Ch 18 Renewable Energy

8/2/2019 Ch 18 Renewable Energy

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Warm up

What is renewable energy?


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Renewable Energy

SEV4 Resource allocation and use


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Renewable Energy

Sources that are constantly being formed

Solar

Wind

Moving water

Earths heat


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Solar Energy

Already commonly used

Water cycle

Photosynthesis

Wind

Sunshine warming a room

Solar cells


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Passive Solar Heating

Use sun to heat something directly

Northern hemisphere homes

Large, south facing windows absorb heat inwinter

Overhangs block sunlight in the summer

Insulation is important


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Active Solar Heating

Suns energy is gathered to heat abuilding or water

Solar water heaters

Water heated on roof

Hot water used to heat water supply

Photovoltaic cells

No moving parts, no pollutionNeed many cells to produce decent yields


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Wind Power

Air is heated unevenly wind

Wind power Electrical energy

Fast growing resource 3 months to build a windmill


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Wind Farms

280,000 homes in CA powered by wind

Take up little space

Farmers add windmills to farm Sell power to cities


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Currently Underused

Windiest areas on earth could generate10x energy used worldwide.

Transportation of energy is challenging

Wind farms may make hydrogen fromwater in the future. Hydrogen used asfuel.


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Biomass

Plant material, manure, other organicmatter used as fuel

Challenges

Trees renewable, but must be managed

Burning wood or manure air pollution


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Methane

Decomposition methane (CH4)

Can be burned for heat or electricity

China 6 million homes use methane forheating/cooking

England Methane from cow manure as fuelfor electricity

USA electricity from methane generated bylandfills


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Alcohol

Ethanol fermenting fruit or agriculturalwaste

Gasohol

mix of gasoline and ethanol

Produces less pollution when burned


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Hydroelectricity

Produced from moving water

20% of electricity

How it works Reservoir holds water

Water turns turbines/generator

Generator turns movement into electricity


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Benefits of Hydroelectricity

Expensive to build but cheap to operate

No air pollution

Last longer Flood control

Water for drinking, agriculture, industry,

and recreation


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Disadvantages of Hydroelectricity

Disrupts river flow

Ecosystems flooded behind dam

River flow diminished below dam

Displaces people

Farmland downstream less productive

Decay in reservoir

greenhouse gases


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Modern Hydroelectricity

No new dams in the USA

Brazil, India, and China still building largedams

Micro-hydropower


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Geothermal Energy

From the heat in earths crust

Use water or steam to turn turbines

The Geysers in CA powers 1.7 millionhomes

Philippines, Iceland, New Zealand, Japan,

Mexico, and Italy Renewable, but must be managed


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Geothermal Heat Pumps

Heat and cool homes

Temp underground is constant

Loop of fluid in a pipe underground andinto house


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Assignment

Answer #5 on p. 499

Ticket out the door


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Warm up

What is the differencebetween renewable energy

and alternative energy?


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Alternative energy

Still in development

Some renewable energy was oncealternative energy.

Govt investments are vital todevelopment.


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Tidal power

Benefits

Tides happen 2x a day

Generates electricity

like hydroelectric dams

Drawbacks

Expensive

Few suitable locations


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Ocean Thermal Energy Conversion(OTEC)

Benefits

Cold and warm oceanwater are available atdifferent depths

Cold water boils at lowtemp in vacuumchamber

Steam can turn aturbine

Drawbacks

Not cost effective

Uses 1/3 of the energy

it produces Environmental effects

unknown


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Hydrogen

Benefits

Abundant

No air pollutants when

burned (plants may produce

it)

Drawbacks

Generating it usesenergy, money, andmakes pollution

Explosive anddangerous


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Fuel Cells

Produce electricity chemically

Combine H2 and O2 and electricity isproduced.

Water is only byproduct


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Energy Efficiency

What you get out vs. what you put in

%Energy efficiency =

Much energy is wasted

Useful energy out

Energy in x 100


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Efficient Transportation

Public transportation

Hybrid cars

Efficient gasoline engine

Electric engine

Aerodynamic


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Cogeneration

Production of 2 useful forms of energyfrom 1 fuel source

Use waste heat from a furnace to turn aturbine


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Energy Conservation

Saving energy

Use energy efficient devices

Wasting less energy


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Cities and Towns

Osage, IA

3,600 people saved $1 million/year

Sealed doors and windows

New efficient furnaces

Insulated water heaters

Businesses moved to the area

Unemployment is down


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Around the Home

Spend $1,500/year on energy costs

Much is wasted

Insulation

Efficient windows

Weather stripping

Wash clothes in cold water

Documents

Ch 18 Renewable Energy