The future of energy generation and storage

[sptrawler]

Yes. It is just that I suspect that 12 months ago the issue was conceptual but in the last few months the long term breakdown of major elements in our power supply has sharpened the focus.
Certainly brings up the urgency of more solar and wind power as well as battery and hydro storage.

There is nothing conceptual about blowing up power stations, that adds load to the rest of the aging infrastructure, it works in the generators interest to bend to public pressure and remove coal generation.
What is the down side to them? they get paid more for the remaining plant to generate, they get rid of workers and they can pretend they are going to fix it with renewables.
Your last sentence, is the very reason we find ourselves in this situation, politicians being driven by delude public opinion to resolve what is a technical issue.

 

[basilio]

That's funny SP. I was under the impression you had finally understood and agreed that the future of energy generation in Oz was with cheaper non polluting renewable energy with supporting battery and hydro - as distinct from keeping very tired, grossly polluting and unsustainable coal fired power stations operating.

 

[sptrawler]

That's funny SP. I was under the impression you had finally understood and agreed that the future of energy generation in Oz was with cheaper non polluting renewable energy with supporting battery and hydro - as distinct from keeping very tired, grossly polluting and unsustainable coal fired power stations operating.

You were under the impression I understood, your funny.
I know enough on the subject, to know it can't be done before the existing generation falls in a heap.
As I've said before, it isn't lack of will, it is lack of time and suitable alternatives at this point.
But as always the vocal minority wont listen to reality, it is a sign of the times, everyone with no knowledge has all the answers.
Luckily W.A hasn't got itself into the mess, the eastern States have.

 

[Smurf1976]

How serious is the news of continual long term failures of Victoria's power supply?

I'll steer clear of the politics and focus on the technical and financial (including investment) aspects of it all.

Firstly, what has happened?

Following is the status of all out of service plant in Victoria. Where I haven't stated a reason that's because it's not public knowledge and whilst in some cases I know the answer, it would be inappropriate to say so.

Loy Yang A unit 2 - major damage requires a complete rewind of the alternator, at a cost of $57 million, to repair. AGL has awarded a contract to GE Power Australia to perform this work. They're aiming for a return to service in December 2019. Capacity of this unit is 530 MW and the fuel is coal. Owner = AGL.

Mortlake unit 2 - major incident will take a few months to fix but Origin haven't confirmed the details there yet beyond saying they're aiming for 20 December 2019. Capacity is 275 MW and the fuel is gas (open cycle gas turbine). Owner = Origin.

Yallourn W unit 3 - tripped yesterday morning due to a boiler tube leak. In layman's terms - pipe has a big hole in it. Solution = put the fire out (easy just stop feeding coal in), let it cool down, humans go in and fix it, start it back up again all of which will take a few days so it's not a major drama. Capacity is a bit variable subject to conditions but ~380 MW. Owner = Energy Australia.

Newport D (single unit station) - tripped this morning from full load about 8:45am. No major problem, just a minor hiccup, and commenced startup about 10:15 and has been at full load since about 5pm. Capacity is 510 MW and the fuel is gas with diesel as backup (this is a steam turbine plant not gas turbine). Owner = Energy Australia.

Somerton is a 4 x 40 MW open cycle gas turbine station. Two units, so 80 MW, hasn't been available for quite some time now. Fuel is gas. Owner = AGL.

Loy Yang A unit 3 - 560 MW coal-fired plant is out for maintenance. Owner = AGL

Yallourn W unit 4 - 380 MW coal fired plant out for maintenance. Owner = Energy Australia.

Jeeralang B unit 1 - 84 MW open cycle gas turbine. Fuel is gas with diesel as backup. Owner = Energy Australia.

Clover whole station (2 x 13 MW) - out of service for major maintenance. This is a hydro plant owned by AGL.

Does all this matter?

In the short term it's an economic issue but not one which threatens supply. Power not generated cheaply at Loy Yang or Yallourn is being produced more expensively elsewhere. Spot prices are higher than they otherwise would be, there are impacts on individual companies since those who are filling the gaps aren't necessarily the same companies who are having problems, but overall it's an economic issue.

