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UBS: Australian households could go off-grid by 2018

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Global investment bank UBS has highlighted the challenges facing Australian energy utilities by suggesting that the falling cost of solar and battery storage means that the average Australian household could find it cost-competitive to go off-grid by 2018.

The report by its Australian based analysts says the current cost of going off-grid for a households consuming the average of around 7 megawatt hours would be around $39,000.

That translates to an average cost of around 44c/kWh for the life of the system. That leaves it in the hands of early adopters and hobbyists in the city, but assuming capital cost falls of just 5 per cent per annum, by 2018 it would become cost competitive for average households with staying on the grid.

For those in remote rural communities it may already be attractive – a situation recognised by Rob Stobbe, the head of SA Power Networks, who suggested last week that rural communities could soon decide that looking after their own energy needs will soon be a viable option.

The UBS conclusion follows recent reports from the Rocky Mountain Institute that suggested that households in major US cities such as New York and Los Angeles could find it cost competitive to leave the grid by 2020. Given that Australian households have far higher grid prices, it is not surprising that the inflection point could arrive earlier in the major capital cities such as Brisbane, Sydney, Perth and Adelaide.

This, of course, has major implications for both network operators and generators and retailers. UBS suggests Australian listed “gentailers” such as Origin Energy and AGL Energy are facing profit falls of around 10 per cent in coming years just from the anticipated growth in rooftop solar PV. UBS anticipates the amount of solar PV to grow to 5 gigawatts (up from just over 3GW now) in the next few years, and revenue and profits from retailers will fall as volume declines and discounts are offered to try and match the cost of solar.

It is the off-grid calculations that might ring the biggest alarm for incumbent industries. It is impossible to know how many households would choose such a route, but the UBS graph below highlights how attractive this might be over the next decade on current cost curves.

UBS offgrid solar

As RenewEconomy pointed out from the Energy Networks Association conference last week, there is a growing recognition, particularly among regional network operators, that a new business model is needed to deal with technological changes,

UBS takes up this point as well, but notes: “The current regulatory system for networks (cost minimisation) and the desire to protect the current asset base of the unregulated companies make them poorly placed and incentivised to respond to the disruptive change.”

This latter point is crucial because while some utilities recognise the changes that need to be made, the industry as a whole are fiercely guarding (as you would expect), the value of the assets that have been invested, including the around $45 billion allowed by regulators in the last five years – even though much of this has been criticised as un-necessary.

But such considerations may be forced upon them. UBS says the cost of solar is falling at an average rate of 5 per cent as the global deployment continues to surge. This means that even a decision by the “anti-renewable” Australian government to remove support measures, the fall in global prices would partly offset a potential 30 per cent cost increase in Australia.

It notes that lithium-based storage is starting to become commercially available and the cost currently comes to around $0.70 kWh of energy consumed. That is 40 per cent above the cost of grid-delivered electricity in Sydney, and while there may be limited scope to reduce the costs of the battery side of the storage devices, the balance of system costs could fall greatly if demand rises.

UBS argues that battery storage at the household level is likely to be most cost effective if the household remains connected to the grid, and simply uses the grid when storage is insufficient. “Since the current grid is largely a sunk cost there is little penalty to society for using the existing grid in this fashion,” it notes.

“Storage intuitively makes the most sense the further consumption is from production, i.e. where the grid costs are highest, as the regional networks with just three or four customers per kilometre of poles and wires. UBS notes that it is “interesting to obverse therefore that some of the network owners are now themselves looking at micro grids and community level storage.”

But other network operators and retailers are not responding in the same fashion. Tariffs for solar exports back to the grid are being cut, or exports made impossible, thus increasing the incentive for customers to install battery storage, even for those in the cities, and taking it beyond the “hobbyists” and early adopters and into the mainstream.

UBS cites several factors for this:

  • Increased penetration of PV solar and the low export price for the electricity of those not receiving a feed-in tariff means that there is a ready market for storage if the price is right. As global decarbonisation increases it’s very likely that solar will become more and more attractive and therefore a bigger and bigger market for affordable storage will develop.
  • Lithium ion technology has many of the characteristics required for residential storage: (i) it can be almost fully discharged without damaged; (ii) it’s less than half the size per unit of capacity compared to lead acid; and (iii) it’s capable of high energy output relative to capacity over a sustained period. Price is the problem.
  •  Driven primarily by Tesla Motors, electric car production is increasing – leading to increased battery production, with the stationary storage market expected to grow from 27MW in 2013 to 1,753 MW in 2022, with the market value soaring to $6 bn in 2020.

