ENERGY SOURCES-

ALTERNATIVE ENERGY

Integrated Science C

Mrs. Brostrom

OBJECTIVES: Describe the availability, current uses

and environmental issues related to the use of hydrogen fuel cells, wind and solar energy to produce electricity.

Describe human efforts to reduce the consumption of raw materials and improve air and water quality.

THE ENERGY PROBLEM How will society meet

growing energy demands in a sustainable manner?

Fossil-fuels currently supply ~80% of world energy demand.

Only about 50 years left for fossil fuels if we use as current rates

TYPES OF ALTERNATIVE ENERGY Nuclear Energy Solar Energy Hydroelectric Energy Wind Energy Wave Farms Biomass Geothermal Energy Hydrogen Fuel Cells

SOLAR ENERGY Energy received from the sun in the

form of radiation Renewable resource Can be used to heat homes, generate

electricity Photovoltaic cellsSolar cellsSolar collectors

SOLAR PANELS Solar collectors

are dark colored boxes that have glass or plastic tops used to heat water in pipes running through it

 

Photovoltaic cells are an electrical device that converts the energy of light directly into electricity by the photovoltaic effect

SOLAR POWER GENERATION

Not all parts of Earth get the same amount of sunlight Solar farms located in desert/high intensity/long

sunlight hours Parabolic mirrors reflect/focus sun’s rays onto

metal water pipe located along focal axis of mirrors.

High temperature produced

SOLAR POWER Advantages:

doesn’t pollute air or waterRenewable resource

DisadvantagesWeather- cloudsTime of day- nightExpensive- but there are many programs to subsidize costs

HYDROELECTRIC ENERGY Falling water releases energy Depends on sunlight

Rivers are created through the processes of the water cycle

Energy is harnessed by damsCreate large holding places for waterFalling water pours through turbines and

makes them spinTurbines are connected to generators that

produce energy

HYDROELECTRIC DAM

HYDROELECTRIC POWER Renewable

resource Advance sin

technology could make energy generation more efficient at existing dams

Dams can alter a river’s flood and erosion pattern

Most big rivers have dams alreadyLittle potential for

expansion

http://www.youtube.com/watch?v=tSBACzRE3Gw 4:35

WAVE FARM

WIND POWER Indirectly connected to solar energy

because wind is caused by unequal heating of air

Windmill drives an electric generator

OFFSHORE WIND TURBINES

Larger average wind speed than onshore

Easier planning consent Technical expertise

exists from oil rig experience

Suitable location

http://www.youtube.com/watch?v=K6BkPmKBJ9Y1:56

WIND POWERAdvantages: Renewable

resource No pollution Low cost

Disadvantages: Wind can be

unreliable Bird/bat kills Disruption of

marine floor habitat- offshore

Eye sore- not in my backyard

BIOMASS Energy generated from the combustion of

plant material and animal waste In CT, all of trash is combusted at trash to

energy facilities Ethanol

Fuel made from corn or sugarAll gasoline contains 10% ethanol

BiodieselMade by transforming animal fat or vegetable oil

with alcohol .Fuel is made from rapeseed (canola) oil, soybean

oil, or recycled restaurant grease. Directly substituted for diesel either as fuel or as an oxygenate additive

BIOMASS ENERGYAdvantages: Renewable resource Reduction of waste Extremely low emission of

greenhouse gases compared to fossil fuels

Ethanol is Carbon neutral and forms a part of the carbon cycle

Growing variety of crops increases bio-diversity

Disadvantages: Biomass processing

technologies and biofuels use have the potential to increase emissions of ozone precursors

Increase in NOx emissions

Excessive inhalation of ethanol is harmful

Burning biomass deprives local eco-systems of nutrients

Increased use of pesticides and fertilizers to produce energy crops contaminate ground and surface water

GEOTHERMAL ENERGY SOURCES

• Geothermal energy is produced from reservoirs of hot water and steam under the Earth's crust.• Beds of molten magma heat water or steam• Wells are drilled ad the steam rises• Turning a turbine to generate electric power

• Major source of energy in volcanic areas

• New Zealand, Iceland, California

GEOTHERMAL ENERGYAdvantages: No air pollution Easy to harness

when magma beds are close to the surface

Disadvantages Use of this

resource is limited due to lack of magma beds close to the surface

HYDROGEN FUEL CELLS A fuel cell is a device that converts the

chemical from a fuel into electricity through a chemical reaction with oxygen

Chemicals constantly flow into the cell so it never goes dead

Use hydrogen and oxygen as the chemicals

https://vimeo.com/26927550 1:45

FUEL CELL ENERGYAdvantages: Most abundant

element on Earth No harmful

emissions Efficient- more

energy for less fuel

Renewable resource

Disadvantages: Needs fossil fuels

to break apart H from O

Expensive Hard to transport No existing

infrastructure to support H fuel

Highly flammable