Archive for the ‘Electricity’ Category

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?


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)

The Gap

June 18, 2022

Here is a simple plot to demonstrate the challenge facing our new government, and all future governments, if they want to transition to a zero carbon economy.

This is the gap between all non-fossil fuel generated electricity- solar, wind, and hydro- and total consumption in eastern Australia over the past two weeks (3rd to 17th of June) for every 30 minutes of the day.

That gap- 12,000 to 16,000 MW for base load and 16,000 to 30,000 MW for peak load- is now filled by gas and coal.  Snowy 2.0 will only provide an extra 2,000 MW of storage.

That’s just for electricity- don’t forget electric vehicles and hydrogen!

(Source: OpenNEM)

The Real Cost of Renewables

June 13, 2022

Electricity prices are increasing, we know.  Here is a plot of electricity prices across the eastern states in the National Electricity Market.

Fig. 1:  NEM Prices 2009-2022

There is a shortage of available coal and gas generation, resulting in record prices.

Fig. 2:  NEM Coal & Gas Prices 2009-2022

Of course wind and solar are much cheaper:

Fig. 3:  NEM Wind & Solar Prices 2009-2022

See?  Renewables are cheaper.

Not so fast.

Figure 4 shows electricity consumption for the eastern states last week (Friday 3 June to Friday 10 June).

Fig. 4:  NEM Total Consumption 3 June – 10 June

Note the daily cycle between baseload and peak load.  Figure 5 is a plot of consumption for each 30 minutes of the day:

Fig. 5:  NEM Total Consumption by Time of Day

The baseload- the minimum amount of electricity to meet the needs of streetlights, hospitals, smelters, and households- occurs every day between about 3.30 a.m. and 5.00 a.m., and last week was from 20,600 to 22,300 MW.

Peak load rose to 35,386 MW.

Figure 6 shows how wind and solar performed last week:

Fig. 6:  NEM Wind & Solar Consumption 3 June – 10 June

The bleeding obvious is that while solar provided more than 10,000 MW for 30 minutes on Saturday 4 June, it produced absolutely zero every night.  Wind never reached 7,000 MW.

That’s the reason we need storage.  If we can store the excess from solar, we could use it to supplement wind when needed.  Much money has been invested in large scale batteries.  However, batteries provided a maximum output of 324 MW last week- pathetic really.

We do have hydro-electricity, mainly in Tasmania and the Snowy Mountains.  Figure 7 shows how hydro contributed last week:

Fig. 7:  NEM Hydro Consumption 3 June – 10 June

Hydro helped twice a day at peak times, and also provided a substantial supply in daylight hours- over 2,000 MW on 8 June.  The previous week- at 6 p.m. on Thursday 2 June- wind could manage only 3% of the NEM load, and hydro provided 19.33%, or 5,382 MW.  Last Thursday 9 June at 6 p.m. hydro provided 5,519 MW.

That’s why we need more storage.  Forget batteries- the only realistic storage is pumped hydro, where excess off-peak electricity is used to pump water to storage dams.  Wivenhoe Dam in Queensland has been doing this for 40 years.

So the politicians dreamed up Snowy 2.0.  This scheme, whose timeline for completion has blown out to the end of 2026 according to Chris Bowen (Weekend Australian June 11-12), will cost 4.5 billion dollars to build, plus another $1.5 billion to $2 billion for extra transmission lines.

 “Snowy 2.0 will provide an additional 2,000 megawatts of dispatchable, on-demand generating capacity and approximately 350,000 megawatt hours of large-scale storage to the National Electricity Market. To provide context, this is enough energy storage to power three million homes over the course of a week.”

That’s a cost of $3.25 million per MW.

That’s the “good” news.  Now for the interesting news.

As we saw above, baseload last week was 20,000 to 22,000 MW- and winter has only just started.  If fossil fuels are removed eventually, baseload at 4 a.m. must be met by some combination of wind and hydro as there is no sun at that time of day. 

The current hydro capacity is 9,285 MW.  Snowy 2.0 will provide an extra 2,000 MW.

The current installed capacity of wind generation is 9,202 MW- and that is going full bore day and night, with optimum wind conditions and no stops for maintenance.  32% of capacity is the average reached.

The total installed capacity of wind, current hydro, and Snowy 2.0 is 20,487 MW.  That is still short of baseload with winter to come, and peak load last week was 35,386 MW.  That doesn’t allow for population increase or economic growth either.  Where will the extra 15,000 MW of wind powered and pumped hydro electricity come from?  It’s an impossible dream.

