Brown Coal Electricity

by Pat Lane, 2019

I have worked on the IT side of coal generation and mining in Victoria’s Latrobe Valley for many years.

yallourn-brown-coal-power-station
Marcus Wong Wongm CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons. Yallourn Brown Coal Power Station Cooling towers on the left, emitting mainly steam, a natural gas and air. Exhaust towers on the right emitting mainly nitrogen, carbon dioxide and wisps of water vapour, all natural gases. See: http://carbon-sense.com/wp-content/uploads/2010/05/coal-burning.pdf

The first time I visited a black-coal-fired power station, I looked around and asked “Where is everything?”

Brown coal stations are huge compared to their black coal cousins. There are two main reasons:

  1. Brown coal has very low energy content. Latrobe Valley brown coal has a Net Wet Specific Energy of between 5.8 and 11.5 MJ/Kg. By comparison, Bowen Basin black thermal coal has an energy content of around 25 MJ/Kg., two to four times more.
  2. The biggest difference between brown and black coal is moisture content. Brown coal can have as much as 70% moisture compared with black coal’s 8-10%.

I’ve heard brown coal described by station operators as “wet dirt”.

Before brown coal can be burnt, it has to undergo a fair amount of care and nurture. Here’s an abbreviated description of what goes on:

  1. Furnace flue gasses pass through a huge rotary air heater to pre-heat the air going into the coal drying shafts. The pre-heated air has to be hot enough to dry the coal, but not so hot as to set it on fire. That comes later.
  2. Brown coal is transported to the upper levels of the power station by conveyor to be fed into vertical drying shafts.
  3. The coal is dropped down the drying shafts and mixed with the pre-heated air to dry the coal.
  4. The dried coal hits big beater wheels in the coal mills at the bottoms of the drying shafts and it blown up into the furnace in the form of tiny particles of coal, called ‘p.f.’ for ‘particulate fuel’.
  5. The coal burns, radiating heat into boiler tubes embedded in the walls of the boiler, turning the water in the tubes into steam, the steam into rotary motion in the turbines and the rotary motion into electricity in the generators.

There is much more to this process, of course, but that’s general idea. In a black coal power station, most of the coal handling is much, much less complex and, hence, much, much smaller.

There are other complications, of course. I remember when the East Field Mine at Yallourn was first opened, mine employees found that there were seams of black sand running through the coal. A mining manager explained that “separating black sand from brown coal is like separating fly poop from pepper; it’s possible, but very labour intensive.”

So why go to all the trouble of mining brown coal? Again, there are two main reasons:

  1. It’s cheap. When I worked at Yallourn, the short-run marginal cost of generating one megawatt of electricity was $2.00. That’s cost of winning enough coal to make one megawatt. This doesn’t include capital costs of plant and equipment; just the operational costs. Latrobe Valley brown coal is relatively cheap to win because it’s near the surface. Very little overburden (surface dirt) needs to be removed before the coal is exposed. Once uncovered, there’s little contamination, bits of black sand notwithstanding.Two bucks is cheap. That’s why in the 1999 financial year, the average annual wholesale price of one MW of electricity in Victoria was among the cheapest in the world at just $24.51.

    So far, for the 2019 financial year, it’s among the world’s most expensive at $111.30.

    It’s not going to get cheaper anytime soon. The table below, compiled from information supplied by the Australian Energy Market Operator, compares usage, total and average price paid for New South Wales, Victoria and South Australia for the first 28 days of January 2019.

    State Electricity usage (MWh) Total price paid Average price paid $/MWh
    New South Wales 11,936 million $687 million $57.34
    Victoria 6,771 million $1,272 million $187.83
    South Australia 2,002 million $385 million $192.26
    Totals for 3 states 20,709 million $2,344 million

    Analysis by The Australian on 30/1/2019 reveals that South Australia and Victoria together spent the nearly half of this total of this, $1.1 billion dollars, on just two days, the 24th and 29th of January.

    No points for guessing which two of the three are the ‘greenest’ states.

    In any case, a state like Victoria could make a nice down-payment on a new power station with the nearly $1.3 billion paid for wholesale generation so far this month.

    I remember when Yallourn Energy was sold in April, 1996, it went for $2.4 billion, near enough to the monthly bill for just these three states.

  2. The other reason brown coal is a good fuel for generating electricity? There’s heaps of it. Geoscience Australia estimates 43 Giga-tonnes (Gt) of ‘Economic’ reserves of brown coal in Victoria. In 2013-2014, the Victorian electricity industry used approximately 57.8 Mt. At that rate of usage, there’s enough for another 754 years.