UBS notes that the cost of household storage varies, with some reports suggesting that lead acid battery storage can be achieved for  less than $0.30/kWh. But it notes that the focus is on lithium technologies, and the economics of systems such as this of Zen Energy are coming down quickly.

“Based on about $30k installed for a system that can deliver 5 kW of power and 14 kWh for 3000 cycles, the cost per kWh comes to $0.71 kWh. This compares to $0.50 kWh for peak electricity in Sydney. In other words, it’s not economical yet, but it’s not hard to imagine costs coming down further over the next five years. The Zen system is packaged with the “command and control” system that decides what the household system should do at any time i.e. buy from grid, charge from solar or supply to the house.”

 

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  • Barry

    Hi Giles, is the UBS paper available to the public? If so, can you provide a link to it?

  • Zvyozdochka

    The WA Govt budget just put power prices up again. The pressure/incentive to leave the grid continues. Not too bright these business-as-usual people and I think that’s where they’ll come unstuck.

  • http://www.aboutpeople.com.au/ Ian Cleland

    The technology is not just there it is ready. This is why I am bringing a team together that will biuld a zero carbon development in Sydney. It is as much to show developers that the time is right for a complete change in how we develop cities. This will include energy supply. In the next four years it going to happen.

    See my comments on http://www.architectureanddesign.com.au/news/australia-s-tallest-timber-commercial-building-to#comment-1375991236

  • Warwick

    Hmmm, optimistic. UBS needs to examine the need to have enough storage to be able to cover enough days of below average insolation (usually winter). 7000kWh consumption per annum is an average of about 19kWh day yet the storage is only 14kWh…that means probably means the lights go out in winter as consumption goes above the average on a few cloudy or wet winter days.

    • Ronald Brakels

      A generator would be used to make up for any shortfall and only a small generator would be required as the household would have battery storage. Not that there is any need for households in Australian towns and cities to purchase generators as there is an existing functioning grid already functioning and existing in those locations.

      • Warwick

        It’s not mentioned in the article….having a dirty little Honda two-stroke in the garage hardly does much for sustainability!

        • Bob_Wallace

          My (four-stroke) generator is running right now.

          People really don’t want to give up the grid and access to low cost wind power then replace it with a noisy, fuel-sucking generator. That’s just not right.

          AU needs to figure out a solution to their high grid costs before they tear their grid apart. Would that take a massive government bailout/write off?

          The grid’s a pretty magical thing. Try living for a while where there’s no grid.

          • Ronald Brakels

            People running the grid would rather get more of the money than less of the money. For this reason they will remove the current incentive that exists for people to purchase energy storage and a generator and drop off grid. It just remains to be seen if we have a sensible transition or if it requires thousands of households dropping off grid before supply charges are eliminated. I am highly optimistic…that the Crows will win the championship.

        • Ronald Brakels

          They are completely unnecessary.

          • Warwick

            Only if they don’t disconnect, yet UBS is claiming that an “average household” could go off-grid in 4 years time….however the last paragraph is for a system that remains on-grid with inadequate storage for an “independent” home.

            They need to provide some detail regarding the cost of a true “off-grid” scenario as this will be much more expensive than the 5kW panel with 14kWh of storage solution.

          • Motorshack

            I live in Northern New England (i.e. the one in the U.S.), and we routinely lose the grid from ice storms, sometimes for several weeks on end. When that happens a very great many people simply fire up their household generators, turn off some of their loads, and they do fine.

            (And, of course, some of us just settle down in bed with an LED flashlight, and a few days worth of books and alkaline batteries. Nothing like years of winter camping experience to make ice-storms a non-event.)

            Plus, if you do have batteries for the PV system, you only need to run the generator a few hours to charge the batteries, and then you can shut it down for the rest of the day.

            As for “dirty”, that is relative.

            Running a small generator a few days a year, and then using absolutely clean solar PV the rest of the time is not perfect, but it is still vastly cleaner than getting all your power from a coal-fired generator (which in many cases also has to be kept running even when there is no demand).

