Thread: Katoomba Monthly Temp average set to be SMASHED!!! AGAIN!!!

On the 7th February I posted

Originally Posted by FenceFurniture

We have four quite distinct seasons up here, and the change from summer to autumn is usually the most noticeable of them. There is usually a period of a week around end of Feb to early March when it is quite apparent that Summer is over. (quoted some temps etc...)

Right now it's a little too early to tell but we may well be going through that period from last Monday through to the end of next week - which would make that seasonal change 3 weeks early.

Since then we have had 1 day >25° and only 4 days >23°. On the other end of the scale we have had 7 days <20° for Feb.

The monthly average is currently 0.4° lower than the long term average, and in fact if the first two days of Feb are taken out, the the current monthly average would be more than 1.5° lower than the long term.



So this...

Originally Posted by woodPixel

FenceFurniture, those low temperatures are from Mother Nature to lull you into a sense of summers completion. She will come back in a fortnight and brutally mug you with cudgels. You will rue those words of finality

....didn't happen. No cudgelling

It's a very early Autumn, and thank gawd fer that!

Originally Posted by markkr

Brown Brett, utterly brown.

Mark, I imagine that has swung back t'other way again?

Originally Posted by ian

Tassie has a wind resource as good as, perhaps greater than, that in WA.
The distance of an undersea DC connector from Tassie is an order of magnitude shorter than that required for one connecting WA with Victoria or NSW.

....

Do we need both?
You betcha, PLUS Snowy 2.

I expect we will eventually have elements of all of the options we have raised. The cost-benefits will sort that out, skewed as always with a dose of political and other self interest.

I expect Tassie's 'water batteries' will be the impetus for an upgrade to their interconnector(s), but doubt that their wind resources will be a factor in that.

Yes, their west coast has one of the best wind potentials.

Wind map of Australia.jpg

But, that west coast is also where there is the greatest density of wilderness and a world heritage listing.

Tas by satellite.jpg

The inland ridges along that west coast are never going to be available for wind farms. Unless located offshore, it is never going to happen.

Whether economic or not, the coastal strip along the south coast of the mainland has the most potential for the further development of wind power. An east-west interconnector would be necessary to unlock the WA end of that.

I see us getting a little starry eyed over Tasmanian Hydro power. These are a few details on the DC link from Wikepedia:

Basslink - Wikipedia

and a bit more information about DC links in Australia including the Basslink line.

3 awesome HVDC projects in Australia you should know about | EEP

It occurs to me that we have discussed the cost of transmission lines on this thread and whether that was a relevant issue to consider. When Basslink was commissioned in 2005 the cost was in excess of $800m,a blowout from the original estimate of $500m. Interesting to note how much it costs to use the services of the line. Remember this is just the line and represents more than half as much as it would cost to build a power station of the same capacity.

I would also repeat that the connector was designed to supply security for Tasmania in case they suffered a drought more than to export power to the mainland. The fact that they can, and do, export power back to the mainland is a side benefit, but not it's primary purpose.

It also seems to me ridiculous to consider extra DC interconnectors unless similar quantities of dam storage were built or at least similar dams were available. I had not realised, until I read the articles above, that the existing line is privately owned. So that again begs the question of who would put money up for a new line particularly bearing in mind there may be no water to go with it?

I believe it is a mistake to fancifully state we will just put something here or there without examining the practicalities. Sorry to seem negative, but we had an extremely stressful day at the office yesterday (nearly losing the unit on several occasions) and my pragmatic side has aligned with the new moon.

Regards
Paul

Originally Posted by Bushmiller

we had an extremely stressful day at the office yesterday (nearly losing the unit on several occasions)

Please explain?

Originally Posted by Bushmiller

It also seems to me ridiculous to consider extra DC interconnectors unless similar quantities of dam storage were built or at least similar dams were available.

Having lived through the resistance to a Gordon below Franklindam, I'm confident that no further dams will be built anywhere in the wilderness west coast area of Tasmania.

Pumped hydro may still be a possibility with the existing dams, if the economics of that stacks up.

Originally Posted by FenceFurniture

Please explain?

Brett

Glad to explain. This region has been in a drought for at least two years but in the last month it has rained at last. Some areas have had up to 200mm in this period. This is not drought breaking rain as the moisture levels are not more than 100mm down in the ground in most areas, but it is enough to disrupt coal supplies to our boilers.

