© 2006 by Taylor & Francis Group, LLC
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1
Electric Energy and
Electric Generators
1.1
Introduction ........................................................................1-1
1.2 Major Energy Sources .........................................................1-2
1.3
Electric Power Generation Limitations .............................1-4
1.4
Electric Power Generation..................................................1-5
1.5
From Electric Generators to Electric Loads ......................1-8
1.6
Summary............................................................................1-12
References .....................................................................................1-12
1.1 Introduction
Energy is defined as the capacity of a body to do mechanical work. Intelligent harnessing and control of
energy determines essentially the productivity and, subsequently, the lifestyle advancement of society.
Energy is stored in nature in quite a few forms, such as fossil fuels (coal, petroleum, and natural gas),
solar radiation, and in tidal, geothermal, and nuclear forms.
Energy is not stored in nature in electrical form. However, electric energy is easy to transmit at long
distances and complies with customer’s needs through adequate control. More than 30% of energy is
converted into electrical energy before usage, most of it through electric generators that convert mechan-
ical energy into electric energy. Work and energy have identical units. The fundamental of energy unity
is a joule, which represents the work of a force of a Newton in moving a body through a distance of 1 m
along the direction of force (1 J = 1 N × 1 m). Electric power is the electric energy rate; its fundamental
unit is a watt (1 W = 1 J/sec). More commonly, electric energy is measured in kilowatthours (kWh):
(1.1)
Thermal energy is usually measured in calories. By definition, 1 cal is the amount of heat required to
raise the temperature of 1 g of water from 15 to 16°C. The kilocalorie is even more common (1 kcal =
103 cal).
As energy is a unified