            It is also often the case that the people designing a proposed system will also be the ones selling the batteries, so it might be smart to keep an eye on that potential conflict of interest, as well.

            You also might want to check on the experience of those who have already been off-grid for years. They routinely plan on running a generator a few days to a few weeks a year, and it seems to work out very well, if I can believe what I read.

            Finally, if you look reasonably aggressively for the fat in the usual project budgets (like thousands in bank interest for unnecessary borrowed capital), it turns out that there are lots of ways to save enough on overall system costs to make up for the somewhat high price of storage.

            In short, my own conclusion, from my own design exercise, is that batteries are feasible right now, as is going completely off-grid.

            The only reason that I am not rushing to do it is that most of my power comes from a low-carbon nuke, and they still only charge me $0.17 a kilowatt-hour. Otherwise, I would be gone from the grid already. Indeed, long gone.

          • Bob_Wallace

            I’ve been off the grid for over 25 years.

            I can’t give you a number for what my electricity costs as I have no way to measure my consumption. However I can do this for you…

            Battery storage with lead-acid batteries ~ 20 cents/kWh.

            Electricity from solar panels at $2/W (a good installed price) and 20% CF (4.8 avg solar hours per day) ~ 8 cents/kWh.

            The price of solar then is some mix of 8c direct use and 28c stored use.

            Then backup. A cloudy day (after a cloudy day or two has used up what I had stored) means ~4 hours of generator operation. One gallon of $4/gallon fuel. Plus about $100 per year for generator replacement.

            I wouldn’t get off the grid if I had access to 17c/kWh electricity. Probably wouldn’t get off at 25c.

          • Motorshack

            That’s all in the same ballpark as my own design figures.

            One question: how much do you actually run the generator?

            I’m guessing it is not as much as some people fear, even with only a day or two of stored power in the batteries.

          • Bob_Wallace

            That one I can answer with numbers.

            I bought the current gen in November, 2011 so at this point it has three winters on it. It won’t get much use from now until next fall. Right now the hour meter says 865 hours.

            That’s 288 hours per year. At four hours per gallon and $4/gallon I’m spending roughly $300 a year for fuel.

            I travel four to six weeks each winter which is the cloudy season. Were I home the bill would probably be $100 higher.

            $400 for fuel, say $100 for generator replacement = $500.

            At $0.17/kWh = 2,971 kWh. 2,971/365 = 8.1 kWh per day.

            I don’t use 8 kWh per day. I could pay for 17 cent electricity with what I spend just for backup generation.

          • Motorshack

            That’s quite interesting, for several reasons.

            First, anyone who bought a generator and some batteries could both go off-grid and drop their electric bill from typical Australian levels right away. No need for solar panels at all, if sticking it to the power company is all one wants to do.

            Second, you only use the generator in the winter months, so in the summer one could evidently rely solely on solar panels and batteries. That would be a big improvement in environmental terms, on top of the cost savings of being off-grid.

            In short, Warwick probably does have it wrong when he says above that going off-grid is not yet cost-effective, because the batteries are too expensive. At least, if your experience is anything to go by. One can get by very nicely on a rather small battery bank.

            Finally, I agree that going off-grid when grid prices are only $.17/kWh is hardly worth the bother. My current interest is not leaving the grid, but, for the moment, doing some little research projects testing the cost-effectiveness of various technical refinements.

            In particular, my current project is to do a head-to-head empirical comparison of static versus tracking solar mounts. As with the use of backup generators, I don’t think many people are yet aware of the real technical and economic trade-offs, so I am putting my engineering experience to use getting some very solid quantitative data.

            For one thing, I am betting that I could cut winter-time use of backup generators by a substantial fraction.

          • Motorshack

            Oops!

            I was writing that last in the middle of the night, after a few hours sleep, and I see that I had what is now an obvious brain fart. Somehow I managed to get it into my head that 2917 kWh was what you had gotten from 288 hours of generation, and I promptly drew a completely fallacious conclusion.

            You don’t say what size your generator is, but using figures for a locally available model (Generac 3250) that is likely of similar size, I get $.78 per kWh, which is clearly more than even the Australian grid is charging. So, equally clearly, going off grid with a generator and some batteries is not cost-effective.