That it's an economic issue not a threat to supply is primarily because demand in Victoria peaks during Summer not Winter such that having some plant out isn't a problem within reason. That the Murray-Darling Basin Authority wants to transfer quite a lot of water out of Dartmouth reservoir into Hume dam (for reasons completely unrelated to electricity supply) is a bonus since that means substantial running of Dartmouth power station (hydro, 160 MW, AGL) which is adding more supply than it would if not for the bulk water movement objective of the MDBA.

In Summer however it's a very different story since even with all plant in service, total demand can exceed capacity in Victoria meaning that any problem, however minor, adds to the shortfall and that remains true even with maximum supply from other states included.

Further, supply in SA tends to be finely balanced during extreme hot weather such that any problem can only be addressed by means of supply from Victoria. Supply which won't be available if there's plant out of service in Victoria.

The reason this matters is simply due to that lack of sufficient capacity. It's the same with anything eg let's consider a large workforce as an analogy:

52 weeks in a year.
Less 4 weeks recreation leave. That's 8% downtime in itself.
Less an average say 1 week sick. There's another 2%.
Less any workers compensation issues
Less any other sort of leave eg paternity or leave without pay
Less unfilled positions due to staff turnover for whatever reasons
Less long service leave for those who are there long enough.

End result being that if you simply must have 100 people on the job each day and can't go below that well then you need somewhere around 120 employees in order to have 100 actually turn up on any given day.

Now this is where the trouble starts.

Talk to an engineer about all that and you'll get a lot of nodding and so on even if said engineer has never given any previous thought to human resources. It's just maths and it all makes sense really.

Talk to an economist or business guru and depending on their view of the world they'll be getting all excited saying this is inefficient and must change. Can't have 120 employees to do the work of 100 that's too inefficient and so on. That might sound familiar to many.....

Same problem with power generation. You need spare capacity, 20% or so, to account for the inevitability that things can and will fail and they need maintenance. If it's all new and well maintained then you might get away with a 15% margin but if it's older then you'll need 25% due to more problems being inevitable. If the standard of maintenance and operation is less than perfect then it'll be even higher especially as plant gets older and the effects of past operation and maintenance take their toll.

That Victoria doesn't have that 20% margin, indeed its actual capacity is about 88% of historic peak demand on a stand alone basis or 94% with supply from Tas and NSW included so that's a negative reserve margin, is why it's rather precarious and any plant outage during Summer does pose a direct threat to supply.

Amidst all this, AGL have changed their mind about mothballing Torrens Island A units 1 & 2 in SA. These are old (in service since 1967) steam units originally designed to burn oil in the boilers but later converted to gas and with a capacity of 120 MW per unit. They were about to be shut in a few weeks but for the moment at least they've been given a reprieve - that's the second time they've been saved from the scrap heap now. Getting hold of enough gas is likely to be somewhat problematic at times but there's always oil as a workaround to that albeit an expensive and smelly workaround.

The TIPS A units are functional but, well, it's 1960's plant that's been run pretty hard over that time and as has been noted elsewhere it's a credit to the original designers, who did it all with pencil and paper no computers back then, that it still runs pretty much perfectly (it was run right up to 100% of its original design capabilities last Summer without any drama). It's inefficient by today's standards most certainly, technology has improved greatly since it was designed and built, but it works. There's a limit to how much more it's got left in it though - 52 years and counting is certainly getting old for steam plant.

The big trouble here is that the whole thing is seen as an ideological debate rather than a technical problem.

I've intentionally made no comment on the merits of one technology over another here and that's because the technology itself isn't the problem but rather, the use of it.

If you've got antique steam plant well then there's no real point anyone standing around acting surprised when there's a breakdown. I mean seriously - who here drives around in a 1973 car or has their 1968 washing machine still in regular use and expects it to work flawlessly day after day? Anything which runs at hundreds of degrees and high speed has a finite life that's the nature of it.

