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ENERGY FORMSBY
Rakesh HResearch Scholar
Department of BiotechnologySahyadri Science College,
Shivamogga.KUVEMPU UNIVERSITY
Nature of Energy
• Energy is all around you!– You can hear energy as sound.– You can see energy as light.– And you can feel it as wind.– Can verify as work.
Nature of Energy
• You use energy when you:– hit a softball.– lift your book bag.– compress a
spring.
Nature of Energy
Living organisms need energy for growth and movement.
Nature of Energy
• Energy is involved when:– a bird flies.– a bomb explodes.– rain falls from the sky.– electricity flows in a
wire.
Nature of Energy
• What is energy that it can be involved in so many different activities?– Energy can be defined as the ability to do
work.– If an object or organism does work (exerts
a force over a distance to move an object) the object or organism uses energy.
Nature of Energy
• Because of the direct connection between energy and work, energy is measured in the same unit as work: joules (J).
• In addition to using energy to do work, objects gain energy because work is being done on them.
Forms of Energy
• The five main forms of energy are:
– Heat– Chemical– Electromagnetic– Nuclear– Mechanical
In your syllabus
• Hydroelectric Energy• Fossil Fuel Energy• Nuclear Energy• Wave Energy• Wind Energy• Solar Energy• Geothermal Energy
NONRENEWABLE AND
RENEWABLE RESOURCES
HMMMM....
What do you think nonrenewable resources are?
Break it down...
Nonrenewable?
Resource?
NONRENEWABLE RESOURCES
A nonrenewable resource is a natural resource that cannot be re-made or re-grown at a scale comparable to its consumption.
NUCLEAR ENERGY
Nuclear fission uses uranium to create energy.
Nuclear energy is a nonrenewable
resource because once the uranium is used, it is gone!
COAL, PETROLEUM, AND GAS
Coal, petroleum, and natural gas are
considered nonrenewable
because they can not be replenished in a
short period of time. These are called fossil
fuels.
HOW IS COAL MADE ???
HOW ARE OIL AND GAS MADE ???
WHAT WAS THE DIFFERENCE BETWEEN COAL AND OIL/GAS?
HMMMM....
If nonrenewable resources are
resources that cannot be re-made at a scale
comparable to its consumption, what are renewable resources?
RENEWABLE RESOURCES
Renewable resources are natural resources that can be replenished in a short period of time.
● Solar ● Geothermal● Wind ● Biomass● Water ● Wave
SOLAR
Energy from the sun.
Why is energy from the sun renewable?
GEOTHERMAL
Energy from Earth’s heat.
Why is energy from the heat of the Earth renewable?
WIND
Energy from the wind.
Why is energy from
the wind renewable?
BIOMASS
Energy from burning organic or living matter.
Why is energy from biomass renewable?
WATER or HYDROELECTRIC
Energy from the flow of
water.
Why is energy of flowing
water renewable?
Hydroelectric power (often called hydropower) is considered a renewable energy source. A renewable energy source is one that is not depleted (used up) in the production of energy. Through hydropower, the energy in falling water is converted into electricity without “using up” the water.
Hydropower energy is ultimately derived from the sun, which drives the water cycle. In the water cycle, rivers are recharged in a continuous cycle. Because of the force of gravity, water flows from high points to low points. There is kinetic energy embodied in the flow of water.
Kinetic energy is the energy of motion. Any moving object has kinetic energy.
Humans first learned to harness the kinetic energy in water by using waterwheels.
A waterwheel is a revolving wheel fitted with blades, buckets, or vanes.Waterwheels convert the kinetic energy of flowing water to mechanical energy.
Mechanical energy is a form of kinetic energy, such as in a machine. Mechanical energy has the ability to do work. Any object that is able to do work has mechanical energy.
Early waterwheels used mechanical energy to grind grains and to drive machinery such as sawmills and blacksmith equipment.
Waterwheel technology advanced over time. Turbines are advanced, very efficient waterwheels. They are often enclosed to further capture water’s energy.
Not long after the discovery of electricity, it was realized that a turbine’s mechanical energy could be used to activate a generator and produce electricity. The first hydroelectric power plant was constructed in 1882 in Appleton, Wisconsin. It produced 12.5 kilowatts of electricity which was used to light two paper mills and one home.
