hydro electricity

kronoSX

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Is there no places left in sa to build hydro electrical plants that can make a difference and not destroy the ecosystem surround.Also how long does it take to build such a system.Why cant some of the dams here be retrofitted .
 
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wingnut771

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Is there no places left in sa to build hydro electrical plants that can make a difference and not destroy the ecosystem surround.Also how long does it take to build such a system.Why cant some of the dams here be retrofitted .
What do you do during the drought years when there is no water?
 

Oldfut

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Is there no places left in sa to build hydro electrical plants that can make a difference and not destroy the ecosystem surround.Also how long does it take to build such a system.Why cant some of the dams here be retrofitted .
Not straight hydro I think, maybe some off channel options but, as noted, subject to water flows. But lots of pumped storage and smaller options (I have worked on a few). Sadly all controlled by the ANC regime and too much infighting as to which faction will get the cream. The level of the cream usually kills the project.

What is quite lucrative for the ANC aligned is to "investigate" the options. So I have seen studies where basically Australian design has been copied and sold to an ANC state entity as consulting. Never built. Same with nuclear, some ANC connected apparatchiks (J&J, Vivian Reddy's laaitie etc as I recall) have had very lucrative "consulting" contracts to investigate nuclear power. Values up to around a billion ZAR, to slip under the corruption radar.
 

wetkit

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For Hydro to work, you need height!!!
Sadly most of our dams does not meet this requirement.
Also, when most of our dams were build 30 to 40 years ago, coal power was so cheap, the added cost was not deemed feasible.
 

Gordon_R

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South Africa is a water scarce country, unlike places such as Canada and Norway which have large hydroelectric capacity. The largest river in SA is the Orange, which already has two medium size plants at the Gariep and Vanderkloof dams. Unfortunately full-time use of these is a tradeoff between electricity and irrigation, with seasonal droughts being a factor.

There are also a few large pumped storage schemes, notably Drakensberg and Ingula. Other than those, we have very few options.

Reference: https://en.wikipedia.org/wiki/List_of_power_stations_in_South_Africa
 

Big Rat

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For Hydro to work, you need height!!!
Sadly most of our dams does not meet this requirement.
Also, when most of our dams were build 30 to 40 years ago, coal power was so cheap, the added cost was not deemed feasible.
How much height though?
I'm thinking Clan William dam, you have the flow pipe at the bottom, so constant water flow. instead of gravity letting the water fall over the turbine, can that force coming out the pipe not be used to turn a smaller turbine?
Instead of vertical assembly, make it horizontal. might not make as much as normal setup, but a few megawatts can help the surrounding area surely?
 

kronoSX

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i read somewhere in the states they diverted one dam to a smaller dam where the water decended and provide hydro power during the day,then at night when electricity is low consumption they pump water back up into this dam then the cycle starts again.I dont see why we cant have this.Also put anti evaporation balls in the dam that is being used.So many options for short term use to ease the grid but no one cares.What a **** storm.
 

wingnut771

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i read somewhere in the states they diverted one dam to a smaller dam where the water decended and provide hydro power during the day,then at night when electricity is low consumption they pump water back up into this dam then the cycle starts again.I dont see why we cant have this.Also put anti evaporation balls in the dam that is being used.So many options for short term use to ease the grid but no one cares.What a **** storm.
That is pumped storage. We do have that. They use them for during peak demand as it only lasts a few hours.
 

MightyQuin

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i read somewhere in the states they diverted one dam to a smaller dam where the water decended and provide hydro power during the day,then at night when electricity is low consumption they pump water back up into this dam then the cycle starts again.I dont see why we cant have this

We do...it's called the Palmiet Pumped Storage Scheme...

Also put anti evaporation balls in the dam that is being used.So many options for short term use to ease the grid but no one cares.What a **** storm.

Those balls ARE a schit storm....firstly they were used to stop the formation of a carcinogen called bromate. But some tree huggers missed that part and started writing about saving of water through evaporation...which that project was not for.

Secondly the manufacturing processes of those balls USED more water than those balls could ever save.

