Global Ozone Project Curriculum Lesson: Renewable Energy Rev
10A Brian Carpenter, Jessa Ellenburg and John Birks
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Learning Objectives At the end of this lesson students should
be able to: Identify Non-Renewable Energy Sources. Identify the top
five Renewable Energy Sources. Identify Pros and Cons for each
Renewable Energy Source.
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Global Ozone Project Curriculum Part 1: Introduction to Energy
Use
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Energy Introduction Heat Engine: a device that can convert heat
energy to mechanical energy. Fancy name for a car engine, a power
plant, your refrigerator, air conditioner, etc. Efficiency of a
heat engine is expressed in terms of the temperature difference
between the hot side and the cold side. Efficiency = (T hot T cold
)/T hot Cars are only about 20 to 30% efficient. Coal fired power
plants are around 35% efficient.
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Electricity Introduction Generating Electricity To get
electricity, we convert mechanical energy to electrical energy
Converting mechanical energy to electricity is done by
electromagnetic induction discovered by Michael Faraday in 1831.
Michael Faraday
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Electricity Generating Electricity Spinning conductive wires
inside a magnetic field causes electrons to move inside the wires,
and moving electrons are electricity. We can use both renewable and
nonrenewable energy sources (fossil fuels) to do this.
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Energy Sources Major Renewable Sources Solar Hydropower Wind
Biomass Geothermal Major Non-Renewable Sources Oil Coal Natural gas
Nuclear Fuelwood
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From Energy Sources to Electricity
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US vs. Global Energy Use US Energy UseGlobal Energy Use
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Energy Production by State
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Global Ozone Project Curriculum Part 2: Renewable Energy
Technologies
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Renewables Major Renewable Energy Sources Hydropower Biomass
Geothermal Wind Solar
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Active Solar We utilize two types of Solar Energy: Active Solar
& Passive Solar Active Solar: Technologies like Solar Panels
(Photovoltaics) are used to convert solar energy into electrical
energy.
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Passive Solar - Heating and Cooling Passive Solar: Direct use
of suns heat energy for home heating.
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Passive Solar Water Heating Another use of passive solar to
heat water for household use.
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Solar Potential for the US
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Costs of Solar Electricity (Active Solar) Costs of PV
electricity: Industrial system (500 kilowatt system, about $2.5M).
Sunny day: 15-20 cents/kWhr, 35-55 cents on a cloudy day. Home
system (2 kilowatt system, about $18,000). Sunny day: 35
cents/kWhr, 80 cents on a cloudy day. Compare this with electricity
from coal: Peak cost: 15 cents/kilowatt-hour. Off-peak cost: 10
cents/kilowatt-hour or less.
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Pros and Cons of Active Solar (Solar Panels) Pros: Solar panels
give off no pollution, the only pollution produced as a result of
solar panels is the manufacturing of these devices in factories,
transportation of the goods, and installation. Solar energy
produces electricity very quietly. The ability to harness
electricity in remote locations that are not linked to a national
grid. The installation of solar panels in remote locations is
usually much more cost effective than laying the required high
voltage wires. Solar energy can be very efficient in a large area
of the globe, and new technologies allow for a more efficient
energy production on overcast/dull days. Space is not an issue
because solar panels can be installed on top of many rooftops.
Solar is cost-effective. Although the initial investment cost of
solar cells may be high, once installed, they provide a free source
of electricity, which will pay off over the coming years. Utilizing
solar energy decreases dependence on fossil fuels. Cons: The major
con of solar energy is the initial cost of solar cells. Currently,
prices of highly efficient solar cells can be above $1000, and some
households may need more than one. Solar energy is only able to
generate electricity during daylight hours. The weather can affect
the efficiency of solar cells. Pollution can affect a solar cells
efficiency.
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Pros and Cons of Passive Solar Heating/Cooling Pros: Renewable.
No fuels required. Non-polluting. Carbon free except for production
and transportation. Simple, low maintenance. Hot water provides
some storage capacity. Operating costs are near-zero. Quiet. Few or
no moving parts. Mature technology. Good return on investment. High
efficiency. Can be combined with photovoltaics in highly efficient
cogeneration schemes. Cons: Intermittent. Low energy density. Does
not produce electricity. Supplemental energy source or storage
required for long sunless stretches. Expensive compared to
conventional water heaters. Construction/installation costs can be
high. Hard to compete against very cheap natural gas. Some people
find them visually unattractive. Manufacturing processes can create
pollution. Installers not available everywhere. Generally not
practical to store or sell excess heat. Produce low grade energy
(heat vs. electricity). Dependent on home location and
orientation.
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Future of Solar Power Ways to improve: 1. Concentrators: these
are mirrors that concentrate the suns energy to improve efficiency.
2. Hybrid Solar Systems: combine solar with other forms of energy
production to make cheaper and more reliable. For example,
solar-wind, and solar- hydro. 3. Consider Cost of Pollution: Cost
of coal-based electricity is cheaper in part because pollution is
not factored into the cost. Cost of pollution from solar (in
manufacturing process) would be much less.
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Hydropower Basics: Form of solar energy, as the sun drives
water evaporation from the ocean and winds carry the moisture
overland. Largest form of alternative energy used today.
