more of a marketing issue that can mainstream batteries and turn them into accepted thing instead of something that only “off-grid crazys” would be interested in.

Mike M.
Reply to  Willis Eschenbach
May 3, 2015 8:12 am

12 kilowatt-hour $2,750 is still about $230 per 12 kW-hr, about 2/3 of the cost of Musk’s batteries. By the time you factor in an inverter and installation, the fractional difference in cost will be much less. In a few years it the cost will probably be the same since lead-acid batteries are a mature technology while Li-ion is relatively new and still improving. And Li-ion is much smaller and lighter.
The real issue is how many charge-discharge cycles you get. The link guarantees 1500 cycles for Pb-acid, that is 4 years if you cycle it every day. So you are looking at $0.16 per kW-hr just for the capital cost of the batteries. That is not competitive and it is not going to get better. I have not seen anything on how many cycles can be expected from Musk’s batteries, but I doubt it is even close to 1500.
Battery storage for load leveling is still not close to being economical. What is intriguing about Musk’s project is that it *might* get there whereas Pb-acid never will. And his hype and salesmanship means that he might be able to get rich people to pay for the development until it is cheap enough for the masses.

Reply to  Willis Eschenbach
May 3, 2015 2:48 pm

Much agree – existing lead acid battery banks been around for YEARS and are LOWER cost. I trying to figure out why using expensive lithium batteries in place of lower cost lead batteries makes any sense?
For a car (or laptop), then weight is a HUGE issue (and li-ion is rather lightweight), but for a pallet with some batteries on it for home use, the case for li-ion batteries makes little sense.
Of course building that massive plant (with lots of government funding and tax breaks) means that it makes business sense to “try” and sell such banks.
The main problem is lead-acid banks exist, are a mature technology and are cheaper, better choice and longer lasting.
Albert D. Kallal
Edmonton, Alberta Canada

Reply to  Willis Eschenbach
May 3, 2015 5:51 pm

Hi Willis Eschenbach
I enjoy you take on things.
Just wondered if you had checked out LENR recently?
Mr Rossi has Got a LENR power plant in operation at this time.
So soon Tesla will be making steam powered cars.

A. Scott
Reply to  Willis Eschenbach
May 4, 2015 2:16 am

Exactly Willis …. or I believe 9 or 10 standard deep cycle 12v marine batteries would give you the same effective power – for about $100 each.
The Tesla battery is all hype … it is nit revolutionary, it does not change the world, it does not make it any easier, more efficient or more likely that people can go solar (or wind) and most certainly is no game changer.
It is a hugely expensive plain old battery … in a pretty wrapper. Supported by a whole lotta pure hype – all hat, no cattle kida claims.
The average US home uses appx 30kWh per day … one of these will barely provide 1/3 of a single days avg usage. To provide even 3 days backup would require at least 10 of these – or realistically more (considering you cannot discharge them 100% without destroying them)… and 3 days is not enough to cover the regular periods where there is no sun and/or minimal wind for extended periods.
The ONLY hing they are really good for is IF enough home had them, then can perform some load shifting – with utilities drawing on them at peak demand periods ad then recharging them during cheaper off peak hours.

Bruce Foutch
May 2, 2015 9:45 pm

Can this be far behind?

May 2, 2015 9:47 pm

Power: 2.0 kW continuous, 3.3 kW peak. yay, hooray- i can run the toaster- but not the fridge…
i’d have to spend 7000$ to run the fridge.
well, i’d have to spend 7k for a promise, at least. actually running the fridge is still just pie in the sky.
is it not a red flag warning when somebody is selling, with great fanfare, something that does not yet exist?
i’m sure he’s done the numbers, though- would be interesting to see how much of the accounting depends on money piped in from the taxpayers’ main vein.
all this tell and no show… it has a certain familiarity…

Reply to  gnomish
May 2, 2015 9:53 pm

… and don’t even think about running a 3-ton air conditioner. Much less two of them.

Mike McMillan
Reply to  gnomish
May 3, 2015 1:30 am

Other way around. Toasters run twice+ the wattage of a fridge.

May 2, 2015 9:52 pm

I wouldn’t put it up the wall… since entire solar installations get stolen from roofs, how convenient would it be to just take it off the wall? Hope it comes with GPS tracker and alarm…

Reply to  Matt
May 2, 2015 9:53 pm

Those extras require another battery.

May 2, 2015 9:52 pm

You can save a ton of money … if you don’t count the costs.

Eugene WR Gallun
Reply to  Max Photon
May 2, 2015 10:49 pm

Max Photon — you got it exactly. == Eugene WR Gallun

michael hart
Reply to  Eugene WR Gallun
May 3, 2015 5:32 am

Yes. I didn’t buy a Ferrari today and I’m still wondering what to do with the money I saved.
Tomorrow I think I’ll not buy two Ferraris. At this rate I’ll soon be rich.

Reply to  Eugene WR Gallun
May 3, 2015 7:19 am

“Tomorrow I think I’ll not buy two Ferraris. At this rate I’ll soon be rich”
Hmm, similarities. Do you happen to work as a climate scientist?

May 2, 2015 10:00 pm

Tesla Home Battery Hype
So is this a giant breakthrough in $/kWh of storage? Let’s see…
Why Tesla’s Powerwall Is Just Another Toy For Rich Green People
“And here’s where the economics of the Powerwall break down. If you do not have a big enough solar system to get your home entirely off the grid, then there is simply no point whatsoever in paying 30 cents per kwh to get electricity via the Powerwall. At night, when you’re not generating solar power, you could simply get your electricity from the grid. For an average 12.5 cents a kwh.
I’ll say it another way: unless your solar-powered home is entirely disconnected from the grid, or your solar system is big enough to provide for all your electricity needs, an expensive battery backup system like Powerwall does not make economic sense.”

Reply to  Kuldebar
May 2, 2015 10:10 pm

I guess that “not making economic sense” thing is what guarantees it success amongst
– Obamas subsidies ranking and other carpetbagger programmes
– the low information Green voters

May 2, 2015 10:04 pm

As others have said: How are these “low cost”? 4 lead acid deep cycle 6 V batteries, 420 amp hours per battery cost me $1600 (Canadian). Suitable for use with my 2 110 watt panels. I still need to run my generator whenever I have a serious power draw (such as a toaster). Not to mention lead is recycled, but lithium isn’t. As Willis says. More Tesla hype.

May 2, 2015 10:06 pm

If I could get a 1.5 to 2kiwh battery I’d be in the market for one of these, price being acceptable. I’m a low power user, have solar hot water and wood fired heating and have a 1.5kw grid connect solar system. Half of the power from the grid connect system goes back into the grid, I consume the other half. I get paid for the half that goes back into the grid.
I’m in the process of setting up an additional solar (with battery storage) system, more as a project than for any other reason. Unfortunately the 7kwh and 10 kwh batteries are much bigger than I need and way outside my financial capacity. I guess I will be buying 1kwh worth of solar gel or AGM batteries to do the job that I want. I’m open to any other “polite” and useful suggestions.

Grey Lensman
Reply to  TedM
May 2, 2015 10:28 pm

Ted, get a scrap Prius battery. About USD 150. car may be a write off but the battery good. Make sure it comes complete with all safetys etc

Reply to  TedM
May 3, 2015 12:24 am

Take a look at these batteries…http://www.rollsbattery.com/

Reply to  TedM
May 3, 2015 4:51 am

Check out Aquion Energy. link
These batteries are designed for stationary use and thus can be relatively large and heavy. No hazmat or rare materials are used. As far as I can tell, the performance equals or exceeds Tesla’s. They are much cheaper than Tesla batteries (close to the cost of lead-acid).

Reply to  commieBob
May 3, 2015 7:00 am

Of course now Aquion, Rolls and others will be able to increase prices. They may have to put existing product in a fancy case with blinking lights in order to compete on esthetics though.

Reply to  commieBob
May 3, 2015 12:45 pm

@ Piper… I have noticed that Rolls has increased the price on all of their products from what it was last year, by a substantial amount to boot. That is unfortunate, and I see that as a business mistake on their part. It equates to a similar issue that Hughes Sat had with their pricing range and limited features with their service. Would you rather have 1 million customers paying high prices, or would you rather have 50 million satisfied customers making a reasonable monthly payment?

