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Global Ozone Project
Renewable Energy
Rev 10A
Brian Carpenter, Jessa Ellenburg and John Birks
Learning Objectives
At the end of this lesson students
should be able to:
• Identify Non-Renewable Energy
• Identify the top five Renewable Energy
• Identify Pros and Cons for each
Renewable Energy Source.
Global Ozone Project
Part 1:
Introduction to Energy
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 = (Thot – Tcold)/Thot
• Cars are only about 20 to 30% efficient. Coal fired
power plants are around 35% efficient.
Electricity Introduction
Generating Electricity
– To get electricity, we convert
mechanical energy to electrical
Michael Faraday
– Converting mechanical energy to
electricity is done by
electromagnetic induction
discovered by Michael Faraday in
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.
Energy Sources
Major Renewable Sources
• Solar
• Hydropower
• Wind
Major Non-Renewable Sources
• Biomass
• Oil
• Geothermal
• Coal
• Natural gas
• Nuclear
• Fuelwood
From Energy Sources to Electricity
US vs. Global Energy Use
US Energy Use
Global Energy Use
Energy Production by State
Global Ozone Project
Part 2:
Renewable Energy
Major Renewable Energy Sources
• Hydropower
• Biomass
• Geothermal
• Wind
• Solar
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.
Passive Solar - Heating and Cooling
Passive Solar: Direct use of sun’s heat
energy for home heating.
Passive Solar – Water Heating
Another use of passive solar – to heat water for
household use.
Solar Potential for the US
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
• 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.
Pros and Cons of Active Solar (Solar Panels)
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.
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 cell’s efficiency.
Pros and Cons of Passive Solar Heating/Cooling
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.
Low energy density.
Does not produce electricity.
Supplemental energy source or storage
required for long sunless stretches.
Expensive compared to conventional water
Construction/installation costs can be high.
Hard to compete against very cheap natural
Some people find them visually unattractive.
Manufacturing processes can create
Installers not available everywhere.
Generally not practical to store or sell excess
Produce low grade energy (heat vs.
Dependent on home location and orientation.
Future of Solar Power
Ways to improve:
1. Concentrators: these are mirrors that
concentrate the sun’s 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 solarhydro.
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.
• 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.
Hydropower - Dams
• Height of dam and
mass of water
determine useful
• Efficiency is very
good to excellent,
generally 80 to 90%
efficient in converting
potential energy to
electrical energy.
• Potential Energy =
Hydropower Generation
Hydroelectric power production costs less than half of fossil fuel
derived electricity (does not include construction costs).
Future of Hydropower
Tidal Power: Propeller Systems
Tidal Power:
Wave Systems
Tidal Power:
Pros and Cons of Hydropower
• Very clean.
• Cheap.
• Flood control (primary reason for dams).
• Multiple crops per year possible.
• 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
Loss of wild rivers
Wind Power
• 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%.
US Wind Power Potential
Midwest has more than 90% of US potential
Wind Power Pros/Cons
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 kilowatthour 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.
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.
• Energy from the sun, via photosynthesis in
• 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.
What is
• Any plant
tissue can be
used for
energy, but
the faster the
plant grows,
the more
useful it is.
How does it work? How do we convert
biomass energy to useful forms of energy?
• Direct burning
• Gasification
• Cofiring
• Fermentation
Future of Biomass
Developing ideas
• 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
Biomass Pros and Cons
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
Energy intensive to produce
Land utilization can be considerable
Requires water to grow
Not totally clean when burned (NOx, soot, ash,
CO, CO2)
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 CO2 are emitted during
Not easily scalable
Geothermal Power
Geothermal Electricity
Geothermal in the Home
Geothermal Potential in the US
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
• Could use this energy to create hydrogen gas from seawater.
• Could be used to desalinize water.
• Mariculture (seafood farming)
Geothermal Pros and Cons
• Almost entirely emission free.
• The process can scrub out sulfur that might
have otherwise been released.
• No fuel required (no mining or
• Not subject to the same fluctuations as
solar or wind.
• Smallest land footprint of any major power
• 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.
• 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
• Minimum temperature of 350F+
generally required.
Emerging Technologies
There are many interesting emerging
renewable technologies. A few examples
Soccer Ball Charger
Spray-on Solar Panels
Green Gasoline
What will you come up with??
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