Transmission Line Costs

Ok, I've remembered the deal here. I learnt this 20 years ago, so I'm
a bit rusty ;-)

The power dissipation down a transmission line is actually very
small. One important loss is resistive losses. That's why high voltages
are used for long distance in fact- the current is inversely related
to the voltage.

The resistive losses are proportional to the square of the current,
so going from 110 volts to 230 kilovolts means that the dissipation,
already fairly low for wire, goes down by more than 4,000,000 times.

That's good for a long, long distance.

There are some losses due to transformers, and they are significant, but
designing transformers with 95% efficiency is not impossible, and they
are one time losses, you step up, you transmit, you step down. In fact
they probably dominate.

The real problem in power transmission is phase. By the time electricity
has traveled 1500 miles crosscountry it is now exactly out of phase with
the grid that it enters (roughly speaking) and then something goes bang
;-)

Anyway, it's horribly efficient (90% or so). There are much bigger
inefficiencies in the power generation side. The generators are down
about 45-55%.

>
>>Mitchell,
>>
>>For investor-owned utilities, this data are located on the FERC
>>
> web site
>
>>(www.ferc.fed.us). Please look under electricity then under the
>>
> FERC Form 1.
>
>>The information will be on the Lines Added Schedules of the individual
>>filings.
>>
>>The information is not compiled, but is the only source for public
>>
> and private
>
>>utilities. EIA does not collect cost information. (EIA is currently
>>
> requesting
>
>>authority to collect this information, but none would be available
>>
> until next
>
>>year.)
>>
>>Transmission losses are found in the Form EIA-861 data base and
>>
> Elec. Power
>
>>Annual Vol. 2 publication. Both can be downloaded from the EIA
>>
> web site
>
>>(www.eia.doe.gov).
>>
> My preliminary analysis:
> The FERC information from Form 1 is volumous in the extreme. 300
> pages for a good sized utility company. But other than being able
> to tell that California Independent System Operator Corp. spent $56,
> 652,914 for total transmission expenses ($43million of which was
> spent on Load Dispatching) on a revenue of $186,406,885 from page
> 321, I am not sure that it means anything to know that TXU has a
> 345KV 60cycle 3phase line 148 miles long going from Gramham PLT to
> Morgan CR no3. There are hundreds of pages in these reports listing
> every transmission line and substation in the United States.
>
> The EIA information at least tries to be useable. Form EIA-861,
> table 1, contains three columns on "wheeling" which means transmission
> of energy though a utilities network to be used elsewhere. The problem
> with this data is that many of the utilities do not seem to have
> the information or know how to fill out the forms. The South Texas
> Electric Coop Inc received 267337MWh of energy and didn't deliver
> any for a 100% energy loss. On the other hand a number of large
> utilities managed to receive and deliver exactly the same amount
> of energy for no transmission loss. The Georgia Transmission Corp
> seemed to have the most realistic numbers. They received 29,991,
> 760MWh of energy and delivered 28,759,589MWh for a 4.1% loss in transmission.
> They don't generate or sell power so I expect that their numbers
> are the most realistic for our discussion.
>
> We will have to find cost data from somewhere else.
>
> Mitchell James
> mejames@...
> http://www.InnerTransit.net (Email distribution for multilevel organizations)
> http://www.InnerTransit.org (Homebase for collaborative engineering)
>

civilization?"