Calculating coal CO2 emission intensity (kg CO2 emitted/kWh delivered)

In summary, the conversation is about calculating the CO2 emission intensity of brown coal in a steam power plant based on its energy and carbon content. The discussion covers various approaches and calculations, ultimately leading to the conclusion that burning 1 kg of coal produces 2.38 kg of CO2 and 4.5 MJ of electrical energy, which needs to be converted to kWh.
  • #1
Hi all,

Would really appreciate some help on this problem I can't seem to figure out.

Brown coal has an energy content of 15MJ/kg, carbon content 65% by weight, burning in a 30% efficient steam power plant. Calculate the CO2 emission intensity (kg CO2 emitted/kWh delivered).Assume complete combustion where all the available carbon in the fuel is converted to carbon dioxide gas.

Thanks in advance :)
 
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  • #2
You need to at least make an attempt before anyone will help you. What do you know and what have you tried?
 
  • #3
I'm getting confused about how the carbon content effects the efficiency i.e. the amount of energy obtained when the coal is burnt. Here's what I've come up with so far:

Brown coal: 15MJ/kg

Efficiency = power output/power input. --> 0.3 = x/15
x = 4.5 MJ. So after burning the coal we get 4.5MJ worth of useful energy/kg. Thus, 10.5MJ/kg is not useful. Would it be right to assume that this useless energy comes from the 650g of carbon in 1kg of coal? Don't know how to proceed after this.

Any help would be great, thanks :)
 
  • #4
How much CO2 is produced from burning 0.65 kg Carbon?

What's the nuclear mass of carbon and oxygen?
 
  • #5
Ok so C + O2 --> CO2
After a quick mole calculation, with C:CO2 in a 1:1 ratio I get 2.38 kg of CO2 produced from burning .65kg of Carbon. Would the kWh (energy) delivered by burning this coal just be 4.5MJ or is it something else?
 
  • #6
darkPassenger said:
Ok so C + O2 --> CO2
After a quick mole calculation, with C:CO2 in a 1:1 ratio I get 2.38 kg of CO2 produced from burning .65kg of Carbon. Would the kWh (energy) delivered by burning this coal just be 4.5MJ or is it something else?

Yes, I think you're on the right track now. I think you're correct that burning 1 kg of coal produces 2.38kg of CO2 and 4.5 MJ of electrical energy. But you still need to convert 4.5MJ to kWh in order to get the final answer.
 

What is the purpose of calculating coal CO2 emission intensity?

The purpose of calculating coal CO2 emission intensity is to measure the amount of carbon dioxide emitted per unit of electricity produced from burning coal. This helps to assess the environmental impact of coal-fired power plants and track progress towards reducing emissions.

How is coal CO2 emission intensity calculated?

Coal CO2 emission intensity is calculated by dividing the total amount of carbon dioxide emitted from coal combustion by the total amount of electricity delivered from coal-fired power plants. This results in a measure of kg CO2 emitted per kWh delivered.

What factors can influence coal CO2 emission intensity?

The main factors that can influence coal CO2 emission intensity include the type and quality of coal being burned, the efficiency of the power plant, and any emissions control technologies in place. Additionally, the source of electricity demand and the overall energy mix of a region can also impact emission intensity.

How does coal CO2 emission intensity compare to other energy sources?

Coal CO2 emission intensity is generally higher than other energy sources, such as natural gas, nuclear, and renewable energy. This is due to the higher carbon content of coal and its lower efficiency compared to other fuels. However, emission intensity can vary depending on the specific characteristics and technologies used for each energy source.

What are some ways to reduce coal CO2 emission intensity?

There are several ways to reduce coal CO2 emission intensity, including improving the efficiency of coal-fired power plants, using cleaner coal technologies, implementing emissions control technologies, and increasing the use of renewable energy sources. Additionally, reducing overall electricity demand through energy efficiency measures can also help to lower emission intensity.

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