1. Renewable Energy Sources

2. Standard: SEV4e. Describe alternative fuels and their required technology
- What are renewable resources?
How are alternative energies considered renewable?

3. What is renewable energy?
Energy from sources that is constantly being formed

4. Major forms of renewable energy
Solar
Wind
Biomass
Hydroelectric (Water)
Geothermal (heat)
Tidal
Hydrogen

5. Solar Energy
Energy from the sun

6. What is the sun? Sun in the center of our solar system
Hot ball of plasma and gases
Provides energy/light to the planets of our solar system
Formed 4.6 billion years ago
About  93,000,000 miles from Earth
Takes 8.3 minutes for sunlight to reach the earth

7. What does the sun do for us?
Provides energy in the form of light
The energy emitted is from nuclear fission reactions
This energy travels through space and penetrates the Earth’s atmosphere
The sun’s energy powers many of Earths Forces:
Wind
Photosynthesis (plant growth)
Water cycle

8. How is the sun’s energy used?
Direct absorption
Earth is heated due to the electromagnetic waves emitted from the sun
Aides photosynthesis
Provides visible light
Creates the seasons on Earth
Indirectly
Generates electricity using solar cells
When cloudy, the sun’s rays can still be damaging to your skin

9. 2 Types of Solar Heating
Passive solar heating- uses suns energy to heat something directly
Examples:
Building being orientated to catch the most of the Sun’s energy through their windows
Ancestral Puebloans lived in cliff dwellings and used sun to warm their homes

10. 2 Types of Solar Heating
Active Solar Heating: Solar cells are attached to a home to collect the suns energy and then convert it to electricity or heat water
About 8% of the United States use this method to heat water

11. What are solar cells? Also known as photovoltaic cells
They are used to convert the sun’s energy into electricity

12. Wind Power
Energy created from the wind

13. How can we create wind energy?
The sun heats Earth unevenly, which causes air masses to flow in the atmosphere
We use a wind turbine to turn mechanical energy into electrical energy
This is one of the fastest growing energy source in the world

14. What are wind farms? Large array of turbines in windy areas Benefits:
Take up little space
Can sell electricity back to electric company
Cons:
Must have wind!
Transporting the electricity from rural areas

15. Wind power facts
Estimated that the windiest places on earth could generate 10x the energy used world wide
Wind mills were first developed in China and Persia around 2000 BC
A single wind turbine can power up to 500 homes
There is enough on shore wind in the US to power the country 10x
As of May 2014, 46,000 homes in the US used wind power

16. Biomass power What is biomass fuel?
Any organic material that is used for energy
Examples
Manure
Plant materials
Wood
Dung
Methane
Alcohol

17. How is biomass fuels a renewable resource?
Biomass fuel is a major resource in developing countries
Biomass can be renewable as long as:
The amount used is less than what is needed
No harmful effects or pollution is produced

18. Hydroelectricity Power from moving water
Also known as hydroelectric energy
Accounts for about 20% of worlds power

19. How does a hydroelectric power plant work?
A dam is built across a river to create a reservoir
When the water is released, it passes through a turbine and this creates electricity!

20. Benefits of hydroelectric power
Do not release air pollutants
Hydroelectric plants last longer than fossil fuel plants
Dams provide flood control, water for drinking and recreation areas

21. Disadvantages of hydroelectric power
The is expensive to build and changes the river flow
Can disrupt ecosystems both up and down stream

22. Geothermal power Energy that is created from within the earth’s crust
Normally found near steam vents or underground hot springs
More than 60,000 home in the US are heated by geothermal power

23. How does geothermal power work?
A plant is built above a water deposit in the earth’s crust
Steam rises through a well to the plant
It is driven through a turbine to create electricity
Leftover liquid is pumped back into the hot rock

24. Geothermal heat pumps
The ground is always warmer than the air in the winter and cooler than the air in the summer
Some homes have a loop of piping that extends underground.
This piping circulates fluid underground. Depending on the time of the year, the pipe conducts either heat or cool air into the home.

25. Tidal and hydrogen power
Tidal and Hydrogen power are energy sources that are still in development.
Because of this, these sources are known as alternative energy
For these sources to become practical, they must be proven to be cost effective and have few harmful effects on the environment.

26. Tidal power
Tides are the movement of water caused by the gravitational forces of the earth, sun and moon.
Tides rise and fall twice a day

27. Tidal dams Work much the same way as a hydroelectric dam
When the tide rises, water becomes trapped in a dam
It is then released through a turbine back into the ocean

28. Hydrogen Fuel Hydrogen is the most abundant element on earth
When hydrogen is burned it combines with oxygen to produce water vapor
Hydrogen gas is produced by splitting hydrogen molecules with electricity
Hydrogen fuel can be made from anything that has a high amount of hydrogen (like plants)

29. The challenge of hydrogen fuel
1. Hydrogen fuel production is not very efficient
Requires a lot of energy, is expensive, and currently causes pollution
2. A lot of hydrogen is needed to produce the same amount of energy as a tank of gasoline
This means that hydrogen has to be compressed (compacted)
We do not have the technology to do this safely yet

30. Fuel cells
Combines hydrogen with oxygen in the air tot produce electricity
Water is the byproduct
Fuel cells can be fueled by using anything containing hydrogen
Examples
Natural gas
Alcohol
Gasoline