Coal Generation Sets New Record After Liddell Closes!

The National Electricity Market lost 2,000 MW of generating capacity last Friday.  In spite of this, coal fired generation increased its share of total generation, to a record for the year to 30 April, of 67.52%, as Figure 1 shows:

Figure 1: Percentage of Total NEM Generation: Coal, Wind, Solar

The other immediate result was that the Capacity Factor of the remaining coal generators suddenly increased by about 5%. 

Figure 2: Running Average Coal Capacity Factor % 1 April -1 May 2023

The remaining coal fired stations ramped up their generation to make up for the shortfall- mainly Eraring in NSW:

Figure 3:  Eraring Electricity Generation 27-29 April: average 69%

Eraring maintained a Capacity Factor of around 95% for most of Saturday until Sunday morning when it dropped to 37% during daylight, then back up Sunday night and most of Monday.

Figure 4:  Eraring Electricity Generation 30 April – 2 May: average 72.1%

Why couldn’t wind and solar fill the gap left by Liddells’s closure?  Because there was not much wind or sunshine!  Figures 5 and 6 show Saturday to Monday generation at Stockyard Hill wind farm and the New England solar farm- two of the biggest:

Figure 5:  Wind Generation at Stockyard Hill: average 3.4% Capacity Factor

Figure 6:  Solar Generation at New England: average 6.7% Capacity Factor

Of course, in the coming winter there will be increased demand, and coal generators will need to be maintained.  We are not out of the woods, but the above graphs show how resilient, reliable, and efficient our much-maligned coal fired power stations are.

Could we lose 2,000 MW of solar or wind generation and have the rest immediately increase production?  Not likely!

And are Batteries and Hydro capable, and how efficient are they?

Figure 7: Battery Capacity Factor (Percent)

Batteries nearly reached 0.1 % of their stated capacity.

Figure 8: Hydro Capacity Factor (Percent)

Hydro did better- but even when producing over 28% of total NEM generation could only reach a Capacity Factor of nearly 0.4%. 

These dams and batteries are very inefficient for their cost.

Let’s see what the future holds!

(Source: OpenNEM)

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Electricity Generation: The Impact of Rooftop Solar

Capacity Factor of an electricity generator is its actual generation as a percentage of its installed capacity.  A generator with an installed capacity of 1,000 Megawatts that generates 500 Megawatts has a Capacity Factor of 50%.  Obviously it is a good idea to have CF as high as possible as that will give a better return for the time, money, and effort used to build and run it.

In this post I am looking at Capacity Factors of all generators in the National Electricity Market (NEM), firstly excluding rooftop solar, then looking at CF when rooftop solar is included.

I use data available from Open NEM for the week from 8^th to 15^th March.

Firstly, Figure 1 shows the total of all major generators in Queensland, New South Wales, Victoria, Tasmania, and South Australia.

Figure 1:  Total NEM Generation 8-15 March

Solar and wind get preference, such that coal is curtailed when the sun is shining, but has to ramp up to meet demand from late afternoon to breakfast time.  Hydro and gas follow the same pattern at a much lower level, while wind generation adds its two bob’s worth at unpredictable times.

Figure 2 shows the Capacity Factor for the whole network (if there was no rooftop solar):

Figure 2: Capacity Factor NEM (excluding rooftop solar)

During this week CF varied in a regular cycle, from 27.9% to 43.8%.  Figure 3 shows this daily cycle:

Figure 3: Capacity Factor by Time of Day- NEM excluding rooftop solar

The NEM is at its most efficient- makes best use of generation resources- between 6pm and 7pm at night.  There is a lower peak in CF at 7am to 7.30am.  There is a drop in CF in the early morning (at baseload time), but the lowest CF is between about 11.30am and 12.30pm on several days.

Capacity Factors for coal, gas, and hydro have cycles reflecting that of the NEM without rooftop solar.

Figure 4: Capacity Factor by Time of Day: Coal, Gas, Hydro

By contrast, wind’s CF, which on the afternoon of the 8^th was briefly over 50%, could be as low as 2.4% and averaged 20.5% for the week.

Figure 5: Capacity Factor by Time of Day: Wind

Decidedly unreliable and inefficient.

Solar generation is much more reliable (in the sense of predictable) as we see in Figure 6.

