Solar storage below $100/kWh – with the help of a steam engine

solar storage

Terrajoule, the Australian-led California-based start-up that proposes to use steam engine technology to help deliver cheap solar storage at a distributed level, has raised $US11.5 million in a funding round, and revealed that it is ready to deliver storage at less than $100/kWh, way cheaper than batteries.

The company has tapped funds from companies that include Air Liquide, a specialist gas producer, and investment firm New Enterprise Associates, as well as a bunch of individual investors including Australia’s Craig Winkler, the founder of accounting software company MYOB.

It will use the money for the next stage in the rollout of its technology, which it claims to be a breakthrough because it can deliver on-demand solar power to businesses at a cost five times below the cost of battery technology, and without degradation from life cycles.

As RenewEconomy wrote in its profile of the company last month, the company is planning on volume production of its technology in 2015.  It has already teamed up with solar power systems supplier JKB Energy, and Roush Industries, a leading developer of automotive and energy systems.

It is targeting systems from 100kW to 20MW that operate 24/7, and promises a “compelling” payback for off-grid and on-grid power. Its initial focus will be industrial and agricultural sectors, particularly in those locations which have expensive or inadequate grids, or where waste heat can be used to improve the efficiency of industrial operations.

solar storageThe first pilot project was installed in an irrigated almond farm in California’s Central Valley (pictured), and the company sees a huge demand among the irrigated farm community, particularly in the solar-rich south west of the US, and in Australia. Irrigated farm operations in Australia are watching with interest, because if the company delivers what it says it can, it will be an attractive proposition.

Terrajoule says it is aiming in 2015 for a price per peak watt of $1.50 to $2.00 at a 20 per cent capacity factor, depending on system size, the strength of the solar resource (DNI) and other factors.  Mostly, this is comparable to the price for a PV solar panel system (without storage) at the equivalent capacity factor.

But it says its price of net electrical storage capacity will be less than $100/kWh.  This is a fraction of the cost of most battery storage technologies, and comes without cycle limitations, degradation of capacity, disposal costs, and all balance of system costs. It sees further cost falls as production is scaled up.

Terrajoule’s chief technology office Robert Mierisch searched back into the historical manuals to develop his idea of using the 300-year-old technology of a steam engine and a pressurised water tank as the means of storage and delivering electricity and/or waste heat on demand. Its proposal use a type of steam engine that has been out of service for decades, apart from tourist ferry or two, has raised eyebrows.

But Arno Penzias, from NEA Venture Partner, and Nobel Prize winner in Physics in 1978, said the company has made outstanding technological progress. “Terrajoule’s energy storage solution removes a fundamental obstacle to the next few decades of sustainable energy growth,” he said in a statement

According to Terrajoule (it now has its own website), the essential characteristic of the its system is its ability to rapidly respond to changes in load, functioning equivalently to the diesel generators it replaces, and without volatile fuel costs.

“Energy storage is based on pressurized saturated water, with 98% storage/retrieval efficiency,” it says in its press release. “Energy conversion is performed via reciprocating steam piston engines that are highly efficient across a wide range of operating power. The system generates steam through mature solar concentrator technology” (such as parabolic troughs).”

As the company explains on its website:

“Major problems are sometimes resolved with unexpected solutions.  Who expected that reciprocating steam piston engines would play a major role in 21st century energy growth?

“Reciprocating steam engines powered the industrial revolution and steam itself is ubiquitous throughout industry to this day.  Actually it is the phase change between steam and water that makes water a fundamental component of both life and industrial processes.

Steam is fundamental to the conversion between thermal energy and electricity, and steam piston engines built with modern automotive technology are back.”

We explained more about how it works in our profile.

Terrajoule CEO Steve Bisset said the funds would enable the company to bring the technology to global markets, although it will be careful and cautious about the pace of deployment and the markets it is targeting.

“Developing a game-changing energy storage solution is about more than technology. We’ve focused on building the right value proposition, market channels, and capital partners to build a business with global reach and scale without depending on government subsidies,” he said.

This means avoiding the need for massive capital requirements which has challenged developers of other technologies. Air Liquide, which provides specialty gases to a variety of industries, is attracted to the technology because it will help boost the efficiency and reduce the carbon footprint of its hydrogen units.

Comments

19 responses to “Solar storage below $100/kWh – with the help of a steam engine”

  1. Richie Farrell Avatar
    Richie Farrell

    $100/MWh I hope…

    1. juxx0r Avatar
      juxx0r

      It’s $100/kWh of storage, not of generation.

