Energy Resources - hydroelectric, wind and solar energy

1. Hydroelectric Energy

2. Hydroelectric energy
• caused by gravity
• An object at rest in a higher elevation has potential gravitational
energy, which is transformed to kinetic energy when the object
moves to lower elevation.
• Hydropower - power generated by energy from falling water or fast
running water

3. Applications of Hydropower
• Ancient times
• Used in the operation of mills, lifts, and provision of water
• 19th Century
• used in the production of electricity (hydroelectricity) via dams

4. Hydroelectric Dams
• Water passes through a tunnel
or large pipe (penstock) to reach
the turbine
• Water pressure causes the
turbine to rotate and generate
electricity.
• The amount of water entering
the penstock is controlled by the
intake.
• Excess water during rainy season
flows to the spillway to prevent
overflow or dam breach

5. Hydroelectric Dams
• The potential of hydroelectric
dams depend on the volume of
water stored in the reservoir and
the difference in height between
the source and water outflow
(head).
• The higher the dam, the higher
the head, and the stronger the
pressure to turn the turbine.
• The head is lower when the
reservoir is not in full capacity
even if the dam is high.

6. Hydroelectric Dams
• Large-scale dams - can generate hundreds of megawatts (1 MW =
1000 W)
• Small-scale hydropower or run-of-the-river hydropower (10-30 MW)
• Mini hydropower - <500 kW
• Microhydropower - <100 kW
• Small-scale systems could be used if it has the following:
• sufficient flow
• proper height of fall water
• rugged areas - have steeper gradient of streams that could generate the
desired power even with smaller flows

7. Small-scale Hydropower System
• A diversion structure (weir) is
constructed along the stream to
divert water and flow through a
canal (headrace) into a forebay
where sediments and debris
could settle.
• The outlet of the forebay has
screens. Water from the forebay
passes to the penstock, flows to
the turbine in the powerhouse,
and flows back to the stream.

8. San Roque Dam, San Manuel, Pangasinan
• The largest hydroelectric
dam in the Philippines
• 200 m height

9. Other Hydroelectric Power Plants in the
Philippines
• Agusan Dam
• Angat Dam
• Binga Dam
• Bustos Dam
• Caliraya Dam
• Casecnan Dam
• Kalayaan Pumped-Storage
Hydroelectric Project
• Lumot Dam
• Magat Dam
• Pantabangan Dam
• Pulangi Dam
• Sumag River Diversion Project
• Umiray–Angat Transbasin Project

10. Advantages of Hydroelectric Energy
• It only requires moving water in order to work.
• It does not pollute itself. Only the construction of power plants can be
potential sources of pollution.
• It is the most affordable cost of power when spread out over the
system’s lifetime costs.
• It is reliable. As long as there is water, electricity can be generated.
• It is flexible. Water flow can be adjusted and even conserved
according to the need for power.
• It is safer compared with the use of fossil fuels and nuclear energy,

11. Disadvantages of Hydroelectric Energy
• lack of water during drought
• limited areas where structures could be built
• expensive initial cost
• limited lifetimes of dams and reservoir
• reservoir will be filled with sediments, which will block the dam
• environmental effects
• alteration of the river system
• displacement of communities or ecosystems living in the area converted into
the reservoir

12. Solar Energy

13. Solar energy
• Energy from the Sun
• The amount of solar energy that Earth receives from the Sun in an
hour is more than enough to satisfy the global energy needs for a
year.

14. Applications of solar energy
• Plants and some animals use solar energy for photosynthesis
• Animals use this energy by consuming plants and absorbing vitamin D
(calciferol)
• Greenhouses allow plant growth and household heating
• Direct solar energy provides heat just below the boiling point of water

15. Solar collectors
• Concentrated solar power
• It involves, mirrors, lenses,
and tracking system that
focuses light into a receiver
and generates heat.
• The heat is used to generate
elctricity from conventional
steam-driven turbines

16. Solar collectors
• Photovoltaic or solar cell
• It directly converts solar energy to
electricity at the atomic level
• It consists of semiconductor
materials made into thin sheets
called wafer

17. Solar collectors
• Photovoltaic or solar cell
• The wafer are treated to form
an electric field (positive on
one side and negative in the
other side)
• The solar energy releases
electrons from the atoms of
the semiconductor material
when exposed to the sun.
• The electrical conductors on
the positive and negative
sides capture the electron
and generate electricity

18. Advantages of Solar Energy
• Reduced electricity bills
• Low maintenance cost

19. Disadvantages of Solar Energy
• Needs a large area
• Associated with pollution
• Weather dependent
• Solar energy storage is expensive

20. Wind Energy

21. Wind
• Wind is a form of solar energy caused by a combination of three
concurrent events:
• The sun unevenly heating the atmosphere (different atmospheric pressure)
• Irregularities of the earth's surface
• The rotation of the earth
• Wind varies in duration and strength
Short-duration, high-speed wind = gust
• Long-duration wind with different strengths = breeze, gale, storm, and
hurricane

22. Wind energy
• Mechanical energy produced from wind flows or air current
• It is used to turn wind mills and wind pumps and sail large ships
• It is the mainstream energy source in areas with consistent strong
wind all year round
• It is harnessed using turbines attached to towers with a height of 20-
100 m.

23. Wind farms
• A collection of individual wind turbines
• Modern systems have three long blades that spin and cause the
turbine to generate electricity
• Wind farms are connected to an electric power transmission network
or power grid

24. Advantages of Wind Energy
• Free fuel
• Does not emit greenhouse gases
• Does not disrupt farmland operations
• Reduces dependence on fossil fuel

25. Disadvantages of Wind Energy
• Dangerous to wildlife (especially birds and bats)
• Noise pollution
• Expensive initial cost
• Unpredictable like wind strength