Unravelling the Baseload Furphy – part 1 of X

The Australian Energy Market Operator (AEMO) have released their 2012 Statement of Opportunities report and there are some very interesting outcomes for the enthusiast. However, the main reason I want to talk about this today is to start addressing some of the common misconceptions about the electricity market and point you at some of the more accurate answers.

Baseload. It’s the word everyone knows about electricity generation now, bandied around in pubs and on QandA. Broadly speaking, baseload generation can be thought of as ‘energy supply that is available all the time’. It was mostly created as a term to differentiate fossil fuel power from renewables, whose energy source is intermittent. A less conciliatory way of thinking of baseload is “electricity supply which is too inflexible to switch on or off”.

It extends from the idea that the big thermal power plants (in particular coal and gas boilers, not turbines) require a long time to start up and shut down. Big coal burners I’ve worked on in the past require 24 hours notice to heat a boiler and get to full load; gas boilers are slightly faster because the fuel ignites more easily but we’re still talking about 16 hours. At the other end, shutting down a boiler from flat out can take more than 8 hours.

Each power station will have a number of boiler-turbine trains, rated to about a quarter of the output. So in a week where demand goes from zero, to maximum and back to zero a powerplant would spend 4 days (of a total of 28 “boiler days”) starting boilers and not making electricity, and another full day shutting them all down.

To avoid start-ups and shut-downs, generators do some cunning things. Off-peak hot water is the classic; this allows residential consumers to receive a signal from the network that they could start heating water now, and that spare load overnight is dumped into hot water for reduced price. This does however give an artificial indication of how much electricity we need overnight. Related, I have heard that Japan solved this problem (nukes operate much the same way as a coal plant) by encouraging similar cheap power overnight, leading to the extraordinary streetlights in Tokyo we see today.

So, think of baseload supply as “on regardless of if you want it or not”. One does not build more baseload supply to meet higher peak demands.

And finally we are at today’s furphy; that baseload supply is “planned” and “controlled” by government or AEMO. That we “need” baseload supply and that someone should fix it.

AEMO’s Statement of Opportunities, linked at the top of the page, is about as close to planning and controlling the market as they get. This is an assessment of network capability over the coming years. A guess at how our electricity demand will grow (although it has shrunk in the last three years, hence the revision of requirements) in coming years, and whether we have the generation capacity to meet it.

But that’s the end of AEMO’s involvement. Now, potential investors will look at this information and decide if they really do want to build a power station. And if they do, what sort will it be? There is no mandate that new generation be baseload, intermittent or peaking. Each individual investing corporation decides for themselves whether or not they can make money in the current market. And given what I’ve told you above, do you think baseload generation would be a new investor’s first choice?

The table on page 3 of the Executive Summary supports this; new generation projects announced across the NEM, include 14GW of wind, a little under 12GW of Open-cycle gas (classic peaking power) and about 3GW of both black coal and combined cycle gas, the two major baseload technologies.

The rest of the report discusses outages and developments on existing equipment. Again there are some interesting bits and bobs in here (I didn’t realise there was any hope of Munmorah or Morwell ever running again). In particular a 566MW open-cycle gas turbine plant in Mortlake is a large development, equating to being able to deliver about half a coal plant’s output in under an hour.

And lastly, mostly for my interest, the 60MW upgrade to Eraring powerstation, with another 60MW coming. I’ve seen this before in other plants, and in those cases the extra capacity has come from an uprated turbine; all other components are unchanged. This suggests that there are STILL developments being made in turbine design, which I find endlessly fascinating. That we can still take a plant that was designed 40+ years ago and wring another 5 or 10% out of it with a new turbine design blows my mind.





About evcricket

Extreme gardener, engineer and bird nerd. View all posts by evcricket

8 responses to “Unravelling the Baseload Furphy – part 1 of X

  • Kudelka Cartoons › Time: what even is it?

    […] Law is (no googling chaps) start jumping up and down and shouting baseload at you like they know what it means and then there’s the Greens getting mad because we’re all going to die and then Julia […]

  • Steve

    I thought the term “baseload” predated the renewables comparison even. I thought it was to distinguish always-on generators from “peak load” generators.
    I totally agree with what you are saying – people present “baseload” as though it is the preferred kind of power generation, when really it is inflexible by nature and requires lots of peak load and demand manipulation in order to be useful and low cost.

    I like to understand generation roles as “cheap-load”, “peak-load” and “green-load”.

    Peak-load is there because it is fast enough to respond to changes in demand. Weakness is cost and CO2.
    Cheap-load (otherwise known as base load) is there to provide lots of cheap kWh. Weakness is flexibility and CO2*.
    Green-load is there to provide low CO2 kWh. Weakness is cost and flexibility.

    All three have one use, and two weaknesses. All three are required.

    * Some people might like to consider nuclear as a CO2 free cheap load. Except it isnt cheap.

    Nuclear: not cheap, not flexible, but is CO2 free. It is green load.

  • metaboleus

    well said, look forward to reading the rest. baseload is sort of forced waste. the reason the power companies are happy for us to waste energy at a prodigious rate.

  • Robert Merkel

    metaboleus, it’s not that simple (it never is). As I’m sure Evcricket will explain somewhere in this series, there were good reasons why coal baseload power stations were chosen to provide the majority of Australia’s power given the technology, economics, and scientific understanding of the times when they were constructed.

    A lot of things have changed since then.

  • Tyler

    interesting stuff, can’t wait to read the rest!

  • Dean Rizzetti (@Deanrizzetti)

    Interesting post. However, I’m a little confused. I though baseload referred to the amount of power we needed at all times to meet the minimum demands of customers. Baseload plants are therefore the power stations that can provide this energy – renewable or fossil fuel driven.

    Seems like the definition above has that a little backwards, suggesting that baseload is a function of the technology, not of energy demand.

    • evcricket

      Dean, “baseload” is sometimes used in that context, but it’s not really useful. “The amount of power we need at all times” is simply the minimum demand. Referring to the minimum as “baseload” is not really helpful.
      So yes, baseload is a function of the technology. Exactly as I wrote in the post above.

  • Sigh. Windmills Don’t Work Because Coal is Baseload « Evcricket's Energy

    […] you’re at it, if you haven’t read the first baseload post here that will provide some […]

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