            Still, as your experience shows, there is a place for a backup generator in a cost-effective off-grid system. One just wants to minimize its use as much as possible.

            Which, again, is why my little research projects are focused on getting as much as possible from a solar PV system with storage.

          • Bob_Wallace

            I’m on my 5th(?) generator. One Generac suffered from “stretched valve stem”. The second Generac was stolen (by someone very strong, there was a single set of boot prints though the snow as the person carried the gen away). The third (and last ever) Generac had a defective low oil shutdown and threw a rod (it may have also been leaking oil). Then a sweet diesel with a Robin/Subaru engine. I spent more on repairs than it cost. Then a very nice Honda which started burning oil. Now a Duracell (who knew).

            Six so far. Probably unneeded detail, but an indication that one doesn’t just buy a generator and that’s that.

            All have been rated in the 2,000 to 3,000 watt range. And they all seem to have used about a quarter gallon per hour.

            The price of panels keeps dropping (aside from short term variation). What’s making sense to me is to oversize arrays. Mount some facing east and some facing west to extend the solar day and to maximize a bit of early morning or late afternoon sunshine that might peak through. Later on, as volume production drops the price of batteries increase storage size. Squeeze the generator out.

          • Motorshack

            Interesting testimony on the relative durability of IC engines versus solid state electronic materials.

            Also, before you spend a bunch of money on an over-sized static array, you should take a look at http://www.redrok.com. The website is not fancy, but the owner is an electronic engineer who has been doing stuff with tracking mounts for over fifteen years. You might be surprised at how simple, inexpensive, and effective they can be. The guy at redrok is mostly into the electronic controls, but he has lots of links to quite a variety of products and projects.

            The basic design problem with tracking mounts is to build something that is simple, cheap, and precise, yet will stand up to high winds in a storm. Fortunately, that is not too hard to do, once you see the general idea, which apparently some people find counter-intuitive.

            Another thing worth considering is reflectors on the sides of the mount to increase the effective size of the collecting surface, but without paying for any more silicon. The only thing is that you do not want to overdo it, because you can overheat the panels and reduce their efficiency. A concentration ratio of about 2:1 is pretty safe, but will still increase the system yield by a big margin. On redrok there are some links to commercial systems that both do active tracking and use reflectors.

            In any event, good luck minimizing the use of the generator.

          • Bob_Wallace

            People who I know who use tracking have repair problems. That’s not to say that someone won’t invent a tracker that doesn’t break at some time. But any time you add movement to a system you add significant fail points.
            And I live in a place that gets very strong wind at time (top of a ridge).

          • Motorshack

            Well, there is usually some increase in complexity whenever you try to optimize the yield from a system, and that does naturally increase the number of points of potential failure. So, it is definitely a trade-off.

            The approach I have taken myself was inspired by the way the rigging on a sailboat works. Sails generate tons of force, yet a rather small amount of mass in an aluminum mast and steel stays is more than sufficient to control such forces.

            In contrast, the popular tracking mounts that use a single column with a large array poised on top are putting all the force on one badly overworked, overly-complex joint, and that is all but asking for rapid failure.

            In other words, the key thing is not mass but geometry.

            If the geometry is right then you do not even need a permanent foundation, any more than a good tent does, much less a foundation that involves tons of concrete and steel.

            The really nice thing is that the technology involved is very low-tech stuff that has been tested for centuries. Plus, it is available at the local hardware store, and it is well within the intellectual reach of anyone who can tie their own shoes.

            The only high-tech bit is the sensor that tracks the sun, and the guy at redrok will sell you that, off the shelf, for about $35. The “weather dome” for the sensor is a recycled plastic peanut butter jar. The motor I will be using is $15, plus some roller chain, sprockets, etc. Exclusive of the electronics and motor, the drive train is comparable to that of a single-gear bicycle.

            In short, if you buy even one 250 watt panel for an over-sized array, you will probably be spending as much or more than I will on my entire tracking mount.

            I’d post pictures, but I am still at the stage of sourcing my materials, so it will be a few weeks, at a minimum, before I will be in a position to show pictures of the finished mount.

          • Bob_Wallace

            As someone who has sailed a lot and been though some extreme storms I’m quite familiar with how hardware fails. I sailed back from the Coronado Islands to San Diego once without the starboard shrouds. Jury-rigged the halyard to keep the mast upright and avoided tacking.

