1. Energy
Energy production and consumption, Agriculture and Chemical Manufacturing underlie most environmental issues
freons-stratospheric O3 depletion
CO2-global warming
Agricultural run off contaminating water ways
Urban smog and aerosols
PCB contamination of the Great Lakes in the US
Acid rain and acid aerosols

2. Energy from the earth
54.4x1020 kJoules of the sun’s energy strikes the earths surface each year
Sun
earth
Of this ~30% is reflected back to into space (albedo)
One Joule = 4.2 calories. It takes ~2000 K- calories to feed a human each day
What fraction of the earth’s energy striking the earth, if turned into food, could feed the planet

3. SO what is a joule?? Work = force x distance
Force = mass x acceleration
f = m x a
a = D velocity / D time = dv/dt
velocity = D distance / D time
a= D distance / D time2
Work = force x distance
W = f x d
W= m x a x d and W = m x d2 /t2
Work and energy have the same units
(The First Law U2 - U1 = q - w )
a joule is defined as accelerating 1 kg of mass at 1 meter/sec2 for a distance of 1 meter
A watt is a unit of power = 1 joule/second or energy/time

4. What is the total human energy utilization compared to the Sun’s energy striking the earth?
54.4x1020 kJoules of the sun’s energy strikes the earths surface each year
# of kJ striking the earth/year, minus reflection (albedo =0.3)= total energy
54.4x x 0.7= 38.1x1020 kJoules
what fraction of total sun’s energy absorbed by the earth is used by human activity ?
people use 3.7 x10 17 kJoules/year
3.7 x10 17 / 38.1x1020 = = 0.1%
so if we harnessed 1/1000th of the sun’s energy we could supply all of our needs

5. Worldwide energy use and how do we use fuels (1993)
Oil 34.1%
Coal 24.1%
natural gas 17.4%
Biomass 14.7%
Hydro %
Nuclear %
energy use/y Population (1993)
world 382 x1018 joules 4.87x109
Indust. world 347 x1018 joules x109
Developing world 35 x1018 joules 3.65x109

6. Where are the global energy reserves
oil
Figure 1.5 Spiro
page 10
Former USSR
Middle East
Asia and Australia including China

7. Where are the global energy reserves
Natural gas
Former USSR
Middle East
Asia and Australia including China

8. Where are the global energy reserves
Coal
Former USSR
China
Australia

9. Earth’s nonrenewable energy resources (1980)
estimated stock consumption (world)/year
x 1021 J x1018J
petroleum
Natural gas
coal
oilshale 2,000 0
uranium (non-breading water reactors)
Thorium and 10, Uranium (in breeder react)
Deuterium and Li in sea water for fusion

10. Worldwide energy use and
how do we used fuels

11. how long will the oil last??
1980 estimate of reserves Oil 1x1022 J
Where does a number like this come from? Let’s look at a 2004 Christian Science Monitor article:
World wide proven Oil reserves = 1.1 to 1.3 x1012 barrels
1 barrel of oil = 42 US gallons or liters
If hydrocarbons have a density of 0.9 kg/liter
1 barrel = x 0.9x1000 grams
= 1.43x105 grams oil /barrel

12. ~0.8x1022 joules 1x1022 joules = 1.43x105 grams oil /barrel
We will see later that one gram of oil
gives off 44 kJoules/g when it is
burned
We said there were 1.2x1012 barrels
known reserves
This means that we have 1.43x105 x
1.2x1012 x 44 x10000 joules of oil=
~0.8x1022 joules
WE SAID THE 1980 ESTIMATE
1x1022 joules

13. 1x1022 joules in reserves
1980 estimate of oil usage /year x1020 J/year
Estimate the # years of oil left if we used at the above rate from 1980 to 1990 and 2x’s the 1980 rate after 1990 = ??

14. 1200 x 109 in reserve New data WE use globally (2004)about
30x109 barrels/year
If we have
1.2 x1012 in reserve or
1200 x 109 in reserve
Others say World wide oil reserves have grown 15% between 1999 and 2004 and have grown by a factor of 5 since WWII

15. These estimates place the global reserves at ~3x1012 barrels and suggest that we have only used 25% of the total oil on the planet
What we know is that major importers are not waiting around to see who is right!!!
The US, China, Japan are scrambling to tie down interests in Russia, West Africa, Iraq, Iran and Libya

16. What happens to the fuel we burn
Burning “old” carbon: fossil fuels add CO2 to the atmosphere that has been buried as carbon under the earths surface eons ago.
Burning “new”: biomass fuels puts CO2 in the atmosphere that has just recently been remove from the atmosphere by plants. These kinds of fuels would be considered green house neutral.
Given the exponential increase in our use of fossil fuels, one must ask, how much longer this can go on?
Some people in the automotive industry said in 2000 (conversation of Kamens with D. Schuetzle of Ford) we will see significant shortages by 2015