May 2, 2015 10:11 pm

Hello to all.
I read the article here on WUWT, then I went to the Tesla website ….
…. and read through their material.
Here is the opening paragraph from their web page:
-begin cut & paste-
Powerwall is a home battery that charges using electricity generated from solar panels, or when utility rates are low, and powers your home in the evening. It also fortifies your home against power outages by providing a backup electricity supply. Automated, compact and simple to install, Powerwall offers independence from the utility grid and the security of an emergency backup.
-end cut & paste-
Ok, sounds like a clean, complete, automatic power storage unit.
Accepts power from the line, or solar panels, etc, stores the power, then provides useable power when needed.
On the Specifications, an item caught my eye.
Here are the specs, cut & pasted from the Tesla webpage:
-begin cut & paste-
Technology Wall mounted, rechargeable lithium ion battery with liquid thermal control.
Models 10 kWh $3,500 For backup applications 7 kWh $3,000 For daily cycle applications
Warranty 10 years
Efficiency 92% round-trip DC efficiency
Power 2.0 kW continuous, 3.3 kW peak
Voltage 350 – 450 volts
Current 5.8 amp nominal, 8.6 amp peak output
Compatibility Single phase and three phase utility grid compatible.
Operating Temperature -4°F to 110°F / -20°C to 43°C
Enclosure Rated for indoor and outdoor installation.
Installation Requires installation by a trained electrician. DC-AC inverter not included.
Weight 220 lbs / 100 kg
Dimensions 51.2″ x 33.9″ x 7.1″
1300 mm x 860 mm x 180 mm
Certification NRTL listed to UL standardsdo
-end cut & paste-
What stands out to me is ‘Installation’, where it specifically states “DC-AC inverter not included” (!)
Having repaired a neighbor’s sailboat power system, I learned very quickly that the inverter/converter is an expensive unit! The specifications state that this is not included.
Does this have to be purchased separately?
As furnished by Tesla, does this unit provide 60-cycle AC power, as one would assume from the smooth-reading opening paragraph, or as the specifications state, 350 – 450 volts (DC? The spec sheet does not specify AC or DC, but I have never seen an ‘AC’ battery!)
What’s the scoop?

Reply to  JimBob
May 2, 2015 10:29 pm

Voltage 350 – 450 volts
If there was an inverter included, its would output would be standard household voltage or there would be no point including it. And as your cut/paste says, it doesn’t.
They seem to be glossing over charging system as well. If your going to charge from the grid off peak, you’ll also need an AC to DC converter that puts out the same voltage as the battery, 450 volts! The more we learn the sillier this thing gets.

Reply to  JimBob
May 2, 2015 10:57 pm

350 – 450 V/DC? Strewth! Some rail transport systems uses DC power not too much more than that. I would not like to have one of those stuck on ANY wall in a house. I saw an article on an Aussie MSM website. The article included no details about the system at all, just how much it cost and how much was being invested. As has been said in other posts, it’s just an expensive toy for rich boys.
As has already been said, there are plenty of deep-cycle, lead-acid batteries available which, IMO, would provide a proven, reliable and safe storage system.

Reply to  Patrick
May 3, 2015 7:03 am

[I]t’s just an taxpayer-subsidized, expensive toy for rich boys.

Reply to  Patrick
May 3, 2015 7:08 am

Aargh, I fugged-up the italics below.
[I]t’s just an taxpayer-subsidized expensive toy for rich boys.

Reply to  Patrick
May 3, 2015 9:02 am

Remember to close your HTML tags:
Insert drivel here

Reply to  Patrick
May 3, 2015 9:05 am

Aargh, it at my newly-invented HTML aargh tags!
(Another good joke consumed by the internet.)

Reply to  JimBob
May 3, 2015 6:17 am

Question based on the specs you pasted, specifically: “Operating Temperature -4°F to 110°F / -20°C to 43°C”
Doesn’t that rule out places that are fantastic for solar, such as Arizona (Phoenix averages 113-115 F in summertime) and the lower Nevada desert?

Reply to  Arsten
May 4, 2015 1:26 pm

Also means you can’t place it outside anywhere much north of the Mason/Dixon line.

May 2, 2015 10:13 pm

3500? Hot D@mn! Add that to the cost of my array, plus the charge controller and sine wave inverter and my system pays for itself in 15 years!!! Woohoo!!!!!

Reply to  probono
May 4, 2015 1:27 pm

Did you factor in having to replace the batteries every 10 years?

May 2, 2015 10:14 pm

The $100 a month for the battery is just part of the cost of course. You still need a few of those solar panels plastered to your roof, lots of wire and controls, switches, etc. So unless your power bills are among the highest in the US, or you really need to be off-grid, the economics don’t work. Power here, for example, is about .09/KWh, so it won’t be too attractive to us.
Musk’s business relies on government largess to succeed. This is no different.

May 2, 2015 10:18 pm

So you go off grid. Instead of off peak hot water at its hottest in the morning you run it at 3pm. Because it’s way too big a drain for late night.
What if we have a string of cloudy, rainy or snowy days? Are people going to be left to have no power at all?
Are they going to go off grid in the long summer days but then reconnect mid winter? If so, no grid charges for 8-9 months a year is going to annoy utilities immensely. They should have the wires physically removed and serve the same waiting period to switch back on.

May 2, 2015 10:21 pm

Aww but seriously, 16 GC-2s give me 840 Amp-Hrs @ 24 volts. for 1200$. But it’s only money. Save the world!!!

Grey Lensman
May 2, 2015 10:32 pm

As he is not selling toy cars, except in California, he is dumping batteries. To max his profits he had to buy millions but the stock is mounting up.

Reply to  Grey Lensman
May 3, 2015 12:32 am

Tesla stock should become a great short at some point.

Reply to  goldminor
May 3, 2015 2:30 am

Now would be prudent. Even the people from the “land of fruit and nuts” must wake up sometime, but then again….

Just an engineer
Reply to  goldminor
May 4, 2015 6:23 am

At 5+ days to cover, maybe he’s trying for a “short squeeze”.

May 2, 2015 10:32 pm

So can most people afford to buy, or is it even practical, to have enough solar on your roof to run a washing machine, dryer, refrigerator, air conditioner and your daughters blow dryer?
I can see battery power for a few lights, a TV and computer for an evening.

May 2, 2015 10:32 pm

Ted M says:
I’m open to any other “polite” and useful suggestions.
Get a gasoline powered generator. About $1 per 10 Watts is typical. A 4 kW generator for $400, etc.
Store a few 5-gal. gasoline containers with preservative. If you need power, that $400 generator will supply enough for your refrigerator, computer, and a few other appliances.
If you need more power, get a 7000 – 8000 Watt generator for ≈$700 – $800.
Tesla’s idea might be practical in another 10 years. But let the rich folks pay to bring the costs down. In the mean time, you can have backup power for about one-quarter of Tesla’s. And the technology is off the shelf and proven.

Reply to  dbstealey
May 3, 2015 12:22 am

“Let the rich folks pay to bring the costs down?” Economy of mass production only works on the overhead component of item cost. Overhead costs for material-intensive items (like batteries) are minuscule. The commodity material cost of 1000 batteries is 1000 times as much as for one battery. The costs ain’t coming down.
Total power failures (right now) are rare events and of short duration. You might price inverters that will produce enough AC power from your car’s alternator to keep a computer running during a temporary outage. (Not a fridge, sorry.)
This is, at best, just a scheme to sell extra Tesla spare parts.

Reply to  jorgekafkazar
May 3, 2015 9:02 am

“You might price inverters that will produce enough AC power from your car’s alternator to keep a computer running during a temporary outage. ”
Consumption of a notebook computer can be brought down to about 50W, at least if you throttle the CPU via power management accordingly. A matching inverter to supply the notebook power supply is readily available for about 50 EUR /Dollars; plugs into the cigarette lighter. I have one in my car for eventual emergencies.

Reply to  jorgekafkazar
May 3, 2015 3:40 pm

Good idea, Dirk!

