[LINK] Back of Beyond Power Transmission Costs and Efficiencies.

[Tom Koltai]

In response to Greg Kim and Andy...

OK, here goes.... (difficult to do within the restrictions imposed on an
ASCII text based transmission medium ...)

On further reading, the hotrocks project will in fact be a 50 MW plant
so the 2 MW dissipating to zero by Melbourne doesn't apply.[5]

For the other Linkers scratching their heads about power loss...  

Start Prologue/
The cost of delivering 50 MW of power from the Hotrocks project to
Portland Victoria, with less than 2% power loss  (direct) would be
approximately 1.2 billion dollars Therefore unrealistic and commercially
unviable.
/end prologue
Disclaimer - There are many factors involved, right of way, terrain,
temperature variations along the transmission lines, wind shear [HV
cables swinging in the wind] , therefore this  number should definitely
be discounted as a back of the envelope stochastically generated A--e
Pl--k.
================================

In simple terms, higher amounts of power can be transmitted if
transmission voltages are higher. [2]

The majority of Australia's Grid (was in 2004) at 330 kV (that's 330,000
volts).

Let us say that the power in Innamincka will be generated at 23000
Volts, it then needs to stepped up to 330 kV for the long haul in
between transgrid points, when it leaves the Grid network, it is
transformed down to 132 kV and then after distribution to the regional
substation it is transformed again down to 33 kV and when it gets to the
city substation it is transformed again to 11 kV and sent around to the
transformers you see on poles in the street, these transformers then
transform the power one more time down to 415 V for reticulation to you,
the user.
http://kovtr.com/data/Key_Elements_of_the_Grid.gif


Now we need to analyse the power loss at each of these Voltages.

6.6 kV     PLP km  278%
11 kV      PLP km  100% 
20 kV      PLP km    30%
33 kV      PLP km    11%
Source [1]

PLP = Power Loss Per 

Australia is upgrading her transmission Grid gradually. But it is a
hodgepodge of different transmission voltages.

345 kV    PLP 200 km       8%
500 kV    PLP 200 km       2%
765 kV    PLP 200 km     <1%
http://kovtr.com/data/Graph_Relative_line_losses_for_various_transmissio
n_voltages.gif

Unfortunately the cost of a substation to step up the power to 765,000
volts (for a 50 mW plant is close to 50 million dollars.) and the cost
of the transmission line exceeds 1 million per kilometre. 

Quote/ [Ref: Table 3. Typical Capital Costs for Electric Transmission
Lines, by Voltage [4]]
New 345 kilovolt (kV) single circuit line $915,000 per mile
New 345 kV double circuit line $1.71 million per mile
New 138 kV single circuit line $390,000 per mile
New 138 kV double circuit line $540,000 per mile
New 69 kV single circuit line $285,000 per mile
New 69 kV double circuit line $380,000 per mile
Single circuit underground lines Approximately four times the cost of
aboveground single circuit lines.
/Quote
Source: American Transmission Company, 10-Year Transmission Assessment,
September 2003.

Quote/  [4]
In a recent proposal to build 34 miles of 500 kV in California, the "per
mile" cost of the project was $10 million.
/Quote

Therefore as can be seen from the brief insight that I have tried to
give, Transmission losses vary depending on the voltage, the feeder
length, the number of interconnects into the feeders and the
interconnects into the transmission long hauls.

In Australia, in 2005 based on the Grid as it was then constructed and
all of the information that I compiled over four months [incomplete for
parts of South Australia and northern QLD] [remembering that NT and WA
are not part of our eastern seaboard power grid] and analysed over three
weeks of mind numbing excel data comparison modelling...

The transmission loss was 2 kW per kilometre and I will defend that to
my grave.
Of course, with the Grid constantly being upgraded and with new
consumers [read Greenfield developments] and decreasing industrial
requirements, that 2 kW figure today may have changed by as much as 5%
to 2.1 kW or maybe down to 1.9 kW.

("And sometimes I should just shut-up and not say anything", he says
after an hour of compiling this stuff....)

References:

[1] Electricity distribution network design Page 168 Table 9.1 Relative
Characteristics of medium-voltage overhead lines. [ E. Lakervi, E. J.
Holmes]
http://books.google.com.au/books?id=HMLBEXay1DUC&pg=PA168&lpg=PA168&dq=R
elative+line+losses+for+various+transmission+voltages&source=bl&ots=x2vF
YxkjVS&sig=BSqbWkXSUk_rxZFNbVBvwdZ8p3Y&hl=en&ei=6SOaTdzXBY66vQPQ5IDkCw&s
a=X&oi=book_result&ct=result&resnum=7&ved=0CEEQ6AEwBg#v=onepage&q&f=fals
e
[2]  Practical Concepts in Capability and Performance of Transmission
Lines [CLAIR 1953.]
http://www.nerc.com/docs/pc/spctf/Practical_Concepts_in_Capability_and_P
erformance.pdf
[3] http://www.aep.com/about/transmission/docs/EnablerforCleanEnergy.pdf
[4] Electricity Transmission - A Primer
http://www.raponline.org/Pubs/ELECTRICITYTRANSMISSION.pdf
[5] http://www.geodynamics.com.au/IRM/Company/ShowPage.aspx?CPID=1464
(Rename to Showpage.pdf - stupid IE format closed eco system Microsoft
web servers - should all be crushed and remanufactured as iPads..)