Solar thermal plant approved for Port Augusta greenhouse

Plans for what will be Australia’s largest solar tower power and water distillation plant has been approved for construction at commercial greenhouse business in South Australia, which already uses solar power and seawater to grow vegetables.

The proposal by Sundrop Farms to build eight more greenhouses, totalling 20 hectares, which will use 36MWth of solar-thermal energy to heat the greenhouses and desalinate water from Spencer Gulf, was this week approved by the Port Augusta council, subject to conditions. timthumb.php

The plans approved include the construction of a 100 metre high solar power tower topped by a 15 metre high solar receiver, and a ‘solar field’ of around 11,000 stands, each holding three heliostat mirrors.

The plans also include the construction of two Multiple Effect Distillation (MED) plants, several seawater pipelines, a pipe for brine dispersal into the gulf, and a visitor centre to help promote tourism interest in the venture.

According to council notes, the solar tower will contain a boiler to generate steam, which is condensed into hot water to heat a large hot water storage tank (storing up to 22,000 cubic metres of hot water) situated adjacent to the tower.

The solar thermal infrastructure will heat a closed loop system of hot water that heats another closed loop, transferring heat to the greenhouses by circulating through the internal pipework. After being circulated through the greenhouses the water is returned to the hot water storage tank for reheating.

Some of the stored heat will also be used to distil seawater in the two (MED units to distil seawater into fresh water for the plants in the greenhouses.

According to the council submission, around 3,000 megalitres of seawater a year will be drawn from Alinta’s Northern 2 intake channel, to produce over 335 ML of freshwater for use in the greenhouses and for other purposes on the site.

Most of the solar thermal generated steam will be used for the greenhouses and the desalination, but the steam will also be used to spin a turbine that powers a generator, producing up to 1.5MW of electricity to run the site. A connection to the mains power supply will provide backup power.

A diesel driven backup boiler will also be installed, to supplement the hot water if the solar thermal power supply is disrupted.

According to Sundrop, work on the expansion is expected to begin this year. Last year, the Clean Energy Finance Corporation said it would help finance the facility, which could cost up to $100 million.

The project is expected to employ more than 200 people and will produce over 15,000 tonnes of tomatoes a year for metropolitan markets across Australia. The company hopes it will be the fore-runner of many more projects in Australia and other desert regions, particularly in the Middle East and north Africa.

Comments

10 responses to “Solar thermal plant approved for Port Augusta greenhouse”

  1. MrMauricio Avatar
    MrMauricio

    There you have it-an integrated independent non-polluting sustainable industry of the future.It will bring tourists as well.Tourism to renewable energy facilities is booming in Europe

    1. Beat Odermatt Avatar
      Beat Odermatt

      You mean Port Augusta will one day welcome tourists and keep shops open on Saturday afternoons.

  2. Beat Odermatt Avatar
    Beat Odermatt

    I guess that en environmental study
    into the impact of brine disposal into the Spencer Gulf has been
    undertaken. It would be a great pity if the brine would kill off the
    sea grasses (fish nursery) in the area. I am sure they are aware that
    this section of the Spencer Gulf with its very shallow waters is a
    very fragile part of the Spencer Gulf. It would be a great pity if we
    spend 100 Million Dollars to kill of a multi million dollar fishing
    industry to grow tomatoes. I remember ETSA had to undertake a lot of
    research work to study the impact of warm water disposal from the
    Port Augusta power stations.

    1. Peter Smith Avatar
      Peter Smith

      The fact that only 11% of the seawater is converted to fresh means that the returned brine has only an 11% increase in salinity, providing a minimal threat to the environment.

      1. Beat Odermatt Avatar
        Beat Odermatt

        That is interesting. It seems you have access to some information which can support your statement? I hope it is not based on the old engineers slogan; “The solution to pollution is dilution.”?

        1. vikraman Avatar
          vikraman

          The thing about the contents of the brine is that its exactly the same as seawater. Its just concentrated by 11%, which means the seawater goes from ~35 g/kg salt to 39 g/kg salt. The natural variablity of seawater is between 30-40 g/kg in a broad sense and up to 500 g/kg in hypersaline environments. Most saltwater ecosystems can easily tolerate salinity levels up to 70 g/kg if the salinity increases slowly as demonstrated in this paper; http://www.science.fau.edu/biology/koch/Documents/Publication%20PDFs/HypersalinityKochetal07a.pdf

          Hope that answers your question.

  3. michael Avatar
    michael

    did I read that correctly… 3,000ML of seawater taken in order to produce 335ML of freshwater?? that’s only an 11% yield, surely not a viable process once you pump the water up from the sea and then the brine back.

    1. Peter Thomson Avatar
      Peter Thomson

      That would be the case if the primary purpose of the plant was desalination, but the primary purpose is actually to provide a continuous supply of low-grade heat to the tomato greenhouses.
      The plant is designed overall to provide heat, electricity and fresh water in the quantities needed to grow the fruit, presumably with a small surplus in each case.
      Future plants may perhaps be sized and designed for ‘triple output’, where fresh water and power are primary products, with low-grade heat and a smaller percentage of the electricity and fresh water output used to grow plants.

      1. michael Avatar
        michael

        So what’s the excess 2670ML of sea water each year for? It says the water circuit for heating is a closed loop

        1. Peter Thomson Avatar
          Peter Thomson

          The article does say the water is also used “…for other purposes on the site.” My guess – and it is a guess – would be that it is used for cooling and for brine dilution, to maintain a low salinity increase as per Beat’s discussion below. It would be very interesting to read the proposal to see what it is they are doing and why.

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