Likewise there's no point anyone blaming the machinery or its original designers and builders if it fails due to poor operating and maintenance practices. That's a fault of one lot of humans who ignored the other humans saying there was a need to check things with the machine, it's not the fault of the machine itself that it needs maintenance otherwise it breaks.

No point blaming genuine bad luck for causing a problem when anyone with knowledge knows that bad things do happen and that there's a need to be prepared hence the spare capacity. Every grid in the world, at least in developed countries, was designed with that in mind. Heck there's even a completely fictional novel, written by a fiction author not an engineer, based around the concept and that book's 40 or so years old.

Likewise no point in blaming something brand new like a battery if the humans choose to run it flat before its needed, meaning it can't do anything when it needs to.

And so on.

As with investing and trading, if you want it to work then stick to facts and maths not ideology and politics.

 

[sptrawler]

Smurf, I was of the understanding that you understood that all we need is some more renewables and storage, I mean you do seem to have a grasp of the situation whats the problem ffs. Lol

 

[Smurf1976]

I mean you do seem to have a grasp of the situation whats the problem ffs.

Lack of common sense is the problem but that extends far beyond issues of power supply and covers rather a lot of things.

Coal is bad they tell us. Meanwhile there's people posing for the perfect "selfie" at an ash dump:

https://www.news.com.au/travel/trav...e/news-story/9c84e6bd6ae44a8e0158babe66e96fa4

I've seen enough politics to regard most of it, from all sides, as a load of nonsense really. If the people in those photos knew it was coal ash then they'd be running away in horror and then wondering why the lake isn't black.

Public debate on all scientific matters has simply become far too lightweight, lacking in detail and centred around ideological "beliefs" rather than any actual science and that's the ultimate cause of rather a lot of problems from the energy situation through to households being in so much debt.

We're living in a more technologically complex world than ever and yet somehow we've managed to produce a general public which seems incapable of applying high school level maths and science in their thought processes and actually thinking.

 

[qldfrog]

Can not say it better, and that public or its representatives is in control and make laws
How can Putin and Xi not be ROL.

 

[SirRumpole]

On the question of storage, a few comments:

So far as dams are concerned they're absolutely a site specific thing in every way - cost, effectiveness, ecological impact.

For example the Miena dam (Great Lake) and the now demolished Lagoon Of Islands dam in Tasmania are less than 25km apart measured in a straight line.

Miena has been an outstanding success, having improved endangered species habitat as a benefit aside from that of storing water. In all honesty I've never heard even one person argue that it shouldn't have been built - even the more hard line greens don't seem to take issue with it and that's a proper big dam not something small. There's plenty of other big dams much the same - nobody with any credibility has any real objection to them on ecological grounds.

Lagoon Of Islands however, well from an environmental perspective it was the biggest failure so far as dams actually built in Tas are concerned and after half a century of trying to make it work ecologically, and building additional things like a canal to achieve that, well the Hydro finally gave up and demolished it. By "demolished' I mean that literally - it's outright gone, removed in total. Not just the water let out or the dam breached but the entire dam wall and everything associated with it has been removed completely. It's really gone.

A point about dams though is that to the extent they have an impact it's largely one that's reversible on a human time scale. If the dam is no longer required then drain the water out, revegetate the area, and within a century it'll be back almost perfect to how the area was before the dam was built. That's a point that even those who were firmly in the No Dams camp during the big debates have made in more recent times - the impact is largely a reversable one.

At the very least, the impacts of a dam are an order of magnitude more reversable than the impacts of coal mines, fossil fuel combustion, nuclear waste and so on. They beat all of those.

So far as the need for dams or other means of storage is concerned, I'll refer back to the chart of wind energy output I posted earlier.

Small pumped hydro schemes with "turkey nest" dams and/or batteries do the job of meeting daily (summer) or twice daily (winter) peak demand without difficulty so long as they can be and are recharged between those times. That's dead easy so long as the backbone of power generation is fossil fuels (or nuclear).

In a 100% renewable system however, and faced with a week long wind drought right in the middle of Winter when solar yield is at its worst and daily energy demand is high, that idea fails completely. No longer is is charge and discharge twice a day. Now it's discharge and then discharge again and keep discharging.

