Future of the Australian Electricity Market

[Bushmiller]

The report on the Callide C4 damage (nearly three years ago now) has been released.

CS Energy releases technical report into 2021 Unit C4 incident - CS Energy

Regards
Paul

[Warb]

The hype around an electric vehicle not making a pleasant sound, the lack of charging stations, the time taken to charge etc. are all either ludicrous or surmountable and are largely thrown into the debate because of prejudice, self interest or, mostly, reluctance to change.

I must admit that I do like the sound of a sporty petrol engine, but it wouldn't stop me buying an EV. Apparently I'm not alone in that "like", because I saw an ad for an EV yesterday on the TV, and I'm sure I heard an engine sound when the "sporty" version was on the screen.

There are additional issues that worry people, me included. Firstly, and this also applies to some modern ICE cars, what is the longevity of these machines? It costs a lot to buy one, but at what point does it become worthless, or at least start to require big $ spends to keep it on the road? This, of course, also applies to anything else where single components like computers cost more than the vehicle is worth. I know the theory that third party companies will make replacements, but I also know that this doesn't always happen - a friend had to write off a John Deere tractor after a small engine bay fire (itself due to poor design of fuel lines) because the electronics got toasted and they cost more than was economical to repair. I've also seen the lengths that some companies go to in order to prevent third party products being used. Then, of course, there's the problem that it requires enough market volume to warrant a third party even bothering! I have read that in the US, an EV drops 60% of its value in the first three years. Unfortunately it's hard to compare that to anything else, given that we're only just recovering from the post-covid shortages where 3-year-old cars cost more than new ones, because you couldn't actually buy a new car!

Depending on the individual, another big issue is design. There are some very attractive EV's out there, but also some seriously unattractive ones!

I think the amount of tech can also be off-putting, though that also applies to some modern ICE cars. I picked my (ICE) car up from a service yesterday, and they'd upgraded the firmware. I no longer had a speedo on the dashboard, only on the HUD (which after a year I still haven't really got accustomed to using), and various other "features" were set differently from how I left them. When added to the raft of features disabled for the Australian market (but still in the manual, so you get excited and then find you can't use them) or designed for other markets where the rules, roads and driving styles are very different from Australia, there's a certain desire to return to a car that has simple buttons and does what you tell it, rather than you having to fight the steering wheel to avoid an enormous pot-hole because the car is trying to "lane assist"......

On the other hand, I do like the EV mode on my wife's hybrid - you can sneak up on people in carparks!

[BobL]

It acknowledges problems, particularly around refueling, but there I think back to the early days of the ICE. I think I read that fuel was obtained from the local pharmacy until fuel stations abounded. It also concludes that H2 will not be for every application even if it is adopted, but seems more likely for heavier goods vehicles and coincidentally that seems an application which tests the limits of CURRENT batteries.

Due to thermodynamics H as a transport fuel is unlikely to be much more efficient than it is today.
OTOH Batteries as a technology are likely to have some way to go.
Existing batteries are already used in delivery vans, light trucks, mining machinery and even trains.
The one thing that existing batteries still cannot do easily is compete with long distance haulage trucks although the Tesla Semi is already producing some surprising long range performances. The weak link with long range electric road haulage is the need for specialised very high wattage (ie 750kW) re-charging systems but these are on par with the cost and amount of tech required for H transport but once built won't need to continually require fuel delivered to them.

Interesting article heR bout how Pepsi in the US is using electric Trucks to haul up to 22.5 tons of product
Pepsi Reveals Everything About The Tesla Semi Trucks | NextBigFuture.com
In the same article there's also a list of other large electric trucks undergoing testing.

[Chief Tiff]

The report on the Callide C4 damage (nearly three years ago now) has been released

That was fascinating to watch; clearly explaining the cascading failure events. What I don’t understand though is why the DC interconnector wasn’t immediately re-closed to restore DC power from Station battery to C4; that would have allowed the emergency generator supply interconnector breakers to close restoring critical AC power to the C4 auxilliaries.

