Transcript Renewable Energy

Renewable Energy
Energy
• An essential part of modern society
• Need reliable supply
• The U.S. constitutes less than 5% of the
world population, but uses 26% of the
world’s energy.
Primary Sources of Electricity
50%: Coal
40%:
• Natural gas
• Oil
• Nuclear
9%: Hydroelectricity
1%: Solar, Wind, Geothermal, Other
Vocabulary
• Alternative: options besides fossil fuels.
• Renewable: energy source that is replaced
or restored as it is used.
• Nonrenewable: once you burn them, they
are used up.
Need for Alternative Energy
• Burning fossil fuels causes air pollution
and is a big contributor to global warming.
• Oil spills, acid rain, and national security
are other problems associated with fossil
fuels.
• Fossil fuels will eventually run out.
Increase in Renewable Energy
• Government has began to recognize the
need for renewable energy sources.
• Many states are now requiring that
renewable energy sources make up a
certain amount of its electricity supply.
Solar Energy
• Solar energy—power from the sun
• Advantages: clean, inexhaustible
• Disadvantages: Needs sun (generate
electricity only on sunny days), not always
reliable, needs huge amounts of land.
Nevada Solar One
• Example of large solar power plant
• Boulder City, NV (40 miles from LV)
• 300 acres, the size of about 200 football
fields
WIND ENERGY
WIND ENERGY
WIND ENERGY
Advantages:
• Fueled by the wind, so it's a
clean fuel source
• No combustion of fossil fuels,
no air pollution
• Wind supply is abundant and
can’t be used up (renewable)
• Lower cost
WIND
ENERGY
Disadvantages:
• When the wind isn’t blowing, the windmills aren’t
turning and no power is being generated or
sometimes the wind can be too strong.
• A single windmill will not produce a lot of electricity.
Instead, hundreds or thousands are needed
depending on the production goals.
• For some people, a lot of windmills can be an
eyesore.
• Take a large amount of space
• Noise produced by the rotor blades
• Birds have been killed by flying into the rotors
Biomass
• Energy derived from burning organic
material such as wood, alcohol, and
garbage.
Pros and Cons of Biomass
• Advantages:
Cheap source of energy, reduces landfills.
• Disadvantages:
Causes air pollution.
May use more energy than it creates.
Hydroelectric
• Energy produced by running water.
• A dam is built to hold back the water,
forming a lake behind the dam.
• As water is released, its force turns
turbines in the dam that generate
electricity.
Hoover Dam near Las Vegas
Turbines inside Hoover Dam
Advantages
Clean energy
Low cost
Disadvantages
Lake formed upstream fills with
sediment.
Downstream of dam, erosion
increases.
Land above the dam is flooded and
wildlife habitats are destroyed.
Tidal Energy
Uses energy from the tides to create
electricity.
Advantages: Reliable and predictable
Disadvantages: Expensive to build and
limited availability of sites with enough tidal
range.
GEOTHERMAL ENERGY
Geo means
Thermal means
Geothermal energy is the use of Earth’s
natural heat.
Crust
Mantle
Outer core
Inner core
Geothermal Reservoir
When the hot water and steam accumulate in permeable and porous rock, a
geothermal reservoir forms.
Powerful Energy Source
Geothermal reservoirs can reach
temperatures of 700˚F/370˚C
(more than 3 times boiling).
Generation of Electricity
Injection Well
Production Well
Geothermal power plants
have no smoky emissions.
They emit water vapor.
Those white plumes you see at geothermal power plants are steam (water vapor).
Geothermal plants do not burn fuel or produce smoke.
Advantages of Geothermal Energy
• Clean energy – no burning, little to no air pollution,
no fossil fuels
• No “smog” or acid rain emissions
• Uses little land, less than all other energy types
• Is renewable and sustainable
• Generates continuous, reliable power – 24 hrs/day
• Less expensive than other energy plants
Disadvantages of Geothermal
• Limited locations (no resources in Eastern
USA)
• Risks of being near faults and volcanoes
• Steam and flash plants – release some
gases from deep in Earth
• Steam from some plants may be
unappealing (but still better than fossil fuel
plants)
Geothermal Power Plants