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AlexQuote:
Originally Posted by AlexS
Bit like this perhaps except we called them "Four Figure Tables" and you can see why from the cover. :rolleyes: Mine date from 1965.
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I have been away from home for a couple of weeks so had no access to ancient hoarded treasures. I only ever used these in exams. Calculators were not allowed.
Regards
Paul
This will be very nerdy, but when I can't sleep I do square roots in my head to four digits. :)
I'm unwell :)
Square root of 2 = 1.4142135, 3= 1.7320508
WP, I think we share some common traits.
ajw
Its not hard to work out on paper, but the trick is keeping the totals in working memory. It can be quite challenging.
I often fall asleep 😂😸, or if I can't clear my mind this works wonders. Its akin to a meditation.
They're the same ones I had at school. Must have been the standard issue. Later, at tech, I bought a set that had all the physics info inside the covers.Quote:
Originally Posted by Bushmiller
Never heard of Duck Reach Power Station? Well, this is a little off beat but as we have talked extensively about the methods of storing electricity using other energy sources I thought this might provide a little amusement and some insight.
I think of hydro electric schemes as very fifties, but on a recent visit to Tasmania I came across this station at Launceston and it brought home to me how wrong I was on that score. By the way it is pronounced "Lonceston." :) (Not a great revelation for Tasmanians)
Duck Reach power station is situated at cataract gorge and was commissioned in December 1895. It originally just supplied street lighting in Launceston. It was later enlarged to 2MW! It was destroyed in an extreme flood event in 1929 and rebuilt in 1932. It was closed down in 1956.
This is all that remains today:
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The turbines in their heyday:
Attachment 509118
After the 1929 flood
Attachment 509114
Some technical information describing the tunnelling through 860 meters of rock, which was and maybe still is, considered an engineering feat.
Attachment 509116Attachment 509117
Perhaps they shut it down prematurely :wink:.
Regards
Paul
There was a small Hydro power station just south of Pemberton setup in the 1930's which made it the first and only town to be powered by hydro in WA.
I'm pretty sure it only ran 48V system and was primarily used for lighting.
In 1954 the town was finally collected to the south west power grid
I remember playing around in some of the disused houses at the end of our street that had the cloth covered wiring hanging out of the damaged ceilings which were installed as part of the system.
The old dam has been upgraded and now provides water for the town.
Paronella Park in Qld had the first hydro scheme in that state, just to supply power to the (rather large) house. Just checked, it's been restored and is in use again.
Paronella Park Hydro scheme
When I worked in Bougainville, I was asked by one of the Bougainvilleans I worked with whether a small hydro scheme would be suitable for his village. We looked at what the demand would be - electric refrigerators were the main thing they wanted, replacement of current small generator capacity plus a few other essentials. A scheme that would supply these was feasible. Then we (he and I) looked at what other things people would buy as soon as they had power available. The capacity of the river to meet this new demand would soon be exceeded.
I understand that there are now several small hydro schemes running to villages, cobbled together from equipment from the mine etc.
Just revisited the costs of installing solar in Hobart. Like many, I use most electricity in the evening when the sun ain't shining.
- Current cost of electricity = ~25 cents/kwh,
- Current feed-in tariff = ~6.5 cents/kwh.
Conclusion: Currently cheaper to buy from Aurora than to install solar. Its all hydro power so no moral imperative.
Future: I looked at trends in the wholesale price of electricity.
Attachment 509154
The retail feed-in tariff has been significantly above the avaerage wholesale price for the last three years. This should place further downward pressure on the feed-in tariff. Why would Aurora want to pay 6.5 cents to someone with a solar system when the can buy the same kwh of electricity wholesale for 2.8 cents?
Solar panel prices are still trending downward.
Feed-in tariffs are trending downward and are likely to continue.
Conclusion: Watch and wait.
It seems that every small town on a river in the US had a small dam or multiple dams for hydro electric purposes and saw milling and they are now being removed for environmental reasons, mostly to try and increase fish stocks. Most of these dams go back to the late 19th century, early 20th century but some as late as the mid 20th century. YT has a lot of video of dam removal as well.
dam removal projects 2021 - Google Search
This brings me back to my chorus that every power supply has a flaw. Hydro's weak point is the effect on the rivers downstream.