Wind and solar, no storage, gets to ~ one third renewable energy without any hassle at all.

It gets to about 50% with some minor shooting of itself in the foot, loss of efficiency at fossil fuel power stations, but it does get there.

Add small pumped hydro and batteries and lifting that to ~75% is pretty straightforward and all very doable.

For the remainder to work in an economical manner (note "economical" as opposed to "technical" since the economic constraint is the harsher of the two) realistically it's big hydro or it's fossil fuels.

A related issue there is that whilst peak power demand in most states peaks in summer, total energy use peaks in winter. If look at Victoria for example, well the amount of energy used for heating buildings during Winter, almost all of which is supplied from gas, exceeds the total electricity consumption of Victoria, SA and Tas combined.

Assuming the ultimate intent is to go to renewable energy, not just renewable electricity generation, then heating loads are a major consideration since it means that maximum consumption occurs at the time of year when wind and especially solar are least effective. A point that brings us straight back to big storage projects which are able to run solidly for extended periods without recharging.

In that context I'll note that the existing NSW, Vic and Tas hydro assets, with some reworking, and proposed large scale pumped storage schemes get us a long way down the road but not to the end.

More will need to be done, particularly in the 2040's, but so long as the approach toward dams is pragmatic rather than ideological it ought to be doable.

There's no need in 2019 to be contemplating building dams which flood areas of high conservation value. There was an argument there in a world where wind and solar weren't viable options, oil supplies were threatened and prices had just tripled whilst taxpayer funds weren't available to subsidise energy projects which had to be cheap and pay their own way. That was the world of 1979 but it is not the world of 2019.

On the other hand, deliberately putting the boundaries of National Parks and the like just a few meters past a dam site for no reason other than to stop it being built, the stuff worthy of conservation being downstream not upstream, is just playing politics and not at all sensible or helpful in a move toward greater sustainability. Pragmatism not ideology is what's required in all of this.

There's also the question of whether or not we're actually going to 100% renewables? Or are we going to some lower figure in practice?

If you don't like dams, you can try this system of hauling railway carriages uphill and letting them run down again.

https://www.aresnorthamerica.com/ar...il-energy-storage-using-trains-to-store-power

 

[basilio]

f you've got antique steam plant well then there's no real point anyone standing around acting surprised when there's a breakdown. I mean seriously - who here drives around in a 1973 car or has their 1968 washing machine still in regular use and expects it to work flawlessly day after day? Anything which runs at hundreds of degrees and high speed has a finite life that's the nature of it.

Likewise there's no point anyone blaming the machinery or its original designers and builders if it fails due to poor operating and maintenance practices. That's a fault of one lot of humans who ignored the other humans saying there was a need to check things with the machine, it's not the fault of the machine itself that it needs maintenance otherwise it breaks.

No point blaming genuine bad luck for causing a problem when anyone with knowledge knows that bad things do happen and that there's a need to be prepared hence the spare capacity. Every grid in the world, at least in developed countries, was designed with that in mind. Heck there's even a completely fictional novel, written by a fiction author not an engineer, based around the concept and that book's 40 or so years old.

Lets get it clear folks. An engineer like Smurf is pointing out that our coal fired power plants are well and truly run down and on the way out. Repairs are possible but expensive and probably throwing good money after bad (even if it is essential in the short term)

In 2019 the most cost effective and environmentally appropriate solution is fast tracking of cheaper, cleaner , renewable energy supplies with necessary hydro and battery back ups. And I'm sure there will be some extra items for good measure.

Trying to say we should repair old coal plant indefinitely or build new coal fired power stations flies against all economic and environmental factors.

I thought this thread was trying to take us in a constructive direction as to how we make a power grid fit for purpose in the 21st Century - not just defend old technology that has clearly passed its use by date.

