Chapter 11Chapter 11Resources and EnergyResources and Energy

Section 4Section 4

Alternative Energy SourcesAlternative Energy Sources

Notes 11-4Notes 11-4

Solar EnergySolar Energy

FactFact: Sun puts out enough energy every : Sun puts out enough energy every 15 minutes to meet the needs of the world 15 minutes to meet the needs of the world for one year.for one year. How can we capture that energy and put it to How can we capture that energy and put it to

good use?good use? Why aren’t more people using solar energy as Why aren’t more people using solar energy as

a source of energy?a source of energy?

Solar EnergySolar Energy Passive SystemPassive System::

Sun enters the dwelling and heats the areaSun enters the dwelling and heats the area Windows facing the sun all dayWindows facing the sun all day

Requires no working partsRequires no working parts Active SystemActive System::

Uses solar collectorsUses solar collectors Box with a glass top, placed on a high surface Box with a glass top, placed on a high surface

(roof).(roof). Box has tubes that circulate water through the Box has tubes that circulate water through the

buildingbuilding Cloudy days must used stored heat to maintain Cloudy days must used stored heat to maintain

heat in buildingheat in building

Passive Solar EnergyPassive Solar Energy

Active Solar EnergyActive Solar Energy

Solar EnergySolar Energy

Photovoltaic cellsPhotovoltaic cells:: Convert sunlight directly into electricityConvert sunlight directly into electricity Found in calculatorsFound in calculators Making energy for cities is in the experimental Making energy for cities is in the experimental

stagestage

Geothermal EnergyGeothermal Energy

Water can be used that has been heated Water can be used that has been heated by magma by magma Water is heated as it flows through rockWater is heated as it flows through rock Hot water or steam is used to create Hot water or steam is used to create

electricityelectricity Turning turbines to create electricity in generatorsTurning turbines to create electricity in generators

Water can be pumped into the area that Water can be pumped into the area that has the hot rockshas the hot rocks Through a well that has been dugThrough a well that has been dug Hot water or steam can be used as a direct Hot water or steam can be used as a direct

source of heatsource of heat

Geothermal EnergyGeothermal Energy

Iceland uses geothermal heatIceland uses geothermal heat http://www.youtube.com/watch?annotation_id

=annotation_136343&src_vid=-ajqiPe_9Ko&feature=iv&v=h1LMFyCgs14

http://www.youtube.com/watch?v=kjpp2MQffnw&feature=related

Water and Wind EnergyWater and Wind Energy

Hydroelectric energyHydroelectric energy:: Energy produced by running waterEnergy produced by running water 11% of energy in US comes from 11% of energy in US comes from

hydroelectric power plantshydroelectric power plants Water spins the turbines which spins a shaft Water spins the turbines which spins a shaft

that goes to an electric generatorthat goes to an electric generator

Hoover DamHoover Dam

Water and Wind EnergyWater and Wind Energy TidesTides::

Dams are built to trap water at high tideDams are built to trap water at high tide Water is released to low tideWater is released to low tide Creates moving water and works just like itCreates moving water and works just like it

WindWind:: Small wind mills can give enough energy for Small wind mills can give enough energy for

homeshomes Large wind mill farms can produce enough for Large wind mill farms can produce enough for

neighboring communitiesneighboring communities Wind is not a constant and can not always be Wind is not a constant and can not always be

depended on depended on

Wind TurbinesWind Turbines

HomeworkHomeworkTest Ch. 11Test Ch. 11

Friday, Dec. 14Friday, Dec. 14