The animation showed the DC interconnector being a big-arsed hand operated switch; do you think that is an accurate representation? Certainly if I opened a hand switch and the lights went out I’d be somewhat tempted to close it again rather sharpish…. with it being DC I wouldn’t have to worry about phase alignment…

[GraemeCook]

For commercial transport, you require abundant energy to drag a 55tonne B-double hundreds of kilometres across the country, and you can't sit around waiting for it to recharge.
....
a friend tells me that a B-Double drinks about 80l/100km

A friend has quoted 100l/100kms. Same ball park.

One "solution" might be that B-doubles become B-two and a half's, towing a smallish battery trailer, which they drop off every 500 kms and replace with a fully charged one.
But how do you recharge a B-battery trailer out the back of woop-woop, with a diesel generator?

And I don't think hydrogen is sufficiently compact or safe for long distance haulage. Doesn't liquefy like LPG, doesn't dissolve like acetylene, not compact like diesel.

But we might seem an entirely different solution. Long distance haulage might revert to ships and trains which are cost effective when they do not have to compete with heavily subsidised semis.

[Bushmiller]

And I don't think hydrogen is sufficiently compact or safe for long distance haulage. Doesn't liquefy like LPG, doesn't dissolve like acetylene, not compact like diesel.

Graeme

The transport issue might not be as dire as you imagine. We used to get our H2 delivered from Brisbane (200Km). Now it comes from Orange (not the fruit ) which is about 800Km. In the future I could envisage H2 plants cropping up all over the place.

Transportation may becomes less of an issue than moving petrol and diesel around all over the country. Large Depots could conceivably have their own H2 making plants. You only require electricity and water for the raw materials. A lot easier in some regards than an oil refinery.

Regards
Paul

[Bushmiller]

That was fascinating to watch; clearly explaining the cascading failure events. What I don’t understand though is why the DC interconnector wasn’t immediately re-closed to restore DC power from Station battery to C4; that would have allowed the emergency generator supply interconnector breakers to close restoring critical AC power to the C4 auxilliaries.

The animation showed the DC interconnector being a big-arsed hand operated switch; do you think that is an accurate representation? Certainly if I opened a hand switch and the lights went out I’d be somewhat tempted to close it again rather sharpish…. with it being DC I wouldn’t have to worry about phase alignment…

Chief

I only viewed the link after I had posted. I don't think it is the final appraisal of the sequence of events. There is still a further investigation to occur and, of course, the animation is a little sanitised and probably doesn't convey the sheer terror of the moment. However, I agree with you that it was a pretty good explanation and there were at least two levels of emergency back up that failed them. The first being the C4 battery itself (wasn't connected yet, which was very unfortunate but they could not have two batteries in parallel) and the second being the Emergency Diesel Generator that ran but couldn't be connected to the unit. Both these are usually designed to keep essential auxiliaries running during times of crisis.

As to reversing the throw of that isolator connecting the standby DC charger from C4, I would need to know more about what indication there might have been in the switch room. Were the people doing the switching aware that everything had gone pear shaped? The people switching should have been in communication with the control room, the control screens went blank and for some while they would not have known where they were except the alarm screen was still working and it had just gone ballistic. Perhaps the people switching were waiting for the DC charger to "pick up" the load and were unaware that it was incapable of doing this.

I am not sure how or when the reality dawned on them as to what what had happened. The alarms would have alerted them to being in deep excrement. It would have been truly frightening. If we lose even a single screen here, we freak out: The loss of all screens except the alarm screen would have been a nightmare. Clearly they realised they had lost control of the unit except it hadn't tripped, which was the fundamental problem, as they initiated a site evacuation and I think the other units were all tripped manually. This enabled everybody to exit except for a skeleton crew of operators to supervise the safe shutdown of the remaining units and another couple to ponder the C4 dilemma. I am guessing the numbers there from what we would do.

The surprising thing is that this was the third battery charger to be upgraded and returned to service. They had already replaced two chargers and this situation did not arise before. Something must have been done differently. For example, was the time between running the two chargers in parallel (station and C4) and opening off the station charger isolator longer? Did that allow the C4 charger voltage to decay too low and consequently fail when it was required to pick up the charging regime? Was anybody aware that could potentially happen.

