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Interesting comments on Onslow project, also says Huntley is currently costing 30c a kilowatt hour due to surging coal price (4x the cost of wind power).
https://www.stuff.co.nz/business/129...y-concrete-dam
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 Originally Posted by kiora
Surely he would know?
https://businessdesk.co.nz/article/e...-a-digital-age
Onslow project: an 'analogue solution in a digital age'
The Lake Onslow pumped hydro project is an ‘analogue solution in a digital age’ and the government even just talking about it as a possibility is chilling investment, a global energy investment manager says.
Vimal Vallabh, Morrison & Co’s (MCO) global head of energy, said the pumped hydro scheme is an outdated idea and there are better solutions to solving New Zealand’s dry year problem to ensure energy security as the country pushes towards 100% renewable electricity generation."
Esp.. when you look at the issues of the Hydro scheme on the Clutha river..
. the engineers who designed the Roxburgh dam never expected its reservoir to “silt up” so quickly. There have been unconfirmed reports that the dam’s two low level sluice gates were jammed and rendered inoperable within the first 15 years, indicating reservoir-wide sediment transport to the dam wall.
New Zealand’s first concrete gravity dam was commissioned in 1956 on the Clutha River near Roxburgh. It represented the progress and hope of a new era, bringing electricity to the masses. At the time, large dams were designed in relative isolation to their environments, with little regard given to future impacts, and none whatsoever given to the ultimate challenge of decommissioning. Today, thousands of ageing dams around the world are nearing the end of their economic life cycle, and dam removal and river restoration is becoming an accepted reality.
Although large concrete gravity dams have a theoretical design life of 80-100 years, the actual lifespan of a dam is determined by the rate at which its reservoir fills with sediment. In severely eroding catchments, millions of cubic metres of sediment can be transported annually. The average lifespan of a large dam in China is 45 years.
http://mightyclutha.blogspot.com/201...burgh-dam.html
I live next door to "lake Dunstan" .... and the slit buildup in places just in a few years I've lived here is a worry ... lake very brown slit looking after all the rain we got ..
As for NZ not having much coal..
New Zealand has in-ground coal resources of more than 16 billion tonnes, of which 80% are lignite in the South Island...
"With a good perspective on history, we can have a better understanding of the past and present, and thus a clear vision of the future." — Carlos Slim Helu
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Originally Posted by JBmurc
..... As for NZ not having much coal..
New Zealand has in-ground coal resources of more than 16 billion tonnes, of which 80% are lignite in the South Island...
well we can forget about that and about the oil and natural gas that's sitting untapped off our shores, green ideology over practicality of energy supply have put end to any of that. Indonesia, ship us more dirty coal, we're far to environmentally focused to use any fossil fuels
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Originally Posted by 850man
well we can forget about that and about the oil and natural gas that's sitting untapped off our shores, green ideology over practicality of energy supply have put end to any of that. Indonesia, ship us more dirty coal, we're far to environmentally focused to use any fossil fuels
Yes we are the NIMBY #1 nation .. we have one of the highest ICE ownerships per population in the world... yet our Govt virtue signals like we are leading the green movement >>
"With a good perspective on history, we can have a better understanding of the past and present, and thus a clear vision of the future." — Carlos Slim Helu
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Member
Ive been wading through this report on and off.
https://www.gtk.fi/en/time-to-wake-up/
Will we actually be able to transform to green energy?
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Originally Posted by mcdongle
I guess reducing our environmental footprint always works. We probably just end up with less vehicles, less travel and less waste. More walking, cycling and public transport and less unnecessary travel would be a start. Our choice whether we reduce our environmental footprint or whether nature reduces our numbers.
But in a way it feels a bit like the 1890'íes when scientists predicted traffic in towns will break down because cities will get burried in horse droppings ...
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"Prediction is very difficult, especially about the future" (Niels Bohr)
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It needs something like this
"Cummins Calls Dibs On New Long Duration Energy Storage Iron Salt Formula"
https://cleantechnica.com/2022/08/18...-salt-formula/
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Originally Posted by kiora
It is highly unlikely that the economics of Lake Onslow will be beaten by any alternative energy storage methods. Lake Onslow combines the reliability and flexibility of hydro with an extremely long equipment usage lifetime and open ended energy storage period with minimal evaporative losses. Lake Onslow also allows for a significant increase in intermittent renewable generation without grid stability issues
The only real issue is political
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Originally Posted by JBmurc
Esp.. when you look at the issues of the Hydro scheme on the Clutha river..
. the engineers who designed the Roxburgh dam never expected its reservoir to “silt up” so quickly. There have been unconfirmed reports that the dam’s two low level sluice gates were jammed and rendered inoperable within the first 15 years, indicating reservoir-wide sediment transport to the dam wall.....
Yes, the low level sluices did jam up in the 1970s, but not due to silt. It was due to rust from lack of use. A floating caisson was designed and built to block off the sluices while they were repaired.
One of the sluices jammed again in the late 1990s and actually damaged the concrete when a roller came misaligned. Following that incident the sluices were modified with hydraulic lifting equipment to replace the old winch style.
The low level sluices are now regularly used during flood events.
Siltation is an issue in Lake Roxburgh, and yes, it did happen faster than expected. However since 1994 there has been a flushing regime during large floods that keeps that silt moving downstream. It is effective in that the volume of silt in Lake Roxburgh has been reduced over the past 25 years.
When Clyde was built that also had the effect of reducing the amount of silt entering Lake Roxburgh. It was expected that it would take 150 years from dam completion before any action would be needed. That time frame has now been reduced to 125 years as there is less sedimentation transported down to Roxburgh than what was expected
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Given what we have seen over thee last 2 months in Europe, China and USA, with lakes/rivers literally drying up - it jsut makes the Onslow proposal even more attractive.
Meanwhile, in related news, Tesla has a 12% (!) share of New Zealand new passenger car sales in August. Phenomenal.
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