Posts Tagged ‘Australia’

Extreme Weather Events: 2

January 20, 2023

Further to my post yesterday about the Climate Council’s recent fear mongering, with my look at whether the recent flooding at Fitzroy Crossing could be due to increasingly severe rain events, here are two more locations.

I calculate the 10 year running standard deviation of daily rainfall, the 10 year mean, and because the standard deviation must change as the mean changes, I divide the 10 year standard deviation by the 10 year mean.

Early this year there was sever flooding in northern New South Wales. Brays Creek is near Mt Warning about 40 km north of Lismore. Here is the standard deviation divided by average rainfall:

Rainfall over the past 10 years is less extreme than it was 40 to 50 years ago.

The Bruce Highway to north Queensland was blocked for several days, as it normally is every Wet season, by flooding at Goorganga Plains just south of Proserpine. Is rainfall becoming more extreme? Here is the raingauge at Lethebrook, using the same technique.

Nothing exciting to see there either.

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Extreme Weather Events: 1

January 19, 2023

Last night On Wednesday night 18 January, the Climate Council released their latest doomsday publication, with the support of Beyond Blue (they’re now off my list of charities to donate to.)

“HIDDEN MENTAL HEALTH TOLL OF WORSENING CLIMATE DISASTERS ON AUSTRALIANS REVEALED WITH NEW NATIONAL POLL”


Climate Councillor, climate scientist at the Australian National University and author of Humanity’s Moment: a Climate Scientist’s Case for Hope, Dr Joelle Gergis said: “The results of this poll are confronting. It’s heartbreaking to realise that many Australians are living with significant levels of distress related to the reality of our changing climate. It shines a light on this invisible mental health crisis that is undermining the stability of our local communities all over the country.

“We need to have a national conversation about climate change adaptation and listen to the experiences of people who have lived through these disasters.

Extreme weather events are going to escalate as our planet continues to warm, so the impacts we have witnessed in recent years are really just the tip of the iceberg. We urgently need to develop plans that protect and support our local communities as climate change-fuelled disasters continue to upend the lives of countless Australians.”

Time for a reality check:

Is there evidence of increasing climate extremes?  Rainfall and temperature are easily measured and data is freely available from the BOM.

First example:  The recent flooding at Fitzroy Crossing. 

A useful measure of extremes is Standard Deviation.  For this technique I am indebted to Willis Eschenbach whose recent post at WattsUpWithThat sparked my interest.

I calculate the 10 year running standard deviation of daily rainfall, the 10 year mean, and because the standard deviation must change as the mean changes, I divide the 10 year standard deviation by the 10 year mean.

The nearest rain gauge with a reasonably long record is Fossil Downs.  Here is the 10 year average daily rainfall:

As you can see average daily rainfall (which nearly all falls in the Wet) has nearly doubled since the decades to the 1960s.

10 year standard deviation:

No wonder people are anxious!  The 10 year figure is very high (but not as high as the 1980s!  Was it more extreme 40 to 50 years ago?)

But here is the standard deviation divided by average rainfall:

This shows that relative to the average, rainfall extremes are actually getting smaller.

Over the next few days I will show rainfall and temperature plots for several Australian cities.  Stay tuned.

Australia’s Energy Future

January 17, 2023

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

December 10, 2022

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)

UPDATE 12 October 2022: Covid-19 and Australian Mortality

October 9, 2022

Please note: I have decided to remove Figure 3 from this post as I confused myself with the ABS changes to baselines and mortality counts. I will be very soon posting a further analysis of Covid which will present information in a much improved manner.

In a post last week (October 5) Jo Nova raised questions about an apparent surge in mortality in Australia this year.

There may be a simple explanation.

Also, it is time for an update on Covid-19 and mortality.

I have looked at ABS data for Australia as a whole and for four states: New South Wales (which eased restrictions earlier than some thought wise); Queensland (which had rigid border restrictions, then opened at the start of the Omicron wave); Victoria (which had lax early restrictions then became overly rigid); and Western Australia (which maintained border restrictions until 4 March this year).