Figure 6: Capacity Factor by Time of Day:  Solar

Solar CF is between about 40% and 60% in the middle of the day.  Note that utility solar, with tracking panels, reaches close to maximum CF by mid-morning and maintains higher CF than rooftop at nearly every 30 minute period of daylight.  Between sunset and sunrise, CF is zero.  All those millions of panels are useless.

When we include rooftop solar in the generation mix, see what happens to the CF for the whole NEM grid:

Figure 7: Capacity Factor by Time of Day- NEM excluding rooftop solar

Maximum CF is now in the middle of the day.  Figure 8 shows the difference rooftop solar makes to the CF of the whole network:

Figure 8: Change in Capacity Factor by Time of Day with Rooftop Solar

Before 9am and after 3.30pm the system is worse off. While the CF for the whole network has been increased in the middle of the day by between 2% and 6%, the average has been reduced by 4.5%, at baseload times by about 6.5%, and in the evening by nearly 10%.  Every additional panel will reduce CF even further, and this is not even considering the additional network capacity needed to keep the system balanced with such a wildly fluctuating supply.  Not a bad effort for a generating system with an average CF last week of 14.9%.

The final two figures compare actual generation at 12 noon and 4am.

Figure 9: 12 Noon Generation 8-15 March 2023

That’s all the renewables enthusiasts see: solar outperforming coal.  They are willfully blind to baseload needs:

Figure 10: 4:00 a.m. Generation 8-15 March 2023

When the remaining 1,500 MW of Liddell are lost in April, and 2,880 MW at Eraring in August 2025, the 4,330 MW gap in supply at 4:00 in the morning won’t be filled by rooftop solar or by solar farms: it will be made up by the remaining coal units working even harder (giving coal an even higher CF) until the strain is too much and they break down, and by gas and hydro.  Inevitable result: higher prices and probable blackouts (sorry- load shedding).

People of my generation often say we have lived through the best of times.

What will the coming generation say?

(Source: OpenNEM)

The Surprising Cost of Electricity

Using data from OpenNEM here is a plot of the cost per MegaWatthour of the main sources of electricity across eastern Australia since 1999.

Figure 1: Historical Cost of Electricity

Plainly the price of electricity supplied by major generators rocketed up in 2022.  Gas and coal were far more expensive than wind and solar. 

QED, would say Chris Bowen and Albo.

But hydro was more expensive than coal- and has been for most of the last 24 years.  Snowy Hydro 2.0 might not be such a good idea.

However, which generation had the biggest percentage increase in price from 2021 to 2022?  Gas?  Get ready for a surprise!

Figure 2:  Percentage Increase in Market Value per Megawatthour from 2021 to 2022

Blame the Russians or evil gas and coal exporters as much as you like- our saintly renewable generators had the largest increases.  Wind generated electricity increased the most- by a country mile.

They’re not above making a fast buck at the expense of Australian consumers.

(Source: OpenNEM)

A Snapshot of the National Electricity Market

Here is a point in time snapshot of electricity generation across the eastern states of Australia, in five simple plots.

Figure 1:  Total Installed Capacity of all Electricity Generators at 14 February 2023

Note that while coal is still king, rooftop solar capacity is rapidly gaining.  Figure 2 shows relative capacity in a pie chart:

Figure 2:  Percentage of Total Capacity

If you are any good at Maths you will see that fossil fuels account for just over 45% of generation capacity while renewables (including hydro) account for almost 55%.

Figure 3 looks at actual generation for the year from 14/2/22 to 6/2/23- 52 weeks- in a pie chart.

Figure 3:  Percentage of Total Generation over 52 weeks

Now that is interesting: coal supplied 58% of electricity generation from just 30% of generating capacity.  Renewables, with 55% of capacity could only manage 36% of actual supply.  Gas made up the remaining 6%.

What about in one 24 hour period?  Monday 13 February had close to ideal conditions for renewables: fine, sunny weather with the monsoon far to the north, moderate winds, and dams full.  Figure 4 shows the percentage of total generation for one day:

Figure 4:  Percentage of Total Generation on one day

Coal has slipped by one percent, gas by two percent for a total of 61%.  In ideal conditions, renewables provided 39%. 