 

[sptrawler]

Lets get it clear folks. An engineer like Smurf is pointing out that our coal fired power plants are well and truly run down and on the way out. Repairs are possible but expensive and probably throwing good money after bad (even if it is essential in the short term)

In 2019 the most cost effective and environmentally appropriate solution is fast tracking of cheaper, cleaner , renewable energy supplies with necessary hydro and battery back ups. And I'm sure there will be some extra items for good measure.

Trying to say we should repair old coal plant indefinitely or build new coal fired power stations flies against all economic and environmental factors.

I thought this thread was trying to take us in a constructive direction as to how we make a power grid fit for purpose in the 21st Century - not just defend old technology that has clearly passed its use by date.

I give up. Lol

 

[Humid]

https://www.smh.com.au/national/gor...mbarrassing-in-new-twist-20190711-p5269z.html

Cleaner....
This joint runs 5 gas turbines for the fridge

 

[basilio]

Lets get it clear folks. An engineer like Smurf is pointing out that our coal fired power plants are well and truly run down and on the way out. Repairs are possible but expensive and probably throwing good money after bad (even if it is essential in the short term)

In 2019 the most cost effective and environmentally appropriate solution is fast tracking of cheaper, cleaner , renewable energy supplies with necessary hydro and battery back ups. And I'm sure there will be some extra items for good measure.

Trying to say we should repair old coal plant indefinitely or build new coal fired power stations flies against all economic and environmental factors.

I thought this thread was trying to take us in a constructive direction as to how we make a power grid fit for purpose in the 21st Century - not just defend old technology that has clearly passed its use by date.

I give up. Lol

Totally understand your sentiments SP.

I mean we could reference all the (CSIRO) analysis which shows how much more cost effective new renewable energy sources are compared to coal fired stations - even when they include back up batteries.

We could talk about the rapid rate of improvement of these new technologies in terms of cost effectiveness ie 3rd gen solar cells, rapidly reducing battery costs, flow battery technology, distributed small scale hydro to store excess solar energy.

We could recognize the huge health effects of coal fired power stations through particulate pollution let alone their impact on global heating.

Maybe we can see how much water is required to cool these power stations (a VERY big amount) and ask if we can afford to use that resource so recklessly.

Perhaps we could look at the the value of a decentralized power system in terms of creating extra power redundancy across the country, increasing local employment, giving local communities an opportunity to be self sufficient in their critical energy needs.

Finally we can assess the current state of Oz's coal fired power stations and realise they are generally on their last legs and as result costing a bomb to keep operating. They will need to be replaced and given the rising maintenance costs and reliability issues isn't sooner rather than later a good idea ?

In fact I think this thread has covered all of these bases. But as you say so eloquently "LOL".

You can take a horse to water but you can't make him drink.

 

[Smurf1976]

Amidst all this, AGL have changed their mind about mothballing Torrens Island A units 1 & 2 in SA.

A minor error on my part there - the plan was to mothball 2 x 120 MW units but they were numbers 2 & 4 not 1 & 2.

There's 4 x 120 MW at Torrens Island A commissioned 1967 - 70 and 4 x 200 MW at Torrens Island B commissioned progressively 1977 - early 80's.

All "A" units were built to fire oil and later converted to gas. B units 1 & 2 are gas only, B 3 & 4 are gas or oil (and can switch between them whilst remaining fully operational) and were built with provision for the addition of coal firing although that was never done (that is, the coal handling equipment etc was never installed so not one piece of coal has ever been used, but the boilers and site layout were designed to allow for it to be easily added if required).

At present only B1 and B4 are running and both at about 60 MW each so 30% of capacity, the rest are idle, due to high wind generation and low demand in SA. In that role they're primarily providing stability to the system (aka system strength) with their actual output being incidental to that role.

This facility was originally built by the Electricity Trust of SA, that is the state government, and is now owned by AGL.

Photo (not mine) for those interested: https://pbs.twimg.com/media/CGoU0lRUQAIiv3a.jpg

 

[sptrawler]

Totally understand your sentiments SP.

I mean we could reference all the (CSIRO) analysis which shows how much more cost effective new renewable energy sources are compared to coal fired stations - even when they include back up batteries.

