1. Air, Earth, Fire and Water An Introduction to Environmental Science
Energy ~ Fossil Fuels

2. Energy ~ Some Basic Ideas
Energy is the ability to do work
It is measured in J or kJ
Energy can be converted from one form to another
There are many different types of energy: Kinetic, Potential, Nuclear, Chemical, Electrical, Magnetic, Heat, Sound
Unit 1 ~ Energy ~ Fossil Fuels

3. Formation of Fossil Fuels
Work is the transfer of energy.
About 300 million years ago huge forests covered many areas.
These forests died and were replaced by others; until over the ages a thick layer of plant matter was built up this was called peat.
Over the years the seas came in and covered the peat with mud and sand. Thousands of years later the seas retreated and new forests grew. This happened many times and the compressed peat turned into coal.
Unit 1 ~ Energy ~ Fossil Fuels

4. Formation of coal www.minepermits.ky.gov/.../coal_formation.htm
Unit 1 ~ Energy ~ Fossil Fuels

5. Formation of Fossil Fuels
As this vegetation decays, the peat changes to coal, and methane gas is also formed.
Over the ages huge quantities of methane gas have been trapped under impervious rocks.
These methane sources have been found in many places including the North Sea and off the South coast of Ireland.
Unit 1 ~ Energy ~ Fossil Fuels

6. Unit 1 ~ Energy ~ Fossil Fuels
Types of Fossil Fuels
Coal
Oil
Gas
Peat
Unit 1 ~ Energy ~ Fossil Fuels

7. Unit 1 ~ Energy ~ Fossil Fuels
What is a Fuel
A fuel is a substance which can be used as an energy source.
We can burn fuels to create energy to power our homes, our cars and industry.
The amount of energy a fuel contains can be measured by burning a known mass
This gives us the fuels heat of combustion in kJ/kg.
Unit 1 ~ Energy ~ Fossil Fuels

8. Unit 1 ~ Energy ~ Fossil Fuels
Heat of combustion
Heat of combustion of a substance is the heat change which occurs when one mole of the substance is burned in an excess of oxygen.
A reaction in which heat is liberated is known as an exothermic reaction.
A reaction in which heat is taken in is known as an endothermic reaction.
Combustion reactions are exothermic.
Unit 1 ~ Energy ~ Fossil Fuels

9. Burning of fossil fuels
Carbon:
C (s) + O2 (g) → CO2(g)
Methane:
CH4 (g) + 2O2 (g) → CO2 (g)+ 2H2O (g)
Oil:
C6H6(l) + 7.5O2(g) → 6CO2(g) + 3H2O(g)
Unit 1 ~ Energy ~ Fossil Fuels

10. Some fuels are better than others!
The different fossil fuels give our different amounts of heat/kg and produce different amounts of CO2
Thus some fossil fuels are better for the environment:
Gas > oil > coal
Unit 1 ~ Energy ~ Fossil Fuels

11. Unit 1 ~ Energy ~ Fossil Fuels
Burning natural gas
Unit 1 ~ Energy ~ Fossil Fuels

12. Unit 1 ~ Energy ~ Fossil Fuels
Heat of Combustion
Calculate the heat of combustion of ethanol from the
following experimental results, taken using a bomb
calorimeter:
Mass of ethanol = 20 g
Mass of water in calorimeter = 10 kg
Initial temperature of water = 18 ˚C
Final temperature of water =32 ˚C
Specific Heat capacity of water = 4200 J/kg˚C
Unit 1 ~ Energy ~ Fossil Fuels

13. Unit 1 ~ Energy ~ Fossil Fuels
The calculation
Heat gained by water ΔH =
(Temperature rise, ۫C) x (Mass of water in calorimeter, kg)
x (heat capacity of water, J/kg)
= 10 x 4200 x 14
= J = 588 kJ
Thus the combustion of 20g of ethanol liberates 588 kJ
1 mole of C2H5OH = 46g
Therefore combustion of 46g liberates
46 x 588 kJ = 1352 kJ/mol 20
Heat of combustion = kJ (exothermic reaction)
Unit 1 ~ Energy ~ Fossil Fuels

14. Different Types of Fuels ~ Solid, Liquids, Gases
Predict what types of fuel you think would give the most energy?
Why?
Kerosene
Coal
Ethanol
Unit 1 ~ Energy ~ Fossil Fuels
Gas
Oil

15. Unit 1 ~ Energy ~ Fossil Fuels
Exothermic Reaction
Unit 1 ~ Energy ~ Fossil Fuels

16. Exothermic and Endothermic Reactions
Unit 1 ~ Energy ~ Fossil Fuels

17. How much fossil fuels is used worldwide?
Source: Worldwatch Institute.
World Fossil Fuel Consumption per Source,
(in million of tons of equivalent oil)
Unit 1 ~ Energy ~ Fossil Fuels

18. Unit 1 ~ Energy ~ Fossil Fuels
Irish energy use
Unit 1 ~ Energy ~ Fossil Fuels

19. How much energy do we import?
Unit 1 ~ Energy ~ Fossil Fuels

20. Unit 1 ~ Energy ~ Fossil Fuels
Where do we use energy?
Unit 1 ~ Energy ~ Fossil Fuels

21. Unit 1 ~ Energy ~ Fossil Fuels
Energy in the Home
Ireland imports most of her energy needs at present.
We are still using fossil fuels to power most of our homes.
By completing an energy audit on your homes use can determine how much of these fuels you are using unnecessarily.
Unit 1 ~ Energy ~ Fossil Fuels

22. Unit 1 ~ Energy ~ Fossil Fuels
Energy Loss
Common Areas of Energy Loss:
Radiation
Conduction
Convection
Condensation
Air Infiltration
Leaving Electrical Items on Standby
Energy Efficient Light Bulbs
Unit 1 ~ Energy ~ Fossil Fuels

23. Unit 1 ~ Energy ~ Fossil Fuels
Energy Loss
Unit 1 ~ Energy ~ Fossil Fuels

24. Unit 1 ~ Energy ~ Fossil Fuels
Energy Types
Types of Energy:
Nuclear
Kinetic
Potential
Heat
Sound
Light
Electrical
Unit 1 ~ Energy ~ Fossil Fuels

25. Energy Efficient Home of the Future
Unit 1 ~ Energy ~ Fossil Fuels

26. Unit 1 ~ Energy ~ Fossil Fuels
Conclusion
Energy is something that we use in everything we do in every aspect of our lives.
Fossil fuels are being depleted rapidly and cause harmful gas emissions when they are burned to produce energy.
We should all watch our energy consumption in order to save energy for the future.
Unit 1 ~ Energy ~ Fossil Fuels