Knowing the installed capacity for all generators and the actual electricity supplied we can calculate the capacity factor of each:

Figure 5:  Capacity Factor for all Generators 13/2/23

Coal                       62.13%

Wind                     32.93%

Solar (Utility)       32.85%

Hydro                    19.60%

Rooftop Solar      17.29%

Gas                        8.24%

Battery                  3.38%

Distillate               1.14%

Bioenergy           -0.15%

(-0.15% for bioenergy?  That’s not a typo: when sugar mills are not crushing, bioenergy is a drain on the network.)

Solar farms are nearly twice as efficient as roof top solar, for the simple reason that rooftop panels are usually fixed while panels in solar farms track the sun.  Maximum capacity factor for a solar farm could in theory approach 50%, while that of household solar, no matter how much installation increases, won’t get much higher than now.

You can be assured that wind and solar are generating as much as possible.  Coal and gas must reduce supply to allow for this- if it wasn’t for renewables they would have a much higher capacity factor.  This is a problem renewables will never be able to solve- wind and solar energy are too diffuse to be much more efficient.

I hate waste.

We will see how this compares in winter, with much less sunshine and Liddell coal fired power station closed.

(Source: OpenNEM)

Australia’s Energy Future

What are the likely prospects for electricity supply in 2023? In a nut shell, much higher prices, but we may avoid blackouts-just.

In April, Liddell coal fired power station will close. Data from OpenNEM shows an extra 2,827 MW of wind and 1,895 MW of solar farm capacity will come on line during the year, and as well rooftop solar will continue to grow rapidly. There will be an extra 154 MW of gas generation at Snapper Point in South Australia. There will be no change to hydro capacity. Figure 1 shows the changes in installed capacity from 2022 to 2023.

Figure 1: Installed Capacity

Across the National Electricity Market, generation and consumption are virtually the same (hydro pumping and battery charging accounts for much less than 1 percent.) Over 24 hours, daily consumption in Gigawatt hours in 2022 is shown in Figure 2.

Figure 2: Daily Electricity Consumption

Capacity factor is actual generation as a percentage of installed capacity.

Figure 3: Daily Capacity Factor

Note that in optimum conditions wind has a capacity factor almost as high as coal; low wind results in capacity factor dropping to 7.6 %. On average wind’s capacity factor is 34.9 %. Wind generation varies, and is mostly greater at night.

While there is a massive amount of solar generation each day, depending on cloud conditions, after sundown solar energy is virtually zero. At the early morning and early evening peaks, and all through every night, the amount of daily solar generation is irrelevant, and the nation relies on coal, gas, hydro, and whatever wind is available. When wind energy is very low, fossil fuels and hydro have to increase generation.

In Figure 4, projected consumption for 2023 is calculated from 2022 average capacity factors and 2023 installed capacity.

Figure 4: Projected 2023 Daily Consumption

Assuming there is no increase in demand in 2023- in other words, no population increase, no new electric vehicles or other gadgets, no economic growth- we can directly compare 2022 consumption with 2023. It is likely that the economy will slow, which might be the only thing to save the NEM. Here are three scenarios for 2023 after Liddell closes.

Figure 5: Third Worst Case

If we have a year with winds similar to last, on average there will be 6.8 GWhr less electricity per day. In 2022 there were 197 days when wind generation was below average. Of course, coal, gas, and hydro will easily increase generation to cover this shortfall, but at greater cost than 2022.

But that is the average day. We need to look at hour by hour demand and generation during each day.

Figure 6 is a plot of electricity supply by source for 30 minute periods for the week of 29 May to 3 June 2022.

Figure 6: Electricity Generation 29 May to 5 June 2022

Battery, biofuel, and diesel generation are not shown as they are tiny. Note the morning and evening peaks, the early morning base of about 19,000 Megawatts, and the daily solar curve, which decreases to virtually zero at local sundown.

Figure 7 shows the above data just for 2nd June.

Figure 7: Electricity Generation 2 June 2022

I am interested in electricity supply at 6.00 p.m. (the down arrow) as this is close to the daily peak. At 6.00 p.m. solar was irrelevant; and wind generation was extremely low all day- but wind generation can be much lower. In 2022 there were 18 days with less wind generation than that.

What if similar conditions occur in June 2023?

In the next figure I assume identical weather conditions- temperature, cloud, rain, and wind- and use the planned capacity increases for gas and wind, and the decrease for coal, to estimate generation for a similar day in 2023.

