Redflow to fast-track battery storage for homes and miners

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Australian battery storage maker Redflow to target residential and mining market after cost reductions take cost of storage close to grid tariffs. Predicts grid may be relegated to role of back-up.

Brisbane-based Redflow says it is fast-tracking the rollout of its battery storage products to the residential and mining sector, in yet another sign that storage costs are falling quicker than most imagined.

Redflow, which is bringing it unique zinc bromide flow battery to market, says its new products are 40 per cent cheaper than its first generation products, and are now approaching grid tariffs in some markets.

So much so, that CEO Stuart Smith says the grid, the backbone and chief source of electricity more than a century, could soon be relegated to the role of mere “back-up”. This, of course, has huge implications for existing utilities – be they network operators, retailers, and/or generators.

“We believe we have a disruptive, scalable technology whose applications are continually expanding,” Smiths says.

“The future where the grid progressively becomes a backup rather than the primary source of energy is fast approaching by integrating our products with renewables such as solar and wind at a residential and commercial level.”

Smith’s comments may be interpreted by some as mere enthusiasm from an aspiring player in the new market, but they should be seen in the overall context of change. Even AGL Energy said last week that battery storage is now becoming “interesting” for its consumers, and it tipped rapid change. Many experts say battery storage will follow the same cost trajectory, and system impact, than solar. Some say it will be even greater.

Smith’s comments came as the company announced the roll-out of two new products, the ZBM2 and ZBM3, which it will use to fast-track its entry into the residential and the mining markets.

Its previous focus had been on the telco sector, where storage is favoured for use to help provide power telecommunication towers. That is already economically viable.

Redflow says the new products designed for residential, commercial and the mining sectors – to be released in April – are cost-competitive already in some markets.

“This is an important step forward for us and our cost of ownership is fast approaching grid tariffs in some European countries before subsidies,” Smith says.

Redflow’s cost estimates are fascinating, because it has chosen to focus on the delivered energy cost of the storage, what it calls the “cost of ownership” rather than capital cost common in the industry.

Stuart argues that this removes misleading information caused by differences in depth-of-discharge, required operating temperatures and other factors. For instance, some might say their battery costs $800/kWh, but this takes no account of the depth of discharge of number of cycles.

redflow costs update

Redflow’s first product ZBM, was a 3kW/8kWh system that produces 48V with 10MWh warranted energy throughput over its maintenance free operating life. That was priced at $US0.70c per kWh (rather than $700/kWh as the capital cost).

ZBM2 is a a 5kW/10kWh product, also producing 48V with twice the total warranted energy throughput at 20MWh The nominal deliver cost is 31 per cent lower at $US0.48 (€0.42) per kWh.

The ZBM3 is a 5kW/11kWh product producing 53V and a 220% increase in energy throughput capacity. Total energy throughput is warranted at 22MWh at a cost only 39% above the base price of the ZBM. But its energy delivery cost per kWh f is 37% better at $US0.44 (€0.38).

Smith says that initial markets will be in Europe, in countries such as Germany which has high electricity prices and lots of solar. But it will also become compelling in Australia.

Imagine, for instance, the 6c/kWh that solar households now get paid for exporting electricity to the grid. Imagine, also, the 52c/kWh they pay for importing at peak times in some instances.

That means that once battery storage gets below $A0.46/kWh, it is economic. It’s not quite there yet, but clearly not far away.

The ZBM3 will also be used in the Redflow Large Scale Battery containerised solution which has been re-rated to 660kWh per 20 foot shipping container for approximately USD$665,000 (€585,000). With 22,000 kWh energy throughput for each battery (there are 60 batteries in each container) the fully containerised cost per kWh reduces to USD$0.50 (€0.44).

“We believe these cost reductions make our product cost competitive in initial markets targeted and also open other markets such as residential and mining which we now intend entering earlier than previously planned,” Smith says.

Smith says the mining sector is an obvious target, with some paying up to $A2.50/kWh for diesel.

He says the zinc bromide batteries lend themselves to “energy use” rather than “power use”, meaning over a longer time frame rather than the short, sharp bursts required of, say, lithium ion batteries in the recently announced solar plus storage plan for Sandfire Resource’s deGrussa copper mine.

This will also suit the residential sector, which can use the storage to provide electricity in the evening hours, and depending on needs, overnight as well.

The Redflow products are now being manufactured by Flextronics and a number of trials underway are in progress in South, Central and North America, Europe, Australia, New Zealand, Philippines and Africa.

However, the company said sales in commercial quantities are currently slower than expected as the sales cycle for new technology and capital goods is longer than anticipated. It says the first small commercial orders have been received and it is confident that commercial scale sales will commence in the first half of this calendar year.  

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  • Ken Dyer

    According to my calculations based on my 3KW system, with average daily usage over 15 months of 4KW, with average daily feedin of 11KW reimbursed at 8 cents per KW, my net cost per KW, taking into account Service charges averaging 30 cents a day and Electricity charges averaging 30 cents a day less solar feeding averaging 15 cents daily, my net cost per KW totals 45 cents, below the threshold that is reported in the article. I will be in the market for a battery solution in the second half of 2015.

    • john

      Redflow a company based in Brisbane is just one of many that may survive in the battery market.
      Some have raised too much money without a underlying income stream.
      However the basic fact is that being able to store energy and especially using flow batteries that can go to 0% state of charge and then at any state be charged or discharged will prevail.
      With the simple fact that costs of production goes down with volume this technology will find a ready market as the retail price goes down.

