Renewable and Alternative Energy

Leon County Schools

8th Grade Comprehensive Science

What is Renewable Energy?

• An energy source that:

– is replaced quickly by natural processes

– is environmentally friendly and does not cause pollution

– does not contribute to global warming

– does not come from fossil or nuclear fuel

– can not be depleted

Examples of Renewable Energy

• Solar

• Wind

• Tidal

• Hydropower

• Geothermal power

• Biomass

Solar PowerHarnessing solar energy to produce electricity

• Positive:– The most abundant source of energy on Earth– Does not pollute the planet– With the right technology, could easily supply our

current and future energy needs.

• Negative:– Some hazardous materials are used in the production

of solar panels– Solar panels take up a lot of space.– Solar panels are expensive and are not very efficient

yet

Wind PowerUses the power of the wind to turn turbines which

produces electricity• Positive:

– Environmentally friendly– Low cost– Wind farms can be established on land or in the

ocean

• Negative:– Only produces energy when the wind is blowing– Large turbines can injure birds and disrupt

ecosystems due to noise

Tidal PowerTides are used to turn turbines to produce

electricity

- Positive- Non-polluting- Reliable and predictable

- Negative:- low capacity for producing electricity- misses peak demand times- could disrupt or damage aquatic ecosystems

http://www.youtube.com/watch?v=qRUl1mJQHmc&feature=player_embedded&list=PL7AC997353CC33B26

HydropowerDams use the flow of water to turn turbines to

produce electricity• Positive:

– Currently supplies 20% of the world’s electricity

– Non-polluting– Low maintenance, low cost once built

• Negative:– Can cause a lot of damage to ecosystem’s

around them– Takes years and a lot of money to build

Image take from: www.clipartof.com

GeothermalUses heat found within earth to produce steam to

turn turbines

• Positive:– Clean energy stored within earth– Cannot be depleted and is not harmful

• Negative:– High installation costs– Not available everywhere

Image take from: abcteach.com

What is an Alternative Energy source?

• An energy source that:– may or may not come from natural processes.– can be depleted in some cases– may not have the undesirable effects of fossil

fuels (pollution, etc)– May be more efficient than the current fuel used

Image taken from: http://www.google.com/images

Examples of other Alternative Energy Sources

• Alcohols such as methanol and denatured ethanol

• Biodiesel

• Natural gas (compressed or liquefied)

• Propane

• Hydrogen

• Coal-derived liquid fluids

Biomasswood, waste, garbage, landfill gases and alcohol fuels are burned to produce heat and electricity

• Positive:– Abundant, found everywhere

– Less CO2 emissions than fossil fuels

• Negative:– Produces some air pollution (CO2)

– More expensive than coal

Image taken from: http://cr.middlebury.edu/es/altenergylife/sbiomass.htm