29 Aug '10 14:48>
Originally posted by Andrew HamiltonI did, and had not realized that we were talking about large power stations. I had assumed we were talking about waterwheels and suchlike.
.... and is called “run-off-the-river” hydroelectric (you can Google this).
I come from Livingstone which is right next to the Victoria falls which has a “run-off-the-river” hydroelectric power plant.
But; unfortunately, its really big disadvantage is that it doesn’t store potential energy. Now if only we can find an economic alternative way to store that energy that is as good but cheaper than using dams, that could be a huge potential improvement to hydroelectric in the future.
The Wikipedia page
http://en.wikipedia.org/wiki/Run-of-the-river_hydroelectricity
suggests that the storage advantage of a dam has to do with storing energy seasonally, not daily.
Thus if you were to use some form of battery technology or nanospring, you would need a vast amount of storage capacity. A whole dams worth.
At the energy density of lithium batteries, what sort of volume would we be talking about? If we were to put the potential energy of all the usable water in the Kariba Dam into electricity and store it in batteries, we would be talking about millions or billions of car batteries.