Hydroelectric power (hydropower) systems convert the kinetic energy in flowing water into electric energy.
How a Hydroelectric Power System Works - Part 1
Flowing water is directed at a turbine (remember turbines are just advanced waterwheels). The flowing water causes the turbine to rotate, converting the water’s kinetic energy into mechanical energy.
The mechanical energy produced by the turbine is converted into electric energy using a turbine generator. Inside the generator, the shaft of the turbine spins a magnet inside coils of copper wire. It is a fact of nature that moving a magnet near a conductor causes an electric current.
How a Hydroelectric Power System Works – Part 2
The amount of electricity that can be generated by a hydropower plant depends on two factors:
• flow rate - the quantity of water flowing in a given time; and• head - the height from which the water falls.
The greater the flow and head, the more electricity produced.
How much electricity can be generated by a hydroelectric power plant?
WIND POWER - What is it?• All renewable energy (except tidal and geothermal power), ultimately comes from
the sun
• The earth receives 1.74 x 1017 watts of power (per hour) from the sun
• About one or 2 percent of this energy is converted to wind energy (which is about 50-100 times more than the energy converted to biomass by all plants on earth
• Differential heating of the earth’s surface and atmosphere induces vertical and horizontal air currents that are affected by the earth’s rotation and contours of the land WIND.
~ e.g.: Land Sea Breeze Cycle
Wind Power
• Wind power is extracted from air flow using wind turbines or sails to produce mechanical or electrical power. Windmills are used for their mechanical power, wind pumps for water pumping, and sails to propel ships.
• As of 2013, Denmark is generating more than a third of its electricity from wind.
• The first windmill used for the production of electricity was built in Scotland in July 1887 by Prof James Blyth of Anderson's College, Strathclyde University).[17
• Environmental benefits
• No emissions
• No fuel needed
• Distributed power
• Remote locations
Limitations of Wind Power
Power density is very low. Needs a very large number of wind mills to produce
modest amounts of power. Cost. Environmental costs.
material and maintenance costs. Noise, birds and appearance.
Cannot meet large scale and transportation energy needs.
Geothermal Energy
Sources of Earth’s Internal Energy
•70% comes from the decay of radioactive nuclei with long half lives that are embedded within the Earth
•Some energy is from residual heat left over from Earths formation.
•The rest of the energy comes from meteorite impacts.
Different Geothermal Energy SourcesHot Water Reservoirs: As the name implies these are reservoirs of hot underground water, but they are more suited for space heating than for electricity production.
Natural Stem Reservoirs: In this case a hole dug into the ground can cause steam to come to the surface. This type of resource is rare in the US.
Geopressured Reservoirs: In this type of reserve, brine completely saturated with natural gas in stored under pressure from the weight of overlying rock. This type of resource can be used for both heat and for natural gas.
Hot Dry Rock: This type of condition exists in 5% of the US. It is similar to Normal Geothermal Gradient, but the gradient is 400C/km dug underground.
Molten Magma: No technology exists to tap into the heat reserves stored in magma. The best sources for this in the US are in Alaska and Hawaii.
Solar Energy: The Ultimate Renewable Resource
What is Solar Energy?
• Originates with the thermonuclear fusion reactions occurring in the sun.
• Represents the entire electromagnetic radiation (visible light, infrared, ultraviolet, x-rays, and radio waves).
Putting Solar Energy to Use: Heating Water
• Two methods of heating water: passive (no moving parts) and active (pumps).
• In both, a flat-plate collector is used to absorb the sun’s energy to heat the water.
• The water circulates throughout the closed system due to convection currents.
• Tanks of hot water are used as storage.
Heating Water: Active System
Active System uses antifreeze so that the liquid does not freeze if outside temp. drops below freezing.
Heating Living Spaces
Passive Solar
Trombe WallPassively heated home in Colorado
Solar-Thermal Electricity:Power Towers
• General idea is to collect the light from many reflectors spread over a large area at one central point to achieve high temperature.
• Example is the 10-MW solar power plant in Barstow, CA.
Power Towers
Power tower in Barstow, California.
