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Published on December 31st, 2015 | by Glenn Meyers


Sonnenbatterie Battery System Beats Tesla Powerwall To US

December 31st, 2015 by  

Battery storage is already showing itself as a hotly contested race in the US, even before the 2016 widely expected retail launch of the Tesla Powerwall. This storage race has been fueled further by German-based Sonnenbatterie launching its plug-and-play home battery system in the US prior to Christmas.

As reported by pv-magazine, the US move gives the German manufacturer a head-start on Tesla’s Powerwall. How sales results show after the first quarter remains to be seen.

Sonnenbatterie Manufacture-storage-system-Sonnebatterie_eco

Sonnenbatterie has already made an eye-catching American footprint, manufacturing storage devices in San Jose, California, and having inked distribution agreements with some 30 US dealers. More importantly, sales are already taking place:

“Demand for the battery is already strong, with a Sonnenbatterie spokesperson telling pv magazine’s German-language website that around 1,000 products have already been ordered.”

In anticipation of continued high demand, Sonnenbatterie aims to increase production capacity at its San Jose site. Production is already running at full capacity, the company confirmed.

As we have previously reported, Sonnenbatterie has been successful in Europe, especially in its home country Germany.

The Sonnenbatterie home storage system offers an electricity storage package for the solar homeowner. Alongside a lithium-ion battery, the plug-and-play system also includes an inverter, and control and measurement technology are contained within the box. The system can be accessed via computer or smartphone to ensure homeowners can always monitor their energy consumption usage and patterns.

CEO Boris von Bormann believes his company is providing a comprehensive home storage system. “We’re doing a whole-home backup, and driving critical devices with the Smart Home platform. No one else is offering that.”

The company website provides this perspective:

“The Sonnenbatterie system ensures that you get the greatest possible benefit from your PV system. A household with a Sonnenbatterie and a PV system can meet 70 to 80% of its electricity needs with self-generated electricity over the course of a year, and as much as 100% in the summer.”

With the new year coming soon, the race in the battery storage marketplace will be most interesting to watch.

Image via Sonnenbatterie

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About the Author

is a writer, producer, and director. Meyers was editor and site director of Green Building Elements, a contributing writer for CleanTechnica, and is founder of Green Streets MediaTrain, a communications connection and eLearning hub. As an independent producer, he's been involved in the development, production and distribution of television and distance learning programs for both the education industry and corporate sector. He also is an avid gardener and loves sustainable innovation.

  • vensonata

    Commenters on these battery articles are getting sharper every week. It is good that a few people can really process the numbers on home storage. I would like to see this new arrival to the renewable energy project become as familiar and easy as mpg for cars. I hope that Consumer Reports also does some comparisons. It is confusing the way these batteries are marketed and that is no accident, nor is it mere negligence. What did Elon Musk say about battery makers…something like he had never come across such B.S. in any other field. We need some trustworthy independent sources for the public good to scrutinize the hazy distortion fields which surround this slightly cracked world of battery marketing.
    That said, in brief, Sonnenbatteries is twice as expensive per kwh as the Tesla 7 kwh powerwall. End of story.

    • mike_dyke

      To give the Sonnerbatteries the benefit of the doubt, they do come with an in-built inverter which the powerwall doesn’t which raises their costs a bit. However, it will be interesting to see what happens when that google little inverter competition completes this January (An article on here when it does complete, Glenn?) – Some of the entrants are extremely small which should hopefully reduce prices when they get into production.

      • vensonata

        I am including the inverter calculations. I have been through the math on these two batteries a number of times over the last year. When you strip out the camouflage and decoys, different cycles, different efficiencies, inverter costs etc. the bottom line is Tesla 7 kwh powerwall about 11 cents kwh, Sonnenbatterie about 22 cents kwh.
        The little box inverter, you had to mention that didn’t you, you know I always salivate when that comes up! So I actually saw a photo of one of the 17 finalists inverters. The university of Tennesee, their 2 kw inverter is about the size of a stack of note cards. 4×5 inches x 2 inches thick. Is that about the size of a thick Iphone? 17 finalists, and the announcement of the winner will be made this January. Stay tuned.

