Topping up the National Grid?

[Mikkel]

This is great description for the layperson, and something I'm well aware of. As mentioned, I'm very much an amature, I can't quote you the calculations or formula for working out the friction loss etc, but I've spent half my lifetime working with domestic water supplies (up to four houses off one system) and do have a fair idea of what is involved in getting water from catchment to tap.

Quoting the equations is the easy part - solving them is slightly harder.

Fluid mechanics is an extremely complicated matter because it's very difficult to disentangle or seperate a problem in the system from the entirety of the system. In that regards it's similar to quantum mechanics where you have to include the entire system in your equation...

I can't recall all of the lecture we had on fluid mechanics - it was enough to give me a headache mind you - but I believe the equations are the Navier-Stokes equation and it revolves around considerations of flowlines. And coming to think of it I think that it might actually be limited to the case of laminar flow - i.e. no turbulence, which you would have in a turbine.

To give an example - some years ago they held an international competition where different departments in fluid mechanics from around the globe modelled a certain system, then the system was built and the modelling data was held up against the emperical observations. I believe that the department of fluid mechanics at the Technical University of Denmark (where I got my M.Sc. btw) won the competition - they were off by a factor of TWO! So there you go.

[Coyote]

I've been wondering about wind power. Not those huge wind farms but more a individual domestic mill.
Mum and dad have one up at mangawhia--it's used to charge their deep cycle batteries -but pumps out 240v

http://www.turby.nl/

Saw that on Beyond Tomorrow. Seems like a brilliant idea.

[rainman]

I’ve heard of people producing power privately and selling it back to the grid, so it must be possible

As I understand things, this is not currently a possibility in NZ.It s Green Party policy to establish feed-in tariffs (what you're describing) to encourage development of renewables, but everyone's so keen to bash the greenies on principle that much of their sensible policy (like this) is overlooked.


Disclaimers:
1. I'm not saying there is not some silly policy in there too - they're politicans, thus not perfect. But more sensible than given credit for, by far.
2. There may be significant engineering issues with feeding lots of small power sources back into the grid. Or maybe the guys who manage it are just lazy. I dunno.