Transcript Renewable Energy

Renewable Energy
Chapter 18
18-1 Renewable Energy Today
Objectives
1. List six forms of renewable energy, and compare
their advantages and disadvantages.
2. Describe the differences between passive solar
heating, active solar heating, and photovoltaic energy.
3. Describe the current state of wind energy
technology.
4. Explain the differences in biomass fuel use between
developed and developing nations.
5. Describe how hydroelectric energy, geothermal
energy, and geothermal heat pumps work.
Renewable Energy – energy
from sources that are
constantly being formed
Solar, wind, hydro, and
geothermal
Solar Energy
 Most all renewable NRG
comes directly or
indirectly from the sun
◦Passive Solar Energy
Use the sun’s NRG to heat
something directly
A passive solar home
Ceilings heavily insulated
Thick walls and floors
South-facing double paned
windows
Shade trees for summer
Insulated windows
◦Active Solar Heating
Uses collectors to gather
the sun’s energy
Collectors on roofs
capture the sun’s NRG
and heat a liquid which
flows to a heat exchanger
which heats water for the
building
About 8% NRG used in
US is used to heat
water
Photovoltaic cells convert
the sun’s energy into
electricity
No moving parts
Produce a small electric
current
Need extended periods of
sunlight
Electricity stored in
batteries
Provides about 1 million
households with electricity
Wind Power
 Converts the movement
of wind into electrical
energy
 Faster growing NRG
source
Biomass
 When plant material,
manure, or any other organic
matter is used an NRG
source
◦Include wood and dung (can
cause air pollution and
habitat destruction)
◦ Other source include methane
(gas given off by decomposition)
and alcohol (ethanol- fermentation
of agriculture wastes)
Gasohol – blend of gasoline and
ethanol; less air pollution then gas
Hydroelectricity
 NRG produced by moving
water
 20% of the world’s electricity
 Dams are expensive to build
but inexpensive to operate
 Advantages:
No air
pollution,Provide flood
control, water for drinking,
agriculture, industry, and
recreation
 Disadvantages: disrupts
ecosystems, people are
displaced, dam failure,
sedimentation
Geothermal
 NRG from the heat in the
Earth’s crust
 Pump water heated water
from rock formations and
use the water or steam to
power turbines
 Some
homes used
geothermal heat pumps
 US is the world’s larges
producer
18-2 Alternative Energy and
Conservation
Objectives
1.
Describe three alternative energy
technologies.
2.
Identify two ways that hydrogen could be
used as a fuel source in the future.
3.
Explain the difference between energy
efficiency and energy conservation.
4.
Describe two forms of energy-efficient
transportation.
5.
Identify three ways that you can conserve
energy in your daily life.
Look around the
room…..can you find any
instances were energy is
being wasted??
Alternative energydescribes NRG sources
that are still in
development
Tidal Power
 Uses the 2 tide changes
 Tide difference needs to
be around 16 m
 Cost to build is high
Ocean Thermal Energy
Convection
 Warm surface water is used
to boil sea water
◦Water at lower pressure
boils at a lower
temperature
◦Boiling water turns
turbine
◦Expensive to operate
◦Environmental effects
unknown
Hydrogen
 Hydrogen is found in every
molecule of living thing
 Produced water vapor as a
byproduct
 Takes a lot of energy to
produce
 Energy
can be stored in
fuel cells (produces
electricity chemically)
Energy Efficiency
 How
do we reduce NRG
use??
◦Lifestyle changes?
◦Increase NRG efficiency
The percentage of NRG
put into a system that does
useful work
NRG out/NRG in X 100
More than 40% of NRG
produced is wasted
Decease dependence on
fossil fuels
Use public transportation
Use more NRG efficient
vehicles
Hybrid cars
 Cogeneration
◦The production of two
useful forms of NRG
from the same fuel
source
Using wastes for fuel
 Energy
Conservation
◦ SAVING ENERGY!
Use energy efficient devices
Walk!
Carpool
Buy products that use less
packaging
Turn down your thermostat
(68 in winter, 78 in summer)
Unplug unused electrical
appliances
Clean vents
Water saving devices
WHAT CAN YOU DO???