Please inform yourself first, before posting kak here...
 

PaulMurkin

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i read somewhere in the states they diverted one dam to a smaller dam where the water decended and provide hydro power during the day,then at night when electricity is low consumption they pump water back up into this dam then the cycle starts again.I dont see why we cant have this.Also put anti evaporation balls in the dam that is being used.So many options for short term use to ease the grid but no one cares.What a **** storm.
The ANC only cares if there's gravy to fill their boat factored into the deal
 

itareanlnotani

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South Africa is a water scarce country, unlike places such as Canada and Norway which have large hydroelectric capacity. The largest river in SA is the Orange, which already has two medium size plants at the Gariep and Vanderkloof dams. Unfortunately full-time use of these is a tradeoff between electricity and irrigation, with seasonal droughts being a factor.

There are also a few large pumped storage schemes, notably Drakensberg and Ingula. Other than those, we have very few options.

Reference: https://en.wikipedia.org/wiki/List_of_power_stations_in_South_Africa
Limpopo - lots of potential for pumped storage. Plans even, that continually aren't implemented.

As for water - Eskom is probably one of the biggest users in the country.
Our coal mines misuse a ton of it.

Guess how much water Medupi uses/ will use?


The projected water requirements for the six dry-cooled units of the Medupi power station, once fully operational, are 4,5-million cubic metres of water a year without FGD and about 14-million cubic metres of water a year with FGD
 

Gordon_R

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Limpopo - lots of potential for pumped storage. Plans even, that continually aren't implemented.

As for water - Eskom is probably one of the biggest users in the country.
Our coal mines misuse a ton of it.

Guess how much water Medupi uses/ will use?


The projected water requirements for the six dry-cooled units of the Medupi power station, once fully operational, are 4,5-million cubic metres of water a year without FGD and about 14-million cubic metres of water a year with FGD

There is no doubt that evaporative cooling of coal fired power stations consumes a significant amount of water. However hydroelectric plants 'consume' hundreds of times the volume of water to produce a unit of electricity. This is acceptable for pumped storage schemes where the water is reused endlessly, but is very inefficient if the river runs downstream into the sea.

The simple point is that the latent heat capacity of turning water into steam is hundreds of times greater than it's gravitational potential energy. Hydro power requires large volumes of water moving rapidly through a turbine.

Thought experiment: Take the temperature of a waterfall at the top and bottom, the difference will probably be less than 1C. You can't boil a kettle, or generate useful amounts of electricity that way...

Reference:
 

itareanlnotani

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There is no doubt that evaporative cooling of coal fired power stations consumes a significant amount of water. However hydroelectric plants 'consume' hundreds of times the volume of water to produce a unit of electricity. This is acceptable for pumped storage schemes where the water is reused endlessly, but is very inefficient if the river runs downstream into the sea.

The simple point is that the latent heat capacity of turning water into steam is hundreds of times greater than it's gravitational potential energy. Hydro power requires large volumes of water moving rapidly through a turbine.

Thought experiment: Take the temperature of a waterfall at the top and bottom, the difference will probably be less than 1C. You can't boil a kettle, or generate useful amounts of electricity that way...

Reference:

Overview of pumped storage and Hydro in SA (excellent read, suggest you go through it)

The key to hydro is that you have a large quantity of water. While potential output is a small %, multiply that by the large quantities involved, and you have serious amounts of power.
Its also relatively clean generation. Reusable, although does need water.

Back to your question -

I fail to see the relevance of your thought experiment. , but I'll play -

Take your waterfall height at top -> bottom, lets call that head.
Take the flow (how much water is going through this waterfall), lets call that flow.

Take those two figures and stick them into the calculation here -


What sort of continual output will you get? Is this useful?
Hint, yes. otherwise we wouldn't use pumped storage or hydro as it wouldn't be cost effective.

As an example, Steenbras has a 300m head, and the flow is 75m3/sec. You can do the math :)

Our current hydroelectric plants don't waste water - they store it for use. Most (if not all) of our hydro goes to feeding existing water supply.