      • Ken Dyer

        John, Redflow is going along very well as far as I can ascertain. Apparently their share price has gone up 150% in a very short time.

    • juxx0r

      That’s a grand idea and it will only take you 2.5 million days to come out in front, and that’s if you stored all your 4 kWh.

      • Ken Dyer

        juxx0r, pretty obvious you cant add up, so allow me to enlighten you. A battery system costs as per the article $7000, but it may be less. Now 45 cents per kilowatt multiplied by 4 kilowatts equals $1.80 per day or $657.00 per annum that I do not pay to the electricity company anymore. Now that is a return on my investment in batteries of 9.38% in after tax dollars (pretax might be at least 11%) provided my battery system can supply all the power I need without going to the grid. What this means is that my battery system will pay for itself in about 10 years, not to mention the capital improvement to my property.

        • wideEyedPupil

          Did you include Energy Retailers fixed supply charges in that calculation?

          • Ken Dyer

            Hi wEP, the service charges are included. My feed in just about covers the electricity charges.

        • Blind Freddy of Cairns

          Hey Ken, nice technical argument, however what about the capital depreciation?! I cannot see a lifespan of the system, however bromide is highly caustic so probably not more than 10 years. The cost is actually USD, so in AUD is currently $9,090. depreciation on 10 years straight line is $909 per annum, so at $657 saving on your power bill annually, you are actually $252 in the red! Also not clear if the PV panels, installation etc are included. What about maintenance etc. Would have to be at least 30% cheaper to just breakeven.

          • Ken Dyer

            Hi Fred, thanks for your comment. I am still early days on this, but will do as I did when I bought solar panels – three quotes, tick off against price, maintenance, warranty, servicing, and all those criteria. I am not particularly worried if I incur a small loss if it contributes to reducing atmospheric carbon. However there may be a plus side indicated by this website:

            It is a bit of a balancing act with batteries. How many do you need if you use 4KW a day on average and how deep can you go in the batteries before you impact its life? There does not appear to be a great deal of literature out about it, so hopefully as the domestic battery market ramps up, this sort of information will become more readily available, so one can make informed choices based on their personal situation.
            I live in hope.

        • juxx0r

          So they take the $7000, divide by 10,000kWh to get 70 cents per kWh in USD. They only get this price by averaging over 10MWh, but then you go on to use the average for the ZBM3 which averages over 22MWh to give 44 US Cents per kWh.

          You take your 45 cents AUD which is cheaper than that except it isn’t because that’s 55c/kWh in AUD for the ZBM3.

          You then spread this across your entire consumption, not just those units you need to store, so one can only assume you’re a hobbit or a night shift worker

          So you’re using a cost based on maximum turnover and using that to justify something with minimum turnover. You need to look at their capital cost, break that down with your consumption, put in a cost of capital and balance of system costs and then calculate your own cost per kWh.

          The problem with storage and small consumption is that the fixed charges become rather significant on a consumption basis for the balance of system costs.

          If you take your 4kWh, divide that into the 10MWh, you get 2500 days, take $7000USD , divide by 2500, you get $2.80 or $3.60 AUD, Take your 4kWh divide by that and you get 90c/kWh or twice what you’re currently paying, if you assume that you only need to store half of your consumption, you’re talking $1.80/kWh and it will pay itself off never.

          I admit my 2.5Million days should have 2500 days.

  • john


    I have followed Redflow for a while here is a link from battery news.

    which is the information above about Redflow.

  • Eclectic Eel

    In my past life as a chemistry teacher we used to do experiments with bromine. Bromine is the only non-metal that is a liquid at room temperature. The bromine was kept in small sealed glass vials that had to be snipped to release the bromine into water. Bromine is extremely toxic. I’m impressed at the energy density of the Bromine/ Bromide redox reaction as a battery but can’t see the safety issue being resolved in the home where batteries could fail mechanically or by overheating due to misuse or extreme temperatures. By the way Bromine, along with a lot of other chemicals is no longer deemed safe to use in schools.

    • Brad Sherman

      Good point. I believe I read in some of Redflow’s literature that the batteries, once finally exhausted, must be treated as hazardous waste. It would appear one needs to consider disposal costs for a total life cycle estimate. Hopefully, Redflow or some other enterprise will be able to make a business out of recycling these promising batteries. I imagine they have about a decade to work out how…

  • Peter Campbell

    Hmm. Eventually the 13kWh of LiFePO4 cells I put in my electric converted car might get retired to this use. They could deliver any peak demand the house might take even if they are getting a bit old and tired by then. I would be staying on the grid for a while yet since I am on the 20 year ACT gross feeding tariff and don’t have a lot of roof space left for further PV to feed a battery. I would probably want to just store what I can from a modest number of panels to get me through the peak periods.

    • Miles Harding

      Yes, but the darned things seem to last so well that it may take quite a while to ‘liberate’ a set from the car!

      • Peter Campbell

        Indeed. It might not happen until I find a cheap bargain second-hand Tesla.

  • Tom

    Diesel costs $0.60 max., including distribution. Normally it’s closer to $0.30/kWh.
    Lithium costs the same as their new product per kW/kWh and lasts 10 times longer.
    Unless they hit $0.20/kWh it’s over.