ENERGY
All natural ecosystems must have energy and our modern human civilization must have energy also. In fact, without energy, human civilization ceases to exist.
Electromagnetic Spectrum Many different forms of electromagnetic radiation exist, each having a different wavelength and energy content. Figure 2-11
Fig. 2-11, p. 43 Sun Nonionizing radiationIonizing radiation High energy, short Wavelength Wavelength in meters (not to scale) Low energy, long Wavelength Cosmic rays Gamma Rays X rays Far infrared waves Near ultra- violet waves Visible Waves Near infrared waves Far ultra- violet waves Micro- waves TV waves Radio Waves
Fig. 2-12, p. 43 Energy emitted from sun (kcal/cm 2 /min) Wavelength (micrometers) Ultraviolet Visible Infrared
Two Rules We Cannot Break: the First and Second Laws of Thermodynamics
The First Law of Thermodynamics says that energy can never be created or lost, it can only be changed from one type to another.
ENERGY COMES IN MANY FORMS Electrical Chemical Mechanical Heat Radiation Light Sound Kinetic – the energy of motion Potential – stored energy
We Can Live With the First Law of Thermodynamics, but the Second Law is a bummer.
The Second Law of Thermodynamics says that high quality energy always degrades to low quality energy (low temperature heat) and can never be recovered.
Fig. 2-14, p. 45 Chemical energy (food) Solar energy Waste Heat Waste Heat Waste Heat Waste Heat Mechanical energy (moving, thinking, living) Chemical energy (photosynthesis)
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Current Sources of Energy
CO 2 Production per capita
What is a BTU? A British Thermal Unit is the amount of energy need to raise one pound of water one degree Fahrenheit One BTU = 252 calories One BTU = 1,055 joules
What is a calorie? A calorie is the amount of energy it takes to heat one gram of H 2 O one degree Celsius A food Calorie (with a big “C”) is 1000 calories or a single kcal One calorie = 4.2 joules One calorie = BTU’s
What is a joule? (J) It is the force of one newton over one meter Work needed to make 1 watt of power for 1 second One joule = calories One joule = BTU’s
Energy is used in four main areas: - to make electricity - for transportation - for space heating - for industry
What is a kilowatt-hour?
A kilowatt-hour is using a thousand watts of electricity for one hour.
If you turned on ten 100-watt light bulbs for an hour, you have used up one kilowatt-hour.
Household Energy Demand Fluctuates Throughout the Year
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The Energy We Use Can Be Divided Into Two Main Categories: Non-renewable and Renewable
Nonrenewable Energy Energy sources that are dependent upon fuels or a resource that that may be used up much faster than it is replaced by natural processes
Types of Non-Renewable Energy Petroleum (Oil) Natural Gas Coal Nuclear Tar Sands Shale Oil
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Alternative energy sources that are more or less continuously made available in a time framework useful to humans Alternatives to Fossil Fuels and Nuclear Power (Renewable Energy)
Renewable Energy Energy sources that will be available indefinitely because they are continually renewed by natural processes.
Types of Renewable Energy Solar Water Wind Biomass –burning –conversion to liquid fuels Geothermal Solar-Hydrogen
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Our Energy Future is in Our Hands
Energy Consumption in Developing Countries Only 22.3% of global population lives in developed countriesOnly 22.3% of global population lives in developed countries These people consume 68% of commercial energyThese people consume 68% of commercial energy Each person in a developed country consumes 7.4x’s as much energy as person in a LDCEach person in a developed country consumes 7.4x’s as much energy as person in a LDC
Peak Demand Peak demand for electricity is between 12 noon and 6 p.m. Most consumers are awake, working and needing heat or air conditioning. It is also the time many manufacturers are powering machinery.