Nuclear power not a solution

Here are just a few of the reasons nuclear won't work in Australia:

Currently available nuclear power plants are between 1 and 1.3GW.
and they don't like being trimmed much below 60% of peak output
particularly in the second half of the refuelling cycle.

Minimum demand in SA [South Australia] is around 600 MW and in most cases there will be some wind
running or solar or gas so the plant will need to find export demand for around
500-600 MW and on a windy night again competing with wind and sometimes finding
that there is not enough demand from Victoria or capacity on the interconnect.

To solve that problem, Japan and France have built a lot of pumped hydro (almost
60% of peak nuclear capacity in Japan) or interconnects to other markets. That
capacity can also be used to backup the plant in case of an outage. However, if
you only have one nuclear plant you must have backup equal to the peak capacity
so a 1.1 GW nuclear plant (AP1000) needs 1.1GW of fast acting capacity. i.e a
combination of gas spinning reserves and pumped hydro. Now pumped hydro is great
for a 4-5 hour shutdown but refuelling takes 4-6 weeks every 3 years so that
means all of the nuclear capacity has to be replaced by gas for that time.

There is another little trick to nuclear power. If the reactor is disconnected
by a SA style event [the once in 50 years storm recently, which brought down 19 transmission pylons] for 2-3 hours there is a built up of Xenon 135 which "poisons" the neutron flux and stops the reactor working. The Xenon-135 can take 25-35 hours to die down before the reactor can start up again. Then it can take another 30 hours or so to reach full power. Imagine how much money the gas
generators are going to make during that time

Now to the cost. In SA a nuclear plant might manage 75% utilisation while on
line (same as France) and therefore 72% allowing for refuelling, generating
around 7 TWh per year.

Plant Vogtle in the US is currently less than half complete, 40 months late
already after 5 years of construction and currently estimated at US$21b
including finance costs for two units, if there are no further delays.
We [in Australia] have no experience in nuclear building and none of the skills and heavy
welding, lifting equipment so we learn by doing or import a lot of expensive
French or American labour and we are only building one unit. 

So less 15% for learning curve +20:30% for local costs +5% for seawater
cooling +10% for one unit not two so A$17.5b for one AP1000, plus storage + gas
backup and by the way it will take 10 years from permitting to full power. Then
add about $2-3b for the storage and $1.5-2.5b for a dual circuit interconnect to
the Sydney basin and using Pelican Point + Osbourne as the constantly running
"spinning reserve".

Permitting in the US and the UK where there are experienced regulators take 3-4
years. How are we going to do it quicker? So in total we can expect a 15 year
project from today.

Operating costs for nuclear are pretty cheap, probably around US$25-35 per
MW.hr. say A$40 but at a generous 8.5% weighted average cost of capital and 45
year life, the interest and depreciation works out at A$278 per MWhr + $40
operating costs. Be generous and say $310. Forward prices in SA now for 2020 are
$83/MWhr so the proposed nuclear plant plus infrastructure would increase the
already high SA cost almost 4 times

With falling wind prices, $17.5b over 15 years can build about 10 GW of wind. As
the capacity factor is increasing with every new generation of turbines, we can
expect about 45 GWh of annual generation. Now even if we added 25% of that
amount of wind to the existing fleet we would already be generating all the
power SA needed from wind so again we need gas and extra storage. The advantage
is that even though one or even three wind wind farms could be taken off line by
a storm there would still be plenty generating so with 1GW of storage there
would be plenty of time to power up gas turbines from cold. Thus although there
might be more gas generation over the year, there would be very few times where
the generators are running "just in case" so overall gas costs would be lower.

We have operating costs for wind turbines at about $15/MW.hr and capital and
depreciation over 25 years at the same 8.5% so we are adding about 2.5GW of
wind at a cost of $4.5b, Lets say a new interconnect but because we don't have
the Xenon problem it doesn't need to be large or ro bust and leave the storage the
same. So now we have a total system of $4.5b + $1-1.5 interconnector + $2-3b for
storage say $8b generating about 11 TWhr. or $123/MW.hr with no subsidies i.e.
less than 40% of the cost of nuclear even including the excessive storage.

[From comment from reneweconomy.com.au, via a comment in The Guardian--Hat tip to summerswood.  My minor edits in square brackets]