Changes in the way ABS collect and publish data complicate analysis.  The ABS changed its baseline for calculations from January this year; and, as well, previous State and National mortality data now available for download is only for doctor certified deaths whereas 2022 State data is for total mortality figures (including data from coroners’ reports).    This can be confusing. I work around this by calculating the percentage change from the baseline.  The next figures illustrate this.

Figure 1: National Absolute Mortality (as certified by doctors)

The baseline changed in January 2022 as shown.  There was a large step up in the baseline at the same time as the Omicron wave.

Figure 2: NSW Absolute Mortality (as certified by doctors to December 2021 then all deaths from January 2022))

Notice the huge jump- that’s why I calculate percentage change from the expected number or baseline.

Figure 3: National Percentage Change in Mortality (removed)

The percentage change shows the fluctuations in mortality as a result of the Covid-19 waves, lockdowns, international border closures, and influenza.  There is nothing alarming about recent figures.

The next plot compares NSW with WA.  NSW relaxed restrictions early and WA kept borders closed until March 2022.

Figure 4: Percentage Change in Mortality- NSW and WA

WA missed most of Omicron.

Figure 5: Percentage Change in Mortality- Qld and Victoria

Victoria had major problems with hotel quarantine in the second wave, then imposed very severe restrictions, but again had large Delta and Omicron outbreaks.  Queensland may have had an “early” undetected first wave, a peak in Omicron, but had a larger than expected number of deaths in June 2022 due to a severe flu outbreak on top of already struggling public hospitals.

You will note the large weekly up and down spikes.  This is probably due to late reporting of deaths by doctors and nursing homes.  There was evidence of this in January this year in Queensland, when several weeks of nursing home deaths were added in one week.  The next plot smooths the weekly data with a centred 5 week running mean.

Figure 6: 5 Week Centred Mean of Percentage Change in Mortality

I have indicated the Covid peaks. 

Note: 

Queensland’s possible early first wave, and Victoria’s second, Delta, and Omicron waves show clearly.

Omicron struck Queensland, NSW, and Victoria hard with 27% to 37% increase on expected mortality (5 week averaged).

Queensland had a large number of unexpected deaths in 2021, beginning well before vaccine rollout. 

West Australia’s mortality figures are similar to other states, apart from largely missing Delta and Omicron.

The small peaks around weeks 68 -72 are not associated with vaccine rollout: vaccinations gathered speed after this time (early May 2021).

The ABS data does not show any large surge in unexplained deaths in 2022.

Power Gaps = Blackouts

September 2, 2022

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)

Cheap, Reliable, and Renewable: July 2022

August 2, 2022

Some more plots from the National Electricity Market (NEM) for the month of July to illustrate the problems we continue to face. Figures 1 and 2 are updates of similar figures from June, but Figures 3 and 4 are new and hopefully show the problem even more clearly.

Figure 1: July consumption: all sources (Gigawatts)

Note the dip in consumption every weekend is even more marked than in June.

Figure 2 shows the relative contribution of all major sources, (but including battery, if you can see it).

Figure 2: July consumption as a percentage of total: all sources

Coal usage increased mid month to provide over 60% of all electricity.  The contrast with all other sources is obvious.

For the next plot I calculated anomalies from the monthly means of all energy sources. I have calculated totals for Renewables (Wind and Solar) and for Coal, Gas, and Hydro- the main sources we rely on to keep our electricity system stable. To allow for days when total consumption was up or down, I subtracted Total energy anomalies from Coal, Gas, and Hydro.

Figure 3: July consumption anomalies: renewables and non-renewables

Figure 4 shows how Non-renewables are controlled by Renewables:

Figure 4: Coal, Gas, and Hydro as a Function of Renewables

Wind and solar can sell to the market as much energy as they produce, so on days (and hours) when they can supply more, coal, gas, and hydro must cut back. However, at those times when the sun doesn’t shine and the wind is not as strong, the shortfall has to be made up by non-renewables- and with gas in short supply, that means higher costs.

The average daily price in July was $376.73.

