# Unit conversion

1. Feb 9, 2013

### Young Learner

Today I came across a statistical report of world energy consumption. There was a tab named energy generated and the values were given in TWh. There was a tab named Primary energy consumed and the values were given in Mtoe. I saw that the energy generated by the world is around 20000 TWh and the Primary consumption is around 12000 Mtoe.
My questions are:
1. Why is that the Energy generated and the energy consumed are expressed in two different terms?
2. I came to know that 1Mtoe=11.63TWh, the 12000Mtoe=139560TWh. How come the consumption is so high when the generation is only 20000TWh

2. Feb 9, 2013

### Staff: Mentor

Would coal and oil be classified under "Energy Generated"?

3. Feb 10, 2013

### Young Learner

Does that mean 12000 Mtoe is burned to produce 20000 TWh of energy?

4. Feb 10, 2013

### Staff: Mentor

Where would the fuel burnt in motor vehicles be categorized in these statistics?

5. Feb 10, 2013

### Young Learner

Do you mean that they have specified the primary fuel consumed which also includes the fuel used for transportation.
That was an electrical energy statistics report

6. Feb 10, 2013

### Staff: Mentor

That is my interpretation, though based on scant information. Otherwise, the conclusion is that only 1/7 th of the fuel is converted into electric energy. Maybe they take into account the energy used in mining and transporting the coal, including that as primary consumption?

Last edited: Feb 10, 2013
7. Feb 10, 2013

### Young Learner

I was not able to upload the entire file. So, I just cropped it.
Just see whether you'd be able to come to a conclusion from the following data

#### Attached Files:

• ###### stats.xls
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8. Feb 10, 2013

### D H

Staff Emeritus
Wikipedia indicates that world production of electrical power in 2008 was 20,261 TWh while world consumption of energy was 143,851 TWh (12,369 Mtoe). These numbers are consistent with the values specified in the opening post. A better label for that "energy production" tab would have been "electrical power production".

Does this mean that only 1/7 of the world's energy annual consumption is used for the purpose of generating electricity? No. Actually it's about 36%. Power plants aren't 100% efficient; the second law of thermodynamics gets in the way. A good chunk (61%) of the energy consumed in the production of electricity is turned into heat rather than electricity.

9. Feb 10, 2013

### Young Learner

Fine, I understand. Just one clarification, Does the consumption of energy includes renewable energies such as hydro and tidal or it is just confined to coal and oil.

10. Feb 10, 2013

### Staff: Mentor

Unless the document indicates they excluded some energies, I expect it would be an estimate of energy from all sources.

11. Feb 11, 2013

### Young Learner

Thank You all for the instant replies. :)

12. Feb 11, 2013

### jim hardy

Since you're interested in the subject, here's a link i enjoyed.
It's from 2007 when world use was about a cubic mile of oil per year. They try to put that in some perspective.

http://www.theoildrum.com/node/2186 [Broken]