        • Marion Meads

          The inverters are a tiny fraction of the overall cost and cannot justify why the Sonnenbatterie should have stratospheric prices. But we never ran out of dumb and stupid people in this planet, as Einstein have claimed that stupidity is infinite. Sonnenbatterie, even if it doesn’t make any logical sense will find a market, thanks to its marketing team.

          • vensonata .

            Now, now, let’s give “people” a chance first. They need to be informed by mainstream reliable sources so they can make, if not “intelligent” decisions then at least not seriously catastrophic decisions.

          • bink

            vensonata, I have read the postings on here and the problem is the same. The Uninformed. If FERC order 745 (Demand Response) is ruled legal then you will see demand response aggregrators’ in the ISO and RTO markets purchasing energy and capacity from consumers with home energy storage units for bidding into those markets. Some technologies will benefit more than others due to their greater flexibility and capabilities.

          • vensonata .

            Yes, demand response behind the meter and in front may be the key to the “economic” aspect of storage. Multiple layers of uses will change everything.
            By the way, I am predicting that the U.S. will require a 2 trillion dollar battery by 2035. That may be in a diffuse sprawling version or half in central locations. Either way, 3.5 days of the entire electrical grid of the U.S. needs to be available in chemical storage. That is 40 Twh. It can be used over the year to provide up to 30% of the entire energy demand of the country. It will completely eliminate all variability of PV and wind. Remember…you heard it here first!

          • bink

            well, I am hoping for a 5-10kw 50kWh to be developed for residential consumer for daily use and backup. 20 year life.

          • mike_dyke

            So am I Bink.

        • Karl the brewer

          This one?

          • vensonata .

            I think so. There is another picture with a human in it. You can see it next to a human hand. The battery operated alarm clock beside me is about the same size.
            Although some grid connected inverters have reached below 20cents watt, off grid with grid connect are still about 40-50cents watt. Predictions are for inverters to go to 7 cents watt by 2020. These incredible shrinking inverters might be the reason why.

          • mike_dyke

            That picture also gets me salivating – When I think of the size of my installed inverter compared to that one.
            I’ll have to be patient for the specs I expect, but for a 4kwp PV system, would you just use two by splitting the panels into 2 strings of 2kwp?

          • vensonata .

            They should be “stackable” up to any size. They also will no doubt bring out 5, 7.5 and 10 kw versions. All that matters is they are 10 times smaller per watt than the conventional inverter. (50 watts per cubic inch).

        • Bryan

          A 2 inch thick 4×5 inverter won’t have anything for a surge capacity. No surge capacity, no inductive loads like motors or transformers.

          • vensonata

            We will see.

          • Bryan

            I’ve repaired inverters for the past 15 years. I already know what we will see.

          • nakedChimp

            I’d be most worried about the capacitors (big capacity still needs big capacitors) and heat dissipation..

            But devices like this: will do jobs like this. 450V @ 20A normal load and 40A max for surges. Should be able to deal with most household loads, especially as everything is being converted to inverter technology now. Even fridges have got an inverter nowadays to be able to throttle the compressor.

          • Bryan

            This is a DC to DC inverter which is useless in grid tie and off grid applications.

          • nakedChimp

            Check the datasheet.. that’s a DC to 3-phase driver that is good for 450V @ 20A normal inductive load.. can handle up to 40A for short times..
            It’s exactly what you need for grid-tie or off-grid, maybe not 3-phase, but similar stuff.

            Here are some from ST: that do the same stuff (DC > AC).

          • Bryan

            Right, that’s 3 phase DC not 3 phase AC. I take it that you’ve never heard of a 3 phase DC inductive motor ?

          • nakedChimp

            I take it you have no idea how those IGBT inverter bridges work.. you can have ANYTHING at their output with DC input – they don’t take AC input. They make 1 phase AC or 3 phase AC or no phase DC – they switch so fast that they make ‘common’ AC out of the DC. If you were to look at their output you would see PWM like curves.

            The magic of these things is that they – no matter what – don’t short input lines with their internal switches (big failure) by having the semiconductor switches specially designed, but are as fast and high power as possible.

            I think your misunderstanding stems from the outputs neutral being at 50% of the DC input voltage.. but yeah, have a look at the wikipedia article, they start out simple with DC to 1 phase AC.

