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Introduction to Energy Concepts. Energy. Derived from Green en ( in ) and ergon ( work ) – “ in work ” “ Forceful or vigorous language ” First definition - Aristotle “ Capacity to do Work ” Modern accepted definition “ Energy is Eternal Delight ” William Blake, 1757-1827.
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Energy • Derived from Green en (in) and ergon (work) –“in work” • “Forceful or vigorous language” • First definition - Aristotle • “Capacity to do Work” • Modern accepted definition • “Energy is Eternal Delight” • William Blake, 1757-1827
Four Basic Forms of Energy • Kinetic = 0.5 x mass x speed2 • Thermal– energy of vibrating molecules within a material • Electrical– force between electrical charges • Chemical– electrical energy that holds molecules together • Gravitational– also known as “potential energy”– force x distance = weight x height = m x g x h • Nuclear– forces that hold atoms together
Units of Energy Energy requires a force. Each form of energy has it’s own force: gravity, strong & weak nuclear forces, electrical, and kinetic forces. • Kinetic Force = Mass x Acceleration • Unit of force = 1 Newton = 1 Kilogram x 1 m/s Energy is a measurement of work accomplished by a force • Energy = Force x Distance • 1 Joule = 1 Newton x 1 Meter
Energy and Power • Energy is a quantity, like distance. • 1 kilowatt-hour = 1000 Watts x 1 hour • 1 kilowatt-hour = 3.6 x 106 Joules • Power is a rate, like speed, it is the rate that energy is converted from one form to another. • 1 Watt = 1 Joule / Second
Laws of Thermodynamics • First Law: In any transformation of energy from one form to another, the total quantity of energy remains unchanged. “Energy is neither created nor destroyed, it only changes forms.” • Second Law: In all energy changes, the potential energy of the final state will be less than that of the initial state – (useful energy is always lost.) • “Lost” energy is usually energy that has been converted to heat, but it could be noise (kinetic energy of air), or other forms of wasted energy.
Efficiency • The ratio of the amount of useable energy obtained to the amount of energy input is the efficiency of a process. • This is usually expressed as a percent and it is always less than 100%.
Energy definitions • Primary Energy– amount of energy contained in the initial source of energy • Delivered Energy– amount of useable energy delivered to the customer • Useful Energy– amount of energy attributed to the amount of work accomplished
Solar Wind Biomass Hydro Ocean Coal Oil Gas Nuclear Renewable vs Non-Renewable
Edgartown with 1 m sea level rise and storm surge from Cat. 2 hurricane
Every Year an Average Coal Plant Releases • 3,700,000 tons of CO2 • 10,000 tons of SO2. • 500 tons of particulates • 10,200 tons NOx • 720 tons of CO • 220 tons of volatile organic compounds (VOC) • 170 pounds of mercury • 225 pounds of arsenic • 114 pounds of lead And there are over 600 of them in the US. Source: Union of Concerned Scientists: www.ucsusa.org
CO2– Global Warming CO– Health problem PM–Respiratory and heart disease, haze SOx– Acid Rain, respiratory illness, haze NOx– Ozone formation, acid rain, smog, nutrient loading, global warming Mercury– Neurotoxin Lead– Neurotoxin Arsenic - Poison VOCs– Numerous health problems Ozone– Health problems, damage to flora & fauna Hundreds of other toxic chemicals Types of Pollutants