We could talk about the rapid rate of improvement of these new technologies in terms of cost effectiveness ie 3rd gen solar cells, rapidly reducing battery costs, flow battery technology, distributed small scale hydro to store excess solar energy.

We could recognize the huge health effects of coal fired power stations through particulate pollution let alone their impact on global heating.

Maybe we can see how much water is required to cool these power stations (a VERY big amount) and ask if we can afford to use that resource so recklessly.

Perhaps we could look at the the value of a decentralized power system in terms of creating extra power redundancy across the country, increasing local employment, giving local communities an opportunity to be self sufficient in their critical energy needs.

Finally we can assess the current state of Oz's coal fired power stations and realise they are generally on their last legs and as result costing a bomb to keep operating. They will need to be replaced and given the rising maintenance costs and reliability issues isn't sooner rather than later a good idea ?

In fact I think this thread has covered all of these bases. But as you say so eloquently "LOL".

You can take a horse to water but you can't make him drink.

Well obviously there is nothing to worry about then.

 

[qldfrog]

@basilio, do you really not understand that the problem is NOT cost or even sheer amount of energy produced overall but stability of the system?
How many more reports Smurf need to write on that thread?

 

[Smurf1976]

I'm intentionally staying out of politics but so far as matters of politics, the environment and so on are concerned I will simply say:

*CO2 is a real problem so far as I can determine based on all I've read on the subject. It's a theory that's well understood and goes back at least to the 1890's and possibly earlier (the oldest reference to it that I've personally seen and able to verify as legitimately from that time is from 1890).

*There are other issues with nature, wilderness etc some of which are legitimate and some of which are pure politics for the sake of politics.

*We live in a society which absolutely depends on large scale energy supply. Without that, it is not an exaggeration by any means to say that a substantial portion of those living in the major cities would in practice die of starvation or thirst within a relatively short period. No electricity = no water pretty quickly. No diesel = no food.

*There are credible threats to the supply of electricity, gas and liquid fuels including diesel in Australia in the short to medium term. A crisis with any of those could plausibly occur in the near future - there's no certainty that it will but the risk is real and the consequences extremely serious if it did occur.

*Alternative technologies based on resources other than fossil fuels or nuclear most certainly can work from a technical perspective so long as they are properly applied. This is beyond doubt and for anyone who does doubt it, well you might be rather surprised to find that the hydro and mining industries both make use of solar themselves, including in some critical applications.

*Much of the public debate centres around politics and point scoring rather than anything factual and that applies to all sides. There are those on the engineering or related side who deny the existence of environmental concerns and there are those on the environmental side who simply refuse to accept fundamental physics as true. Neither are much help in moving forward and there are some well known individuals in that category.

As a more specific list of problems being faced in Australia at present:

*Liquid fuel stockpiles are well under the level agreed with the International Energy Agency as being necessary and which Australia is formally obligated to hold. This affects all states and territories.

*Developed sources of natural gas supplying NSW, ACT, Vic, Tas and SA are rapidly reaching exhaustion and a serious supply shortfall is expected from approximately 2024 onward at the latest, with some risks prior to that.

*Dispatchable electricity generating capacity is inadequate across NSW, ACT, Vic and SA if the objective is to maintain a reliable supply at all times.

*A considerable portion of the existing generation fleet in these states is approaching end of life in the foreseeable future. As such, failures are more likely and ultimately this capacity will (must) close in much the same way as ultimately you and I will (must) die.

*A consequence of insufficient and increasingly unreliable generation is a loss of ability to manage fuel supplies effectively across the fleet, with unintended levels of operation being required at some facilities in order to maintain supply leading to vastly more fuel and/or water being used than was intended and problems with obtaining that.

*Cutting across all of this, an economic problem with electricity and gas prices now being relatively high by global standards versus second (gas) or third (electricity) cheapest among developed countries a quarter century ago.

*The CO2 emissions issue also cuts across all of the above and needs no further explanation.

Putting all that together, there's a need for change but it's a need for change which involves building first, proving second and demolishing third not the reverse and doing so in a very timely manner.