            PS: there is no such thing as a 3 phase DC inductive motor.. those are induction motors, with 3 phase for getting the rotation of the magnetic field oriented for turning the motor into the desired direction as 2 phase wouldn’t work and 4+ phase would be overkill.
            If these phases then carry hacked up DC or pure AC sine wave or something else is completely irrelevant, as long as the motor runs (best naturally with pure sine wave).

          • Bryan

            I’ve repaired IGBT as well as FET based inverters at the component level for over 15 years. I was factory trained by Trace Engineering before they became Xantrex so I know all about inverters. See The square wave 3 phase output of the device that you posted is not compatible with the grid.

          • nakedChimp

            Let’s recap:

            A 2 inch thick 4×5 inverter won’t have anything for a surge capacity. No surge capacity, no inductive loads like motors or transformer based appliances. Grid tie only applications yes, off grid no way. You’d smoke the FETS/IGBTs.

            Those IGBT inverter bridges are made for phase/frequency control of inductive motors, which is usually feed as rectified Vdc from 120/230VAC as it enters your premises and would not be good to run your inductive motor.
            They might not be able to run big ass stuff in industrial areas, but they will be good for anything that joe average will throw at them.
            You can also feed them solar PV Vdc or battery power and get the same 1 or 3 phase AC out that is capable of running inductive loads without burning those devices if you stay within spec.
            That is their whole purpose. I doubt that Xantrex or SMA would have put those into their inverters as they usually use discrete FETs/IGBTs for more power.

  • thoughtchallenge

    Isn’t Tesla selling their Powerwall for roughly $3,000 for a 7kwh unit?….I think they’ve already started shipping some too…Also, does this company have a Gigafactory?….Its hard for me to imagine how any company can compete with Tesla when it comes to battery intense appliances such as EVs and the Powerwall….Its why I bought a few shares of Tesla stock….I think its good these companies are pursuing this tech and they might be able to carve out a niche of the market… but, I just don’t see them putting a dent into the market compared to Tesla….

    • Bryan

      Tesla is not going to sell a consumer a 350 volt battery pack without having it installed by an authorized dealer. Do you realize how much liability there would be by allowing a consumer to DIY a 350VDC battery? Ain’t going to happen. So the price is going to be a lot higher than $3,000.

      • mike_dyke

        Tesla’s website currently gives 3.3kW power as the limit. It’s been updated since the 2kW limit.

        Don’t need an authorised dealer – just a powerwall trained electrician.

        • P Roppo

          You can only buy a Powerwall through Solar City with a panel installation.

        • Bryan

          3.3 kW what ? peak or continuous ? Sounds to me like they’re hiding something. All manufacturers post both peak and continuous ratings. They use to post both ratings but not anymore…..why ?

          And what’s the difference between a authorized dealer and a powerwall trained electrician ? An electrician will cost you even more because of their licensing and bonding requirements.

  • MarTams

    At $1857/kWH capacity and 10,000 cycles, that’s a horrendous expense of $0.1857 per kWH of electricity at 100% roundtrip efficiency. At 85% efficiency, it would cost $0.2185/kWH stored and used. It is way better for you to do net metering than using battery energy storage unless you desperately want to go offgrid. The cost of storage is almost double than the national retail price of electricity!

    The fact that they’re sold out means that Californians by and large are very stupid and can’t do simple economic calculations! We seem to be suckers for zero down upfront costs that’s why Solar City can get away with the highest prices.

    • Jenny Sommer

      It doesn’t even make sense in Germany.
      People told me that you could run your fridge or freezer for some days in the US would be an advantage. Apart from a perfect service I never have more than 50€ worth of food in my fridge…

      I am still looking for an answer to why people would buy home storage.

      • Ronald Brakels

        Australia, you’re standing in it,
        Standing in it for Australia,
        So put your hand up,
        You’ve got to stand up,
        And count yourself for Australia!
        In it, in it, in it,
        You’re standing in it!

        Forgive my patriotic rendition of our national anthem, but the Sonnebatterie system is close to the break even point for Australia. And the Tesla Powerwall is cheaper and will pay for itself for people in the right situation. And in Australia such systems let us buy and sell electricity which helps defray its cost. At times people can be paid about $7.20 US per kilowatt-hour they provide to the grid. And be paid to take electricity from the grid at times too.