Solar-Thermal Electricity:Parabolic Dishes and Troughs
• Focus sunlight on a smaller receiver for each device; the heated liquid drives a steam engine to generate electricity.
• The first of these Solar Electric Generating Stations (SEGS) was installed by an Israeli company, Luz International.
• The more recent facilities converted a remarkable 22% of sunlight into electricity.
Parabolic Dishes and Troughs
Because they work best under direct sunlight, parabolic dishes and troughs must be steered throughout the day in the direction of the sun.
Collectors in southern CA.
Direct Conversion into Electricity
• Photovoltaic cells are capable of directly converting sunlight into electricity.
• A simple wafer of silicon with wires attached to the layers. Current is produced based on types of silicon (n- and p-types) used for the layers. Each cell=0.5 volts.
• Battery needed as storage• No moving partsdo no wear out, but
because they are exposed to the weather, their lifespan is about 20 years.
Solar Panels in Use
• Because of their current costs, only rural and other customers far away from power lines use solar panels because it is more cost effective than extending power lines.
• Note that utility companies are already purchasing, installing, and maintaining PV-home systems (Idaho Power Co.).
• Largest solar plant in US, sponsored by the DOE, served the Sacramento area, producing 2195 MWh of electric energy, making it cost competitive with fossil fuel plants.
Efficiency and Disadvantages• Efficiency is far lass than the 77% of
solar spectrum with usable wavelengths.
• 43% of photon energy is used to warm the crystal.
• Efficiency drops as temperature increases (from 24% at 0°C to 14% at 100°C.)
• Light is reflected off the front face and internal electrical resistance are other factors.
• Overall, the efficiency is about 10-14%.
• Cost of electricity from coal-burning plants is anywhere b/w 8-20 cents/kWh, while photovoltaic power generation is anywhere b/w $0.50-1/kWh.
• Does not reflect the true costs of burning coal and its emissions to the nonpolluting method of the latter.
• Underlying problem is weighing efficiency against cost.
– Crystalline silicon-more efficient, more expensive to manufacture
– Amorphous silicon-half as efficient, less expensive to produce.
FOSSIL FUELS 85% of the world’scommercial energy
COAL
OILNATURAL GAS
Coal mines
Surface (strip) mine,Western U.S. Underground (shaft) mine,
Eastern U.S.
The future? Hydrogen fuel cells
Nuclear Energy
Nuclear Fission
• Nuclear fission is the process of splitting a nucleus into two nuclei with smaller masses.
• Fission means “to divide”
• Remember that fission has 2 s’s, therefore it splits into TWO parts.
Fission cont.
• Only large nuclei with atomic numbers above 90 can undergo fission.
• Products of fission reaction usually include two or three individual neutrons, the total mass of the product is somewhat less than the mass of Uranium-235.
Chain Reaction
• A chain reaction is an ongoing series of fission reactions. Billions of reactions occur each second in a chain reaction.
Chain Reaction cont.
• On earth, nuclear fission reactions take place in nuclear reactors, which use controlled chain reactions to generate electricity.
Chain Reaction cont.
• Uncontrolled chain reactions take place during the explosion of an atomic bomb.
Fission Products
• The products of nuclear fission reactions are radioactive, but the energy released from these reactions is less harmful to the environment than the use of fossil fuels.
• The products are intensely radioactive and must be treated and/or stored.
Nuclear Fusion
• Nuclear fusion is the combining of two nuclei with low masses to form one nucleus of larger mass.
• Nuclear fusion reactions are also called thermonuclear reactions.
Nuclear Fusion cont.
• Fusion reactions exist in stars.
• Our sun is a good example of a thermonuclear (fusion) reaction.
• It is almost impossible to create fusion reactions on earth since they need temperatures above one million degrees Celsius in order to take place.
Nuclear Fusion and Fission
Nuclear Fusion• Small nuclei into large• Immense temperature
and pressure• Core of stars
Iron is the “dead end” of both fusion and fission – it is the lowest energy nucleus and cannot be split or fused.
