# Homework Help: Energy Intensity of black coal

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1. Sep 6, 2015

### Jonski

1. The problem statement, all variables and given/known data
Brown coal, energy content 16 MJ/kg, carbon content 65% by weight, burning in a 30% efficient steam power plant.

2. Relevant equations
What is the emissions intensity (kg CO2 emitted/kWh delivered) ?
Compare this to Hazelwood which is 1.53 tCO2/Mwh

3. The attempt at a solution

I really have no idea how to do this question but this is what I tried
I have done a bit of research and worked out that 1kg of carbon = 3.67kg of CO2, so 0.65kg of carbon = 2.39kg of CO2. (1kg * 65%)
The energy produced is also 16MJ * 30% = 4.8MJ
4.8MJ = 1.3 Kwh
so the emissions intensity is 2.39/1.3 = 1.79 kgCO2/Kwh ?

Last edited: Sep 6, 2015
2. Sep 6, 2015

### oz93666

.....energy content 16 MJ/kg, carbon content 65% by weight, burning in a 30% efficient steam power plant..

So if 1kg burns it produces 16x .3 MJ = 4.8 MJ ......1Kw Hr= 3600 K J ... so IKg coal produces 1.333333 KWHrs

This Kg of coal contains 650 gms of carbon ....C... At Wt= 12 ....O At Wt 16 so 12 gms of C makes 44gms CO2

So 650 gms C(1 Kg coal) burns to 2.383 Kg CO2 producing 1.3333KwHrs 1.787Kg CO2 per Kw Hr.