On Thu, 17 Sep 2009 10:37:56 +0100, "dennis@home"
wrote:
"Stephen" wrote in message
.. .
On Tue, 15 Sep 2009 19:18:29 +0100, charles
wrote:
In article ,
Stephen wrote:
On Tue, 15 Sep 2009 13:38:14 +0100, "tim....."
wrote:
"tony sayer" wrote in message
...
In article , Andrew
scribeth thus
On Mon, 14 Sep 2009 14:43:54 -0700 (PDT), "alexander.keys1"
wrote:
There have been a lot of comments recently about the waste of energy
due to appliances being left on standby, and various gizmo's that
are
on offer to turn them off automatically, or otherwise purporting to
save energy. What everybody seems to be forgetting is that an
energy-
saving device comes with most UK socket outlets, it's called a
'switch', and when put into the 'off' position, power cosumption is
zero! None of my appliances, including computers, digital TV
receivers, etc. have come to harm through this practice, I always
switch off at the wall, back in the day when there were fewer
appliances this was standard procedure to avoid fire risk.
They can't switch the power stations off overnight, so they may as
well power the 1W my TV takes to be in standby.
I seem to remember that some hydro electric plant is powered down and
some gas fired .. but coal is rather long winded to slow down and
restart..
basically anything that is high power and heat driven doesnt
appreciate lots of heating up and cooling down.
used to be some of the really big generators needed to be left
spinning while cooling off......
They use the spare overnight power to pump the water back up in a
stored
hydro power station so that it's full in the morning when everyone
turns
their kettles on, so it isn't wasted.
except you only get back maybe 75% of what you put into the pumping
during generation.
And then you lose some more pushing all the power to N Wales and
getting it back again to somewhere useful.
but it was very close to a couple of nuclear power stations (probably now
closed) so the distribution losses would actually be rather low.
it is still running, but nt for much longer
http://www.magnoxnorthsites.com/abou...ts-and-figures
even then the pumped scheme is a bit bigger scale than the local
nuclear station - Dinorwic can generate at over 2 GW.
http://www.fhc.co.uk/dinorwig.htm
all this green electricity that seems a lot more reliable than all
those dinky toy wind turbines....
There is nothing green about dinorwic as far as co2 is concerned.
It is a net producer of co2, far more than the nuclear plant .
It is just a "rechargeable battery" nothing more.
true, but not the whole storey.
Dinorwic is there to improve the operation of the grid as a whole.
What it does is allow the grid to operate with a higher base load from
the more efficient plants and do something useful with the excess as
the load varies.
It is there to satisfy peaks in demand and uses more energy to recharge
overnight than it can ever deliver during the day. In doing so it may reduce
the co2 output from the total generating capacity, it may not depending on
the conditions at the time.
Yes - because the big stations take a lot of time to bring up and even
longer to shut down cleanly.
The biggest innovation in Dinorwic was not using it as a battery, but
how fast it can react to load changes.
Operating the grid with dinorwic in place is supposed to be equivalent
to having another 2 big nuclear stations in operation
To be more green we would just drop the supplies to some areas when the peak
demand got to high, however the customers may revolt.
the assumption here is that shedding load doesnt cause side effects,
and can be done quickly enough without causing stability issues to the
grid itself.
In reality there are lots of sites where unexpected shudowns cause
issues (data centres, hospitals ?).
also many sites where power continuity is critical have backup
generators - now those really are inefficient compared.
then we have all those widely varying input devices that cause
instability and so cannot be relied on within the base generation -
windmills for example.....
--
Regards
- replace xyz with ntl