Green power

[Graeme]

Wind power is very topical at the moment, following the recent visit to South Africa of a Danish representative punting this means of electricity generation.

Much is being written about wind and solar power, but it would seem to me that there is no coherent plan to put the two together. Wind power only produces electricity when the wind blows. This is about 15% of the time. Denmark has an arrangement with Norway and Germany to supply electricity during the 85% of the time when there is not enough wind to turn its turbines. Similarly, solar power is produced only when the sun shines.

A new pump storage scheme is expected to come on stream in Tubatse in Mpumalanga in about 2014. These schemes operate by pumping water from one dam to another dam at a higher altitude and then letting the water run back down to the lower dam via turbines which generate electricity. Such a scheme has been running from the Spionkop dam for some time now. The advantage of these schemes is that the output is beautifully controllable, feeding electricity into the National Grid just when it is wanted during peak demand times.

It would seem to make a lot of sense to erect wind power turbines and solar power installations very close to these pump storage facilities so that the stop/go power produced by them would not require incur expensive transmission costs, and could be used to pump water instead of being fed directly into the grid - or is that asking too much of inter-departmental cooperation?

[duncan drennan]

The Palmiet pumped storage scheme has been going for some time, although it is much smaller than the two you mentioned (around 400MW). What they typically do is use excess energy to pump the water up (turning a coal fired generator on and off to regulate generating capacity is not particularly efficient). Another use of these facilities is to regulate power factor on the grid.

One thing that I am not sure about with any of these facilities is how long they can run for, i.e. energy capacity.

The most effective way to use these facilities is to store excess energy that is available on the grid (regardless of the source). The stored excess can then be used to supplement the grid when necessary. The source of the energy isn't really important, as you would rather use it directly if it is available.

[Superscenic]

plenty of juice.

I live in Cape town. What I can say with absolute certainty is that we have plenty of wind and much much more than 15 %. We also have plenty of sun. When the sun isnt shining, and the wind isn't blowing theres plenty of big wave action.

I also heard that in Denmark they actually switch their wind turbines off sometimes because they generate too much power and the council makes a loss.

[3x-a-d3-u5]

I live in Cape town. What I can say with absolute certainty is that we have plenty of wind and much much more than 15 %. We also have plenty of sun. When the sun isnt shining, and the wind isn't blowing theres plenty of big wave action.

I also heard that in Denmark they actually switch their wind turbines off sometimes because they generate too much power and the council makes a loss.

Hey Superscenic, Have you seen the wind turbines at darling? They are used (i think) to substitute some of cape towns power. See here: http://www.southafrica.info/about/su...rm-darling.htm

I would like to see some wave power generation though, we have plenty of unused waves (From a surfers point of view ).

[Graeme]

I got Denmark's figures from an article about Wind Power in last week's Engineering News. This publication does not usually get that sort of thing wrong. No mention there about having to switch the turbines off during high winds.

[duncan drennan]

Graeme, you might enjoy this story about a new liquid battery which is in development.

[Dave A]

It's amazing how much progress there has been in battery technology of late.

[Superscenic]

OMG nice!

It's happening YAY!!
here are some alternative designs in Digg: http://www.greenoptimistic.com/2009/...ible-to-build/

And here is the link about Denmark producing TOO MUCH power with wind: http://got2begreen.com/green-infrast...ch-wind-power/

"In western Denmark, the price of electricity can sometimes drop to 0 on a windy day which leaves utilities trying to find ways to offload the excess power. What a “good” problem to have!"

http://www.metaefficient.com/cars/danish-drivers-to-fill-their-tanks-with-wind-power.html

"In western Denmark, the price of electricity can drop to zero on a windy day, leaving utilities scrambling to offload excess power or take a financial hit."

Love those wind turbine farms that are now being build in the sea to lessen impact on the countryside and their species. Check those big blue sea expanses with Dali-Like giant white flowers bobbing up and down, so Surreal.

[twinscythe12332]

are there any notable impacts that happen due to these turbines? for example, would a 30 km/h wind hit the turbines, and slow down to a 28km/h wind?

[Superscenic]

http://www.windpower.org/en/tour/wres/pwr.htm

heres a wind speed / output graph from The Danish wind industry foundation.

If thats any help

I think there are many areas wich will still be improved upon. My personal issue is more the birds that get taken out by the blades. That is a huge problem apparently for Danes. They can spin at scary high speeds and birds can't always see them. That why I like the vertical stack design more, its not so pretty but it needs no maintanance or output dampers.

[twinscythe12332]

yeah, my take on the whole matter is that anything we do, we are going to affect the earth some way or another. I don't know if anyone has seen that one short on discovery channel about the mirrors pointing towards a centre pillar with a solar panel. the heat that creates must be intense! wouldn't that cause some sort of reduction in water vapour in the air? what happens if a bird casually tries to land there?

and with the turbines, it does have the ability to trim down local bird populations, as superscenic points out.

I do see the point in green technologies, I just also feel that there is an almost "no consequences" mentality about them. there are consequences, just not on the scale of fossil fuel plants and the likes.

[wynn]

Off the Eastern Cape Coast near East London we have a Continental Shelf that stretches a few Kilometers out to sea before it falls to the depths.
This Shelf is swept by a strong coastal current 24/7/365
There is a proposition to situate any number of submarine generators as is necessary to run the electricity needs of the country.
This would be green, sustainable, cheap to install, run and maintain.

The objections by Politicians is, 'What is in it for me?'

Perhaps the answer to our energy needs is a new Government?

[duncan drennan]

Wynn, do you know who the people are making that proposal?

[insulin]

The power!!

One needs to be open-minded and unfortunately government is a monitory system designed to keep the money slave inline. The truth is electronics is at a point where it needs little power to function. There are other ways to generate power other then wind and sun power. There is a system today that allow us to harness the power of rising hot air! So the truth is industry needs us to be dependent on antiquated technology because industry needs you the money slave to PAY them money. I recommend you open your eyes and see that government do NOT control anything. Industry controls everything!


There is no grater fool then a working man thinking that he is free for we are all slaves to the system.

[Dave A]

There is a system today that allow us to harness the power of rising hot air!

I suggest we install a unit over parliament.