Chapter 21: New renewable Energy Alternatives

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Renewable Energy

sun wind geothermal oceans hydrogen

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Solar Energy

conversion of hydrogen (H) to helium (He) each m2 of area receives about one kilowatt

of solar energy= seventeen 60 watt light bulbs

therefore each house has enough roof area to generate all it needs using solar panels

passive and active solar energy collection

Passive Solar Energy Collection

design of buildings construction materials are chosen to: maximize direct absorption of sunlight during winter keep the interior cool in summer by: south facing windows planting vegetation for shade during summer overhangs to block sun in summer heat-absorbing construction materials

– straw, brick or concrete for example

Passive Solar Energy Collection

Active Solar Energy

solar panels solar cookers photovoltaic cells

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Active Solar Energy

solar panels– few on the roof of a house or building– collection of mirrors

power tower with molten salt creating steam that moves the generator

tubes with oil which creates steam that move turbines

Active Solar Energy

photovoltaic cells– collect sun's energy converting it to electrical

energy using semiconductors.

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Benefits of PV cell

quiet safe require little or no maintenance no moving parts no turbine or generator required each unit lasts 20-30 years

Active Solar Energy

allows families to cook without having to gather fuel wood

lessens daily workload helps reduce deforestation helps relieve social and environmental stress

Benefits of Solar Power

inexhaustible as energy source enough energy to power earth as long as

technology develops allows decentralized control over power producing many new jobs does not pollute

Drawbacks of Solar Power

localization www.aw-bc.com/Withgott

Drawbacks of Solar Power

costs

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Wind Energy

wind turbines windmills have been used for more than 800

years in Europe– drain wetlands– irrigate crops– grind grain into flour

Wind

first wind turbine was created in the late 1800s rural electrification act 1935 killed its development

promoting dams and coal plants not until the oil embargo of 1973 that the idea was

brought back and funding for research was given low costs kinetic energy converted into electric energy different turbines are designed to work at different

wind speeds faster the wind the more energy it generates

Wind: fast growing energy sector

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Offshore Wind Turbines

more expensive more productive shallow areas maintenance

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Benefits of Using Wind Power

cleaner under optimal conditions it is much more effective

than any other conventional energy source small to large scale usage farmland can lease a small area and still be

productive once built, the costs are only for maintenance as efficiency increases the cost of electricity

decreases

Downsides of Wind Power

wind is intermittent and unpredictable good resourses are mostly away from

populations grid has to be built and that costs money conspicuous people object to farms due to aesthetics not-in-my-backyard syndrome threat to birds and bats

Geothermal Energy

generated deep within Earth from an area of volcanic activity along two tectonic plates

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Benefits and Limitations

Benefits– reduces emissions relative to fossil fuels– other pollutants it produces are in very small quantities– filters help control pollutants

Limitations– can produce other pollutants like CO2, CH4, NH3

– sources may not be truly sustainable– limited to area where tectonic plates meet– water used for energy corrodes equipment shortening

lifetime of the plant– chemicals in the water may pollute the air

Ocean Energy Sources

tides waves currents

Tides

rising and fallen of the ocean level twice each day erecting dams across the outlets of the tidal

basins outgoing tide will pass through the turbines

generating electricity no pollution high impact on the ecology of estuaries

Hydroelectricity from Tidal Waves

La Rance- France

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Wave Energy

converting mechanical energy to electricity harness the motion of wind-driven waves at

the ocean surface greater energy is found in deeper ocean sites NY

Wave Energy Generator

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Currents

marine kinetic energy essentially like underwater wind turbines are now been tested in Europe

Hydrogen

Benefits– storage of energy generated by sustainable energy is a

problem, hydrogen fuels cells are promising– Hydrogen is the fuel and it is abundant– clan, bonds H2 and O2 making water as final product

Drawback– to make the fuel (H2) energy is required and carbon based

pollutants are produced– possible risk of depleting ozone from stratosphere if H2

leaks

Bloombox or Bloomenergy

stack of silica plates covered with patented solutions on both sides it converts oxygen into energy with a minute use of energy (gas,

electric, biodisel, etc) one "box" is required for every European home, 2 for every American

home no need of the grid several companies are already using it in California

– EBay– Google– FedEx

CBS 60 minutes 2/21/2010

The End

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