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VK3XX > ENERGY 10.06.05 10:47l 110 Lines 6064 Bytes #999 (0) @ WW
BID : A11404VK3XX
Read: DK3TB GUEST OE7FMI
Subj: Re: Nuclear Power(VK2AAB)
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Sent: 050610/0834Z @:VK3FRS.#MEL.VIC.AUS.OC #:51354 [Kilsyth] $:A11404VK3XX
From: VK3XX@VK3FRS.#MEL.VIC.AUS.OC
To : ENERGY@WW
Hi Barry, and all other readers,
I go along with all you have to say in your bulletin except for one point.
A statement has been made by someone either in the media or a typical
politician to the effect that a desalination plant requires a new power
station to drive it. That may be partially or superficially true but for
at least the last 30 years desalination has been carried out in Middle
East countries and others using a gas turbine electrical generators
fuelled by natural gas to deliver electrical power with the massive amount
of exhaust heat being used to distill sea water. The amount of heat
leaving the exhaust of a simple open cycle gas turbine can approach about
2/3 of the total heat content of the fuel. The other third goes to produce
electricity. There are of course losses to be taken into account but the
overall thermal efficiency of this cycle is in excess of 60% and the hydro
carbon and CO2 emissions are relatively low compared with coal or oil
fuel. Electricity can be seen as a by product of such a cycle as it
certainly isnt necessary to distill water.
Modern gas turbines are more efficient and reliable than those of 30 years
ago so that makes an improvement over the cycle which was commercially
viable long agp when the commercial and political will was there. The gain
in thermal efficiency of the generator set was from higher compression
ratio and higher combustion temperatures.
A typical basic generating unit would now be as big as 50-100 megawatts
(equal to 20 to 40 wind generatos) today and the heat delivered to the
desalination plant would be the equivalent of twice the generation power.
As in many fields, the view of scientists and even engineers is
constrained to the area in which they specialise so water and electrical
utilities do nothing to help the pollies to do the logical thing. Here in
Victoria is a good example. The privatised electrical utilities have
installed several gas fuelled gas turbines purely for power generation at
about 35% thermal efficiency, and probably well over 100MW of them. I am
not aware that any are coupled to a sea water distillation plant. The
investment was made to cope with a summer power shortage and I doubt that
they would run for much more than 100 hrs in any year! But they are
cheaper than investment in proper base load plant. I feel sure that the
same has happened in NSW, Barry.
So we now turn to the nuclear aspect of this theme. I certainly see that
nuclear is a solution for power generation of a magnitude necessary to
cope with industrial growth in any first world country. The worry is that
many third world countries that are embracing this option. Casualties of
nuclear power in first world countries are vastly less over the years than
the casualties in the extraction of coal for steam generation. That doesnt
make it necessarily a desirable option to go nuclear but unless we all
stop using electricity in our homes and factories at the current rate of
increase then the real options are few. Nuclear waste is the problem. In
50 years of nuclear power it has been stored within practical if not
optimal safety facilities. That is because the volume or mass of nuclear
waste compared with waste from coal power generation (ash) is almost
negligible. The problem is entirely with which malevalent powers succeed
in stealing it and reprocessing it for weapons. Even power plant ash has a
good market value because there is so much that profitable uses are found
and are worth while as there is so much of it.
The concern about burying nuclear waste deep in rock is hardly profitable
and I venture to suggest that the sequestration of CO2 from exhaust gases
is no different. The argument about there being an earthquake which lets
it escape some time in the next 10,000 years is certainly valid but as we
dont know what natural or man made disasters are going to befall this
planet in to next decade the risk over 10,000 years needs to be put into
perspective.
After all risk is present in every human activity, some more than others,
and it is that which needs properly assessing and managing. Electrical
utilities which are privately owned dont want to know, politicians dont
want to know as the future for adequate safe power was relinqished to
investors as have many other services which truly should be as much a
priority for governments to control. The trouble is that they know that
they cant do it efficiently, so they get rid of the problem and then they
can offer illusionary tax reductions to the public at election time. If my
bias is showing in my support for public utilities being government owned
operated and funded then so be it.
I will hust return to wwter for a moment. It is said that 70% of the
"fresh" water in Australia is used for irrigation, about 15% is used in
industry and 15% in small business and domestically. In Victoria the fresh
water staorage for Melbourne alone is approaching 2 million gigalitres. So
if only 15% were to be used solely for domestic purposes only 300,000
gigalitres need to be desalinated to replace meet that sector's
requirements. Most of the irrigation is from river water and the industry
and business needs can come from the same source with limited treatment.
By desalinating a significant portion the water quite a lot of electrical
power can be efficiently generated. Much of this can be sea water thus
leaving more for river flows and industry and business to compensate for
less rainfall due to climate change.
It is a very long time since I did the mathematics to determine a
numerical calculation of the amount of water that can be distilled from a
10 MW gas turbine exhaust heat but my recollection of when I was in that
business that it was thousands of gallon per hour. Someday when I have
nothing better to do I might publish some figures on this. If I can
remember how!
Cheers for now and
73 - GORDON, VK3XX @ VK3FRS
Message timed: 17:00 AEST on 10 Jun 2005
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