(P.S.- Hydro is normally included as a renewable, but really it isn’t. In drought years, there’s not enough water to power the turbines, and in wet years- like 2022- water release through the turbines causes downstream flooding, so needs to be curtailed.)

The Cost of Electricity

July 7, 2022

What drives changes in the wholesale price of electricity in the National Electricity Market (NEM)?  Here are some plots that may help understand the problem.

Figure 1 shows electricity generation and wholesale price for the 12 months to 3 July.

Figure 1: Total generation and price

The price had nearly doubled from August 2021 with no great increase in demand, but began to rise more and more sharply since the invasion of Ukraine on 24 February.  Figure 2 shows the percentage contribution to total generation of various sources since then.  I have included batteries for entertainment value.

Figure 2: Percentage contribution to total generation since the start of the Ukraine war.

On 12 June the AEMO intervened in the market and set a cap on prices.  Prices were claimed to have risen because of the shortage of gas and coal and the failure of coal generating sets.  Certainly coal’s contribution had fallen from around 60% of total generation to the low 50s over the three week period leading up to the intervention. 

In this post I analyse how the price of electricity varied with changes in the energy mix during the period of rapid rise.

As both price and generation was changing, it is necessary to remove the trend in price to get an accurate analysis.  Figure 3 shows the price of electricity from the day after the Ukraine invasion to the day after the AEMO price cap, fitted with a 2nd order polynomial trend line. 

Figure 3: NEM wholesale price

Figure 4 shows the detrended price timeseries.

Figure 4: NEM wholesale price detrended

This shows that the price was becoming more volatile.

Now I look at the contribution of each main generation source in relation to the average wholesale price of all electricity (detrended).  In each, the line at zero represents the actual trend.

Figure 5:  Price and percentage contribution of solar generation

As solar generation increased by one percent, the price decreased by $1.63 per Megawatt.  That would be excellent news if the sun shone 24 hours a day.

Figure 6:  Price and percentage contribution of wind generation

Again we see the cost decreasing with more renewable generation- $4.23 less for each extra percent of total generation.  However, the plot also shows the converse- when there is little wind the cost is much greater.

Figure 7:  Price and percentage contribution of hydro generation

Great faith has been placed in the necessity of having pumped hydro as a store of renewable energy, but Figure 7 shows that the cost increases by $7.77 for each extra percentage point of total need that hydro back up provides- well above trend. 

Figure 8:  Price and percentage contribution of gas generation

Gas is in short supply and very expensive, so the cost of providing each additional percentage point of the total generation is $11.08. 

Figure 9:  Price and percentage contribution of coal generation

Here’s something the renewables industry and the ABC won’t tell you.  The wholesale price of electricity actually decreases as the proportion of coal generation increases.  As well, price volatility decreases.  Above 62% the average price across the network is relatively stable, varying by +/- $100 per Megawatt.  Below 62% the price becomes more and more volatile.

As more and more renewables come on line, coal usage will drop, to apparently near universal acclaim.  Figure 10 shows how wind pushes out coal:

Figure 10: Percentage contribution of wind and coal

But there was no new additional wind capacity during this period.

And Figure 9 above shows cost and price volatility will increase as reliability decreases.

How should we keep prices down, and maintain reliability?

Coal is your friend.

Cheap, Reliable, and Renewable

July 4, 2022

(or How Not To Run An Electricity Grid)

Here are some plots from the National Electricity Market (NEM) for the month of June which may illustrate the problems we will continue to face.

Figure 1: June consumption: all sources (Gigawatts)

Note the dip in consumption every weekend.

Figure 2 shows the relative contribution of all major sources, (but including battery, if you can see it).

Figure 2: June consumption as a percentage of total: all sources

You may note that coal stepped up mid-June to produce 60% of all electricity.  The contrast with all other sources is obvious.

The next plots show June monthly average, maximum, and minimum for all major sources.

Figure 3: June consumption Average, Maximum, Minimum

Note that while coal ranged from about 300 to 350 GW, wind ranged from almost half coal’s minimum to very little.