Figure 8: Second Worst Case- similar conditions to June 2022

773 MW short. Coal is already at its maximum output for the year. The shortfall can only come from hydro and gas. Gas can generate an extra 320 MW or so to equal the maximum for the year, and of course can go beyond this (theoretically, but impossible, an extra 4,255 MW to maximum installed capacity); hydro can contribute extra (theoretically, but impossible, an extra 3,454 MW to maximum installed capacity) – but there is a physical limit. This will drive prices even higher.

Which brings us to the Worst Case Scenario:

Worst Case: less wind than 2022 at peak times and anything less than maximum coal, gas, and hydro generation.

After April, electricity supply will be tight. If the wind blows strongly enough, we will be able to manage. Wind must be able to produce at least 1,100 MW every hour at peak times. However, the wind is unlikely to co-operate. Therefore, we will have higher prices.

But to avoid blackouts:

Coal generators must produce at or above the 2022 maximum capacity factor, with minimal planned stoppages and no unplanned breakdowns.
Gas generators will have to increase supply- this will of course result in higher prices.
Hydro dams will have to stay full, with no droughts or floods.

Good luck with that.

(Source: OpenNEM)

Electricity Prices, Reliability and Ideology

So, apparently we will have electricity prices reduced by a cap on the price of gas and coal and by installing more renewables, and we will have more reliability by installing more batteries and hydro.  And Chris Bowen says anyone who denies renewables are cheaper is a liar “This crisis is caused by gas and coal prices, anybody who says it’s caused by renewables is lying..”

Time for a reality check.

All data has been downloaded from OpenNEM.

Figure 1 shows the fluctuation in daily generation of electricity for the National Electricity Market for the year from 3/12/2021 to 3/12/2022, as supply kept up with demand:

Figure 1: Daily electricity generation, NEM

There is a weekly curve with less demand on weekends, showing as the down spikes.

Figure 2 shows how generation was provided by all fossil fuels and all renewables including hydro and batteries:

Figure 2: Daily electricity generation, NEM, fossil fuels and renewables

(Renewable energy advocates will point out how renewable generation rose at the end of October to record levels.  Bully for them.)

Figure 3 shows the daily price of electricity for the same period:

Figure 3: Daily price of electricity

Note prices began to rise sharply in April and fell back again at the end of July, and there were several large spikes that had nothing to do with the price of gas or coal, but the realities of supply and demand.

So are renewables cheaper?  Well yes, apparently some are.

Figure 4: Average daily price of electricity ($ per GigaWatthour)

Clearly, diesel powered generators are by far the most expensive so are only used for small scale or emergency generation.  Black coal is in the middle, and solar power is cheapest.  Chris Bowen and other renewable advocates will NOT be happy to learn that brown coal is cheaper than wind.

The maximum price of electricity is reached when demand is high but supply is struggling to keep up- those spikes in Figure 3.

Figure 5: Maximum daily price of electricity ($ per GigaWatthour)

Renewables are cheapest, with coal next.  All others including hydro are above a million dollars a Gigawatthour.  Diesel is the stand out.

But how much of each is actually used?

Figure 6:  Average daily electricity generation

Coal is king.

Figure 7:  Maximum daily electricity generation

For short periods wind overtakes brown coal.

Figure 8:  Minimum daily electricity generation

The backbone producers of the NEM are the only ones visible- the others are backup only.

The next figures show plots of data at half hour intervals for the first week of December (1/12/22 to 8/12/22).

Figure 9:  Price per MegaWatthour by time of day (in an average early summer week)

This is the daily picture of supply and demand.  Maximum prices are reached in the early evening – 6 pm to 8 pm- and prices are lowest in daylight hours.  Notice that prices are frequently negative between 6.30 am and 4 pm.  Some generators are paying up to $50,000 per GWhr for the NEM to take their power.  They have to make up these losses when demand is higher.

How does this match with generation?

Figure 10: Total generation by time of day

Demand is highest in afternoons when air conditioners are working hard.  Demand is still above 17,000 Megawatts in the early morning hours.  That is baseload.  (The bottom two rows are Saturdays and Sundays, when people sleep in.)

Here is the problem for Chris Bowen and our energy ministers: how long until renewables plus storage can keep the lights on?

Figure 11: Total generation and renewables + storage by time of day

Not for a very long time, even on an average summer day, let alone if the wind fails, or there’s heavy cloud, or extremely hot or very cold weather.  What’s the point of “cheap” electricity if it can’t do the job?