Claude Harvey
May 2, 2015 10:39 pm

I’ve run the numbers and the numbers don’t work. Even if the power to charge the Tesla battery were free, using a realistic service-life expectancy for the battery you’d wind paying more in capital cost per average useable kWh than the typical utility home rate of 12-cents. And that’s without taking the time-value of money into consideration. But then, of course, the power to charge that battery isn’t free and the presumption is that you’d replace purchased utility power for that purpose with power generated by solar cells or wind. Run those numbers on an unsubsidized basis along with the cost of the battery and the result is ludicrous!
If unsubsidized wind and solar economics don’t make sense with cheap fossil sources taking up the “reliability slack” (and which cost is not even counted in the typically promoted “green power equation”), how does anyone imagine batteries costing many times that of fossil sources of power (fuel costs included) can possibly make economic sense as the “slack taker”?

May 2, 2015 10:40 pm

I fail to see how the battery solves anything. It’s quite expensive and, as Willis noted, there are cheaper batteries already available. You need to purchase an inverter and it requires certified installation. Last I looked, too, average electrical consumption was around 18 kWh so you’d need two devices. Then, of course, there’s the solar arrays on the roof. They cost, what?, $30K to $40K. When you’re paying $.10 kWh from a utility, how does any of this make sense? The only way it does for the homeowner is if there are substantial government subsidies. those subsidies are being paid for by taxpayers and, in effect, you have a transfer of wealth from poor to rich. I know a lot of people see this battery as a wonderful technological advancement, but to be honest it really looks like a gimmicky toy for the rich and deluded — no different than the Tesla car.

Reply to  Alan Poirier
May 3, 2015 5:24 am

It doesn’t solve anything. I suspect who advocate solar power using home systems are unable to do the math. Or they are simply solar groupies. Tesla products are toys for the upper class.

May 2, 2015 10:43 pm

Tesla’s idea might be practical in another 10 years. But let the rich folks pay to bring the costs down.

They don’t call them ‘tooling costs’ for nothing.

May 2, 2015 10:44 pm

Some people have decades of experience living with off-grid lead-acid battery power. Industrial battery backup technology has been around a long time, eg Phone systems. Look at the projected life-cycle costs for the Li-Ion vs Lead-acid. I would not trust a Tesla battery with my life.

Reply to  bw
May 2, 2015 11:55 pm

Good point again. Li-ion is an expensive technology. Its good side is the small weight and size per kWs (the little brother of kWh) in cars and mobiles. Installed at home, the weight has little meaning, price/kWh * cycles is the thing.

May 2, 2015 10:44 pm

Claude Harvey,
Correctomundo. Batteries aren’t cost effective.
Gasoline or other fossil fuels like propane and NatGas are the best. They provide lots of power, cheap.
Don’t believe me? Then put your car in neutral, turn off the engine, get out, and push it about twenty miles down the road. Then tell us what a gallon of gasoline (petrol) is worth.
Tesla’s batteries are good advertising. But they can’t compete on either price or peformance with a simple gasoline generator.

Reply to  dbstealey
May 2, 2015 11:08 pm

Excellent comment.

William R
May 2, 2015 10:45 pm

how is this better than a bank of car batteries at a fraction of the cost?

Reply to  William R
May 2, 2015 10:52 pm

You’re helping to cut down on sunspots.

May 2, 2015 11:01 pm

The entire third world is trying to figure out how to get their populations onto the grid.
We’re being persuaded to get off the grid and triple our costs to do it.
There’s a reason why grifters don’t target the dirt poor. It doesn’t matter how stupid you are, if you are dirt poor, you have nothing to be conned out of.
how is this better than a bank of car batteries at a fraction of the cost?
It is better. For Tesla. Musk will have star struck politicians lining up to offer incentives and tax breaks to locate his high profile manufacturing plant in their state. If he plays it well, he might get the thing built for free.

Reply to  davidmhoffer
May 3, 2015 4:21 am

back in the old days you could run a u- boat for 18-20 hrs on batteries , then one day somebody discovered they could use nuclear power.

Robert Ayers
May 2, 2015 11:13 pm

As other posters note, more expensive that current solutions. I own an off-grid house in Arizona. I and my neighbors use golf-cart batteries. (Better than car batteries, designed for deep cycle.) The Tesla battery is about 4x as expensive per kWh. Not clear it will last any longer. Li is good for low-weight, but that it immaterial for a dwelling …

May 2, 2015 11:18 pm

One advantage of the Tesla lithium batteries is efficiency. Those lead forklift batteries are only 60% efficient if you charge them fully (and if you don’t, the service life goes way down). 92% efficiency is quite impressive, the power saved adds up quickly.
If I were building an off-grid residence, I would seriously consider using these batteries. They would be in a separate ‘battery shack’, but that would be true for lead or NiCd as well. As far as an on-grid home, well… no thanks.

Reply to  tweell
May 3, 2015 1:55 am

I just did a search to confirm those efficiency figures and have only so far found this:
“Typical efficiency in a lead-acid battery is 85-95%, in alkaline and NiCad battery it is about 65%. True deep cycle AGM’s (such as Concorde) can approach 98% under optimum conditions, but those conditions are seldom found so you should figure as a general rule about a 10% to 20% total power loss when sizing batteries and battery banks.”
From here: http://www.solar-electric.com/deep-cycle-battery-faq.html
So, who is right and who is wrong?

Robert Ayers
Reply to  tweell
May 3, 2015 1:00 pm

Efficiency of the cycle may be very important for grid storage, but is less important for today’s off-grid rural dwelling. Why? Because solar cells are so cheap these days. A “standard” off-grid installation wants about four days worth of storage. Today, those batteries cost more than the solar cells do. So if I can halve the cost of my batteries by cutting the efficiency 25%, that is a win: I add 25% more PV cells and I’m $ ahead.

May 2, 2015 11:21 pm

Musk is a master at building businesses around government subsidies, as opposed to making side money from them. This one may work as well.
There’s a guaranteed market for the successful player(s).

May 2, 2015 11:23 pm

That’s one expensive battery!

May 2, 2015 11:40 pm

I don’t quite get it. I can do 30kw/hrs with a lead acid marine battery for the same price, that will last 5 hears and several thousand cycles.

Reply to  denniswingo
May 3, 2015 5:31 am

“… I can do 30kw/hrs with a lead acid marine battery for the same price”
Musk knows that, but PbA isn’t new and cool.

Reply to  Paul
May 3, 2015 6:25 am

Or shiny!

May 2, 2015 11:42 pm

But before you buy (expecting that it will lower your electricity bill) you should read this:
“If something sounds too good to be true, it probably isn’t.”

May 3, 2015 12:01 am

To go totally off grid from a fully on-grid position by choice requires a huge investment, 6 to 8 of these batteries, 8KW solar PV array. Do they come with an inverter man enough to cope, unlikely so one of those as well, Without any taxpayer input who can afford that kind of investment other than Elon Musk, Al Gore and others making a mint from renewables.
How long are people in the “third world” going to be happy with a communal TV and a few LED lights. Once they start wanting their own TV, more and brighter lights a fridge of their own an oven than will work in the evening one battery each will be required. Again that is a lot of expense for a community currently on a subsistence model.
I have a friend who will spend 4€ driving many more miles than to the nearest petrol (gas) station to save 3c a litre, as his fuel tank when dry holds 55 litres so I tell him it isn’t saving any money and he then looks at me as if I’m slightly deranged. He’ll be an ideal customer.

Reply to  SandyInLimousin
May 3, 2015 12:31 am

When I did my research back in 2000-ish, the most efficient system was to match your generating system with your appliances. So a 6, 12 or 24 V/DC generating system would need to be matched with 6, 12 or 24 V/DC appliances. No inverter. Inverters are better these days, but still can cause issues with some appliances. It proved to be way too expensive to build a properly sorted off-grid system.
Where most people live, we already have an efficient electricity generating and distribution system.

