Environment

Feb 6, 2018

Crikey’s pocket guide to lesser known alternative energy sources — Part II

How do ocean power and solar thermal energy work? Read on as Chris Woods explains.

Chris Woods — Freelance journalist

Chris Woods

Freelance journalist

Yesterday, we brought you a roundup of how geothermal and bioenergy are helping populate the bustling world of alternative energy sources. Today Crikey continues this exploration with the help of the Climate Council and climate solutions analyst Petra Stock to see what else is going on in Australia beyond the obvious sources of solar and hydro.

Solar thermal plants

How does it work: Plants vary according to resource and technology, but involve concentrating sunlight, generally off mirrors, to heat a substance, either liquid or salt, that can then be used to power steam turbines.

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14 comments

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14 thoughts on “Crikey’s pocket guide to lesser known alternative energy sources — Part II

  1. Eureka Stockade

    Offshore wind power is the winner no NIMBY syndrome

  2. zut alors

    Re thermal storage, in South Australia there is serious development of a Thermal Energy Storage System (TESS) using silicon – touted at a fraction the cost of Tesla batteries & not requiring replacement.

  3. AR

    If you have a roof, you can haz pumped hydro, to complement your PhV.

    1. Wayne Cusick

      You need a big roof tank to do that. And another at ground level or, preferably, below.

      If you had a 1m deep reservoir on top of your house, with a floor area of 200m² and an effective height of 5m (lower reservoir below ground level) your storage would be about 2.7kWh. A fraction of what a decent PV array could do in a day (my 5kW system gets about 25-27kWh on a sunny summer’s day). Meanwhile, you have a 200t water tank on top of your house that needs supporting!

  4. Roger Clifton

    Every one of these whimsical schemes requires fossil-fired backup. Even when its believers can claim to have a token of storage installed (pending mythical investment by the taxpayer), it too will run out one nasty night and require full power from a fossil-fired grid.

    But all fossil fuels must be stamped out in the decades ahead. And without fast-responding backup, these schemes are useless. They will stand unused on our skylines, a taunting memorial to the moral cowardice of the generation that built them.

    1. Wayne Cusick

      “Every one of these whimsical schemes requires fossil-fired backup.”
      No, they really don’t.
      Battery backup is fast responding.
      Hydro (conventional and pumped) is fast responding.
      Gas open cycle is not as fast as the above. Combined cycle gas is slower again.
      Coal is not very fast responding. Not real sure about nuclear.

      “Even when its believers can claim to have a token of storage installed (pending mythical investment by the taxpayer), it too will run out one nasty night and require full power from a fossil-fired grid.”
      So, there has to be days where there is no wind, no sun (even on a cloudy, rainy day, PV solar generates some power), the hydro reservoirs are all at the bottom – all over the eastern states of Australia.
      Also, the night generally has lower demand than the day, the peak demand during the year is in the late afternoon/evening on a hot summer’s day. Roughly the same time as solar’s peak generating time.

      1. Roger Clifton

        Hi Wayne. Batteries can respond fast, yes, but for how long? Any storage runs out eventually. Even the biggest battery in the world (120 MWh) can only supply SA (1200 MW) for one-tenth of an hour.

        Enough storage to cover rare, say once-in-five-years events will never get budget priority. Instead, local schemes that claim to have enough storage to be 100% RE, would prudently stay connected to the grid while hoping that it would not notice their absence. For that event when their storage runs out, they then switch on and burden the grid when it is already at full capacity. If such a grid can be nuclear powered, why waste money on renewable energy?

        1. Wayne Cusick

          Because renewable energy is cheaper.

          Cheaper to install, cheaper to run, less maintenance and less environmental impact.

          The SA battery farm is rated at ~100MW, so can supply ~1 hours worth of power.

          Only some homes and businesses would be disconnected from the grid. The utility scale renewable energy generators are on the grid.

          1. Roger Clifton

            If “the SA battery farm is rated at ~100MW”, then it can only backup 100 MW of wind generation. That’s a small fraction of SA consumption of 1200 MW. That leaves the majority of 1200 MW to be backed up by the connection to the rest of the Australian grid. As a result, most of the electricity consumed in South Australia is generated by local gas turbines and the brown coal burners in Victoria, next door.

          2. Wayne Cusick

            At this time.

          3. Wayne Cusick

            I should say that extra storage is being planned for the next few years, including pumped hydro.
            And South Australia doesn’t have enough renewable energy to cover its needs – yet.

          4. Roger Clifton

            Any increases in storage are more symbolic than substantive. Including its necessary storage (and powerlines and pipelines) makes 100% renewables just too extensive and too expensive. By comparison, nuclear energy is cheaper. Cheaper to install, cheaper to run, less maintenance and less environmental impact. (– to misquote a wise man from somewhere upthread 🙂

          5. Wayne Cusick

            Nuclear power is not cheap,

            It is more expensive to install than coal fired power stations.

            I saw a video a little while ago that explained that renewable energy costs have come down because they are largely manufacturing costs, while fossil fuel power stations have a large operating cost component. Same could be said of nuclear power, I would think.

  5. Roger Clifton

    You’re quite right. Cost of wind turbines has tumbled with mass production in China. Cost of gas backup is low too, because the gas turbines are factory made and practically wheeled into place, ready to fire up, arguably less than 2 $/W of capacity.

    Nuclear generators have yet to be mass produced. Current front runner design (being scrutinised now) is the NuScale, but it is a very conservative passive design with an initial cost of 5 $/W. Other designs are cheaper, but coming later.

    Nuclear pulls ahead on low maintence, low fuel cost, long life and, above all, zero carbon emissions.

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