            Plus I lost a few solar panels when a stationary rack blew apart in a storm. One footing nut lacked a lock washer. Wind buffeting vibrated the nut off. The next morning I got up, looked at the blanket of snow which had fallen over night but didn’t realize for a half hour or so that one of my racks was AWOL.

            Don’t underestimate what the wind can do.

          • Motorshack

            Yes, I’ve been sailing in bad weather too, and where I live we also get the occasional hurricane. I also grew up in an active tornado zone. No question the wind is dangerous, and in some cases will overwhelm almost any structure.

            However, as you point out, even a totally rigid mounting system can fail catastrophically, and that can happen even without any assembly errors of the sort you had.

            So, the question in my mind is: how close can one get to the (economically acceptable) strength of a rigid mount, while still getting the advantages of active tracking? I suspect that it is pretty close, and very close if you keep a bit of an eye on the weather.

            That is to say, as in sailing, you might need to adjust the rigging manually for different conditions on occasion.

            So, given that storms today rarely catch us completely by surprise, I’ve designed my mount so that I can switch off the active tracking, and literally tie the array down in a posture with minimum wind resistance. Even so, the array will still have the output of an optimum static mount.

            Also, if you want to keep most of the advantages of tracking, even in a storm, it will be possible to tie the array at any angle you like, so long as you think the rigging will stand the wind load. It just will not happen automatically, so you will have to make adjustments manually every hour or so. Again, very like sailing a boat in a storm.

            Finally, this will all be ground-mounted, so I can easily inspect it any time I want, and therefore probably catch things like loose connections before they cause a catastrophe.

            Still, despite several hundred hours of design effort, there will no doubt be problems that empirical testing will expose. My point for the moment is only that I have at least studied the problem very thoroughly, and not least by studying the work of others.

            Nothing in life is perfect, but on this item I am cautiously optimistic that I may have a design that might be at least cost-effective in a reasonable variety of situations, and more so than most people would probably expect.

          • Bob_Wallace

            All I’m saying is that it’s wise to not underestimate what the wind can do. If you can ‘reef’ your system down to ‘storm sails’ then that’s a help. Best to make that an automatic adjustment as one is not home all the time.
            And run a parallel path. Keep costing out a fixed array. Or a few different fixed array designs. One with all the panels optimized for southern exposure. One with ~1/2 the panels facing east and the rest west.

            You might want to set up three panels (E/W/S – is your south north?) and record production over a year. That would let you do comparative cost analysis. In a spreadsheet try different combos of orientation (25% E, 50% E, etc.)

            And then gradually lower panel prices. There’s some point at which more panels cost less than tracking. Know where it is.

          • Motorshack

            All good points, and I am definitely keeping an eye on many variations.

            The point about unattended operation strikes me as coming in two flavors. If you are just gone for the day, and a storm is expected, then best to “shorten sail” before leaving home. If you are gone for weeks or months, then there is no point in tracking at all, because you will not be there to use the extra output anyway. Once the batteries are full the system will just be a giant trickle-charger.

            As for running more panels in my experimental setup, that is a bit of a budgetary issue. I am retired, and, for the time being, I am on a very tight budget. Every extra panel is actually a fully separate system, including not just the panel but also a charge controller and battery, as well as custom sensors for monitoring. That is the only way to be completely sure that the results are fully independent from one another. So, I will have to pass on that, interesting as it might be.

            However, if the two panel comparison validates the basic math model, then coming up with estimates of the other cases might still be reasonably accurate.

            Indeed, the data from the tracking mount itself will tell you what any orientation will produce at certain times of day, and from that you can probably deduce what a rigid mount at a given angle will produce over a whole day.

            Also, I could tie the tracking mount all day a various fixed angles, and compare that with the panel that is fixed at due south, which would give still another type of cross check for an abstract model. Doing that for even a few days would enable quite a lot of cross-checking.

            Finally, my actual goal here is to come up with a design that will be cost-effective even in very poor countries, where simply buying more panels is not an option. That is the point of using cheap, simple materials that can be scrounged very easily, and also why the effective use of the system is not dependent upon high-tech, automatic controls. It is quite possible to get good results with purely manual operation, and in many places I expect that will be a very attractive option.