      1. Sean Avatar
        Sean

        25 year life, daily cycle, 1.095c/kwh stored
        Accumulators are a pressure vessel that keeps steam liquid.(to about 350C)

        Downsides include how expensive it is to collect the heat in the first place, and the efficiency (~40%) to go from heat to electricity

  2. Hugh Sharman Avatar
    Hugh Sharman

    Sorry guys! but his has to be quite the daftest and most technically illiterate electricity storage claim I have ever heard of – and then some! I read the story with growing incredulity and disappointment that Giles Parkinson, of all people, did not seek some peer review before publishing. Guess why there are precisely no steam engines being deployed anywhere in the world using a “300 year old design”.

    1. JonathanMaddox Avatar
      JonathanMaddox

      Um. The steam engine itself is 301 years old. Variations on that theme are what keep the lights on in every coal-fired and nuclear power station in the world.

      1. Hugh Sharman Avatar
        Hugh Sharman

        Not steam piston engines, Jonathan! You seem determined to see the good points of this proposal. After reading the comments of the others, I fail to see any merit in it whatever. This “technology” will sink without a trace. Pity the financiers who will lose every penny and further blacken the prospects of the many, much better, ideas fighting for scarce development dollars.

        1. JonathanMaddox Avatar
          JonathanMaddox

          Steve Bisset of Terrajoule addressed some of your skepticism when it was similarly expressed by commenters on GreenTechMedia two years ago: http://www.greentechmedia.com/articles/read/Terrajoule-Unstealths-Distributed-Power-via-Solar-And-Energy-Storage#comment-431507498

  3. Sean Avatar
    Sean

    the article says that isnt the case, $0.0109/kwh of storage (on the guaranteed 25 year life, daily cycled)

    This method uses high temp steam to pressurise and heat the water in the pressure vessel, thus IS a phase change material.

    What isnt mentioned is the cost of the plant required to collect or the motor to convert this energy.

    1. JohnRD Avatar
      JohnRD

      Sean: You can store a lot of heat in in a small volume of water if the heat is released when the water changes to ice when releasing the heat. This is not what is happening in the proposed system. The other problem is that the hot water would have to be stored at high pressure which means very expensive pressure vessels.

      If you want to store thermal energy cheaply you either need to find a material such as molten salt mixtures that can store the heat at atmospheric pressure or a phase change material that allows more heat to be stored in a given volume. (Phase change materials are available with phase change temperatures up to at least 885 deg C – See: http://www.pcmproducts.net/home.htm)

      Molten salt storage without phase change is the storage media used in CST solar thermal power plants in places like Spain.

      1. Sean Avatar
        Sean

        its changing from vapour, to liquid and back to vapour. that’s phase change.

        It is costing $100,000 for the tank.

        1. JohnRD Avatar
          JohnRD

          The energy stored is the energy used to heat up the liquid water.

  4. Ken Fabian Avatar
    Ken Fabian

    It’s not really a surprise that utility scale storage can be done using innovative applications of existing or previously existing technologies; it’s been a case of not really needed with fossil fuel generation, where shipping the coal – or diesel – was cheap and everyone blissfully unaware of the external climate costs, so until recently there was never really much economic motivation to develop it.

    Terrajoule is being innovative using steam engines, Isentropic’s Pumped Heat Energy Storage uses “obsolete” Ericcson cycle. I did wonder if this is similar in principle to the system Ausra was trying to develop. I think at least one of Terrajoule’s top people was with Ausra.

    1. JonathanMaddox Avatar
      JonathanMaddox

      Indeed. Fossil fuel *is* stored energy until it’s burned, as is nuclear fuel; you don’t need to think too much about storing the energy released when you burn it (“burn” in scare quotes for nuclear fission of course). Only when we capture power from sources which are not inherently storeable do we need to consider how to shift that energy from the time of capture to another time when it might be more convenient to make use of it.

  5. JonathanMaddox Avatar
    JonathanMaddox

    It’s called a steam accumulator, and it’s very well understood 19th-century technology. All that’s novel here is using it in conjunction with solar energy and electricity generation. https://en.wikipedia.org/wiki/Steam_accumulator

    1. Sean Avatar
      Sean

      amusingly the main driver for switching away from steam locomotives was that diesels could be linked together with just one driver.

  6. michaelmaloney Avatar
    michaelmaloney

    Technology alone will not work successfully without the aid of other agents, including Mother Nature. In this case, the solar storage requires the help of steam in order to better power up the system. We might be so advanced in technology today but we still need other elements in order for our modern expertise to function properly and progressively. When both powers combine, we get one successful setup.

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