Regards
Paul
Here is something to chew on!
Could super-sized heat pumps make gas boilers extinct? - BBC News
Holes in the ground for heat.
Since Oz is good at digging holes (we seem to specialise in it) then this would be of interest to our political overlords.... just tell them there is oil, coal or gold down there :;
Ooops, only heat? Whoops :doh:
(title flogged from the lyrics of Blue Sky Mine)
FWIW that form of heat like all geothermal heat is originally nuclear.Quote:
Originally Posted by woodPixel
Natural Radioactive decay of certain elements with long half lives.
It's interesting to hear how 15ºC in the UK is considered warm. I know a chap who lives on acreage just out of the city who uses the coolth in groundwater to cool his house in summer. I forget the temp of the groundwater but its warmer than 15ºC. He has a copper pipe heat exchanger under the ground water and uses a solar powered pump to bring a loop of water inside the heat exchanger up to his house where he has another heat exchanger and solar powered fan to dump cool air into his house.
Quote:
Originally Posted by woodPixel
midnight actually filmed one of their videos with a central coast power station in the back ground (i think there's a few other stations in there for "location shots":
https://www.youtube.com/watch?v=SAFv2NEE-_c
Quote:
Originally Posted by BobL
Some 20+ years ago, when most heat pumps only worked efficiently when the ambient temperature was above 5°C, I looked seriously at installing a geotherman heat pump to heat the house and hot water. With the then level of technology they were about 1 - 1.5 COP units more efficient than other heat pumps (COP of 5 vs 3 to 3.5).
At ten metres below the surface in Hobart, the ambient temperature is 15°C winter and summer - it is the average annual temperature for the area, according to BOM. Near the surface the temperature fluctuates with the seasons, but by 10 metres it is stable.
The proposal was to drill one or more holes with total length of 150 metres, insert closed heat exchanger pipes, and bliss!
The heat pump, heat exchanger and installation would have cost around $10,000 then. But our house is built on dolerite and the drilling cost was quoted at $30,000 or so. Ouch!
It was very efficient using engineering or scientific criteria; definitely not so using financial criteria.
Its vaguely tangential to the discussion, but I felt it was worthy.
In Canberra (here!) it often gets blistering (35 but sometimes >40°) and freezing (~-5° to -10).
While these are bragging extremes, they do occur every year. Most of the time it is fairly pleasant (Id guess 25 to 27, with 15 nights).
Heat pumps make a LOT of sense.
About 10 years back I was yarning with a fencing guy (who was, unsurprisingly, putting up a fence) and I noted the size of all the yards combined was HUGE. I enquired why all four houses, in the conjoining corner, wouldn't drill a deep hole for a heat pump and "pipe" the air to each home, somewhat independently.
Sharing would reduce the capital cost.
Air coming out would be 15° and this could fill the houses in summer and take the chill out in winter. As BobL has pointed out a million times, the cost of running a motor for air movement is trivial.
15 in summer would be BLISS... 15 in dead winter means the heater doesn't need to be on.
The cost savings over 4 houses would be HUGE.
I'm now in new units. Every one of them has an reverse-cycle aircon .... some people run them continuously. Its annoying AF.
What a TRAGIC lost opportunity to pump ground heat into 100 units. The cost savings would be HUGE.
Its not just an air fan - you do need a water pump as well, but still cheaper than running a compressor pump.Quote:
Originally Posted by woodPixel
I know of another interesting system that does not even use an underground heat exchanger and that is the Gravity Observatory at a place north of Perth called Ginginr.
The Gravity Discovery Centre - Gingin & Perth
The entire air conditioning system for the visitor centre and the observatories (including a very large lab with the gravity laser interferometer arms that has to run at extremely even temperature) are run using groundwater of which there is heaps.
The cool underground water is drawn by a pump up to ground level and put through a heat exchanger and then just let drain out onto the very sandy soil outside the observatory where it quickly trickles back under ground. Its not something that can be done is a suburban setting but anyone on acreage can probably do this.
The savings especially in summer are quite significant
AGL shuts down the first unit at Liddell.
After 50 years of burning coal to generate power, Liddell power station wind-down begins - ABC News
Regards
Paul
A background piece on the proposed Eraring shut down.