        • Joe Viocoe

          I thought your anthem was Waltzing Matilda

          • Graphite Gus

            Me too!
            Actually I thought it was `Tie me Kangaroo down Sport`

          • StefanoR99

            It’s “Land Down Under” by Men at Work.

          • Ronald Brakels

            Actually it’s not, it’s just easier to get the rights to it.

          • Ronald Brakels

            The author of that song, Jake the Peg with an extra leg, has been jailed for using his extra leg in horrible ways, so it is now musica non-gratia.

            Also, at some point we realized that the verse:

            Let me abos go loose. Lou,
            Let me abos loose,
            They’re of no further use.Lou,
            So let me go abos loose.

            Was really racist.

          • Sim

            Utilities are trying to sing the verse. ” So we tanned his hide when he died Clyde and that’s it hanging on the shed.” They are trying to get the fixed rate up and not pay for receive power from residential solar particularly above 5Kw of panels.

          • Ronald Brakels

            Waltzing Matilda is owned by a copyright troll in the US, so I had to come up with a new anthem for international settings, so I stole Australia, You’re Standing In It.

        • Jenny Sommer

          Until every other home installs batteries.
          I still would prefer a real example.
          Do you know anybody that is running such a system?

          • Ronald Brakels

            One would have to be a bit of a thickie to install an on-grid home energy storage in Australia at the moment because it doesn’t currently pay for itself. An exception being people who use it as part of an uninteruptible power system.

            But, and this is the point, home and business energy storage is effectively* cheaper than it was. And the Tesla Powerwall should allow some people in Australia to save money with on-grid storage.

            *I wrote effectively because lead acid batteries are still much cheaper in terms of kilowatt-hours of storage, but the Powerwall’s 10 year warranty and maintenance free operation makes for much lower running costs and higher reliability.

          • Bryan

            I wouldn’t feel comfortable having a cobalt based Lithium Ion battery hanging on my wall . Give me Lithium Iron Phosphate batteries any day. Longer lived, inherently safer and better power density.

          • P Roppo

            Lead acid does not compare, I have used them for decades off-grid. In fact, LiFePo4’s have reached parity in price when compared accurately, with some astounding advantages.

    • UncleB

      If it is your own renewables sourced energy, it costs nothing. Are we trying to preserve excess renewables sourced power for later use or are we trying to save conventional grid power at low cost times for supplementing our power use at peak cost times, or are we looking at a melange de trois, under computer control? Are the calculations really much more complicated that 4 banger calculator levels? I see even compensations in the programming for the computer control for “Brown Out” conditions?

      • MarTams

        The cost of storage of your free excess energy would depend on total cost of installed storage system divided by its life cycles plus finance charges. And the cost of such storage is way higher than retail price of grid electricity. So Why in the world would you want to install these and lose money? Many Americans are so dumb and gullible to install these systems at the prices shown

  • Calamity_Jean

    Their website doesn’t indicate that they are selling outside Europe yet.

  • mike_dyke

    Commenters always ask about cost of a system here, so I had a look on their website.
    They seem to offer a number of systems going up in 2kwh steps from 4kwh to 16kwh and the price according to the FAQ is “The Sonnenbatterie costs between EUR 1,250 and EUR 1,700 net per usable
    kWh of storage capacity, depending on the size and the configuration. To
    this you have to add the VAT and the shipping and installation charges.”
    For USD = $1365 to $1857 per Kwh.

    However, the systems do include inverter as it’s an AC storage system.

    • Jon Wolla

      Uh, is it really possible to store AC in a battery? I thought all batteries were DC?

      • Marion Meads

        I read it as AC-compatible storage system, so was not in the mood to be literal about this. The energy itself is stored in chemical bonds, so we can argue you are not storing DC energy, rather converting the electrical into chemical.

        • mike_dyke

          Yes Marion, you read it correctly – It plugs into the AC side of your system (e.g.. a wall socket) with it’s own AC-DC inverter to store the electricity in batteries.

    • Marion Meads

      Was really wondering what are in the minds of those people in California ordering this system when there is that TOU rates available and you have solar.