Plenty of opportunity for more hydro (micro, mini hydro in particular) in SA; initial costs are higher, but runtime costs are low, and payback is short. Similar to nuclear, but with faster build times, and no messy nuclear waste to deal with.



An example of a recently built plant - https://www.esi-africa.com/renewabl...isvallei-hydro-now-operational-in-free-state/


We also have opportunity to upgrade the turbines and feed pipes in existing infrastructure to improve output.
 
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kronoSX

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We do...it's called the Palmiet Pumped Storage Scheme...



Those balls ARE a schit storm....firstly they were used to stop the formation of a carcinogen called bromate. But some tree huggers missed that part and started writing about saving of water through evaporation...which that project was not for.

Secondly the manufacturing processes of those balls USED more water than those balls could ever save.

Please inform yourself first, before posting kak here...
i know about the bromate formation those black balls,i call them anti evaporation balls, and also i know they are filled with water at the factory.You nogal lekker rude in your reply but thats ok cause i forgive you.If one dont ask questions how is he suppose to get opinions and answers.

Maybe you giving kAK advice.
 

Gordon_R

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Overview of pumped storage and Hydro in SA (excellent read, suggest you go through it)

The key to hydro is that you have a large quantity of water. While potential output is a small %, multiply that by the large quantities involved, and you have serious amounts of power.
Its also relatively clean generation. Reusable, although does need water.

Back to your question -

I fail to see the relevance of your thought experiment. , but I'll play -

Take your waterfall height at top -> bottom, lets call that head.
Take the flow (how much water is going through this waterfall), lets call that flow.

Take those two figures and stick them into the calculation here -


What sort of continual output will you get? Is this useful?
Hint, yes. otherwise we wouldn't use pumped storage or hydro as it wouldn't be cost effective.

As an example, Steenbras has a 300m head, and the flow is 75m3/sec. You can do the math :)

Our current hydroelectric plants don't waste water - they store it for use. Most (if not all) of our hydro goes to feeding existing water supply.

Plenty of opportunity for more hydro (micro, mini hydro in particular) in SA; initial costs are higher, but runtime costs are low, and payback is short. Similar to nuclear, but with faster build times, and no messy nuclear waste to deal with.



An example of a recently built plant - https://www.esi-africa.com/renewabl...isvallei-hydro-now-operational-in-free-state/


We also have opportunity to upgrade the turbines and feed pipes in existing infrastructure to improve output.

I think you missed the point of my post in response to the OP completely (and are trying to teach an Eskimo about ice). South Africa is a water scarce country, and if all its water were used for hydroelectric, we would still fall short. Pumped storage (which I understand completely) is a different story, and is only useful for load balancing, not primary energy generation. P.S. Look at the list of hydro capacity in the article I linked earlier.

Edit: If you want to read actual data about hydro versus thermal, try this: https://www.osti.gov/pages/servlets/purl/1427501
The generation-weighted average WCFs of thermoelectricity and hydropower are 1.25 (range of 0.18–2.0) and 16.8 (range of 0.67–1194) L/kWh, respectively, and the generation-weighted average WCF by the U.S. generation mix in 2015 is estimated at 2.18 L/kWh.
 
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LaraC

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South Africa has one of the longest coastlines in the world.

Why can't sea currents or waves be used to generate power? :unsure:
 

RVQ

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South Africa has one of the longest coastlines in the world.

Why can't sea currents or waves be used to generate power? :unsure:
Technology is still being developed, is in its infancy and needs significant investment before it reaches wide scale commercial viability
 

MightyQuin

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i know about the bromate formation those black balls,i call them anti evaporation balls, and also i know they are filled with water at the factory.You nogal lekker rude in your reply but thats ok cause i forgive you.If one dont ask questions how is he suppose to get opinions and answers.

Maybe you giving kAK advice.
As usual posters like you double down on the stupidity...

  • What YOU call the balls are of zero consequence and has no bearing on the lack of facts in your OP.
  • The balls are not filled with water at the factory...are you kidding?!?! It is the process of manufacturing those balls, that use the water.
  • I suggest following my "kak" advice and doing better research.
 
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