Reply to  Patrick
May 3, 2015 1:42 am

“When I did my research back in 2000-ish, the most efficient system was to match your generating system with your appliances.”
That’s sadly complete nonsense peddled by people who want to sell an off-grid customers a whole range of quirky low voltage dc equipment.
220Vac is more efficient than 12Vdc for a very simple reason. For any specific power rating, the 12Vdc must supply 18x the current since P=I*V. Losses are a factor of current. To calculate the loss in an section of resistive material you just need P = I^2 / R. So the losses are proportional to the square of the current!! Where P(power) I(current) R(resistance) V(voltage).
So the power losses are vastly increased (per watt of usable power) at low voltage.
Add to that concern the increased fire risk from the burden on cabling and connectors.
This is the reason why power is transmitted on the grid at a minimum of 11,000V.
Because, higher voltage is more efficient.
I run all the normal appliances in a household directly off of a sine wave UPS/inverter. Every kind of tool and household appliance.
It’s a simple system – once your inverter is set up, you just buy regular electrical goods and plug them in. (And my inverter cost me only $1.50 – see above!!).

Reply to  Patrick
May 3, 2015 1:44 am

Correction – where I wrote P =1^2 /R – I meant, of course, P = I^2 *R
Silly me!!!

Reply to  Patrick
May 3, 2015 3:11 am

Nope. I was not being sold a thing. I agree, inverters are much better these days, but still have issues. I would still go with a system that did not need inverters.

Reply to  Patrick
May 3, 2015 3:19 am

I have no idea where you live, but where I am from the UK national grid transmits at between 130 – 200kv/ac. And the efficieny comes from three phase transmision. But you’re talking here a national transmission grid, NOT off-grid, local generation and consumption. You don’t need high AC voltages for that.

May 3, 2015 12:07 am

My green friends are all celebrating about this one. It’s the end of nuclear power! Finally we can store renewable energy! Etc. etc…
I don’t live in a sunny country. We got 5 hours of sunshine in December and January altogether last winter. Yeah, that’s a total of 5 hours in 2 months, not daily! Even though we have constant daylight during the summer, I don’t really get the point of everyone having their own solar array and their own personal storage system. That’s because I prefer to look at the grid as one big solution:
Before the renewables, the grid was simple. We use electricity and the power companies produce it according to the needs. There only needs to be enough of producers to make sure that the lights are on when it’s -30C. This all is a challenge but professionals are really good at running the show.
Then came the wind mills. They mess up the production of energy as wind has the RIGHT to sell every single MWh they produce but not the RESPONSIBILITY to produce energy when it’s needed. They are like spoiled rich kids: Demanding a work and huge salary but coming and going as they please. All the other producers makes sure that the lights are on and they are paid less for their important work.
Then came the household solar messing up the demand. The power producers get paid less as people produce their own electricity but still they need to make sure there’s enough for the rainy day and the night.
Then came the brilliant idea that everyone should be entitled to sell their own electricity to the grid. Suddenly everything is not so simple any more. Now the grid can’t even plan any more. They need to balance a system where people are not only using electricity at random but also producing it at random.
So what we’ve got is a great mess: Those who cause trouble to the grid and make it more expensive for everyone are being paid huge subsidies. They cause horrible problems to reliable energy producers and to the grid. As a result we’ll eventually get to the point where we simply won’t have the capacity needed for the rainy day/week. Or if we do, even that will get horribly expensive and require subsidies.
So we’ll have huge subsidies, expensive electricity, complex grid and that’s going to be called progress.

Reply to  Vieras
May 3, 2015 1:12 am


Reply to  Vieras
May 3, 2015 3:01 am

Couldn’t have said it better +10

Steve P
Reply to  Vieras
May 3, 2015 6:38 am

(frugal always)

Reply to  Vieras
May 3, 2015 6:52 am

Very well stated. I writing up a report on this [and] I will be [plagiarizing] you [a] bit if you do not mind.

Reply to  CNC
May 3, 2015 6:54 am

Sorry for the typos, phones keyboard and text a bit small for me. No edit, to bad

Reply to  CNC
May 3, 2015 9:35 am

Sure, feel free to copy.

Reply to  Vieras
May 3, 2015 7:32 am

My green friends are all celebrating about this one.
The self-flattering bien-pensant crowd will ensure this will be “successful” through the powers of marketing, PR and free media promotion (and of course, taxpayer subsidies) without a single mention of any downsides. Sort of like most other green-led campaigns.

May 3, 2015 12:25 am

I don’t see the point. The whole reason for installing solar panels is to extract subsidies from the government (well, from your neighbor via the government).

Reply to  Peter
May 3, 2015 5:18 am

Well, the whole point of Tesla’s announcement is to get people to push their representatives to enact subsidies for Tesla’s batteries.

Just an engineer
Reply to  Peter
May 4, 2015 6:36 am

Simples, you package the battery as part of the “renewable installation” and collect a larger subsidy.

May 3, 2015 12:32 am

What about battery degradation? For every charge/dicharge cycle, the battery loses capacity. For a Panasonic NCR18650A, rated at 2.9Ah when new, this goes down to2.1 Ah after 500 cycles. This is 27% capacity loss, and on a daily basis, 0.05% per day of use. Assuming that most of the cost of the system are the batteries, this boils down to a loss of value of the system of 810$. This should at least be compensated for by savings in th value of the electric energy stored during this period. Do the math.

Reply to  henkie
May 3, 2015 6:58 am

Yes, correct. Li-ion normally are only good for 500 full charge/discharge cycles.

May 3, 2015 1:08 am

One important question: according to a professor electro-mechanics here on the news, the Tesla pack is batteries only, without the necessary DC-AC converter. If you like to have a nice sine wave at high power, you can double the price…
Seems to me more hype than solution…

May 3, 2015 1:11 am

I think a diesel generator is cheaper especially if you use the waste heat for water heating

May 3, 2015 1:15 am

I thought this was going to be a major step forwards in electricity storage when I saw the pre-release hype, so I was quite interested to see the announcement. However, when I got the bottom and saw 10kWh , I thought I’d misread it. My eye’s were tired, I’d lost a zero or two ??
The energy density is surely better than lead-acid but this seems like a small step forwards rather than a major innovation.
A cheaper alternative is used lead acid cells from forklifts. They are not ideal technically but are usually taken out of service when the can’t deliver the peak power needed to lift a heavy load. For moderate continuous power required for an inverter, they have many years of service left.
you can pick them up for scrap metal costs, and when you are done, you can still sell them as scrap and recover the cost.
Obviously you need to choose cells in a serviceable condition, some may really be beyond use.
I have a mate who runs a forklift business and he’s happy for me to take them away if I give him the scrap value. Saves him the trouble.

The Engineer
May 3, 2015 1:27 am

In Denmark (and I kid you not) the government will tax the saving you make by not buying electricity from the grid (The logic – a saving is the same as an earning – which is taxable)

Reply to  The Engineer
May 3, 2015 7:02 am

I thought the USA was bad….

Reply to  The Engineer
May 3, 2015 3:57 pm

That’s just nuts. I wish you WERE kidding.

May 3, 2015 1:33 am

Why do I sense a ‘taxpayer subsidy’ in the wind?

Reply to  Tim
May 3, 2015 10:36 am

It’s your ‘sense’ of smell. You must be living downwind of Mr. Musk.

May 3, 2015 1:36 am

Has anybody noticed the CO2 projection up to the year 3000 in Elon Musk’s presentation?

May 3, 2015 1:38 am

Did a price comparison with my NiFe batteries. NiFe’s are more expensive than most storage batteries, but are supposed to last longer. Longer than 10 years. The Tesla batteries appear to be about the same price. Considering most people think the NiFe’s are overpriced, so are the Tesla’s.
I love the concept, but price is a big issue for any battery system. I can see some advantages in the Tesla system that are not mentioned in the publicity fluf. There is just too much detail missing at the moment.
Tesla need to spell this out before the ordinary plebs like me will pass them buy.

Martin S
May 3, 2015 1:53 am

More subsidy-farming from the draft- & war-dodger Musk.
I’ve spotted a few Teslas lately. I get an urge to ram them every time.

Reply to  Martin S
May 3, 2015 7:51 am

Got me to chuckle at that one.