      Let us say, you are subscribed to TOU rates as seen here:

      Between May-October, the difference between low and peak demand is quite huge 35.8 c vs 16.6 c, a difference of 19.2 cents/kWH, but since you are producing more electricity during the peak times than you are using, you actually would get more credits for your excess power compared to storing them. You would be crediting yourself 19.2 cents/kWH for pumping the excess back to the grid, whereas, if you store them, based on life cycles and per kWH capacity, it would COST you between 13.65-18.57 cents/kWH. Would you rather earn 19.2 cents/kWH or lose 18.65c/kWH of storage??? This is not even including the energy losses of storage.

      Between November to April, the difference between peak and low is only 1.7 cents/kWH and would you invest in storage system that would cost you at least 18.65c/kWH stored?

      People should at least have basic algebra skills. Both Chrome and Firefox have built-in calculators at the search bar. There is no excuse to be dumb.

      And yet, all their orders have been filled! I will have to hire their marketing department, they’re the asset, and they could proftiably sell bucket of snows to eskimos.

      • mike_dyke

        I agree Marion – it doesn’t make sense when you have the TOU pricing however, for others who aren’t on TOU but just a flat rate (e.g. me) it pays to store excess PV for my future consumption. You’d charge them up from excess PV and use it to offset the time when you need to draw from the grid.

        • Marion Meads

          One of these days, the rules on net metering, TOU rates would dramatically change, and let us hope that the battery energy storage system would have even gone further down than what Tesla is selling and installing them for. A simple recalculation is all we need if it would make senses to use battery storage or not.

          As for me, it does make sense for the society as a whole to have battery energy storage when we have wind and solar towards a cleaner environment. The problem is, the battery manufacturers are always maximizing their earnings rather than helping the planet. They don’t price these things based on production cost plus profit margin, rather they price these based on how much you are going to save, so that to the customers, it seemed to save them money, and they’ll push the margins to as high as they can get away with, and so they earn something like 5 times to 10 times gross margins from production cost. Profit drives these companies, not their desire to save the environment.

          • mike_dyke

            I don’t think it’s going to be that easy a calculation as people’s electricity usage varies between houses. What you need to do is monitor the grid line over a long period (say a year) on a fine resolution (5 minute intervals?) and feed those figures into a computer program which can then calculate the correct size of battery to cover that period i.e. if you put a 2kwh battery in, then you’d save X pounds, for a 4kwh battery, you’d save Y pounds etc. You can then see what size would produce the best return for your money vs the cost of buying the battery system.

          • Marion Meads

            It would be impossible to predict the prices that the CPUC will set for the new net metering, FIT, or TOU rates… And we all know that price as it affects the bottomline is THE most important decision making factor if you care to calculate. As for me, all these calculations are simple once actual prices are known or set in the future. If they’re not, one must assume or project. Of course the battery energy storage companies will project the prices that would justify their bottom lines.

          • P Roppo

            Actually, Tesla’s wall battery is priced fairly aggressively. 3 years ago, I paid ~$1,000/kwh for Carb LiFePo4’s for an off grid house, a good deal at the time.
            The problem with the Tesla plan is that you are required to buy Elon’s solar panels too.

      • Matt

        Main markets:
        1) companies that want to shave peak charges.
        2) Homes: Early adopter that want green bragging rights. Or people who want to be able to island when the grid is down. Notice price is not main factor for either of those.
        Of course i don’t know the detail of CA electric pricing so maybe there are other ways to make this pay.

        • Bob_Wallace

          Consumers with high TOU or tier pricing may find it economic to add storage.

          If you’ve got solar and are getting hit with low ‘sell in’ prices along with expensive evening peak prices then it may work out better to install some storage.

          Same for people with really high useage that throws them into the highest price tier(s). Some storage would let them produce more of their electricity from solar.

          • Joseph Dubeau

            Why not just charge the batteries at night with rates are the lowest. Then sell it back to when the rates are higher.

            How would they know?

          • Bob_Wallace

            You could do that if the price spread supported it. I’m not aware of anywhere that it would work.

          • Ronald Brakels

            In Australia people on time of use payments could do that, or at least the price spread can be wide enough for it to pay for itself with a Powerwall. Actually doing it is another matter.

          • Bob_Wallace

            I was thinking about in the US. Is there much price difference between day and late night pricing in AU?

            Do you have the smart meters to allow TOU billing?

          • Ronald Brakels

            This information might be slightly dated, but in New South Wales people can pay over 50 Australian cents for electricity during peak periods and about 15 cents for off peak electricity. That’s 36.5 US cents and 11 US cents for a difference of 25.5 US cents.