          • juxx0r

            The standard roof pitch round these parts is 22.5 Degrees, but solar panels would be better optimised for winter collection at a higher angle, say 35 degrees. On a battery system this would help minimise overdoing the solar and unless you needed lots and lots of aircon in summer you’d be right.

          • Ronald Brakels

            I pay 31 US cents for a kilowatt-hour of electricity here in Australia or about 45 US cents once supply charges are added in. On average Australians now pay about 28 US cents per kilowatt-hour for grid electricity, not including supply charges. So it’s not going to take a huge improvement in energy storage costs to get people to go off grid – or simply use some energy storage to cut their electricity bills. One of the most cost effective ways to use energy storage is to just have two or three kilowatts-hours of batteries and use them to maximize self consumption of solar electricity during the day and provide some power during the evening peak. The difference between what people get for sending electricity into the grid and what they have to pay for grid electricity can easily be over 25 cents, so once storage costs are clearly below that point it should start becoming popular.

    • Gordon Waldmann

      We fail to remember that the average household consumption is for a 24 hour period. Approx half the time is day. During the day the battery is being recharged. The battery only has to be sized for approx half the average consumption. The important consumption the battery has to supply is in the night. My own testing with LYP batteries supports a large solar array with a battery sufficient to supply overnight needs. We can all do our bit to reduce consumption.

  • Ronald Brakels

    Preventing household going off grid is an easy fix. All that is required is the removal of supply charges so people won’t have an incentive to disconnect. Electricity from the purchased from the grid in the future may not be cheap but it should definitely be cheaper than supersizing the battery bank or firing up a diesel generator. It does not cost that much to maintain the existing grid in towns of reasonalbe size and cities, despite what one might think from looking at current distribution charges in Australia.

    • juxx0r

      You’d have to do something about the disparity between the retail price and the FiT to keep people from using batteries though. But then everyone would have a zero or slightly negative power bill if you removed the service charge. This would make it a service that nobody pays for.

      • Ronald Brakels

        As things stand, people will use batteries. The only thing that seems likely to stop that is a sudden decrease in the cost of grid power and/or a large increase in feed-in tariffs for new solar. And it would be nice to have a slightly negative power bill if the service charge was removed, but that’s not the situation people are generally facing. Look at Queensland where there is now no feed in tariff for new solar, only what you can get from your distributer.

  • Matthew Davies

    Got me thinking that the Rudd/Gillard government could have saved themselves a lot of pain over their various ETS/carbon tax plans to reduce emissions. Why not just give every house in the country solar panels. The current incumbent utilities could have been compensated by way of becoming installers and maintenance providers. If were prepared to spend $37 billion on NBN then dont see why this wouldnt have worked especially considering the economies of scale you would get from buying a countries worth of solar panels :-)

    • Alen

      The idea of the carbon tax is to include the otherwise ‘uncosted’ externalities, and in essence make everyone aware that there is an overall consequence and price to pay for the emissions they’re responsible for. PV panels could reduce emissions related to electricity for residential properties, but with this approach businesses and other industry would still be left needing additional energy, and there would be nothing driving change in generators from continuing to use dirty( and currently cheapest) coal to derive their electricity and supply this demand. Carbon tax can drive R&D in alternative energy, as generators will start to eventually look for cleaner and less emission intense generation to boost their profits. But most importantly in my opinion, it finally attempts to include the externalities of emissions which simply can’t be ignored any longer.

      Also the scale of PV integration you’re talking about could create a lot of grid related problems, especially in rural areas. Slower installation allows at least some network tweaks and fixes before the grid is overpowered.

  • juxx0r

    Who uses 19kWh a day? I’d have to battle a bar radiator against my aircon for 6 hours a day to get up that high.

    If we can reduce our consumption, then the supply charge becomes more significant and the cost of going off grid reduces as well as the reward for going off grid.

    On lithium ion batteries, it’s just not going to happen. Lithium iron phosphate on the other hand you can now buy online for USD $250/kWh and they cycle well into the thousands of cycles allegedly.

    • Chris Fraser

      Swierczynski and others found you could get 10,000 cycles with a DoD of only 30%. Would it be economical to buy 3.3x the kWh in batteries than what you normally consume ?

