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Renewable Energy. PHYS 331 – A Recap of Semester Spring 2019 Prof. Geller. Concepts For Understanding Energy. Work Potential Energy Kinetic Energy Conservation of Energy Types/Sources of Energy. Work is Force times distance. Definition of work
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Renewable Energy PHYS 331 – A Recap of Semester Spring 2019 Prof. Geller
Concepts For Understanding Energy • Work • Potential Energy • Kinetic Energy • Conservation of Energy • Types/Sources of Energy
Work is Force times distance • Definition of work • “work is equal to the force that is exerted times the distance over which it is exerted” • work in Joules = • force in Newtons * distance in meters • W = f * d
Question for Thought • A spring clamp exerts a force on a stack of papers it is holding together. Is the spring clamp doing work on the papers? • A Yes • B No • If the spring clamp does not cause the paper to move, it is not acting through a distance and no work is done.
Power - Work per unit time • Power defined • “power is the amount of work done divided by the time it takes to do that work” • power in Watts = work in Joules / time in seconds • P = W / t
Question for Thought • A kWhr is • A a unit of work • B a unit of energy • C a unit of power • D More than one of the above is true. • A kWhr is a unit of work, and since energy is the ability to do work, it is also a unit of energy. In terms of units, a watt is a joule per second, and an hour, as a second, is a unit of time. The time units cancel, leaving a unit of a joule, which can be used to measure either work or energy.
Kinetic Energy • Definition • “Kinetic energy equals the mass of the moving object times the square of that object’s speed, times the constant 1/2.” • kinetic energy in Joules = 0.5 * mass in kilograms * speed in meters per second * speed in meters per second • K.E. = 0.5 * m * v2
Question for Thought • Does a person standing motionless in the aisle of a moving bus have kinetic energy? • A Yes • B No • Relative to the bus, the person has no kinetic energy because the person is at rest relative to the bus. Relative to the ground, however, the person does have kinetic energy because the person is moving with the same speed as the bus.
Potential Energy • Definition • “gravitational potential energy of any object equals its weight times its height above the ground” • gravitational potential energy in Joules = mass in kilograms * acceleration due to gravity * height in meters • P.E. = m * g * h
Question for Thought • What happens to the kinetic energy of a falling book when the book hits the floor? • A The kinetic energy is destroyed. • B The kinetic energy is converted to heat only. • C The kinetic energy is converted to heat and sound.
Mass as Energy • Definition • “every object at rest contains potential energy equivalent to the product of its mass times the speed of light squared” • energy in joules = mass in kilograms * speed of light in meters per second * speed of light in meters per second • E = m * c2
History of Energy Use • Early civilizations used human muscle power as their primary energy source. • Energy provided by burning wood enabled people to cook food, heat living areas, and develop primitive metallurgy. • Dense, rapidly growing settlements outstripped wood production, thus new fuel sources had to be utilized. • 1890, coal replaced wood - primary energy source
Fossil Fuels • Carboniferous period, (286-362 Mya) • large deposits of plants, animals, and microorganisms. • Led to the formation of fossil fuel deposits.
Industrial Revolution - 1875 • Industrial Revolution - Machines replaced human and animal labor in the manufacture and transportation of goods. • Steam engines converting heat energy into forward motion was central to this transformation. • Countries or regions without large coal deposits were consequently left behind.
Industrial Revolution • Prior to the Industrial Revolution, goods were manufactured on a small scale in private homes – master craftsman • Expanding factories = larger labor pools, move to city • 200 years, energy consumption increased 8X • Increased levels of air pollution.
iClicker Question • Fossil fuels are derived from biological material produced • A at the time of the industrial revolution • B about 300 million years ago • C about 1 million years ago • D about 1 billion years ago • E at the turn of the previous century
iClicker Question • At the turn of this century (2000) most energy was derived from • A Coal • B Wood • C Natural Gas • D Oil • E Nuclear Power
Role of The Automobile • Growth of automobile industry led to roadway construction • Better roads - Higher speeds • Higher speeds - Bigger faster cars = Bigger faster cars - Better roads • Convenience of two-car families • Job growth in automobile-related industries • Major role in development of industrialized nations. • Cars altered people’s lifestyle • Greater Distance Travel • Sprawling Cities • Suburbs • Vacations
Growth in the Use of Natural Gas • Initially, natural gas was burned as a waste product at oil wells. • Before 1940, accounted for less than 10% of energy consumption in United States. • By 1970, accounted for about 30% of energy needs. • In 2003 accounted for 25% of U.S. consumption. • Primarily used for home heating and industrial purposes.
How is Energy Used? • Industrialized nations use energy for: • Residential / Commercial uses • Industrial uses • Transportation • Less developed countries use most energy for residential purposes. • Cooking and Heating • Developing countries use much of their energy to develop industry.
iClicker Question • Oil use in the U.S. has always risen since 1960. • A True • B False
How does the US compare to others in overall energy use through 2002?
iClicker Question • Which of the following countries has the lowest gas taxes? • A France • B Germany • C Spain • D Japan • E USA
The Importance of OPEC • Oil Producing and Exporting Countries • Twelve members • Control over 78% of world’s estimated oil reserves. • 1,000 billion barrels
iClicker Question • The United States imports more energy than it produces? • A True • B False
Energy Flow from Source to Use(USA 2008) Note Changes from 2003, page 17 of textbook
TYPES OF ENERGYand their Transformation Mechanical, Electromagnetic, Electrical, Chemical and Thermal
iClicker Time! Electrical energy is transported to your house through power lines. When you plug an electric fan to a power outlet, electrical energy is transformed into what type of energy? A Mechanical B Electromagnetic C Electrical D Chemical E Thermal
Energy come from Energy Resources, that are converted into energy that we can easily use. Electricity is the main form of energy that we use and can power or charge what we need energy for.
