On 08/06/2013 14:18, The Natural Philosopher wrote:
On 08/06/13 12:10, Nightjar wrote:
On 08/06/2013 07:09, harry wrote:
On Jun 7, 7:37 pm, Nightjar wrote:
On 07/06/2013 18:16, harry wrote:
....
Still a lot of reactors.

Nowhere near as many as they try to suggest and needing a lot less or
either land area (1) or raw materials (2) than renewables.

(1) Per 1000 MWe:

Solar PV: 20-50 km^2
that is about right. 20-50W/sq meter

Wind: 50-150 km^2

That is wrong: its more like 500-1000sq km. (1-2W/sq m)

The figures come from a site promoting the advantages of nuclear power,
so I assume they would not intentionally underestimate it. The top end
of their range is about right for the 6.5 W/sq m achieved in the
Shetlands. It also ties in with the 100 times the area of a nuclear
plant that other sources claim.

Nuclear: 1-4 km^2

That's a bit high. Sizewll including the old magnox reactors is 750mx
500 m, and 1.2GWe so that comes down to 0.35 sk km so you are out by a
factor of up to ten.

The site is American, so they probably have more room to spread out
their plants than we do.


Power desnity is density is 3,400 W/sqm



(2) Per MWe of *installed* capacity. The figures in parenthesis are
the multipliers that must be applied to get the materials requirements
for an actual output, allowing for typical capacity factors:

Solar PV: 40 t steel, 19 t aluminium, 76 t concrete, 85 t glass, 13 t
silicon. (7 Spain to 15 Glasgow)

Wind: 118 t steel, 298 t concrete. (3 to 4)

Nuclear: 36-40 t steel, 75-90 m3 concrete. (1.25)


And remember because on average a nuclear power station produces 3
times as much electricity on average as a wind turbine of equivalent
*capacity* and ten times as much as solar farm over a period of three
times as long as wind power. Or solar.

Hence the multipliers.

So per unit electricity generated a nuclear power station is likley to
generate 10 times as much electricity over its lifetime as te same
capacity wind farm so the ratio of materials for wind to nuclear is
something like 32 times more steel and (assuming you meant cubic meters
not tonnes of concrete),...

Being American, it will be short tons, rather than tonnes. I doubt they
would know a cubic metre if it bit them.

Colin Bignell