1. solar energy

2. What is solar energy? Energy produced by the sun
Clean renewable source of energy
Harnessed by solar collection methods: solar cells
Converted into usable energy: electricity
solar cell
set of solar panels

3. Energy from non-renewable resources

4. Oil in Singapore
Singapore's oil industry accounts for 6% of its economy
The island, which has not a single drop of oil, has built up a huge industry that spans:
- Refining
- Petrochemicals
- Storage
- Trade

5. Oil in Singapore
REFINING: Singapore has a refining capacity of about 1.3 million barrels per day
Singapore refineries get about 60% of their crude oil from the Middle East while the rest is imported from West Africa and its Asian neighbors, including Indonesia, Vietnam, and Malaysia
The crude is refined and sent abroad to Indonesia, Australia and New Zealand, Hong Kong and China

6. Oil in Singapore
PETRO-CHEMICALS: Singapore ranks among the top 10 petrochemical centers in the world
Its chemicals cluster was worth S$75 billion in 2006 and it is still attracting new petrochemical investments
STORAGE: The government expects petroleum storage capacity in Singapore to more than double in the next two to three years
Massive underground storage Jurong Island

7. Oil in Singapore
TRADE: Singapore is one of the top three oil trading centers in the world, behind only New York and London
About US$500 billion of oil trade is channeled through Singapore each year
SHIPPING: Singapore has the world's biggest shipping fuel industry

8. Natural gas in Singapore
In Singapore, natural gas has been used since 1992
Singapore uses gas for power generation and as a feedstock for petrochemical production
Approximately 65% of Singapore’s electricity supply is generated from natural gas and 35% from oil
Singapore gets 80% of its electricity from natural gas imported via pipelines from Malaysia and Indonesia

9. Natural gas in Singapore
The gas terminal on Jurong Island will have a capacity of 3 million metric tonnes a year
Singapore's demand is estimated at 1 million tonnes a year in 2012
It may grow to 3 million metric tonnes a year by
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10. Solar power in Singapore
The viability of solar energy in Singapore at current technology levels will cost about five times as much in electricity tariffs

11. Why do we need solar energy?

12. Energy from the sun is abundant
Solar power systems installed in the areas defined by the dark disks could meet the world's current total energy demand
Source:

13. Energy from the sun
About half the incoming solar energy reaches the Earth's surface
The Earth receives 174 petawatts (PW) (1015 watts) of incoming solar radiation at the upper atmosphere
Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans, and land masses
Earth's land surface, oceans, and atmosphere absorb solar radiation and this raises their temperature
Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14°C
Plants convert solar energy into chemical energy by photosynthesis
This produces food, wood, and the biomass from which fossil fuels are derived

14. Breakdown of incoming solar energy

15. Solar for electricity
For the 2 billion people without access to electricity it would be cheaper to install solar panels than to extend the electrical grid (The Fund for Renewable Energy Everywhere)
A one kilowatt solar system each month:
prevents &0 Kg of coal from being mined
prevents 120 Kg of CO2 from entering the atmosphere
keeps 400 liters of water from being consumed
keeps NOx and SO2 from being released into the environment

16. Global cumulative solar power

17. Solar power in use
Some large companies use solar energy to partially power some of their facilities
Solar panels being tested on Walmart store
Solar panels on Microsoft building

18. General Motors - America
Solar power in use
General Motors - America

19. 60 MWp photovoltaic park in Spain
Solar power in use
60 MWp photovoltaic park in Spain

20. Solar Power in Use

21. Solar power in use

22. How do solar cells work?
Solar cells are devices that take light energy and convert it into electrical energy
Light energy
Electrical energy (carried through wires)
Solar cell - converts light energy to electricity

23. How do solar cells work?
Photovoltaic (PV) Solar Cells generate electricity by the Photovoltaic Effect
Photo + voltaic = convert light to electricity
Discovered in 1839
The photovoltaic effect is the phenomenon where certain materials such as silicon produce an electric current when they are exposed to light

24. How do solar cells work?
Light can be separated into different wavelengths which we can see in the form of a rainbow
Different colors of light have specific wavelengths and energies

25. How do solar cells work?
Like chloroplasts in plants - solar cells can only absorb specific wavelengths of light
Chlorophyll molecules absorb blue and red light, but reflect green light
Reduce text and add an image. Put in active
Absorbed + reflected + transmitted = 1

26. How do solar cells work?
Whether a certain wavelength of lights gets absorbed depends on its energy
Quantum Chemistry: Absorption of light by atoms occurs only when the energy of the light exactly equals the energy required to displace electrons in an atom
About 70% of the radiation energy incident on our cell is unusable

27. Silicon cell average efficiency
How do solar cells work?
Silicon cell average efficiency

28. How do solar cells work? Solar cells are made from Silicon
Silicon under carbon
on the periodic table
Carbon can form a strong
lattice arrangement of atoms: diamond
- Silicon can also form a strong lattice arrangement

29. How do solar cells work?
In a silicon lattice all atoms bond to four neighbours leaving no free electrons to conduct electric current
Silicon crystal is an insulator rather than a conductor

30. How do solar cells work?
Conductor: metals are good conductors of electricity because they have "free electrons" that can move easily between atoms - electricity involves the flow of electrons
Silicon looks metallic but is not

31. How do solar cells work?
You can change the behaviour of silicon and turn it into a conductor by doping

32. How do solar cells work?
There are two types of impurities used in doping
N-type: in N-type doping phosphorous or arsenic is added to the silicon in small quantities
Phosphorus and arsenic each have five outer electrons
Silicon uses four of them
The fifth electron has nothing to bond to and free to move around
Free electrons allow an electric current to flow through the layer of silicon
N-type silicon is a good conductor
Electrons have a negative charge hence the name N-type

33. How do solar cells work?
P-type: in P-type doping boron or gallium is the dopant
Boron and gallium each have only three outer electrons
Silicon needs four electrons to be stable
The absence of an electron creates the effect of a positive charge hence the name P-type
When mixed into the silicon lattice they form "holes" in the lattice where a silicon electron has nothing to bond to
Holes can conduct current by accepting an electron

34. How do solar cells work?
Layers of N-type and P-type silicon conducts electricity
A minute amount of either N-type or P-type doping turns a layer of silicon from a good insulator into a viable (but not great) conductor - hence the name semiconductor

35. How do solar cells work?
In a solar cell flat layers of P and N doped silicon are placed together and the physical boundary between them is called the P-N junction
The junction can be exposed to visible light
The light energy knocks electrons loose, allowing them to flow freely between layers, creating an electric field
A voltage difference is produced between the P type and N type materials
Electrodes connected to the semiconductor layers allow current to be drawn from the device

36. How do solar cells work?

37. Problems with solar cells
Expensive
Made in high vacuum at high heat (high manufacturing costs)
Fragile, rigid, thick
Long return on investment (takes 4 years to produce energy savings equivalent to cost of production)
Source:

38. Summary Solar cells work through the direct conversion of
light into electricity at the atomic level
An thin silicon semiconductor creates an
electric field that is positive on one side
and negative on the other
When light hits the cell electrons are released
and an electrical current is formed
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