The first potential disruption is to delivery of the coal from the mine up a steep incline coal conveyor to the coal silos located inside the boiler structure at the very top of the station. During heavy rain the coal slides back down the belt or alternatively belt can slip on the drive roller. In either instance there is an interruption to coal supply and eventually we have no fuel. However this was not the problem yesterday.

The silos capable of holding in excess of 600 tons each, feed coal feeders which deliver coal to the mill at a measured rate. In our case at up to 65 tons per hour. We have five mills for each unit, but usually run with four mills only. Yesterday we had five mills in service for extra security. The problem is that our coal has a high ash content and a a large clay component. During wet conditions the coal becomes sticky and hangs up in the tubes that run to the feeders. Now there is no coal to that mill.

This happened to us on my unit several time yesterday and on one occasion we lost three feeders in quick succession. This disrupts everything. Fuel/air ratios go ballistic, we are unable to maintain load of course and the unit starts throttling itself back (runback). In short the unit becomes unstable and may trip. If that sounds dramatic, a similar scenario about ten days ago caused us to lose this same unit (tripped on high steam temperature, which had become uncontrollable). Last Friday another wet coal event caused the other unit to trip. We took extreme precautions yesterday and lived to tell the tale without the associated red face.

Regards
Paul

Originally Posted by Bushmiller

The problem is that our coal has a high ash content and a a large clay component.

So at a guess, it wasn't a piece of Millmerran coal that SmoKo and Banarnaby Beetrooter were tossing around the Parliament? More likely it was a piece of the (apparently) world renowned Tahmoor Steaming/Coking Coal from the Southern Highlands (NSW). Closer to the Canberra Bubble too.

Originally Posted by NeilS

Having lived through the resistance to a Gordon below Franklindam, I'm confident that no further dams will be built anywhere in the wilderness west coast area of Tasmania.

Pumped hydro may still be a possibility with the existing dams, if the economics of that stacks up.

Neil

I am pleased you have referenced the economics as that is so important in today's electricity market. In fact my command of the language is unable to stress sufficiently the place it occupies since privatisation of the industry has progressively taken place.

Pumped hydro still comes at a price. If a daytime average price is $70/$80 per MWhr and the night time average may be $40 per MWhr the revenue is potentially back to $40 per MWhr. However that assumes you can pump back up the hill at an economic rate. I don't know the detail here and would be glad to take advice from somebody who knows but I suspect that it takes more than 1MW to pump 1MW of water back to the storage dam. If that is the case, and I am almost certain it would be, it is only during really elevated prices that it would become economic to release water. In a way that is exactly the intent, but the power plant owners wish to make money. They can only do this with a continued supply of electricity. The occasional high price does not keep you in business.

Something else that comes to mind that I have probably touched on before is that all the fossil fired stations enter into contracts for fixed prices with the major players. They can do this because their supplies are reliable. Major players do this so that they are not hit with astronomical bills. However, this may not be available to the "renewable resources," or at least to the same extent. The reason is that if you are unable to supply the power you have to buy it in at the market price, which may be extreme (maybe enough to bankrupt you). At any one time the "spot" price, which is the one that everybody quotes, only reflects a percentage of the demand. How much is that percentage? Nobody knows because it is confidential. Even at our station I don't know how much is contracted, although I can make an informed guess.

I would guess that in the general market at any one time up to 30% or even 40% could be under contract.

Regards
Paul

Originally Posted by FenceFurniture

So at a guess, it wasn't a piece of Millmerran coal that SmoKo and Banarnaby Beetrooter were tossing around the Parliament? More likely it was a piece of the (apparently) world renowned Tahmoor Steaming/Coking Coal from the Southern Highlands (NSW). Closer to the Canberra Bubble too.

Brett

You are correct. I have no idea where Smoko and Beetrooter's coal came from but, despite not being a gambling man (don't bet even on the Melbourne Cup) I would lay my life on the line that it was not our coal. Power stations burn rubbish coal. Export coal is good quality stuff.

As this thread has morphed into a significant information site, this is a link to coal qualities (an Indian ref)

Coal Grades | Ministry of Coal, Government of India

I think our coal is about 32% ash at best and sometimes a lot worse, but I just burn what they give me.

Regards
Paul

It must have been the Coalitions mythical Clean Coal, as it left not a single black mark or speck of dust on a single hand.