But wait, there’s more.

Here’s the bad news:  Hydro electricity is the most expensive electricity in Australia- more expensive than either coal or gas.  In May 2022 it reached $315.91 per MW.

Because it is rapidly despatchable it is sold at times of very high demand, so the operators get top dollar.  Much more than coal or gas.

Figure 8 shows the average price of hydro for each month to May 2022.

Fig. 8:  NEM Hydro Prices 2009-2022

The real cost of renewables will include the cost of storage and emergency supply.

Don’t hold your breath hoping for electricity prices to come down.

Energy Crisis or Ideology Crisis?  The Rubber hits the Road

June 7, 2022

Australia faces an energy crisis as electricity prices escalate, as we were told by the media last week.  Last Thursday evening at 6:00 p.m. the spot price for electricity hit $4,335 per Megawatt Hour.  Blame was immediately cast on our aging fleet of coal fired power stations.  Several were operating well under capacity through planned maintenance or unexpected failures.  Gas powered stations ramped up, but gas costs an arm and a leg because of the Ukraine war.  The weather had turned very cold in southern states and the wind had dropped. 

What shall we do?

Well, firstly, don’t panic.

Secondly, don’t depend on renewables.

Thirdly, enjoy the abundance of fossil fuel powered electricity- don’t restrict it.

And finally, if you must insist on Net Zero by 2050, go nuclear.

Here’s why.

Don’t panic:

Despite our apparently aging, decrepit, obsolete fleet of coal fired power stations operating at only 58% of capacity for the last seven days (10:30 a.m. Tuesday 31 May to Tuesday 7 June) the lights stayed on- just.  Gas and hydro came to the rescue.  With better maintenance and planning, there would have been no problem at all, and no need for cutbacks to industrial production such as aluminium.  So there’s no need to panic- we have ample energy supply.

Figure 1 shows electricity generation for the seven days to Sunday 5 June (p.m.) from OpenNEM.

The vertical line shows 6:00 p.m. Thursday night when the spot price peaked at $4,335.  It was after sundown so no solar, and there was little wind.  The plot shows how gas and hydro ramped up.  Also note the peaks on Monday, Tuesday and Wednesday were higher, and on the weekend demand was lower, so excess electricity could be used to pump water for hydro.

Don’t depend on renewables:

Figure 2 shows the same data as Figure 1 but not stacked, so comparison is easier.

Figure 2: All generation 29 May to 5 June (2:30 p.m.)

Coal of course stands out- nothing comes near.  Note that daylight hours are easy to see from the solar peaks.  Wind varies up and down as weather systems move across.  To fill the gaps on either side of solar, hydro and gas peak together in early mornings and evenings.  And finally you can barely see the contribution of batteries and diesel generators.

Figure 3 shows the relative contributions to the total of fossil fuels and renewables.

Figure 3:  Fossil fuels and wind, solar, and hydro:

The total generation has a daily cycle to match demand, but never dropped below 18,600 MW at night.  That is the minimum that the eastern Australian network must supply at this time of year.  The total rose to a touch under 31,300 MW in the early evening of Monday, Tuesday, and Wednesday, with excess power used to pump water for hydro, reducing to about 30,000 on Thursday and Friday as industries and commerce cut back, and much lower peaks on the weekend.  Note that renewables fluctuate much more than coal and gas.

Figure 4 looks at the percentage contribution of the “old” generation- coal, gas, and hydro- compared with the new- wind and solar.

Figure 4:  Old and new as a percentage of total generation:

Wind plus solar only exceed 50% on sunny, windy days.  Because they get preferential treatment coal stations must cut back at these times.  When wind or solar- or both- cannot meet demand, fossil fuels and hydro must quickly ramp up.  On Thursday night wind and solar contributed just 3% of electricity.

That’s why we cannot depend on renewables.

Enjoy the abundance of fossil fuels:

Coal capacity is 23,049MW.

Gas capacity is 10,967MW.

Together that is 8 percent more than the maximum of all generation on any day of the last week.  Coal alone could easily meet night-time needs.

Hydro-electricity averaged another 9% (peaking at 19.4%).

With proper planning and maintenance that should be a decent buffer for unexpected breakdowns.

Of course gas is very expensive because of global demand.  With more coal generation (HELE power stations) we could have a reliable and cheaper electricity network, without any need for solar or wind power except in remote or special locations.

If you must insist on Net Zero by 2050, go nuclear:

There is no other realistic choice.