Industrialized countries have already tapped much of their
potential. Non-industrialized countries have the most untapped
potential.
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Hydropower - Dams Dams Height of dam and mass of water
determine useful energy. Efficiency is very good to excellent,
generally 80 to 90% efficient in converting potential energy to
electrical energy. Potential Energy = mass*gravity*height
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Hydropower Generation Hydroelectric power production costs less
than half of fossil fuel derived electricity (does not include
construction costs).
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Future of Hydropower Tidal Power: Propeller Systems Tidal
Power: Wave Systems Tidal Power: Enclosures
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Pros and Cons of Hydropower Pros: Very clean. Cheap. Flood
control (primary reason for dams). Multiple crops per year
possible. Cons: Potential is limited globally to about 5 to 10% of
energy needs. Dependability is an issue; prolonged droughts can cut
electrical production in half or more. Dams have drawbacks,
including: Environmental impacts Loss of nutrient flow down river
Loss of sediment flow down river Sedimentation behind the dam
limits lifetime of the dam Flooding of scenic areas and
archaeological sites Ecosystem below the dam is usually changed by
having colder, nutrient poor water Aesthetics Loss of wild
rivers
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Wind Power Basics Use dates back thousands of years in the form
of windmills, sailing ships, etc. Typical efficiency is about 30%.
Maximum theoretical efficiency is thought to be about 60%.
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Windmills
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US Wind Power Potential Midwest has more than 90% of US
potential
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Wind Power Pros/Cons Pros Cost is very competitive, production
costs are about 5 cents per kilowatt-hour (coal electricity is
around 15 cents). This is down from 7 to 10 cents per kilowatt-
hour in 1995 and 15 cents per kilowatt-hour in the 1980's. In this
case subsidies helped to create a viable market. It is estimated
that the costs could be lowered to 3-4 cents per kilowatt-hour as
wind technology improves. Improvements in technology may also open
less windy areas up for economically useful and viable wind power.
Cons Reliability is a key issue, as the wind does not always blow.
Requires a storage mechanism that compensates for reliability.
Recently, aesthetics has become a significant issue. Killing of
birds and bats from high blade tip speeds. Disruption of natural
wind patterns.
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Biomass Basics Energy from the sun, via photosynthesis in
plants. This is the same energy we use as food. This is the same
energy that made fossil fuels; fossil fuels are concentrated over
time by the heat and pressure within the Earth. The oldest form of
energy used by humans: wood fire, a form of biomass.
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Biomass What is biomass? Any plant tissue can be used for
energy, but the faster the plant grows, the more useful it is.
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Biomass How does it work? How do we convert biomass energy to
useful forms of energy? Direct burning Gasification Cofiring
Fermentation
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Future of Biomass GMO Energy Crops - like Poplar and Willow
trees which have been genetically engineered and bred for rapid
growth Algae - also grows rapidly Biodiesel - Canola and Sorghum,
etc. Cellulosic Ethanol Developing ideas
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Biomass Pros and Cons Pros: Truly a renewable fuel Widely
available Generally low cost inputs Abundant supply Can be
domestically produced for energy independence Low carbon, cleaner
than fossil fuels Can convert waste into energy, helping to deal
with waste Cons: Energy intensive to produce Land utilization can
be considerable Requires water to grow Not totally clean when
burned (NOx, soot, ash, CO, CO 2 ) May compete directly with food
production (e.g. corn, soy) Some fuels are seasonal Energy required
to transport Overall process can be expensive Some methane and CO 2
are emitted during production Not easily scalable
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Geothermal Power Geothermal Electricity
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Geothermal in the Home
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Geothermal Potential in the US
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Future of Geothermal Ocean Thermal Energy Conversion (OTEC):
This is a special case of geothermal energy, as the source of the
energy is the sun, warming the surface waters of the ocean. Uses
the temperature difference between cooler deep and warmer shallow
or surface ocean waters to run a heat engine and produce useful
work, usually in the form of electricity. The cold water typically
comes from about 1000 meters. Attractions of OTEC are: Steady
source of energy (all day, all year). Potential large in warm areas
(Florida, Hawaii) requiring air conditioning. Could use this energy
to create hydrogen gas from seawater. Could be used to desalinize
water. Mariculture (seafood farming)
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Geothermal Pros and Cons Pros: Almost entirely emission free.
The process can scrub out sulfur that might have otherwise been
released. No fuel required (no mining or transportation). Not
subject to the same fluctuations as solar or wind. Smallest land
footprint of any major power source. Virtually limitless supply.
Inherently simple and reliable. Can provide base load or peak
power. Already cost competitive in some areas. Could be built
underground. New technologies show promise to utilize lower
temperatures. Cons: Prime sites are very location-specific. Prime
sites are often far from population centers. Losses due to long
distance transmission of electricity. Water usage. Sulfur dioxide
and silica emissions. High construction costs. Drilling into heated
rock is very difficult. Minimum temperature of 350F+ generally
required.
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Emerging Technologies There are many interesting emerging
renewable technologies. A few examples are: Soccer Ball Charger
Spray-on Solar Panels Green Gasoline What will you come up
with??