Nuclear Fission• Large nuclei into small• Critical mass to sustain• Two isotopes we use
235U 239Pu
Anatomy of a Nuclear Power PlantSource: NRC
Anatomy of a Nuclear Power Plant
Source: NRC
Advantages of Nuclear Power
Clean Plentiful Supply High energy content in uranium
• Small fuel pellet• Can provide base load power • Energy savings in transportation
Operating cost is low after construction
The NEED Project
Drawbacks to Using Nuclear Power
Initial construction costs Radioactive waste byproduct Storage Natural disasters
The NEED Project
Wave/Tidal Energy
Wave Energy
WHAT IS IT?• Wave power devices extract
energy directly from surface waves or from pressure fluctuations below the surface.
• Energy extracted from the waves is stored in generators.
• Wave energy can be converted into electricity through both offshore and onshore systems.
• Offshore systems are situated in deep water, typically of more than 40 meters (131 feet). Sophisticated mechanisms—like the Salter Duck—use the bobbing motion of the waves to power a pump that creates electricity. Other offshore devices use hoses connected to floats that ride the waves. The rise and fall of the float stretches and relaxes the hose, which pressurizes the water, which, in turn, rotates a turbine.
•Oscillating water column The oscillating water column consists of a partially submerged concrete or steel
structure that has an opening to the sea below the waterline. It encloses a column of air above a column of water. As waves enter the air column, they cause the water
column to rise and fall. This alternately compresses and depressurizes the air column. As the wave retreats, the air is drawn back through the turbine as a result
of the reduced air pressure on the ocean side of the turbine.
HOW DOES IT WORK?1. Wave capture chamber set into rock face.2. Tidal power forces water into chamber.3. Air alternately compressed and
decompressed and decompressed by "oscillating water column".
4. Rushes of air drive the Wells Turbine, creating power.
•TAPCHANTapered channel system, consists of a tapered channel, which feeds into a reservoir constructed on cliffs above sea level. The narrowing of the channel causes the waves to increase in height as they move toward the cliff face. The waves spill over the walls of the channel into the reservoir and the stored water is then fed through a turbine.
• The TAPCHAN systems overcome the issue of power on demand, as the reservoir is able to store energy until it is required.
•Pendulum device The pendulum wave-power device consists of a rectangular box,
which is open to the sea at one end.
A flap is hinged over the opening and the action of the waves causes the flap to swing back and forth. The motion powers a hydraulic pump and a generator.
Main Advantages
• This is a non-polluting source of energy• Wave turbines are relatively quiet to operate and do not affect
wild life.
Main Disadvantages• Wave energy requires a consistent supply of powerful waves
to fuel a community's electrical needs, but waves are not consistent.
• Spills or accidental leaks caused by hydraulic fluids in the system could also potentially harm marine life.
Tidal Energy
WHAT IS IT?• Tides of water caused by
the Moon and Sun, in combination with Earth's rotation.
• Practically inexhaustible and it is classified as a renweable resource.
• For tidal differences to be harnessed into electricity the difference between high and low tides must be at least 16 feet.
• There are only about fourty sites on the earth with tidal ranges of this magnitude.
Tidal power technologies include the following...
Barrage or damA barrage or dam is typically used to convert tidal energy into electricity by forcing the water through turbines, activating a
generator.
Gates and turbines are installed along the dam. When the tides produce an adequate difference in the level of the water on opposite sides of the dam, the gates are opened. The water then flows through the turbines. The turbines turn an electric generator to produce electricity.
Tidal fence Tidal fences look like giant turnstiles. They can reach across channels between small
islands or across straits between the mainland and an island.
A tidal fence has vertical axis turbines mounted in a fence. All the water that passes is forced through the turbines. They can be used in areas such as channels between two landmasses.
Tidal turbine Tidal turbines look like wind turbines. They are arranged underwater in
rows, as in some wind farms.
• Ideal locations for tidal turbine farms are close to shore in water depths of 65.5–98.5 feet.
• Turbines were submerged in the East River to generate
electricity from rapid tidal currents in New York City in 2007
Main Advantages
• It is predictable. • No waste or pollution• It is very cheap to maintain.
Main Disadvantages
• Building cost is expensive.• Disrupts migration of creatures
in the ocean• Only produces power for only
about 10 hours a day.