            In Western Australia the difference is about 23.8 US cents.

            In Victoria they installed smart meters whether people wanted them or not and charged $300 each for the privilege of having equipment installed in so that electricity distributors could save money.

            In other places one may have to pay for a “smart” meter if one wants to be on a Time Of Use tariff. I put the word “smart” in inverted commas because they can actually quite dumb.

            But the best arbitage comes with using rooftop solar electricity which might be worth 4 US cents if sent into the grid. So someone paying 36.5 US cents for peak electricity in the evening could find energy storage paying for itself if it cost less than 32.5 US cents a kilowatt-hour, assuming of course the storage is used at full capacity everyday, which is unlikely for most households. But many households could certainly come close to using a smalll amount of storage at full capacity.

            So generally speaking, there is no great need to even have the ability to store electricity from the grid in Australia, although it would be useful to have that option.

          • Ronald Brakels

            I should probably also mention that if people can buy and sell electricity based on electricity market spot prices it can be helpful. For example, at 3:30 this morning in South Australia large electricity users were paid to use grid electricity as the price briefly fell to negative 5 Australian cents (negative 3.7 US cents). The Tesla Powerwall comes with software that allows households to do this, at least to an extent, and at times they can be paid $7.30 US per kilowatt-hour for electricity they supply to the grid. Other storage systems can come with this software as well.

          • bink

            Ronald enough already with the Powerwall nobody in the states is enamored with the thing but Musk kool-aide drinkers

          • Ronald Brakels

            I suspect there are quite a few people in the United States living off-grid who will welcome the Powerwall. Its 10 year warranty is 5 to 10 times that of lead acid batteries. And, in case you hadn’t guessed, I’m not in the United States. I’m in the country where on-grid energy storage is starting to make sense. Now it is the only country with a reliable grid where it makes sense at the moment, but I strongly suspect that the cost of energy storage will continue to decline and it will make sense in an increasing number of countries. Australia will lead the world in home energy storage. Provided of course, Prime Minister Turnbull manages to turn the bull around if he remains Prime Minister.

            PS: What part of the Musk Ox is Kool-aide produced from?

          • bink

            First off. There is not enough power and capacity in a Powerwall for anyone to go offgrid for any significant period of time without purchasing at least a third or fourth unit. Anyone can offer a warranty but you are paying for it. I know where you are, you keep talking about it. Powerwall is nothing disruptive. Slick packaging and good PR machine is what sets them apart

          • Ronald Brakels

            What’s that Bink? Go off-grid? Why would someone who is currently on-grid use a Powerwall to go off-grid? That makes no sense at all, as the return from having grid connected solar is far better.

            I think perhaps you don’t understand why we are interested in the Tesla Powerwall here in Australia. Obviously I haven’t explained things very well. You see, retail electricity prices are very high here, while feed-in tariffs for new rooftop solar are very low. About 4 US cents a kilowatt-hour. So it is possible for a household that has high electricity consumption in the evening to save money by storing electricity generated by rooftop solar during the day in the Powerwall and using it at night so they don’t have to pay for expensive grid electricity.

            I say a household with a high electricity consumption because the Powerwall is too large for most Australian households to use at a high enough capacity to make it worthwhile. But there are still plenty that will find it useful. But households that could profit from having multiple Powerwalls for on-grid storage would be quite rare.

            The Powerwall is the first home energy storage system that is cheap enough for it to save households money. That’s why it has created a stir here. But we don’t expect it to be the last. Hopefully there will be a lot of competition in the field of home and business energy storage, driving prices down, and making use of a variety of different battery chemistries.

          • bink

            Go back and read your post from 20 hours ago. You referred to US consumers in the context of off grid not I. I

            was addressing that. I have read your other posts and understand what you are saying may very well be true in Australia.

            I just think reality has set in for those hoping Tesla would come out with a more capable product. Thus far it has been underwhelming, regardless of price.

            Once the deregulated markets develop product and services to compensate behind the meter developers, integrator s and consumers for the storage benefits you are going to realize that the lithium platform will not allow the consumer to bid services. It is a one trick pony. It will not be able to support rooftop PV and bid services when prices are highest, Lithium cannot simultaneously charge and discharge. Plus there is the other problem of power attribute not existing at the same time as energy due to coupling

          • Bob_Wallace

            ” Lithium cannot simultaneously charge and discharge. ”

            What does that mean? Are there times when a specific point on a grid is both over supplied and under supplied?

