Some comments on these comments

@Jerry

When making a comment like "Mate, you are so wrong!" you should read the post properly. I didn't see anything that suggested that hydro was slow reacting so why was he wrong?

And what does pumped hydro have to do with supplying base load? That would be insane. The whole ethos of pumped hydro is that base load (ultra slow reacting capacity) can be kept online during low demand periods just to move water. This energy can then be returned rapidly during spikes, eg half time in a footy match. The only effect on base is that it keeps more online for longer, nothing to do with avoiding extra base.

"The rest is higher cost shorter response systems such as hydro, gas turbine, and some fossil fuel systems."

Maybe you know something I don't but I have never heard of a GT running on anything but fossil fuels (methane, oil, even coal). Maybe you mean CCGT but these are not fast response as the boilers take time to get online.

@ A J Stiles

Firstly, you do not need to run at 3000rpm to produce 50Hz. By increasing the number of pole pairs in the alternator you can decrease the speed, ie 2 poles = 3000, 4 poles = 1500, 6 poles = 1000, etc.

Secondly, there is a wonderful invention called variable pitch blades. This allows you to alter the power transfer from wind to blade in much the same way as altering the flow of fuel in an IC or GT engine.

Back to @ Jerry

" Distances are huge; transmission costs are very high (and lossy)".

Compared to either end of the circuit, transmission losses (the major portion of cost) are pretty minor - even over large distances. If you really want to talk about losses then best look at the power station. A coal fired plant manages to convert about 45% max of the chemical potential in the fuel into electricity and LWR nuclear manages a meager 1.6% utilisation of fuel potential. This makes the 93% efficiency of the transmission line look pretty amazing.

@ All the "the wind doesn't always blow", pro-nuke brigade.

I hope you are aware that the current designs of LWR nuke plants are required to shutdown (zero power) for 2 months every 3 years? That requires quite a bit of planning and backup capacity in itself. Also, should there be a scram at full load (not uncommon), it can take days for a nuke plant to get back up to capacity. Given that nuke has to be base load (slowest response generating plant) then there is quite a bit of redundancy required here.

My personal view is that if the drive for 'the bomb' had not pumped so much tax payers moeny in to nuclear power then we would have a great deal more choices now for electricity generation. As it is, we see governments panicking and backing any old half-arsed project (including wind and new nuclear build) without any real understanding of the ramifications that those decisions have.

@Robbin Nichol

Sorry for the misunderstanding, but having re-read your comment it still looks like you were advocatingg 2.5 ACs in total. ^_^