Figure 4: June consumption Average, Maximum, Minimum as percentages

Coal stands out for its consistency.  And with all the rooftop solar and solar farm expansion, solar cannot produce 10% of our power needs.

The next figures compare coal with renewables to show the daily fluctuation, that is, how much the electricity generated (and consumed) each day compares with the one before.

Figure 5: Percentage daily change in electricity consumption: coal and total

The close match between coal and total consumption is obvious.  Coal’s daily percentage changes (above that of the total) on the 2nd, 13th, 16th, 17th, 18th, 21st, and 30th June correspond to the fall in renewable generation – especially wind- on those dates, as Figure 6 shows for coal and wind.

Figure 6: Daily change in coal and wind consumption (Gigawatts)

The contrast is even starker when expressed as a percentage:

Figure 7: Daily percentage change in coal, wind, and solar consumption

Coal can change on a day to day basis by 20 to 30 percent.  Wind can decrease by 76 percent or increase by 326 percent from one day to the next.  What a way to run an electricity grid!

One thing you can say about renewables: they can be relied on to be unreliable.

Blowin’ in the Wind

June 22, 2022

The energy crisis seems to be ongoing- the new normal apparently.  Is it the fault of old, rundown coal fired power stations with breakdowns?  Is it the fault of greedy, profit hungry energy suppliers gaming the system?  Is it the fault of the Ukraine war pushing up coal and gas prices?  Is it the fault of the previous coalition government for not having the correct climate policy, resulting in not enough investment in renewables?  Or all of the above?

Nope.

Breakdowns last week in under-funded power stations didn’t help, nor a shortage of high priced coal and gas.  And you can’t blame companies wanting to keep their income above their costs. 

But no amount of climate ambition, and no possible amount of renewable capacity, could have averted the problems we’ve had last week and are likely to continue to have.

Figure 1 shows our electricity consumption for the two weeks from 3rd to 17th June. 

Figure 1:  All NEM electricity consumption 3- 17 June

Coal is the heavy lifter.

Figure 2 shows the main energy sources as a percentage of the total usage.

Figure 2:  All sources as a percentage of NEM electricity consumption 3- 17 June

Note again it is coal followed by daylight- and I don’t mean solar!  Note also that coal’s relative contribution increased despite breakdowns and supply difficulties.

The next plot shows the percentage contribution of fossil fuels and all non-fossil sources- batteries, hydro, wind and solar.  I’ve also included the negative contribution of pumped hydro, when dams are refilled using excess electricity- except on 13th and 14th when it was too expensive.

Figure 3:  Fossil and non-fossil generation as a percentage of consumption

Renewable energy advocates like averages- they hide a multitude of sins.  Here are the averages of all sources for each 30 minutes of the day for the last two weeks:

Figure 4:  Average 30 minute NEM electricity consumption 3- 17 June

Coal varies between 12,000 and 16,000 MW per half hour as it responds to the twice daily peaks in demand, and the daily peak in solar output.  Solar is useless for meeting baseload around 4:00 a.m., or either of the daily peaks.  Wind averages a touch over 4,000 MW all day so is also no help with extra demand.  Battery discharge at peak times can barely be seen.  Gas and hydro vary at similar rates to meet demand when needed, though gas output remains higher throughout the night.

How reliable was wind generation, which averaged over 4,000 MW per half hour?  Here is a plot of actual wind generation at 30 minute intervals from 3 June to 17 June:

Figure 5:  Actual wind generation 3- 17 June for each half hour

“Fickle” is not an adequate description.

Of course renewables can provide 18,000 MW at maximum capacity- but at the wrong time of the day.  When the need was greatest, they could provide only 6,880 MW- and 90% of that was hydro.

Our entire electricity generation, including fossil generation, depends on the reliability or otherwise of renewable generation.

Our energy crisis last week was not caused by breakdowns, fossil fuel prices, greedy power companies, coalition governments, or lack of investment in renewables.

It was caused by a lack of wind.

Figure 6:  Actual wind generation 3- 17 June

We are hostages to the weather.  Bob Dylan was right.  The answer is blowin’ in the wind.

(Source: OpenNEM)