Victorian brown coal is an amazing asset for the State of Victoria and for Australia generally. It’s cheap, plentiful and provides the 24×7 reliable electricity that consumers and businesses have enjoyed since the 1920s.

Unfortunately, brown coal is being vilified by activists with a range of agendas, none of which are favourable to either business or to ordinary Australians. Even more unfortunately, our politicians are too weak to even question the propaganda and have jumped on the bandwagon.

Coal royalties collected by the Victorian State government were tripled in January 2017 and undoubtedly had an influence on the decision to close Hazelwood Power station by the owners.

Along with bans on gas exploration, subsidies for so called ‘renewable’ energy sources and accelerating costs for energy, governments at both the state and federal level appear determined to shut down Australian industry, make electricity unaffordable to consumers and to make the once reliable supply subject to the whims of wind and weather.

All of this pain produces no measurable economic or environmental gain.

Meanwhile Yallourn, Loy Yang ‘A’ and Loy Yang ‘B’ will continue to provide reliable baseload supply for Victoria and Eastern Australia.

When they reach the end of their useful lives and are replaced with more windmills and solar gizmos, we’ll step outside on a windless night and ask the same question I posed earlier: “Where is everything?”

References

http://coalmarketinginfo.com/advanced-coal-science/

https://www.sciencedirect.com/science/article/abs/pii/016651629390048F

http://www.coalmarketinginfo.com/coal-basics/

https://www.aemo.com.au/Electricity/National-Electricity-Market-NEM/Data-dashboard#average-price-table

https://www.aemo.com.au/Electricity/National-Electricity-Market-NEM/Data-dashboard#aggregated-data

http://www.australianminesatlas.gov.au/aimr/commodity/brown_coal.html

https://en.wikipedia.org/wiki/Energy_in_Victoria

https://www.minerals.org.au/news/pernicious_coal_royalty_increase_to_hurt_households_and_industries_again

9 thoughts on “Brown Coal Electricity”

  1. Thanks Pat.
    An informative useful guide as to how brown coal was good for us ever since Monash set up the brown coal power generation system in the 1920’s.

    I’m in SA now. SA used to generate brown coal from Leigh Creek at the Port Augusta power plant now demolished.

    Are/Were there any differences between the Latrobe Valley brown coal & Leigh Creek power generating processes ?

    1. I’ve never visited either location and don’t know much about them.
      A quick internet search reveals the coal from Leigh Creek to be “sub-bituminous”, with an energy content of 14-15 MJ/Kg so it’s got a bit more energy than Latrobe Valley coal.
      The moisture content is lower at 24-28% so the power stations would require less coal drying equipment.

      BTW, my information is based on one slide from the reference below so may not be accurate.

      http://www.saexplorers.com.au/archive/2009/09dstevenson.pdf

      I hope this helps.

      Pat

      1. Thanks Pat. That does help.

        Such a shame that the Latrobe valley and all the people in it’s towns are being so needlessly damaged by all this CO2 warming bullshit.

        1. Thanks, Bill.

          I came to the Valley in 1974. Morwell was a thriving country town; not so much now.
          I live outside of Traralgon and when I first started at Yallourn Energy the corporate offices were in Moe.
          I remember visiting China Light and Power’s offices in Kowloon and being surprised prices for a car park there were on a par with housing prices in Moe.
          The Valley has certainly had its issues over the years. I still wouldn’t live anywhere else.

          Pat

          1. I lived in Bairnsdale in the early 1970’s. And so drove through the valley on the way back & forth. to Melbourne. And again in East Gippsland later from 1985-1999.

            I drove it a year or so and now the freeway goes to Rosedale.. Who would have believed that would happen. Of that the brown coal plants would be closing either..

            I am a retired organic farmer and suppport preserving the environment but this CO2 stuff is just dopey Greenism.

    2. Sorry, How remiss of me. I should have been paying more attention to the type of coal when I was walking up the big conveyor ramp at Sir Thomas Playford power station a few kilometres across the desert from Port Augustain in the early 1960s.

  2. It would be interesting to hear from all those who took part in the attempts to sabotage Hazelwood (“the dirtiest in the whole world”) ; has its closure stopped climate “change”, and if not, why not?

    1. I’d love to hear from the Greenists who campaigned to close the Port Augusta power station as well. South Australia has expensive unreliable electricity now. And we need to buy in coal powered electricity from Victoria instead !

  3. I hope someone is recording the names of those who proposed and destroyed the power stations. It would be a good topic for an historical document.

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