To generate electricity… • You need an energy source, e.g. coal • This is burnt to produce heat or steam • The heat or steam then drives a turbine • The turbine then can drive a generator • The generator then produces electricity • The electricity is then transported in cables to where it is needed
Energy Resources can be divided into 2 categories: 1. Non-Renewable Resources For example – coal, oil, gas, uranium or lignite Once used these resources CANNOT be used again 2. Renewable Resources For example – wind, water or solar These resources can be used over and over again
Non-Renewable Resources: COAL What is it? • Formed underground from decaying plant material How much left in the world? • About 200 years Advantages? • Plenty left • Mining is getting more efficient Disadvantages? • Pollution: CO2 emissions (linked to global warming), SO2 (linked to acid rain) • Heavy & bulky to transport
Non-Renewable Resources: OIL What is it? • Formed underground from decaying animal and plant material How much left in the world? • Estimates vary, but average about 40 years Advantages? • Quite easy to transport • Efficient in producing energy • Less pollution than coal Disadvantages? • Not much left • Pollution: air and danger of water pollution through spills
Non-Renewable Resources: NATURAL GAS What is it? • Formed underground from decaying animal and plant material How much left in the world? • Estimates vary from 60-100 years Advantages? • Clean, least polluting of all non-renewables • Easy to transport Disadvantages? • Some air pollution • Danger of explosions
Non-Renewable Resources: NUCLEAR What is it? • Uses uranium, naturally found in some rocks How much left in the world? • Not known Advantages? • Not much waste and few CO2 emissions released, as well as, few other greenhouse gases Disadvantages? • High cost to build and close down power stations. • Waste is radioactive. Problem with getting rid of waste safely
Why is the term, FOSSIL FUEL used for coal, oil, gas and lignite?A Because they all contain fossils.B Because they were once food sources for things that are now fossils.C Because they are derived from living matter of a previous geological age.D Because of their energy per unit of mass.E Because Prof. Geller said so.
Renewable Resources: WIND What is it? It the movement of air from high to low pressure How much left? Lots Advantages? No pollution Disadvantages? Winds change all the time, not predictable
Renewable Resources: SOLAR What is it? Energy from the sun How much left? Lots Advantages? No pollution, can be used in remote areas Disadvantages? Can be expensive, needs sunlight At night it doesn’t work
Renewable Resources: BIO-ENERGY What is it? Biomass and Biogas – • fermented animal or plant waste • vegetation from sustainable sources How much left? Lots Advantages? Good availability Disadvantages? Can be expensive to set up
Renewable Resources: HYDRO What is it? Movement of water drives a turbine How much left? Lots Advantages? No CO2 emissions, can control flooding and provide a good water supply to an area Disadvantages? Large areas maybe flooded. Visual and water pollution
Renewable Resources: GEOTHERMAL What is it? Heat from the ground – often used to heat water How much left? Lots Advantages? No CO2 emissions Disadvantages? Expensive and can only be used in certain parts of the world
Renewable Resources: WATER & TIDAL What is it? Movement of sea drives turbines How much left? Lots Advantages? Can produce a lot of electricity, no CO2 emissions Disadvantages? Not many suitable sites
Energy Transfer Sound (mechanical) Electrical Thermal Mechanical Electrical Chemical Electrical Light (Electromagnetic)
Oil Exploration and Extraction • Oil is a fossil fuel • formed from the remains of plants and animals • died in ancient seas around 300 million years ago • Biota such as plankton fall to the bottom of the sea and decay • form sedimentary layers • little or no oxygen present • microorganisms break down the remains into carbon-rich compounds • organic material mixes with the sediments to form fine-grained shale, or source rock • sedimentary rocks layer generate heat and pressure • distilled organic material forms crude oil and natural gas • oil flows from the source rock and accumulates in thicker, more porous limestone or sandstone known as reservoir rock. • When the Earth’s crust moves, the oil and natural gas is trapped in reservoir rocks, which are between layers of impermeable rock (cap rock– usually granite or marble) http://www.energyquest.ca.gov/story/chapter08.html
iClicker Question • Oxygen is required in the formation of oil in the sedimentary layers • A True • B False
The Search for Oil Oil companies usually contract out the search for oil to exploration geophysicists Exploration geophysicists utilize surface features surface rock reservoir rock entrapment satellite images gravity meters magnetometers hydrocarbon sniffers sometimes called electronic noses seismometers [most common technique used] shock waves developed reflections interpreted Oil exploration methods are still only about 10 percent successful in producing useful well http://science.howstuffworks.com/oil-drilling2.htm http://science.howstuffworks.com/oil-drilling1.htm