Switching off: Inside Eraring power station as staff come to terms with its closure - ABC News
Bit of a curveball but given current world events and the impact of relying on other countries to supply critical services ( like Germany with Russia)
How do you feel about reliance on lithium batteries given China’s control of the worlds resources to manufacture them?
That's bold statement especially give the following Li Ore reserves graph. OK ore is one components but its one of the most important.Quote:
Originally Posted by Beardy
Attachment 509760
I'm more concerned about REE tech (for magnets) which is way more complicated than Li for batteries. BTW Aus does pretty well on REE ores as well.
Quote:
Originally Posted by Chris Parks
pretty accurate description of the electricity commission workersQuote:
“I remember walking in and goin’ oh, there’s a fair few weirdos here. A bit of a hangover from the Electricity Commission,”
will be interesting times for the other coal plants, with liddels unit turning off (and the rest no doubt moth balled as well) and then a year or so later Eraring doing the same thing thats 4000Mw of possible power out of the grid in 3 years.
This was the article that got me thinking
Risky business: the hidden costs of EV battery raw materials | Automotive World
In 1982 I read a Time Magazine article that said the world was going to run out of copper by 1994, and Oil by 2000. Calculations were based on "known" reserves.
Recently I came across this (also based on "known" reserves").
Now copper is not running out till 2040?
It seems theres a lot more to find than we think about.
Attachment 509770
Bob
That chart seems to emphasise the need to step up recycling, certainly for some commodities.
Regards
Paul
Correct, our general attempts at recycling are improving but still pretty much rubbish.Quote:
Originally Posted by Bushmiller
I am also reminded of the following story.
SWMBO's grandfather arrived in WA in the early 1920's and retired on a small farm just out of Perth. Unfortunately he lost his retirement savings in the late 1920s and he took up a gold mining lease at Bamboo Creek , ~70 km out of Marble Bar, from 1929 to 1939.
He and his wife and 2 kids lived in a corrugated iron shack and they had to cart water daily using a yoke and 2 kero tins from a creek 300m away.
Despite that they did OK as he managed to send his two kids to boarding schools in Perth and buy a house in the city.
The mine was a one-man operation, hole in the ground with tunnels following quartz veins with a bucket and hand windlass to raise the ore to the surface - in other words very hard work at the hottest place on earth,
By 1939 he was in mid 60's with deteriorating health issues and to follow quartz veins he'd had to go deeper and needed more people. He had the money to finance a modest mine expansion but the problem was the war had soaked up any spare people so he walked off the lease. He died about a decade later.
The lease lay dormant for 10 years before it was taken up again by a well known mining company and sinking the mine further produced several million pounds and the dollars a year net profit from 1950 to 2009. Then someone decided t0 look at how much gold was in the tailings, For a $250 million dollar investment in a large tailings processing plant there was $27 BILLION dollars worth of gold to be recovered.
As for any gold, as a kid SWMBO wore a gold bangle made from gold from the mine, which had to be cut off her arm when she had her wisdom teeth out as a teenager. Her mum (my MIL) had the cut bracelet melted down to make a few bibs and bibs for her granddaughters - SWMBO did not get any. When MIL passed away a few years back MIL left all her jewellery to SWMBO and amongst that lot there was a pearl ring that belonged to her grandmother which apparently was made with gold from the mine. She wears it every day.
Bob
That is such a lovely, emotional story full of pathos.
Regards
Paul
Yeah or just sour grapes :)Quote:
Originally Posted by Bushmiller
OTOH, if SWMBO's grandpa has made a fortune from the mine the chances of me meeting SWMBO as a teacher at a country high school would have been close to zero.
Those articles per-date 1982 and usually involved a "noted scientist" who took the then known ore reserves and divided it by the then current world usage and produced a finite date when that commodity would be exhausted. Commodity traders assisted with the publicity - it stirred interest and sales.Quote:
Originally Posted by BobL
Interestingly, economists generally got a lot less excited by these doomsday prophets. They had a simple little formular:
S = f(P)
Supply is a function of price. Increase the price and previously uneconomic mines become profitable, abandoned mines can be re-opened, existing mines can be extended, tailings can be reworked, recycling becomes more attractive, substitutes get invented, etc.