34,000 Megawatts of fossil fuelled electricity can be phased out, but on last week’s figures we MUST have at least 31,000 MW or we will have cut backs in industry, commerce, services, and domestic supply.  And last week, at one stage only 665 MW was being generated by wind turbines, and each night there is zero from all the rooftop and solar farm capacity in the country.   Hydro?  We have frequent droughts, so that cannot be relied upon in the long term.

Even in the sunniest continent on earth, and with the usually strong winds across southern Australia, renewables cannot be relied on when needed.  If there is to be limited fossil fuel use, the only alternative is nuclear energy.

I look forward to watching the Greens and Labor squirm over the next few years.

I have included as an Appendix a sample of the major electricity facilities so you can see how their generation varied over the last week.

Appendix:  Electricity generation from a sample of coal, gas, hydro, wind and solar facilities last Friday, Saturday, and Sunday

Coal can ramp up and down as needed- but is hard to do and harder on the equipment.

Gas can quickly fill the gap but is expensive- and sits idle for a long time too.

Hydro is quick to ramp up and down but dams have to have enough water.

Wind is free but doesn’t always blow!

Likewise, sunshine is free but not always there!

OpenNEM Crashes- Atlassian Software Fault?

May 27, 2022

Remember on Monday the OpenNEM showed Rooftop Solar generation dropping out?  It has happened again just three days later:

Not only that, but the whole OpenNEM reporting system seems to have crashed.  The last update was at 1:40 pm on Thursday 26th.  This screenshot was at 9.00 am this morning Friday.

It looks like a software system crash.  Not in electricity production or we’d have noticed, but in the reporting.

This website (OpenNEM) is not that of the actual NEM, but has been set up to make NEM data “more accessible to a wider audience”.  That’s very commendable.  Note who has set it up:

Simon Holmes a Court was instrumental in the Teal wins over moderate Liberals.  He’s pushing rapid transition to renewables.

Dr Dylan McConnell is an energy systems researcher at the Climate and Energy College at the University of Melbourne.

Nik Cubrilovic is an internet security blogger, best known for computer hacking, according to Wilipedia.

And the platform is driven by Atlassian, founded and largely owned by Michael Cannon-Brookes, who is the largest shareholder of AGL and is trying to stop the proposed AGL demerger so that he can get rid of fossil fuels faster.

Couldn’t happen to nicer blokes….

Or maybe they have interests in uranium mines and know that nuclear is the only hope for Net Zero?

What Happened To Rooftop Solar Yesterday?

May 24, 2022

Yesterday, 23 May, something strange happened to electricity supplies across the National Energy Market (NEM).

Figure 1 shows total electricity generation for the last three days across Queensland, New South Wales, Victoria, South Australia, and Tasmania.  Notice the huge drop in generation early yesterday afternoon.

Figure 1:  3 Day Generation, NEM

The drop was entirely due to Solar Rooftop generation going from gangbusters at 1:00 pm to zero from 2:00 pm to 3:00 pm.

Figure 2:  All NEM Generation Monday 23rd.

Figures 3, 4, and 5 show the drop in closer detail.

Figure 3:  All NEM Generation 1:00 pm

Figure 4:  All NEM Generation 2:00 pm

Figure 5:  All NEM Generation 3:30 pm

It happened in every state, from Queensland, producing the most solar power (1,376 MW or 18.6% of the Queensland total):

Figure 6:  Queensland Rooftop Solar:

to South Australia, whose paltry 814 MW was 48.4% of total power used.  Interesting that solar in SA fell off from 12:30 pm.

Figure 7:  South Australia Rooftop Solar (12:30 pm):

At 2:00 pm, the drop in energy supply was nearly half (1,659 MW to 849 MW)- and they were still charging batteries.

Figure 8:  South Australia Rooftop Solar (2:00 pm):

By 3:30 pm, SA solar had recovered to 28% of supply- which was also helped by an almost equal amount of imported electricity:

Figure 9:  South Australia Rooftop Solar (3:30 pm):

In case you think this was caused by the cloudy weather over eastern Australia, it wasn’t:  it was mostly clear.

Figure 10:   BOM radar map at 1.30 pm 23rd May

Network generation fell by 16.5% from 1:00 pm to 2:00 pm.  Did no one notice?  Were there no blackouts?  Why was all rooftop solar in eastern Australia closed down for an hour?  Did you know they could do that?  If rooftop solar can be completely shut down without any ill effects why have it in the first place?

I think this will remain a mystery.