On 01/11/2011 17:24, Roger Chapman wrote:
On 31/10/2011 19:46, John Rumm wrote:
On 31/10/2011 19:24, harry wrote:

Mind you, £0.21/Kwh would still give a better return than money in the
bank these days.
I wonder what percentage of the national load it provides on a sunny
day?
I have done 2747Kwh to date.

It hardly matters, it will need a proper power station sat there in hot
reserve anyway, so its real contribution is of little value.

Nonsense.

Unlike windmills the major contribution of PV panels is reducing demand
on the grid and with a multitude of individual houses any variation in
demand/output will be statistically easy to determine and any
variability will be small in relation to the other factors that the grid
has to take into account.

PV makes very good sense in countries where the sun gets high in the sky
and ambient temperatures and humidity require airconditioning. It is on
the verge of barking mad to subsidise installation of PV panels in the
UK at latitude 50+ N - where net energy payback is about 4:1 - but
installed in sunny places like Australia or Japan you get nearer 7:1.
And more importantly you get the extra energy boost at a time of peak
demand. Load and generation are naturally matched there.

Have you not noticed how the solar powered "please go round the bend"
signs die a horrible death in midwinter when they are really needed.

I don't know what the exact proportion is but even windmills don't need
100% of hot reserve. PV panels shouldn't need very much (or even any)
even if every house in the land was so equipped.

PV panels in the UK at present probably don't need any hot reserve as
their total overall contribution is not statistically significant.

--
Regards,
Martin Brown