Here’s why.

Figure 12: Solar generation by time of day

Most solar farms have panels that track the sun, so they quickly reach near maximum capacity.  Rooftop solar, being fixed, follows the irradiance curve.  But note that while solar electricity is cheapest, it cannot be bought for any price at night.

Figure 13: Wind generation by time of day

Solar power is predictable compared with wind, which can vary from less than 1,000 MW to over 6,000 MW.

In a fit of ideological fantasy, Chris Bowen and our energy ministers think they can firm up renewable supply without using coal or gas.  Figure 14 shows hydro, battery, and biofuel generation on a typical early summer day:

Figure 14: “Green” firming by time of day

You can forget about batteries and biofuel (that’s mostly from burning bagasse in sugar mills during the crushing, so is only available for about eight months).   Hydro is the only source worth considering.

Figure 15:  Fossil fuel generation by time of day

Fossil fuels do the heavy lifting, 24 hours a day, helped by hydro. 

Figure 16:  Gas generation by time of day

Gas helps maintain supply when renewables fluctuate because generators can ramp up relatively quickly.  A lot of the time they are on standby, so have to make money when demand is high.

Figure 17:  Coal generation by time of day

Black coal generation can vary by nearly 50 percent in a few hours, every day.  They’re not designed to do that forever.  Break downs are more likely.  Brown coal is not as flexible as black coal but keeps up a reliable supply 24 hours a day.

There is a huge gap- about 10,000 MW- before renewables and storage can begin to provide for our needs.  Excluding coal and gas from firming supply- to maintain electricity supply when time and weather won’t co-operate- will make the task impossible.  Fossil fuelled generators have to make up for losses or lack of income when solar and wind supply is abundant by higher prices when demand is higher.  Supply and demand is the main reason for high electricity prices- but Chris Bowen and Albo have never run a business.

There is nothing but pain ahead, and things will get worse before they get better.

I’ve bought a generator.

(Source: OpenNEM)

Power Gaps = Blackouts

On Wednesday the Australian Electricity Market Operator (AEMO) gave a warning that should not have come as a surprise to anyone with half a brain, but it made the headlines, including at the ABC:

AEMO warns of power ‘gaps’ in Australia’s biggest grid within three years as coal exodus gathers pace

Planned coal fired power station closures and increasing demand will lead to shortages from 2025 in NSW, Victoria in 2028, Queensland in 2029, and South Australia early next decade.  Of course this is seen as a wake-up call that we need more renewables, more storage, and more transmission lines.  Sceptics will say “We told you so”.

In fact, readers may remember my post from 18 June titled “The Gap”, with this figure.

I have crunched the numbers for daily electricity consumption in the eastern states for the 12 months from 1 September 2021 to 31 August 2022.  Here’s that gap again, in GigaWatthours.

(The wobbles in the Total show the weekend drops and the Christmas- New Year “silly season”, the summer and winter demand peaks, and the spring and autumn “Goldilocks” periods.)

The gap is currently at the very least 307 Gigawatthours.  The average over 365 days is 418 GWhr- and we are supposed to be converting most of our transport to electric (or hydrogen!) in the next few years. 

Hydro produced a maximum of 99 GWhr.  Snowy 2.0 will only produce another 48 GWhr, and you can forget about batteries- minuscule.

Good luck with filling that gap.

How did fossil fuels compare with renewables over the past year?   The next figure shows the percentage of total consumption supplied by coal, gas, and wind plus solar.

Coal had a short period where supply dropped to 52.3%, but averaged 59.9% over the year, rising to 68.9% on Wednesday this week.  The plotted trendline shows a decrease of 0.9% over the year. 

Renewables decreased by a whopping 6.24%- so much for the renewable transition!

Gas filled the gap, with an increase of 6%.

Just so that you are clear that the crisis we narrowly avoided early this winter was NOT caused by unreliable coal fired stations, here is a plot of renewable supply expressed as daily deviation from the 12 month average- anomalies if you like:

Wind and solar were producing much below expected- and erratically- from mid-March to mid-July.

Finally, the next figure shows seven day averages of the major energy suppliers and the total, overlaid with price per MegaWatt.

The high prices coincide with gas and hydro increasing generation when renewables were unable to meet their average supply- let alone the increase in demand.

Mind the gap.

(Source: OpenNEM)