On Wed, 02 Nov 2011 09:12:19 +0000 (GMT), "Dave Liquorice"
wrote:

On Wed, 2 Nov 2011 01:36:30 -0700 (PDT), harry wrote:

Small PV arrays reduce the size needed on th grid as electricity is
produced locally.

So when the sun sets (or is clouded out) you sit in the dark? Don't
watch telly or use any other electrical appliance?

I think that power generators will take into account sunlight
intensity and national cloud patterns to predict needs.

Not with the total installed capacity of less than 1% of demand. ISTR
they work with a 20% margin of spinning reserve. So if a nuke station
and a big coal fired station fall off line at the same time (say
3,400,000 kW) the grid struggles but doesn't collapse.

The UK grid doesn't operate with 20% spinning reserve - that would
mean with the current daily 50GW peak, there would be another 10GW
spinning reserve (distributed across existing generation, and
available by pumped storage)

In reality the spinning reserve, and fast despatch generation combined
are approaching an order of maginitude less than 10GW.

On top of that are industrial customers on interruptable supplies.

Demand predictions made a few hours ahead are usually very accurate


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