17. Carbon cycle

18. Oil Petroleum and gas deposits come from the seas.
Oceans produce billion tones of reduced carbon annually.
Most is recycled to the atmosphere as CO2. A very small fraction settles to the bottom where oxidation is negligible
here it is compacted with clay and sand particles
Anaerobic bacteria digest the bacterial digestible matter, releasing O2 and N2.
The hydrocarbons most resistant are the hydrocarbon based lipids and these persist and are found in their cell membranes indicating that bacteria process organic debris in the oceans and over the eons turned it into oil

19. oil

20. oil
As the sediment becomes buried deeper, the pressure and temperature rise.
Bacterial action decreases and organic reactions occur.
These reactions release large quantities of methane and light volatile hydrocarbons and these become trapped in impermeable rock (natural gas)
Oil results from continued organic reactions and as pressure increases the water is squeezed out of the sediment
This process spans 100s of millions of years and in the short period from 1900 through the 21st century we may deplete most of the known reserves

21. Coal Coal formation is land or terrestrial based
Woody plants 200 million years ago, as they are now, are composed of cellulose and lignins. Bacteria can digest the cellulose over time but lignins are resistant
In swamps the lignins accumulate under water and are compacted into peat
Crustal upheavals buried the peat and subjected it to huge pressures and temperatuers
peat   coal over time

22. Coal formation
In swamps the lignins accumulate under water and are compacted into peat   coal over time

23. Coal formation

24. Fuel energy When we burn a fuel where does the energy reside?
Let s take hydrogen in water as an example. If we were to react H2 with O2 to form water, we would 1st have to break the hydrogen bonds and the oxygen bonds
This takes energy; in the case of H2 it takes 432 kJ/mole (~100,000 calories/mole) for H2 2H.
100,000 calories will supply you with many minutes of food energy??
To break O2 to O. (O2  2O.) requires 494 kJ/mol
When when water forms, however, we get energy back from the formation of H2O because new bonds are formed. Which ones??

25. Fuel energy
The equation for the combination of hydrogen and oxygen if say we were to burn hydrogen would be
2H O2  2H2O
To break a mole of H2 bonds requires 432
We need 2 moles of H2 so this requires 864 joules
To break a mole of O2 requires 492 kJ/mol; so the total energy required to break 2H2 and O2 apart is 1356 kJ
To form water we need to form two O-H bonds. When one OH bond forms it releases 460 kJ/mole
But there are two water molecules that from = 2x 460x2= 1840 kJ/mole
So how much energy is released?

26. Energy from breaking other bonds (enthalpy) kJ/mole
H-H 432
O=O 492
O-H 460
C-H 360
C=O 799
C-C 347
C-C aromatic 519
N=O 632

27. Fuel energy
Let’s do the same thing for burning methane gas; the reaction is methane + oxygen
CH O2  CO2 + 2H2O
We calculated before that to form one mole of H2O we get 920 kJ, so for two moles we get 1840 kJ/mole; to form CO2, which also releases energy, we need to form two C=O bonds {O=C=O} or 2x 799kJ. This gives a total formation energy of kJ
But for this process, we 1st have to break 4 carbon- hydrogen bonds; why?? This requires 410 kJ/mole/bond or 1640 kJ
The total energy release is the energy forming bonds - break bonds
3438kJ – 2628kJ = 810 kJ excess energy

28. Combustion energies from different fuels (kJ)
react. per per per moles
heat mole mole gram CO2 per
kJ O2 fuel fuel 1000kJ
hydrogen H2+O2 2H2O
Gas CH4 + 2O2CO2 +2H2O
Petroleum (-CH2-)+ 3O22CO2 +2H2O
Coal (-CH-)+ 5O24CO2 +2H2O
Ethanol C2H5OH + 3O22CO2 +3H2O
wood (-CHOH-) + O2CO2 +2H2O

29. A Homework problem
Assume as students, that you each use 1000 Watts of power for 12 hours each day (lights, computers, class room air conditioning, etc, travel).
Much of this energy in Thailand and China is generated from coal. Assume that the process is only 50% efficient, and if you use 1000 Watts it really requires 2000 Watts of coal power.
Calculate how much CO2 is going into the atmosphere to maintain you at this level of energy consumption for each year and put your answer in metric tones/year CO2.

30. Hint
1 watt = 1 joule/sec
Estimate the total number of joules used per year if you are using 2000 watts for 12 hours each day
The combustion table gives you the mole of CO2 evolved from burring 1000 kJ of coal.
Convert this to the total moles of CO2 given off per year for 2000 watts at 12 hours each day
Convert to metric tonnes of CO2 per year
One metic tonne equals 1000kg
Much of this energy in Thailand and China is generated from coal. Assume that the process is only 50% efficient, and if you use 1000 Watts it really requires 2000 Watts of coal power.
Calculate how much CO2 is going into the atmosphere to maintain you at this level of energy consumption for each year and put your answer in metric tones/year CO2.