      • Chris Fraser
        • juxx0r

          Thanks Chris, i’d been looking for third party confirmation.
          Given that 10000 cycles is roughly 30 years, and in this sunny land we could get away with 30% DoD in summer and we’d only need higher than that in winter, then LiFePO4 would be well suited. Further you could run up to only 70% charge in summer and higher in winter to further improve the cycling capability and minimise side reactions.

          • Miles Harding

            There is a gotcha with batteries, especially Lithium Ion.
            The life of the battery is more limited by immobilised lithium and reaction products from oxidisation of the electrolyte than by cycling. This makes the calendar more important than usage for many applications. Temperature is very important.

            See this video from Dalhousie University:

            for the details.

          • juxx0r

            Thanks Miles, that was very interesting. From my understanding both before and after that video, the calendar isn’t the issue, it’s the time (and temperature) at high voltage that is, which is why i suggested above to only charge to 70%. If you don’t need to store as much, then don’t. I personally wasn’t planning on charging over 80%, or below 20% giving me only 60% of my installed capacity as useable, but i’m going to want them to last for 20 years.

            The other interesting thing there was when a manufacturer says it’s good for XXXX cycles; if you’re going to lay down some serious cash on their batteries and you want them to last for 15 years, then you’re going to be looking for third party testing.

    • stuart

      BYD claim that their LiFePO4 batteries have a lifecycle of 6000 cycles @ 80% D.O.D

      http://www.byd.com/energy/download/DESS/English-DESS%20Brochure_2013_02_05.pdf

      http://www.solar360.com.au/files/360Storage%20-%20Two%20Pager%20-%20Low%20Res.pdf

      Crunching those numbers in concert with a $250/ Kwh price for the batteries gives a “storage cost” of 5.2c/ KWh.
      If prices get down to $150/Kwh, as TESLA etc seem to indicate they will towards the end of the decade, then storage costs falls to 3.1c/KWh.
      This crude calculation neglects the cost of the battery compatible inverter and battery installation. However my understanding is that cost premium for the advanced inverter ( available from NEDAP and others) is only about 60-70% more than the regular inverter. ie the replacement costs of the batteries are the overwhelmingly important factor when determining storage costs.

      It does appear that storage costs using LiFePO4 will eventually trend down to these sorts of levels. At that point the case for installing batteries to maximise self consumption will be very strong. Solar PV then makes much more economic sense for the many households that are not occupied during the work week.

  • Malcolm Scott

    By 2018 the next generation in batteries will be in new electric vehicles and DC vehicle to home/grid could be commonplace. Going off grid for economic and sustainability reasons seems questionable if at the same time you retain using petrol/diesel powered vehicles. Reports modelling the near future need to also properly consider the impact of EVs at home, needing to be recharged daily, and perhaps at night. Do we assume that EV charging will need to be at work instead (a reasonable strategy) and on those bad insolation days you bring home 10 kWh of excess EV battery capacity for your home? At what stage does $500/yr connection fee become less economic than risk free alternative options? Not seen the UBS paper, but other studies tend not to consider the upside and downside possibilities of having EVs in the model. Progressive people are likely to have EVs in their vehicle mix. We in Australia are really laggards in this sort of thinking.

  • LookingForward

    What the….
    30k for a solar system?!?!
    How much are the softcosts over there?!?!?!

    Here in Holland the most expensive version of a 5KW system (not the basic design, it has better panels with 25 year garanty and a better inverter with 10 year garanty and a better mounting set costs € 8.791,62

    https://www.zonnepanelen.nl/complete-systemen/zonnestroom-zonnepanelen-systeem-5000-watt.html

    Softcosts would be about 1k, unless you are an electrician and install it your self, in US$ that’s about $12/13k total.
    Unless softcosts are rediculous in Australia, you should all buy here and have it shipped. :P

    • juxx0r

      That’s including batteries

    • Ronald Brakels

      Thanks for the Netherlands rooftop solar price, LookingForward, which comes to about $2,600 Australian per kilowatt. That is a little more expensive than the average 5 kilowatt install in Australia before our Renewable Energy Target subsidy which drops the cost to under $2 a watt for households. (This of course does not include batteries or generator.)

  • Matthew Dawes

    What about the use of hybrid systems to cut down the need for battery storage? It is generally windy when it rains and in the evenings. I realise that this is area specific.