I guess there is still more to come out of the investigations. There is also a question, and this was not raised in the animation at all, as to whether Powerlink was asked to disconnect their circuit breaker in the switchyard. That may have prevented the generator motoring at 50MW for some of the time. Clearly there would have been extensive damage still with the bearings wiped and significant rubbing and other heat related distortion, but not as bad as eventuated.

My impression is that this system was a so-called UPS (uninterruptible power supply), but I have seen in the past at other places that it is far from uninterruptible. So still some questions, but a very informative video.

Regards
Paul

[Warb]

A friend has quoted 100l/100kms. Same ball park.

It probably varies with route and driving style, and they drink more at higher speeds - I've seen figures as poor as 160l/100km quoted. The guy I was talking to has several trucks and we were discussing a brand new one he's just got specifically for long distance hauling of (if I remember correctly) bitumen. The conversation also included the fact that the new truck had a tare weight of 3tonne or so less than his Western Star, which means he can carry 3T more load, which makes $x more per trip and pays the loan off y months earlier. I don't remember the details, but he'd gone through it quite thoroughly!

But we might seem an entirely different solution. Long distance haulage might revert to ships and trains which are cost effective when they do not have to compete with heavily subsidised semis.

I've always thought that a return to trains for long distance work would be the best solution, but there's so much money tied up in the haulage industry that it's another issue where there would be a lot of resistance to change on that scale.

[twosheds]

Re Callide C4

From an outsider with no knowledge of the industry one thing struck me immediately as I watched the animation. It stated the ACS (which I assume is a last ditch type of failsafe mechanism) had been damaged in a previous incident and was inoperable. Then nothing further was mentioned about this switch. If this damage to the ACS was known, why it had not been repaired or replaced prior to the maintenance on C4 DC system being completed. Am I correct in thinking that had this ACS operated at the time the destruction of the generator may have been averted?

Your thoughts from those more knowledgeable?

Twosheds

[BobL]

Transportation may becomes less of an issue than moving petrol and diesel around all over the country. Large Depots could conceivably have their own H2 making plants. You only require electricity and water for the raw materials. A lot easier in some regards than an oil refinery.

Humm . . . . if electrical power is being generated to make H, why not put it straight into a swappable battery?
People make out that making H is a doddle and this is indeed the case making small amounts on a lab bench. Making it to scale is a different proposition, the large H plant in Melb can only make enough H for 6 regular cars, or about one truck a day. To scale that up to say 6000 cars a day requires a very large plant

Check out this large battery swapping operation for Sandvik underground mining equipment


Technology enabling electrification journey


Here's a 620kWh swappable battery, semi development in Sydney - 90 ton haulage.
This is already being used for local/regional deliveries

[havabeer69]

I guess there is still more to come out of the investigations. There is also a question, and this was not raised in the animation at all, as to whether Powerlink was asked to disconnect their circuit breaker in the switchyard. That may have prevented the generator motoring at 50MW for some of the time. Clearly there would have been extensive damage still with the bearings wiped and significant rubbing and other heat related distortion, but not as bad as eventuated.
Regards
Paul

I thought it was answered in the video.

they didn't want do disconnect from the grid and cause an overspeed event from all the left over steam? I also wonder if in that last few minutes no one really knew what the machine was doing and so making the call to disconnect from the grid. As you could imagine 5 minutes of that big orange thing clanging and grinding away would be scary as hell in the PCR

[Bushmiller]

I thought it was answered in the video.

they didn't want do disconnect from the grid and cause an overspeed event from all the left over steam? I also wonder if in that last few minutes no one really knew what the machine was doing and so making the call to disconnect from the grid. As you could imagine 5 minutes of that big orange thing clanging and grinding away would be scary as hell in the PCR

HAB

I think they did answer. I was watching the link at work as one of our managers sent us the link for information. It has some extra significance for us at Millmerran as our holding company is the IG (Intergen) mentioned in the JV (Joint Venture). It is a financial involvement as CS Energy operate the plant on behalf of IG. I do have to be mindful that some information is sensitive and consequently I am only divulging details you can find on the net and within those links. Also my role at Millmerran has no involvement with Callide. While I was watching I got called away to attend an ash crusher blockage on the other unit (not mine) and missed that part as a result. I may also have interpreted, not necessarily correctly, some other information I had.

