Sorry for the double response, but I read the pdf.

You state that Australia used 1600 PJ of black coal to generate electricity.  
After using it, did Australia go dark and cease to use electricity?  Without 
tracking down your sources, I am pretty sure this is an annual figure in a 
particular year, and that Australia continued to use black coal.

If your total coal reserves are known (we're not that wise, we keep finding 
more) the joule (with suitable prefix) would be an acceptable way to state the 
resource; it is also suitable for any given heap of coal.  It does represent a 
total available energy; when you use it up, you go dark (or find something else 
to use).  However, you don't just use an amount.  You use an amount per year 
(or per day).  It confuses power and energy to omit the "per annum" or 
something similar.  Once you incorporate it, you are talking (average) power 
whether you use 1600 petajoules per annum or 51 Gw (thermal).  The relationship 
is as simple as the number of seconds in a year (except for "what's a year?").

I have no issue with reference to annual energy usage, but omitting the per 
annum is omitting a unit, we all know "naked numbers" are dangerous, and 
attempting to assert it is NOT average power is technically incorrect.  I urge 
you to fully unitize your numbers.




________________________________
From: Pat Naughtin <[email protected]>
To: U.S. Metric Association <[email protected]>
Cc: U.S. Metric Association <[email protected]>; gmail aaj <[email protected]>
Sent: Mon, June 7, 2010 12:36:46 AM
Subject: [USMA:47525] Re: One unit only

Dear Stan, 

It seems really odd to me that engineers, who probably know much better, are 
using a power unit when they are referring to energy.

As far as I know power and energy were clearly distinguished as two quite 
separate and distinct physical realities late in the 1700s or early in the 
1800s (I would like to have an exact date but this is the best I can do at 
present).

As you know the unit for energy in the International System of Units (SI) is 
the joule (symbol J) and the unit for power in SI is the watt (symbol W). It 
makes no sense at all to me to pretend you are talking about energy when you 
are trying to describe it with the SI unit for power.

You will recall that I am really concerned about this issue because until 
journalists and politicians are able to comprehend the nature of energy and how 
to measure it, we have no chance that they might begin to comprehend issues 
such as 'global warming', 'climate change', or 'the end of oil' as these are, 
in essence energy issues, and not power issues.

My approach is to use the SI unit, joule, only, and to use it with an 
appropriate prefix to give whole number amounts. See the short article at 
http://www.metricationmatters.com/docs/AWordAboutGlobalWarming.pdf for an 
example of how I use the energy unit, joule.

Cheers,

Pat Naughtin

On 2010/06/07, at 10:17 , Stanislav Jakuba wrote:

I am attaching an energy article that is distinguished for using only one unit, 
the watt (W), throughout. That units was selected as it is both familiar 
everywhere, incl. in the US, and shorter than others that one could select to 
express the average energy usage. The watt (as GW) is the only unit need for 
these kinds of global statistics, and using it exclusively enables immediate 
comparisons.
> 
>I do not mean to start a debate about the opinions expressed in the treatise, 
>although I will certainly read all. Instead, I do hope to "persuade" everybody 
>in the energy business to settle on this unit for any kind of energy usage, 
>i.e.power, anywhere in the world instead of the plethora of units common 
>in energy related statistics. On the scale of countries, only one prefix also, 
>the G, suffices.
> 
>Stan Jakuba
> <Pacific Gas & E.3USMA.doc>


Pat Naughtin
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