May 3, 2015 2:09 am

Three decades of green hype. And we have been told on a weekly basis that some company or group of scientists have invented a completely revolutionary battery, wind turbine, wave generator, solar panel, solar thermal plant etc.
Meanwhile, back in reality the only renewable systems generating low cost kilowatt/hours (before subsidies) are hydroelectric and standard vertical axis on-shore wind-turbines.
P.V. solar costs are falling, as they have been historically by about 50% every 7 years.
They observe a trend that is much like Moore’s law. So they will soon hit parity with grid electric.
But, the basic technologies that work in energy storage and generation are almost exactly the same technologies as 30 years ago. AGM lead acid batteries are widely used in telecoms and data-centre back up systems. Wind turbines got bigger. Hydroelectric is the same as it always was – big and cheap.
What is most fascinating to observe is that every single whacky idea produced in the interim seems to have fallen by the wayside.
And yet still, announcements like this can pull in a fresh wave of investment and govt. subsidies.
When I see these units being bought by industry to replace AGM lead acid banks – then I’ll take interest.
Until then, I’ll stick this in the “green hype” category. Along with almost every other bullshit revolutionary idea that has come and gone.

Reply to  indefatigablefrog
May 3, 2015 2:11 am

Apologies – I mistakenly wrote kilowatt/hours. When I meant, of course, kilowatthours. Whoops.

Reply to  indefatigablefrog
May 3, 2015 2:16 am

I’m clearly half asleep, I also wrote “vertical axis wind turbines” – when I meant “horizontal axis”. I’ll have to make more of an effort to proof read these posts in future. I sometimes forget that you can not edit. Apologies again.

Geologist Down The Pub Sez
Reply to  indefatigablefrog
May 3, 2015 4:23 pm

What has not been falling is the amount of CO2 emitted to produce the silicon metal for the most common type of PV cell. It is a very large number

Reply to  Geologist Down The Pub Sez
May 13, 2015 8:27 am

What’s the total budget? For CO2 produced by manufacture versus CO2 not produced during the lifetime of the unit (compared with coal gen. for example.)
Anyone know?

May 3, 2015 2:40 am

May 3, 2015 at 1:18 am
1200 watts x 24 hours is 28.8 Kw-h. Close enough to 30 Kw-h per day.
What’s your problem?
Our house’s daily useage is about half that.
Musk drives me nuts. SpaceX is the best thing to happen to the human race in a long time. Hope is somewhat alive that it in fact *has* a future, even though I think Elton John had it right about Mars (How about an cis-lunar, space habitat based civilisation instead, Elon).
Yet he’s dicking around with electric cars and “renewable” energy etc. WTF?????

Reply to  Mike Borgelt
May 3, 2015 4:05 am

Usage varies with house size, heating and cooling systems, insulation, household equipment and amount of electrically heated hot water used.

Big D in TX
May 3, 2015 2:46 am

Nearly 100 comments already, but I feel this needs to be said. Of course this is a good idea, everyone knows it’s a good idea. But like most green energy technologies, it’s not quite there yet.
10 kwh is a joke. It’s a relatively tiny amount of power. Let’s put this into perspective… Mr. Musk’s fancy car has up to an 80 kwh battery! In the announcement video, he explicitly refers to electric heating, i.e. not having to worry about the cold if you lose power. Unless this battery is simply providing a spark for a gas powered furnace, it’s an even bigger joke. An average space heater draws up to 1500W… so you can keep one room warm for about 6 hours, yay… Electric resistance heat takes huge amounts of energy. A small window A/C, maybe around 500W… so if you happen to live in a trailer, or single room apartment, it might keep you comfortable over night… but if you live in a trailer or single, you likely aren’t affording the cost and space requirements for this thing.
As for keeping this battery charged, one would need quite the solar system or turbine! Which is going to be significantly more expensive than the battery itself, if you can even have the generation where you live (good luck getting a turbine permitted unless you live in a rural area).
Let’s talk about energy consumption. I do some energy consulting and efficiency audits in Texas, one of the sunnier states. Yes, some people have solar panels, but they are still very rare, and in practically no cases a “good deal”. When asked about them, I usually just tell customers that I don’t think breaking even in 10 years is a good way to invest $5000.
I’ve seen literally thousands of customers across the state, and can tell you first hand that 99% of them have absolutely no conception of what a “kwh” is, or how much energy they consume. This is partly the fault of deceptive or fraudulent sales people, hawking windows, radiant barriers, and other expensive nonsense, and partly just a lack of education and understanding. In fact, most people have no idea how their HVAC system works, or how their car works, or how to take care of a home, but they spend tens of thousands on these things – how can we expect the general public to worry more about something that costs them so much less? Also typical home square footage is a premium with no basements, which means stuff like HVAC gets pushed into the attic. Stupid, but standard. Where is this closet sized beast going to go?
An “average” home here consumes around 40 kwh daily. Of course this is in reality heavily weighted toward summer and winter seasonal usage – meaning when you need power most, this battery will help the least. It *might* be able to power a smaller, efficient home with conservative occupants, in spring and fall months, without letting everything drop off in the middle of the night. But that’s it. Unless you live in something that meets Passivhaus standards or close to, this is really a tiny amount of energy to be able to store and draw upon. We need at least 10 times this in a smaller and cheaper package for it to matter to anyone. But for that to matter, we need distributed generation to be 10 times cheaper and more available. So good luck with that. The grid isn’t going anywhere, any time soon.
/rant… It’s just plain frustrating to see something so pitiful get so much attention. Stick to the car for now, that’s not so terrible… we’re all waiting on the “affordable” EV for the average layperson to really “revolutionize” things, and not just be a tax shelter for the wealthy.

Reply to  Big D in TX
May 3, 2015 7:31 am

Math, it is a….. reality kind kills it. Something with 10x the capacity would might just cut it for the normal USA home.

May 3, 2015 3:01 am

‘When you factor in the satisfaction of tearing up your last electricity bill,
Straight after you live in area where the lack of sunlight or wind is never a problem, and when you no longer need to connect to any grid , some of the charge covers the cost of the physical make up of the grid no matter what the power source .
So the author may have a long wait .
Still Musk’s abilities to self promote remain high and no doubt fat government subsides , payed for by the taxpayer , will be winging there way to him , so it is not all bad news.

Proud Skeptic
May 3, 2015 3:11 am

I have read nothing about this battery that would make me think that it is cost effective. In fact, the 1000 cycle limit, which is new information to me, makes it worse…Imagine having to replace thousands of dollars worth of batteries ever three years.
That said…this is another small incremental step toward what one day might prove to be a viable energy storage medium sometime (in the distant future).

JJ, too.
Reply to  Proud Skeptic
May 3, 2015 11:21 am

Proud Skeptic,
Cars are not ‘cost-effective’. Neither are clothes or food. If you up-size them, they are even less cost effective. But we do it anyway and all the time.
The wealthy will buy these to feel good about saving the environment. The off-grid cabin types will purchase them because they can actually supply the low energy needs of a small abode or trailer with just a few PV panels. The third world chronically poor can be provided with these by their governments to power refrigerators and lights with the addition of a small windmill or PV system.
Not everyone thinks, or can operate by, the ‘cost effective’ psychology. This system will win or lose based on how it sells and functions in the real world. But one thing is for sure…it will lead to better and more cost-effective systems in the future. And that is what is so important about Musk pursuing leading edge thinking in potentially future technologies.

James Loux
May 3, 2015 3:32 am

jakee308 apparently has a challenge with multiplication, so his concerns about the Forbes article lose all credibility.
Li ion batteries have two distinct advantages over other designs; energy density and depth of discharge. Neither of these advantages is of significance in a stand alone home system. Li ion batteries have several disadvantages compared to other designs; thermal runaway, hazardous materials, cost of materials and disposal of materials. All of these disadvantages impact their use in a stand alone home system through increased cost and safety concerns. As an engineer, I am frustrated to see an excellent technology misused in an application where it can only fail to compete successfully.
The 300+ VDC battery working voltage is appropriate for large scale inverters in the 100kW size and up. There are plenty of these available for utility and commercial installations, not individual homes.
There is nothing in this promotion by Tesla that is new or different from the present state of battery technology, which means that it is all hype.

