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Energy storage start-up targets Australia, promises compressed air technology “half the cost” of batteries

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A Canadian company that claims its compressed air technology can store energy for half the cost of grid-scale batteries, and provide back-up network capacity on par with a new natural gas plant, has partnered with engineering company AECOM in Australia to target the country’s National Electricity Market.

salt_cavern_CAES copy

Toronto-based Hydrostor said on Tuesday that it would work with AECOM to assess the Australian market and identify potential sites for deployment of its Terra energy storage solution in Queensland, New South Wales, Victoria and South Australia.

The start-up claims it can deliver the lowest installed cost per kWh available for bulk energy storage today – including pumped hydro – with its technology that uses excess electricity to compress air and store in underground in a specially constructed tank.

“Hydrostor’s entry into the Australian market changes the conversation on cost effective, emission-free alternatives to fossil-fuel generation and limited storage technologies,” said the company’s CEO Curtis VanWalleghem.

“Hydrostor Terra beats natural gas to deliver essential services and dispatchable capacity, while offering longer duration and longer life storage of 30+ years versus batteries, at half the cost. Terra’s sizing and siting flexibility also offers significant advantages over pumped hydro.”

What sets Hydrostor’s technology apart from other compressed air storage systems is that it uses the heat generated by the compressors – which it stores in a thermal management system – in place of natural gas.

So, when energy is needed, the Terra system returns the compressed air, heating the surfacing air stream using the captured heat, which moves a turbo-expander connected to a generator, which creates electricity.

The company says it is particularly well suited to the Australian market, being able to provide essential stabilising services like inertia, system strength and voltage control; adding flexibility via both fast ramp rates and long duration dispatchable capacity; and lowering emissions.

Hydrostor Terra

“At half the cost of competing battery technologies, (it) is uniquely positioned to support several of the key outcomes outlined in Dr. Alan Finkel’s report on the future security of the NEM,” a company statement said.

“Terra enables the transition away from fossil-fuel generation by delivering the same essential security services and dispatchable capacity, without the trade-off of increased emissions.”

The technology does, however, need to be deployed “within proximity to a body of water,” the company says, or using a surface pond as part of a closed loop system.

Like pumped hydro, it can also be installed in legacy mine sites or at retired coal-fired plants, which the company notes has added benefits of repurposing site infrastructure and getting mine and coal plant employees back to work.  

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  • Bill Holliday

    Why can’t the underground storage store the hot gas as generated during gas compression as well as the compressed gas? Rock is a moderately good insulator and in the long term not much energy would be lost.
    Actually, energy storage as heat in hot water would be a much cheaper energy solution if the low grade heat energy could be used for something.
    Why are people so worked up over centralised energy generation and storage when the really revolutionary event is localised generation and storage?

    • MaxG

      According to the neoliberal doctrine, profit has to be amassed amongst a few; certainly not benefit a broader public. The public is considered sheep; fleeced to the bitter end… when the system collapses.

    • joono

      Agreed, distributed and democratised is the way to go.

    • Jo

      90 degrees hot water will not turn your lights or you TV on and they won’t run your heatpump air conditioner either. The storage mentione above is about electricity.

      • Bill Holliday

        Where I live, domestic hot water and home heating represent 60 % of domestic energy requirements.

        • Jo

          Well, but why would you compress air for that. You can store heat as heat which is much more economic.

          • Mike Westerman

            Using CAES with no heat recovery gets you to about 60% cycle efficiency. Storing energy as heat then using a heat engine to recover it gets you to 20-30%

          • Bill Holliday

            Precisely. Read my initial post.

  • john

    Considering the Australian market has a high cost i would imagine they may have a market.
    The difference between buying the power at wholesale rates and on selling it will prove the technology.
    It totally depends on the efficiency of doing this exercise.
    If they can do it below say 70% of power outcome perhaps they have a case to store power and sell it into the market on the wholesale market.

    • Jonathan Prendergast

      Obviously it also depends on capital cost, per MWh/MW

  • Mike Westerman

    I’d like to see their cycle efficiency: any thermal process is going to be limited by the Carnot efficiency plus heat losses. The energy density of compressed air before the compressor losses start to mount up is also limited, compared say, to the head of water in a pumped hydro scheme, so the size is fairly limited compared to pumped hydro, but it does have the advantage of being “local” provided no-one minds you digging a big cavity below your house or street. The cost of that cavity is also going to be high compared to a pond.

    • MaxG

      You know how it works… if you have nothing useful to contribute, create some ‘hot air’ :)) … like snake oil :))

      • Mike Westerman

        Lol! Altho I reckon the snake oil might run smoother!

    • Jo

      This is not a Carnot process (=converting part of a difference in temperature in useful energy). This is simply compression/decompression.

      • Bruce Miller

        I believe Compression/decompression is a Carnot process.

      • Mike Westerman

        The enhancement this process offers over standard CAES is in the heat recovery bit which is limited by Carnot efficiencies, even if the original compression was adiabatic (which it would try to be) and reversible. From a bit of reading on this process, they have yet to demonstrate it at scale and round trip efficiency still <70%

    • Bruce Miller

      The round trip efficiency is quite low compared to batteries, but it can be improved by burning gas to change the thermodynamics. We did an investigation on this (and other) technologies several years ago .

  • Ian

    Anyone know of any salt caverns nearby? Anyone? Maybe some disused gas reservoirs might do. BTW, cycle efficiency is typically around 65% or less. LAES is just as effective and can be located anywhere if you want that type of tech.

  • DJR96

    And how many subterranean cavities are sufficiently airtight to act as a compressed air receiver? Very few I would think. The efficiency would be horrendous.