That I've given up on the political aspects is because politics seems incapable of achieving any of the above, indeed it's an obstacle to most of it.

 

[sptrawler]

It will come to a head and then the emotion and politics will be stripped away, the truth will then have to be accepted and technical realities will prevail.
Therefore in a lot of ways the problem will be self resolving. IMO

 

[Smurf1976]

@basilio, do you really not understand that the problem is NOT cost or even sheer amount of energy produced overall but stability of the system?
How many more reports Smurf need to write on that thread?

It comes down to multiple parameters all of which need to be met in order for it to work.

Energy, that is power x time, is one and there are lots of ways to do that. Wind, solar, coal, conventional hydro, gas, nuclear, oil etc all do that. Pumped hydro and batteries can not do this however.

Dispatchable power, that is the ability to match input to the grid with load in real time, requires that generating plant can ramp up and down accordingly. In order to do so it needs to have access to an energy source available in real time as required. Coal, conventional or pumped hydro, gas, nuclear, oil or batteries can all do this. Wind and solar cannot directly do this, they can only do it indirectly as the energy source for pumped hydro or batteries (or other methods of storage like running trains up hills etc). Or they can do it crudely when the sun is shining / wind is blowing by simply wasting some of their potential output - but they can only do that so long as the sun / wind doesn't drop below the required level and trouble is that happens extremely often.

System strength, that is a generic term encompassing serious power engineering aspects, requires that generating plant can in real time control frequency and voltage plus deliver high fault currents as required. An inverter and battery system can do part of that but struggles with the fault current. Synchronous condensers can handle the voltage and fault currents but don't add any energy. Big rotating synchronous machines driven by steam / hydro / gas turbines or diesel engines can do the lot. Wind and solar, of themselves, aren't much help hence the situation in SA where wind generation is off loaded at times and gas-fired plant directed to run despite losing money - that's for system strength not because AEMO likes burning gas.

Now if the aim is to have a system which doesn't require fossil fuels then it can be built certainly. Just needs lots of wind and solar, lots of energy storage, big synchronous machines (hydro) and big inverters (batteries) and a sufficient transmission grid and it will all work yes.

Where it goes wrong is when I hear people claiming that building 3000 MW of wind farms in Victoria is somehow replacing the 1500 MW Yallourn power station since both will produce a similar energy output over a 12 month period. Same energy yes but the wind farms aren't adding much dispatchable power at all and do nothing much for system strength either. As such, those wind farms are not actually a replacement for Yallourn.

Now if someone built 1500 MW of large scale pumped hydro to go with the wind farms and put some synchronous condensers in the network in appropriate places well then that's now a replacement. It also works if some (note "some" not "all") of that hydro is replaced with batteries so long as they're big enough.

What I hear a lot of though is akin to suggesting that a truck load of bricks and roof tiles is a replacement for a house. It's a replacement for the bricks and tiles which comprise a house yes but with no framework, ceilings, plumbing, floors and so on it's not an actual replacement for a house it's only part of what's needed to build one.

In saying all that, there's no choice but to ultimately make renewable sources work for the simple reason that's in the name. They're renewable whereas fossils are finite even without considering the CO2 problem. So it has to happen, and it can be done, but we need to build the complete house before knocking the old one down (or having it fall down of its own accord), we can't just dump a few pallets of bricks and tiles on the site and say there's your house.

 

[Macquack]

Loy Yang A unit 2 - major damage requires a complete rewind of the alternator, at a cost of $57 million, to repair. AGL has awarded a contract to GE Power Australia to perform this work.

Geez, that's a lot of money for a alternator repair. Can't they get a cheaper Chinese exchange unit off ebay?

 

[SirRumpole]

In saying all that, there's no choice but to ultimately make renewable sources work for the simple reason that's in the name. They're renewable whereas fossils are finite even without considering the CO2 problem. So it has to happen, and it can be done, but we need to build the complete house before knocking the old one down (or having it fall down of its own accord), we can't just dump a few pallets of bricks and tiles on the site and say there's your house.

I really hope that there is someone like you giving advice to the government and I really, really hope that they are listening.