At this point I should reiterate that it would have been the most horrendous situation I can imagine and my heart goes out to the operators who remained to deal with the catastrophe during those 34minutes. Also, I would remind everybody that hindsight is a wonderful thing. There are no doubt things that could have been done differently. Who has seen "Sully?" The movie about landing a plane on the Hudson river.

Just before I continue, there are another couple of articles available. This is a press conference held on 13 Feb 2024:

CS Energy press conference - C4 tech findings - 13 Feb 2024.m4a (dropbox.com)

and this is a more detailed report, on which the animated video is based. The timeline is quite interesting.

CSE C4 TURBINE REPORT FINAL.pdf

HAB has touched on the ever-present bad dream of all operators, which is a turbine overspeed. Although a physically large lump of machinery, a turbo generator spins very easily and not much energy, in the form of steam, is required to get it moving. The usual technique of disconnecting a machine from the grid is to reduce load until the machine is making either no load or very little load (a small amount is being consumed by the unit's own auxiliaries) and an alarm is created "Generator Motoring." At that point it will either trip automatically or it can be tripped manually. Before that happens it is important that the steam valves shut. There may be two pairs of stop and control valves or four pairs of valves. If the generator continues to make power and the "Motoring" alarm doesn't initiate it means one or more valves are leaking steam. Under those conditions you must not disconnect from the grid via the GCB (Generator Circuit Breaker). If you do, the turbine is no longer physically held by the grid at 3000rpm and it will overspeed.

In the case of C4, loss of AC and hydraulic power would cause the stop and control v/vs to slam shut. Back in the control room they couldn't be sure if the v/vs had shut because they had lost all indication with the screens being down. This was referred to in the press conference as being "black." Consequently they were hesitant in asking Power Link to disconnect them from the switchyard.

Even if they could ascertain it was safe to disconnect from the grid, they had lost all remote control and would have had to go to the GCB locally and tripped it manually. That would have been really scary and very, very inadvisable.

The incident would not have occurred if when the Battery Chargers were separated, the voltage on C4 was higher than the station charger. I guess that when the two previous chargers were replaced (C3 and the Station) the relevant battery had the higher voltage and the incident slipped by. In this incident "all the holes in the cheese lined up."

Regards
Paul

[havabeer69]

yeah to help clear up millers post

putting the generator onto the "grid" acts like a huge big electric handbrake on the generator/turbine so if you need to make more mega watts, you need to over come the big electric force so the answer is more steam pressure.


the problem is, if you suddenly take the grid handbrake away BUT all that steam pressure is still available for use (stop and throttle valves not closed) it will just full send the turbine, there's no brake or anything you can apply either. 90tons of steel with blades already spinning at speeds like mach2 is just free to launch its self. It's actually quite a real danger and there are other mechanical safety devices in place to top this happening.

[GraemeCook]

Humm . . . . if electrical power is being generated to make H, why not put it straight into a swappable battery?

Makes a lot of sense, Bob. Possibly, they could also be connected to the grid during peak demand periods.

PS: Swappable batteries are a better idea than my battery trailer. Just like swapping BBQ bottles, only faster.

[Bushmiller]

It's actually quite a real danger and there are other mechanical safety devices in place to top this happening.

HAB

Thanks. I like your analogy and in fact I often use automotive analogies to describe what is happening in both the boiler and the turbine.

Absolutely, but if the DCS control has been removed maybe not. At Bayswater there were both mechanical and electrical overspeed trips, but at Callide, with both electrical and mechanical systems out of service the operators had an unenviable dilemma. The steam valves were shut as it happens, but they could not really tell for sure.

I hope to retire before I ever find myself in that position.

Regards
Paul

PS: I am not sure the blades reach twice the speed of sound or else we would have a continuous sonic boom occurring, but the tip speed is awfully bloody fast and possibly just under the speed of sound. It is why the 660MW units at Vales Point and Bayswater have two LP cylinders. Otherwise, the blades with just a single cylinder would have to be too long, be rotating too fast and be exerting significantly increased centrifugal forces. As it is when turbines overspeed their longest blades (LP cylinder) may let go. The 60Hz units as seen in the US tend to be longer (in the case of the generator) and slimmer as they run at what would be above (3600rpm) the overspeed trip point of the Australian units.