Reply to  James Loux
May 3, 2015 5:47 am

“The 300+ VDC battery working voltage is appropriate for large scale inverters in the 100kW size and up…not individual homes”
That’s not true at all. Some residential grid connected PV inverters run up to 600 VDC, 480V nominal, transformerless (I assume they mean 60Hz), conversion efficiency ~96%.
SMA’s SB 3000TL-US ~$1,500 USD

James Loux
Reply to  Paul
May 3, 2015 1:27 pm

Paul –
Yes, Sunny Boy inverters allow solar panel strings to be anywhere from 5 to 14 panels long, with an input voltage range of 150VDC to 450VDC for grid connected systems. SMA Sunny Boy’s target market is grid connected 240VAC, so their system design did not have to consider the impact of long strings of 12V batteries to match that voltage. The Tesla Li ion batteries would match their input voltage, but SMA’s inverter design is focused on grid connected operation. Their Secure Power Supply feature does claim to provide daytime power during grid outages, so the inverter may well be able to stand alone, but battery sourced operation is not referenced at all. Although it appears that SMA’s inverters may work in a stand alone system with batteries connected, their inverters were designed for PV panel power control, not batteries as a source of power. Do you have experience that they will operate reliably with batteries as a source?

Reply to  Paul
May 3, 2015 5:55 pm

James, the SB series of PV inverters (and most others) will not export power unless there is already a grid present to push into. It’s a safety feature to prevent islanding. They do make other inverters that target micro-grid applications that might be suitable.
I have no experience operating the SMA on batteries (or even PV, but hopefully soon). I would imagine the MPPT feature wouldn’t be the thing to use on a battery, or maybe it is? The Secure Power Supply feature requires a manual switch to work properly, and to restore grid output operation. Not very useful in my book.
If we are really serious about efficiency & cost reduction, the best approach would be to drop AC for home power, in favor of high voltage DC. The first stage of almost every electronic device and appliance is a rectifier and filter to turn the AC into DC for a SMPS or motor inverter.

Ivor Ward
May 3, 2015 3:38 am

I have a plan. Drill and frack for gas. Build super efficient gas power station. Use electricity from said station. Relax in warm glow. (I cannot see a flaw in my plan)

Just an engineer
Reply to  Ivor Ward
May 4, 2015 9:54 am

And the problem with coal is?

May 3, 2015 3:52 am

Here’s a rough and ready price comparison chart for various battery technologies.
The figures presented are per kWh: $150 for lead acid. And $400 for lithium.
Those figures make sense.
It seems to me that the battery reported here is therefore unremarkable.
Tesla have only managed to reduce the lithium price to $350 per kWh. If you buy 10KWh’s worth for $3500.
Probably because they have cleverly designed it to provide a weirdly high DC voltage that necessitates having it and all related components purchased from and fitted by Tesla.
It’s possible therefore that they are promoting the battery in order to attempt to lock people into using their system and services.
It’s still more than double the cost of the same capacity of lead-acid.
Maybe that is why industry power back up is all lead-acid rather than lithium.
People will fall for this though.
And sadly, many of the people who fall for these scams are technically illiterate politicians who get all excited and flustered, and rush in where angels would fear to tread – with vast quantities of taxpayers money.
Here’s that handy chart of battery tech. costs per unit of energy:

May 3, 2015 4:04 am

Many commenters have assumed the desirability of going off grid. some have even noted the possible economic effects of a large portion of the user base going off-grid. So I pose this question.
As public policy, for an entire society, which is the more effective strategy:
A) Use subsidies, user fees, rate increases, taxes, surcharges, etc. to coerce consumers to go off-grid, by increasing prices until they have no choice, except for some otherwise unaffordable solution.
B) Maintain a grid which is as cheap and reliable as possible, making maximum use of economies of scale.
Lets see what people have to say.

Reply to  TonyL
May 3, 2015 4:14 am

B. An analogy would be that there is massive support for high-speed rail (Option A) between the major cities here in Australia. As yet, I have not seen how that would be paid for and how that would compete with the, current, most efficient means to travel between the major cities in Australia which is by air.

Chargeable Lank
May 3, 2015 4:28 am

The Tesla lithium ion batteries have a considerable cobalt content. Where will this metal come from? Not the USA which has zero cobalt producing mines. Tesla will almost certainly rely on China which processes cobalt from the Democrattic Republic of the Congo. The DRCongo in central Africa supplies more than 60% of the world’s cobalt supply.
Cobalt prices will almost certainly appreciate if Tesla progresses with these energy storage systems.

May 3, 2015 4:34 am

I like the idea of moving partially or fully off the grid. In many locations, electricity costs are greatly increased by nonsensical grid-connected wind and solar schemes.
Grid distribution and administrative costs add greatly to the burden. In Calgary, the cost of electrical generation is relatively low – about 6 to 9 cents/KWh, but that cost is then doubled or tripled by high distribution and administration costs.
Rather than using batteries, I am more encouraged by other off-grid technologies, such as those that convert methane (natural gas) directly to electricity.

Keith Willshaw
Reply to  Allan MacRae
May 3, 2015 6:27 am

You oant like it in a cold winter when the wind and solar output is negligible and the battery is flat. Survival in that scenario means means burning anything flammable – if you have a fireplace or stove that is.
Using methane is NOT being off grid , it simply changes the nature of the grid and the most efficient way to turn gas into electricity is a Combined Cycle gas turbine plant such as the installations in Calgary owned by ENMAX.

Reply to  Keith Willshaw
May 6, 2015 9:45 pm

Your first paragraph clearly does NOT refer to my comments – you are probably correct, since I’ve lived through a long winter power outage and it was certainly difficult, but you are off-topic.
Your second paragraph is interesting. The grid is defined in my comment as the electrical grid, nothing more. Your comment about GTG’s is valid to the extent that mini-GTG’s are available in sizes suitable and affordable for homes or apartment buildings, and progress is reportedly being made in this field.
My main point is that electricity from the electrical grid has been made much more expensive (and less reliable) by foolish grid-connected green energy schemes and by excessive administrative and distribution costs. Getting off-grid will, I suggest, become the best way to overcome this politically-driven excessive increase in our home energy costs.
Regards, Allan

May 3, 2015 4:42 am

Is anyone doing research into more efficient compressors for cooling and refridgeration? It seems another way to skin this cat is to target the big draws.

Grey Lensman
Reply to  Jean Parisot
May 3, 2015 4:54 am

Simple, use a heat exchanger on your outdoor unit. rather than driving a fan and chucking heat out into the desert air, You heat your hot water and make your unit more efficient at the same time.

Reply to  Jean Parisot
May 3, 2015 9:22 am

Get a gas fridge. You only need power for the bulb and fan.

Grey Lensman
Reply to  siamiam
May 4, 2015 2:49 am

Use a solar water heater to heat the bulb. Instant aircon when you need it

Bruce Cobb
May 3, 2015 4:44 am

All of this, the “green energy” market, ‘lectric cars, and the resultant high cost of electricity is thanks to CAGW – the biggest lie in human history. We’ve been sold a pg in a poke and we’re arguing about how to keep the costs down for feed and housing.

Grey Lensman
May 3, 2015 4:55 am

Green free renewable energy results in electricity at four times the price that is also unreliable.

Reply to  Grey Lensman
May 3, 2015 7:59 am

Here in the UK, many solar panel farms are being paid 43pence/kWh for their output to the grid.
The current wholesale price of electricity is about 4 to 5pence/kWh.
So, in this instance the solar p.v. is costing us 10 times the market rate.
And bear in mind that it is actually worth less than a dependable supply.
Since it is unpredictable, unreliable and the peak solar output occurs when there is low demand.

May 3, 2015 4:57 am

This Tesla battery is utter crap and the idea is stupid. BTW it’s nothing new, some tech freaks with PV-panels use such batteries since years. BTW you can just take a bunch of car batteries and connect them with a control devices (example: http://www.solaranlagen-portal.com/photovoltaik/stromspeicher/energy-3000-powerstation). Beside some tech-nerds nobody does this – because it’s far away from economic. The price of 350 $/kWh storage is crazy. In a large scale this price goes down to maybe 10 cents per kWh, google for Batterie-Speicherkraftwerk Berlin Steglitz or Golden Valley Electric in Fairbanks battery for more details. The best solution are still pumped storage hydro power station, if you storage there energy for a day, the costs go down to maybe 3 cents per kWh. If you store energy for a longer time, the costs increase accordingly. But 350 $/kWh is just a ridiculous pile of turd.
For German speaking people read more about the topic:

May 3, 2015 5:24 am

Would a flywheel stepped up during the day by a solar panel and turning a generator at night be useful?