Back in the late 1970's Saudi oil minister, Sheik Zaki Yamani, as head of OPEC, unilaterally raised the price of oil and caused the first oil shock. Governments were outraged; French President de Gaulle was particularly affronted and vocal - "... holding the world to ransom when you just pump the stuff out of the ground." Yamani's response was: "You are absolutely correct, Monsieur President, and we have a special deal for France. We will sell you unlimited quantities of oil at exactly the same price that you sell us mineral water."
The price of oil has changed a little since then.
I remember a lecturer i once had.(1985).
He said, ask me when oil will run out. So, we asked. He said 20 years.
He said, ask how i know. So, we asked...
He said, in Warsaw uni, in 1930, they told me that oil would run out in 20 years. In 1950, in the us, they told me oil would run out in 20 years. In (somewhere), in 1970, they said oil would run out in 20 years.
So it is clear, everyone agrees that oil will run out in 20 years...
Fusion is the same.Quote:
Originally Posted by russ57
Many metals can extracted from seawater (just need cheap energy - Fusion right??) , and apart from oil and gas theres 70% of worlds crust the has not really been looked at for minerals.
A few years ago I had dinner with a Texan oil engineer and his wife. We discussed oil, naturally. There is a near infinite quantity - its only the matter of price to extract it.
At $2 a litre, no so much left, at $20 a litre, plenty.
Curiously I was interested in ethanol/methanol production. Turns out Manildra here is one of the very biggest. A casual chat with them revealed they are more than able and capable of producing as much ethanol as needed at an energy price point BELOW fossil fuels right now.
It would be curious to know what the future holds.
It would be interesting to know how much wheat would be needed to replace Austraiia's petrol using ethanol.Quote:
Originally Posted by woodPixel
My understanding is that on world wide scale to replace liquid fossil fuels fossil fuels the limit is the amount of water and space required to grow the crops and leave enough left over the grow crops for food.
Crops like corn use huge amounts of water.
I was also amused by Mandrila's clim "GMO-free wheat as feedstock", does it really matter?
It is generally agreed that the fuel from crops idea often proposed is not feasible at all. The only reason NSW mandated 10% was because Manildra lobbied the government and convinced them that Manildra would make a ton of money and therefore it was a good idea. The tin pot refinery they have at Nowra couldn't even be considered to produce more than a trickle of Ethanol that would be required if a major move to synthetic fuels was made.
Not sure about the lifecycle CO2 reduction "efficiency" of ethanol produced by fermenting wheat, but in the US ethanol is mainly produced from corn and this video America Was Wrong About Ethanol - Study Shows - YouTube suggests that, in the US at least, the CO2 emmissions from corn based ethanol production is no better than those from gasoline, and potentially 24% more than those from using gasolineQuote:
Originally Posted by woodPixel
I believe the input of non-gmo is due to a fair chunk of the ethanol being used for grog or sanitiser.Quote:
Originally Posted by BobL
As for water, it would be VERY interesting. Wheat is just the plant of choice. I'm aware of HEMP crops being used too.
Hemp is amazing. It grows so fast it's a weed :) plus it grows many crops a year.
Its bet the only reason Manildra use wheat is due to being primarily a flour producer.
Yes on Manildra being evil. Reading the Michael West media site covering Dark Companies, its clear this country has a cosy political relationship with kleptocrats.
As for other comments on sustainability.... Maybe we will have no choice. Climate change is getting a bit too real.
Quote:
Originally Posted by woodPixel
Now ethanol has three different names in popular usage:
- ethanol,
- ethyl alcohol, and
- vodka.
It seems such a waste putting it in a car!
I believe ethanol is also known as grain alcohol ;)Quote:
Originally Posted by GraemeCook
but look on the bright side Graeme
If you put ethanol into a car you only pay fuel excise of 22(?) cents per litre (the temporarily reduced rate) -- the excise used to be 44 c/l
If you drink vodka -- which I though was made from fermenting potatoes -- you will be paying something like $20 per litre tax
and if you use it in the tractor, the tax is NIL.
.
.
.
BTW
I thought ethyl alcohol was the highly purified version of ethanol that didn't attarct any tax because it's a laboratory chemical
During WW II ethanol was produced from sugar cane at Sarina in Qld.