1. Energy Sources Sources of Energy PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Energy Sources
Gateway – Energy and the Environment
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2. Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Exhaustible
Any source of energy that is limited and cannot be replaced when it is used, such as oil, coal, and natural gas.

3. Exhaustible Energy Sources
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Exhaustible Energy Sources
Limited availability
Cannot be replaced
Currently provides 85% of energy consumed in US
Examples
Fossil fuels - fuels produced by deposits of ancient plants and animals (Oil, coal and natural gas)
Fossil fuels include oil, natural gas, and coal.

4. Exhaustible Energy Sources Effect on the Environment
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Exhaustible Energy Sources Effect on the Environment
Burning fossil fuel produces air pollution
Acid rain is rain contaminated by the by-products of combustion which condense in our atmosphere. Acid rain kills plants and trees and pollutes ponds and lakes, killing fish and altering the ecosystem.
Air pollution can cause lung cancer in humans.
Continued…

5. Exhaustible Energy Sources Effect on the Environment
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Exhaustible Energy Sources Effect on the Environment
Greenhouse effect – Greenhouse gases surround our planet, which prevents heat produced by the sun from escaping the earth’s atmosphere as easily as it once did.
The greenhouse effect leads to climate change, which could cause melting of ice caps and changing weather patterns.

6. Renewable A resource that can be replaced when needed.
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Renewable
A resource that can be replaced when needed.
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©iStockphoto.com

7. Renewable Energy Sources
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Renewable Energy Sources
Ethanol – Plants such as corn, soybeans, seaweed, sugar beets, and sugar cane can be used to make ethanol.
Methanol is made from coal or renewable sources like wood, plants, and manure.
Methanol and Ethanol can be used as a substitute for gasoline.

8. Renewable Energy Sources
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Renewable Energy Sources
Biomass – Waste products like trees, plants, grains, algae, manure, garbage, sewage, and paper can be converted into energy.
Biomass conversion creates petroleum substitutes and methane gas.

9. Renewable Energy Sources Effect on the Environment
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Renewable Energy Sources Effect on the Environment
Substituting biomass for fossil fuels reduces emissions of greenhouse gases.
Combustion of biomass produces air emissions. The amount of emissions varies widely depending upon the technology being used.
A major benefit of substituting biomass for fossil fuels is that, if done in a sustainable fashion, it would greatly reduce emissions of greenhouses gases. The amount of carbon dioxide released when biomass is burned is very nearly the same as the amount required to replenish the plants grown to produce the biomass. Thus, in a sustainable fuel cycle, there would be no net emissions of carbon dioxide, although some fossil-fuel inputs may be required for planting, harvesting, transporting, and processing biomass. Yet, if efficient cultivation and conversion processes are used, the resulting emissions should be small (around 20 percent of the emissions created by fossil fuels alone). And if the energy needed to produce and process biomass came from renewable sources in the first place, the net contribution to climate change would be zero. Similarly, if biomass wastes such as crop residues or municipal solid wastes are used for energy, there should be few or no net greenhouse gas emissions. There would even be a slight greenhouse benefit in some cases, since, when landfill wastes are not burned, the potent greenhouse gas methane may be released by anaerobic decay.

10. Inexhaustible An energy source that will never run out.
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Inexhaustible
An energy source that will never run out.
Currently provides 3.5% of energy consumed in US

11. Inexhaustible Examples
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Inexhaustible Examples
Solar energy
Hydroelectric Energy
Geothermal Energy
Wind Energy

12. Inexhaustible Energy Sources Effect on the Environment
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
Inexhaustible Energy Sources Effect on the Environment
Minimal pollution or hazardous waste produced
Readily available, without mining or drilling
Not radioactive, so transportation is not an issue

13. So Why Don’t We Use More Renewable and Inexhaustible Energy?
Sources of Energy
PLTW Gateway
Unit 3– Lesson 3.1 – Investigating Energy
So Why Don’t We Use More Renewable and Inexhaustible Energy?
Renewable energy tends to be far away from where the electricity is needed, it has to travel far
Renewable energy impacts the environment because of the amount of land it uses
Many renewable resources are limited and are not always available when the electricity is needed (example: No sunlight at night for lighting homes and businesses).
Unlike fossil fuels, which dirty the atmosphere, renewable energy and inexhaustible energy have less impact on the environment. However, they do have some drawbacks, mainly associated with the use of large of tracts of land that affects animal habitats and outdoor scenery.
For example, solar thermal energy involving the collection of solar rays through collectors (often huge mirrors) need large tracts of land as a collection site. This impacts the natural habitat, meaning the plants and animals that live there. The environment is also impacted when the buildings, roads, transmission lines, and transformers are built. The fluid most often used with solar thermal electric generation is toxic and spills can happen.
Wind power development also has a downside, mostly involving land use. The average wind farm requires 17 acres of land to produce one megawatt of electricity, about enough electricity for 300 to 400 homes. However, farms and cattle grazing can use the same land under the wind turbines.
Renewable and inexhaustible energy development will result in jobs and less oil imported from foreign countries.

14. Draw and Color These Diagrams on Page 33 of your Notebook
Renewable Energy