Reply to  Gribbenski
May 3, 2015 7:42 am


Would a flywheel stepped up during the day by a solar panel and turning a generator at night be useful?

Consider that most people can no longer be trusted to turn their car headlights on, to change gears with a clutch, and regularly change their oil, oil filter, and AC fan filter, do you “trust” a normal householder to safely operate a multi-ton high-speed generator-motor with oil system and filter and oil reservoir and regulator and controller at 3600 rpm? In their ? basement? garage? Back shed? Back porch?
A lead-acid has the same problems: Gallons of high-concentration sulfuric acid, lead plates, and an un-regulated DC voltage (think arc welder in a basement that can be “turned off” when the shelf tips over, gets climbed on 6 year olds, gets in a house fire, gets the lines “touched” disconnecting/re-connecting the batteries, doesn’t get the acid-covered copper bars torqued down firmly, gets the house broken into to steal the copper wires and regulator/converter, needs regular recharge/discharge/floating charge/overcharge maintenance cycles.
I build and re-build power plant-sized and industrial-sized turbines and generators – they are very, very tough to work on. Very easy to screw up while working on them. (For a house overnight, think of a rotating motor-generator the size of your car, and a stator frame weighing just as much.)
The flywheel? When it breaks, or when the bearings break, what stops it? The house across the street? The house behind you? The wall of the apartment house basement – as it chews up all of the structural members columns and beams holding up the apartment building?

Reply to  RACookPE1978
May 3, 2015 8:30 am

RACookPE1978 must have run the numbers.

Reply to  RACookPE1978
May 4, 2015 1:43 pm

A few years back, there was some group trying to push the idea of using flywheels to power cars.
I got them all to thinking when I asked what would happen when you tried to turn the car.

Reply to  Gribbenski
May 3, 2015 8:27 am

An old idea but used in back generation to keep power up while the backup generator starts. I sure other people have though about it but I have not looked at it for 30 year. Like everything just run the numbers to see is economic. It maybe

May 3, 2015 5:32 am

Ain’t nobody moving off grid with no 10K battery.

Reply to  arthur4563
May 3, 2015 8:33 am

For 4-12 hours maybe if your not cooking, washing or drying or cooling/heating your house.

Tom Johnson
May 3, 2015 5:47 am

10 KWh is the same energy as in a quart of gasoline, and storing it costs $3,300??? I’ll sell you my used oil containers for only a hundred bucks each, and they’re reusable indefinitely.

Reply to  Tom Johnson
May 3, 2015 5:57 am

“10 KWh is the same energy as in a quart of gasoline”
ICE that gets 40 miles per gallon = 1 mile per kWh.
Volt users report >3 miles per kWh. YMMV
“they’re reusable indefinitely.”
Both oil and electrons are free for the taking, but on a small scale it’s cheaper to harvest electrons.

Geoff Sherrington
May 3, 2015 6:06 am

Global resource economics.
Each year about 60,000 tonnes of new uranium is mined then purified.
This eventually produces several % of global electricity.
Each year about 40,000 tonnes of new lithium is mined and purified.
This produces zero % of global electricity, but can be used for storage then release on demand of about 0.00001% of global electricity.
Please check my last figure. It looks too high.
For the Musk battery to have global impact, the known lithium reserves are several orders of magnitude too small. It would take decades to upscale. The recovery cost increases as the quality of the ore source gets less as demand increases if indeed there is that much lithium to be found.
If either of these has a future, it is NOT lithium.
(Joke. Besides, who wants a new rechargeable, multi use battery versatile enough to be used off-peak in a mobile smart phone that is six feet high?)

May 3, 2015 6:30 am

Others have pointed out already that if you want a stationary battery, you have no need to use an expensive Lithium battery, as the reason to use Lithium is its light weight, which is of no use in a stationary installation.
I’d like to add: Tesla Motors seems to try to find bigger markets for its automotive batteries; but these batteries are already prepared to survive most car crashes. This is ANOTHER feature you don’t need in a stationary installation.
So, we have a completely wrong requirement analysis. Tesla Motors obviously thinks that advantages incurred by experience curve / economies of scale outweigh these false requirements; but I don’t think so. IF a viable market for stationary household batteries develops, the economies of scale of that market alone would make it worthwhile to develop a system that avoids the false requirements.

Reply to  DirkH
May 3, 2015 6:33 am

…also, the price of Lithium per tonne is going up and up and up over the past years EVEN as the global economy continues to stagnate, due to Lithium’s popularity in mobile devices and drones, so the consequences of Tesla Motors’ wrong decision will get worse as the price rises further….

Jack Smith
May 3, 2015 6:39 am

I generate over 1000 KWh excess electricity a year on my 6.7KW PV array. Fortunately, since I have net metering, I can recover a few shekels @ wholesale rates rather than dump those extra watts into the water heater or A/C. If my utility operator wants me to store it on my property they will need to pay me to install a battery system, I will buy a battery backup system someday when it starts saving or earning me money so I am a future customer when the price is right.
Tesla’s grid scale batteries will be the tipping point though, not the small scale home units.

Richard of NZ
Reply to  Jack Smith
May 3, 2015 6:48 pm

I see that the difficulty is that you voluntarily signed up as a customer of the supply company. You accepted the terms and conditions because you required (or wanted) a cheap reliable source of electrons.
When you decided to start producing some of your own electrons instead of buying them, why did you expect your usual supplier of electrons to buy your excess at random times and quantities, at retail price instead of the production cost that they usually pay for their electrons? You appear to require the supply company to make a compulsory loss so that you can make a compulsory profit! The market should determine the returns of your generation not some political compunction.

Jack Smith
Reply to  Richard of NZ
May 4, 2015 7:24 am

Richard of NZ,
Did you miss the part where I said I get paid at wholesale rates? Granted that’s more than the price of electrons at the nearest central power plant but I assume the cost of building, operating and maintaining my equipment and I don’t get credit for that, nor should I.
PS: Guess what the cost of electrons are when the grid in Texas is at peak demand? Two years ago our PUC (public utility commission) raised the system-wide offer cap (SWOC) to $9,000 per megawatt-hour in 2015. (http://www.greentechmedia.com/articles/read/ERCOT-Will-Raise-Texas-System-Wide-Offer-Cap-to-9000-in-2015). You don’t suppose having your grid bought out by a bunch of Wall St. banks and hedgefunds (look up TXU and Energy Future Holdings) who then proceeded to bankrupt the company just might be more important than me selling solar electricity back to the grid? Maybe your concern about me gaming the system is misplaced?

lif strand
May 3, 2015 6:43 am

The hit of $3500 per battery is not going to make it for most of the people of the world, who must build their systems component-by-component as they can afford it.

May 3, 2015 6:51 am

Ah….hold of on that expected savings just yet.
Electricity is publicly regulated and as such……if the utility can’t meet costs (for whatever reasons in it’s non competitive business models), they will simply raise rates to compensate.
So, without true market forces at work. History has shown us that this will most likely have the opposite intended effect regarding the public’s saving of money…….
The only way this (or frankly any) attempt to reduce electrical costs would work is if the grid was open to any provider and the monopolies to customer bases eliminated. Without that, you could have FREELY generated power and would still cost more.

May 3, 2015 7:24 am

Mistake in tjhe headline:
Should read “Tesla announces very slightly lower costs for incredibly expensive batteries’.

May 3, 2015 7:33 am

the way I see it, the main role of this battery is to store solar produced energy so that it can be used at night.
Tesla’s business model is that early adopters pay a premium while funding the R&D that will lead to less expensive, more mainstream models down the road. this is how they are doing their car production…

Grey Lensman
Reply to  Marcos
May 3, 2015 7:39 am

What car production? Most major car makers around the world have solved how to build a car..