          • bink

            In the context of stacking benefits. There is a lost opportunity benefits or lost revenue opportunity. Recent articles have started to highlight this as issue in battery storage economics.

            Take the Solar City 13 MW installation in Hawaii paired with a 17 MW PV array for renewable peak shaving. It is a 4 hour battery that is shifting renewable energy to peak demand period.

            There are a couple of things in play here. The type of battery being used is an energy (capacity) battery for long duration and because it is a long duration battery it cannot perform the hundreds of short power cycles that a frequency response service would require for 15min intervals.

            Nor does the control scheme allow for a continuous output. This is limited due to the inability of the lithium battery to simultaneously charge and discharge at different voltage levels.

            As I have stated to you before. As the integrator on a large project in the Southwest U.S. my company developed such a scheme for Renewable Baseload Power Plant.

            Our control scheme is a 24/hr continuous output of renewable energy capacity for:

            Ancillary services: regulation (up/down), voltage support, CVS, reserves (spinning/non spinning).

            Reliability: renewable load shifting (peak shaving).balancing (load following)

            The battery needs to be able to simultaneously perform these applications to achieve the control scheme.

            For instance the regulation service signal is superimposed over the discharge for demand response during peak.

          • Bob_Wallace

            ” This is limited due to the inability of the lithium battery to simultaneously charge and discharge at different voltage levels.”

            When is a grid operating at two different voltage levels?

          • bink

            Bob you are supporting a PV array. Our control scheme is different than what you would normally think. solar production is being fed directly into battery (A true paring pf solar + storage) not two different connections. We are charging at one current level and discharging at another. There two applications in play here regulation up/down and shifting. A

            All the solar City array is doing is shifting. NO ancillary services because it is incapable of doing so for a variety the least of which happens to be a lack of simultaneous charge and discharge capability. Jigar Shah spoke to this when he funded a Solar grid Storage project. They thought they could support a behind the meter PV array and bid into the PJM, well they realized the inverter was busy and it was impossible but it really had to do with the technology platform and chemistry. We are able to do that and then some

          • Ronald Brakels

            Yes, Bink, I mentioned people living of grid. You see, in Australia and in America most people live on grid, but their are also a minority of people who live off-grid because grid electricity is not available in their location, or at least not available at a price they are willing to pay.

            People who are living on-grid won’t benefit from going off-grid by using a Tesla Powerwall or Powerwalls. It would be cheaper and easier for them to stay on grid

            But people who are already forced to live off-grid by circumstances can benefit. It can be cheaper and easier for them to use the Powerwall.

            Now there are people who, even for a new off-grid installation, will prefer lead-acid batteries because of their characteristics, but I am certain that given a choice the majority of Australians will prefer the Powerwall.

          • John Ihle

            They would know.

          • Ronald Brakels

            In Australia the lowest off-peak rates only applies to systems, normally a hot water system, on a separate circuit. People can and do hack into these circuits to use the low cost power for other purposes. If criminals are very careful not to use more than a small amount of off-peak electricity so the quanitity used looks reasonable for a hot water system, it might never be detected. But it is a kind of a high risk low return crime. Punishments can include being electrocuted to death.

          • Stan Hlegeris

            Here again Australian consumers lead the way. For new installations, the cost of an imported kilowatt is 3-4 TIMES as high as the payment for an exported kilowatt. In Queensland, for example, it’s now about 28c v. 8c. Storing excess PV output for evening use already makes financial sense; the joy of sticking it to the retailers is a priceless bonus.

      • Robert Smart

        My eletricity retailer Ergon in regional Queensland Australia has the following Tariffs:

        Tariff 11 Residential 24.462 cents per kWh

        Tariff 33 Economy 20.759 cents per kWh

        Tariff 31 Super Economy 13.693 cents per kWh

        Solar feed-in tariff for regional Queensland 6.348 cents per kWh

        I don’t have any storage, so I dump 4 hours of solar power into my 250 litre hot tank.

        Of the 7.351 billion people on the Earth only about 0.321 billion live in the USA!

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