Perhaps it was coated in shellac or a polyurethane from a spray can (propelled by CO2! hahahah! The irony).

Originally Posted by Bushmiller

The silos capable of holding in excess of 600 tons each, feed coal feeders which deliver coal to the mill at a measured rate. In our case at up to 65 tons per hour. We have five mills for each unit, but usually run with four mills only. Yesterday we had five mills in service for extra security. The problem is that our coal has a high ash content and a a large clay component. During wet conditions the coal becomes sticky and hangs up in the tubes that run to the feeders. Now there is no coal to that mill.

This happened to us on my unit several time yesterday and on one occasion we lost three feeders in quick succession. This disrupts everything. Fuel/air ratios go ballistic, we are unable to maintain load of course and the unit starts throttling itself back (runback). In short the unit becomes unstable and may trip. If that sounds dramatic, a similar scenario about ten days ago caused us to lose this same unit (tripped on high steam temperature, which had become uncontrollable). Last Friday another wet coal event caused the other unit to trip. We took extreme precautions yesterday and lived to tell the tale without the associated red face.

(I am being a bit facetious here )

Base Load Coal that can be stopped when it rains... 'cos wind, hydro and solar are stopped by their own lack of inputs

The last para sounds a bit like Fukushima or Chernobyl



(Sorry, I'm feeling rather jolly today!)

Originally Posted by woodPixel

(I am being a bit factious here )

Base Load Coal that can be stopped when it rains... 'cos wind, hydro and solar are stopped by their own lack of inputs

The last para sounds a bit like Fukushima or Chernobyl



(Sorry, I'm feeling rather jolly today!)

WP

I accept your facetious comments in the vein they were intended. A jolly good tale.

It is in some respects the result of privatisation of the industry. I had better elaborate on that before Brett chips in with a Pauline Hansonism (please explain?).

Millmerran power station while being the second most efficient (and consequently second cleanest too, albeit still dirty) was built on a budget and cost $1.4b back in 2002. There were many, many aspects that had been cost cut and millions were spent in the early days to upgrade the station to a workable level.

One of the early problems was this issue of the tubes connecting the coal silos (also referred to as coal bunkers) and the coal feeders. In those early days when the coal hung up in the feeder tubes we rushed out to the feeder and flogged the proverbial excrement out of them with sledge hammers until the coal fell. At times we actually employed people on contract to do only this if we had been able to predict the likelihood of rain. That was OK as it kept us online. Problem was we dented and damaged the tubes and the coal sliding past the dents over long periods of time wore holes in the tubes.

So a number of devices were trialled to free up the coal during these wet coal events. We now have two sets of vibrators ( I realise the opportunities that this opens up, but perhaps comments could be restricted so the thread is not closed down ). We have one knocker ( more opportunity ), which is just an air driven hammer, a jack hammer (common all garden purchased from a hardware store and attached to the feeder tube with tie down straps)) and water jets which are only the choice of last resort. All these can be operated from the control room. In addition to these "coal flow aids" a larger valve was incorporated at the outlet of the coal silo and an expansion box inserted just before the coal feeder (the coal feeder is a short conveyor belt that measures out quantities of coal).

So why have I laboriously mentioned all this? At Bayswater power station in the Hunter Valley we had the same problem. In fact we used to get up on a scissor lift with the sledge hammers there: Quite scary. The feeder tubes like ours at Millmerran were 600mm diameter (made of stainless steel). They were replaced with 900mm tubes and larger valves. Bayswater was a Rolls Royce of stations from the old government days when continuity of supply was the prime concern. Bayswater has four units, eight mills per unit and two feeders for every mill. This meant they replaced sixty four tubes.I don't know what the cost was: Huge. We virtually eliminated coal hang ups overnight.

We did not do that at Millmerran: Too expensive by far and we only had ten feeders to modify.

On the baseload comment I am be bound to point out that we still produce power on rainy days and in this neck of the woods they are not frequent. I don't know that solar and wind can produce power on cloudy and and calm days respectively.

As to Chernobyl and Fukushima most of the workers at those plants would have settled for just a red face.

Regards
Paul

Originally Posted by woodPixel

It must have been the Coalitions mythical Clean Coal, as it left not a single black mark or speck of dust on a single hand.

Perhaps it was coated in shellac or a polyurethane from a spray can (propelled by CO2! hahahah! The irony).

Probably washed coal

Regards
Paul