Ernest Bush
Reply to  Grey Lensman
May 3, 2015 8:01 am

@greg – there is actually a lot of innovative technology in a Tesla car. Their latest model will go from 0 to 60 mph in 3.2 seconds, as I recall. The entire dash board is an LED screen. If they figure out how to get twice the range at about 1/3 the cost sales will increase a lot. The number of charging stations is increasing every day and it only takes about 30 minutes. There are 10 charging stations conveniently located in Yuma, Az. and another 7 at Gila Bend, 116 miles up the road from Yuma on the Interstate.
I’m not that big a fan of electric, however. If everybody were to convert over a short period there would not be enough generating power in the U.S. to keep them all charged, I am told.

Reply to  Grey Lensman
May 3, 2015 8:53 am

Um, the electric cars that Tesla makes. The Model S runs $70-100k and the upcoming Model X will be around $70k. The Model E will be out in a couple of years and the price should be in the $35k range. The early adopters that bought into the Model S are paying for the research that will allow the Model E to be half the cost…

Reply to  Grey Lensman
May 3, 2015 8:56 am

“The entire dash board is an LED screen.”
I see you haven’t seen the inside of a Mercedes S class lately.

Reply to  Grey Lensman
May 3, 2015 8:57 am

May 3, 2015 at 8:53 am
“Um, the electric cars that Tesla makes.”
The FEW and EXPENSIVE cars that Tesla makes.

Reply to  Grey Lensman
May 3, 2015 1:59 pm

May 3, 2015 at 8:57 am
“The FEW and EXPENSIVE cars that Tesla makes.”
I’ve seen more Tesla Model S’s driving around Houston than I have Chevy Volts, and I sell Chevys

Steve P
May 3, 2015 7:39 am

Three blind mice, three blind mice,
See how they charge, goin’ off grid,
The wind didn’t blow, ‘no sign of the sun,
The laundry’s all damp, their toast is not done,
And lIving in darkness is really not fun
For those three blind mice.
– sp –

Grey Lensman
Reply to  Steve P
May 3, 2015 9:14 am

The average house, 1 kwhr. Tesla 85, so to charge in one hour uses 85 houses load of electricity. .0 to 60 wow but runs out in 30 mins with no a/c. Range nowhere near 265, but Tesla knows the true figures from its service data but will not tell anyone.

Ernest Bush
May 3, 2015 7:49 am

Tesla’s batteries are simply a repackaging of his car batteries. They are worthless for home use. The number of discharge cycles is limited as is the lifetime. Until the cost is about halved and the lifetime at least doubled lithium batteries are a rich man’s toy. Also, in Arizona the two major power companies have added grid access charges for solar producers to compensate, supposedly, for not paying their fair share of baseline operating costs. Suddenly, generating excess solar power doesn’t look so good.
A consumer’s best bet is still putting in energy efficient appliances, gas-filled windows, and a heat pump with a high efficiency rating, not to mention more insulation. I have allowed dealers offering both leasing and purchase options to make presentations at my home. None of their solutions would have saved me money. I am 71 and am not interested in twenty year solutions, especially involving current battery technology.
Do not think for a minute that public utilities are not poised to alter their charge structures to make sure they continue to be very profitable. If a lot of people go “off the grid” they will probably end up paying a fee to do this to compensate for their lack of usage of the grid. It has gotten that crazy out there. Remember, home owners in some states have been fined for daring to collect rain water on their property on the theory that rain is a resource belonging to the state.

Steve P
Reply to  Ernest Bush
May 3, 2015 8:02 am

Yes, and So. Cal. Edison is making noise about charging low-usage customers more…

Southern California Edison and other investor-owned utilities propose to raise rates for people who use less energy, and lower rates for people who use more..


Ronald Hansen
May 3, 2015 8:04 am

Simply google Elon Musk rent seeker. He gets rich from from U S government transfers of wealth (money) from middle class taxpayers.

Steve P
Reply to  Ronald Hansen
May 3, 2015 8:14 am

Some guys have all the luck…

Rod Stewart

May 3, 2015 8:38 am

if you get subsidies/tax break I think (if I remember right) you HAVE to hook to the grid to backfeed it.
I very well may be wrong though so if someone knows for sure (this is in US) please correct me.

Curious George
May 3, 2015 8:55 am

Lead acid batteries are heavy, lithium batteries are light. That’s so very important when you have to install them in your home or a garage. /sarc

Man Tran
May 3, 2015 8:59 am

After reading through the comments, I’m surprised no one has mentioned that Musk is going to provide Apple and Google(?) batteries for their mega-sites in CA and China.
I love the idea of letting all those smart, rich companies work out the laws of physics so we can benefit later.
It is also key to the mega installation near Reno that Tesla is building. Your stock price may vary accordingly.
Lastly, I’ve played with electric/hybrid sailboats (poorly). There is a Greman outfit, Torqeedo that is promoting a similar battery for electric propulsion. Might be Tesla’s.

Reply to  Man Tran
May 3, 2015 6:23 pm

“I love the idea of letting all those smart, rich companies work out the laws of physics so we can benefit later.”
Has all been worked out long ago.
“There is a Greman outfit, Torqeedo that is promoting a similar battery for electric propulsion. Might be Tesla’s.”
No. They’re all alike. SAFT makes some, for instance, used in hybrid high end limos .
Musk tries to do volume business to reduce cost. That’s all.

May 3, 2015 9:02 am

Where do all of the vapors expelled while charging/discharging these batteries go? What will the levels be in a community when 1/2 the homeowners have them.?

May 3, 2015 9:04 am

of good lord … its not cheap (lead acid batteries for the same capacity cost less than $1,000) its not new … nor will it save you money over a good coal fired plant …
Musk is great at marketing and this author is just another sucker that Musk will prey on …

May 3, 2015 9:10 am

Jack up your house, slide a skateboard under it, slap on one of these batteries, and you’re ready to drag race a Prius.

Bill Webb
May 3, 2015 9:14 am

It appeared to me upon seeing a pic of a Tesla car battery internals, that, they use Kapton insulation. Research Kapton in aircraft wiring. In aircraft wiring it represents an extremely serious known fire hazard once environmental degradation occurs. While the circumstance of usage may be different, it raised questions in my mind as to whether they understood the risks of Kapton. The application may be totally safe given the manner in which they engineered their batteries. But, they need to answer that question.
Insofar as the battery itself, they need to post charge profiles for bulk charging, absorption charging, and float charging. From what I have seen about batteries in the past, if, you want to go solar battery back-up, or, off-grid, Rolls-Surrette lead acid, or, the old Edison nickel-iron batteries are still best in the long run on a cost analysis bases. Nickel-iron can be over or under charged, and, they never wear out. Simply disassemble and wash with water and potash once they degrade. Voila! Good as new. The first Edison batteries still run today.
Re-cycling lithium-ion is nasty and much more expensive at this point in time according to a chemist friend. Currently, these batteries are not really re-cycled. Tesla brushes this aside saying they are incorporating this capacity into their battery plant. But, in reality, re-cycling is an exogenous variable to their cost model, which, will be incorporated at some point.

Reply to  Bill Webb
May 3, 2015 10:00 am

Bill Webb

Insofar as the battery itself, they need to post charge profiles for bulk charging, absorption charging, and float charging. From what I have seen about batteries in the past, if, you want to go solar battery back-up, or, off-grid, Rolls-Surrette lead acid, or, the old Edison nickel-iron batteries are still best in the long run on a cost analysis bases. Nickel-iron can be over or under charged, and, they never wear out. Simply disassemble and wash with water and potash once they degrade. Voila! Good as new. The first Edison batteries still run today.

I like the Ni-Fe – simple, heavy, reliable. Less harardous for today’s “home owners” and businesses. Certainly not “exotic” though. Are the “old” Bell telephone battery Ni-Fe, or were they lead-acid plates – but with metallic lead, not foamed crystal lead like today’s car batteries?

Geologist Down The Pub Sez
Reply to  Bill Webb
May 3, 2015 4:35 pm

If anything like the propose Tesla system goes forward we will HAVE to recycle lithium-containing items. Let’s see, we can start with collecting Corningware pots from all those “antique” shops – they are about 5% Li2O by weight. I wonder if that will be enough?

Just an engineer
Reply to  Geologist Down The Pub Sez
May 4, 2015 10:39 am

And as a result of more batteries?