9
CHAPTER TWO
2 POWER PLANTS ECONOMICS
2.1 Definitions:
2.1.1 Energy and power
Energy is the ability to do work and can exist in very many forms e.g. mechanical work, electrical
energy, heat energy, chemical energy as well as kinetic and potential energy etc. Energy can be
converted from one form to another. Units of energy are kJ, kcal and Horsepower. Power is
primarily associated with mechanical work and electrical energy. It is defined as the rate of flow of
energy. The units of power are kJ/s, kcal/s, W, kW, and MW.
2.1.2 Power plant engineering
Power plant is a machine or assemblage of equipment that produces and delivers a flow of
mechanical or electrical energy. The source of energy for power in a power plant can be fuels,
flowing streams of water, ocean tides and waves, winds, solar rays, terrestrial heat and atomic
nuclear.
Fuels currently provide more energy than any of the other sources initiated. The principal fuels are
coal, natural gas and petroleum products. Others include biomass such as wood, agricultural and
industrial residues etc. They are characterised by sufficient carbon or/and hydrogen, which during
combustion produces large quantities of heat. The combustion process therefore converts chemical
energy of the fuel into mechanical.
Flowing streams of water contains energy in the form of mechanical energy. It may exist as
kinetic energy of a moving stream or as a potential energy of water at some elevation with respect
to a lower datum level, e.g. the water held behind a dam.
MPE 571E: POWER PLANT ENGINEERING
, 10
Ocean tides and waves can be used for the generation of electrical energy and is practical in a
few favourably situated sites where the geography of an inlet or bay favours the construction of a
large-scale hydroelectric power plant. During high tide, water could be collected in the bay by
opening gates and closing them at low tide using the water collected to run a low-head hydraulic
turbine. There is an enormous amount of energy present in ocean waves, but it is so distributed
and variable that the development of it on a large industrial scale presents complexities that have
not yet been solved.
Kinetic energy of the wind can be converted into mechanical energy. The cost of installation and
the variability of operation have limited the use of wind power to electrical generation. There are
several wind energy farms in Europe whereas in developing countries small-scale applications of
wind energy are found in services such as water pumping and charging of storage batteries.
Other forms of energy for power plants include solar energy in which by using concentrators,
high temperature could be achieved for the production of steam electrical generation in a turbine,
terrestrial heats -natural steam escapes from surface units in many places with temperature high
enough and can be used for electrical generation. During the atomic fission of Nucleus Energy
thermal energy is released which is converted to electrical generation.
Power plant engineering is thus the art of selecting and placing the necessary power -
generating equipment over the working life of the plant and the operation of the completed plant
in a manner to provide cheap, reliable and continuous service.
2.2 Types of Power Plants
Based upon the various factors the power plants are classified as follows:
1. On the basis of fuel used
a. Steam Power Plants
i. Condensing Power plant
ii. Non-condensing Power plant
b. Diesel Power Plants
c. Nuclear power Plants
MPE 571E: POWER PLANT ENGINEERING
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d. Hydroelectric power plants
e. Gas-Turbine power plants
2. On the basis of nature of Load
a. Base load Power Plant
b. Peak Load Power plant
3. On the basis of location
a. Central Power Station
b. Isolated Power Station
4. On the basis of Services rendered
a. Stationery
b. Locomotive
2.3 Principles of power plant design
While designing a power station the following factors need to be considered
1. Economy of expenditure i.e minimum
a. Capital Cost
b. Operating and maintenance costs
2. Safety of plant and personnel
3. Reliability
4. Efficiency
5. Low cost of energy generated
6. Reserve capacity to meet future power demand
7. Simplicity of design
8. Ease of maintenance
9. Good working conditions
10. Minimum transmission losses
These factors are greatly influenced by the site of the power plant, availability of raw materials,
availability of water, type of load, maximum power demand and the generating equipment
among other considerations
MPE 571E: POWER PLANT ENGINEERING
CHAPTER TWO
2 POWER PLANTS ECONOMICS
2.1 Definitions:
2.1.1 Energy and power
Energy is the ability to do work and can exist in very many forms e.g. mechanical work, electrical
energy, heat energy, chemical energy as well as kinetic and potential energy etc. Energy can be
converted from one form to another. Units of energy are kJ, kcal and Horsepower. Power is
primarily associated with mechanical work and electrical energy. It is defined as the rate of flow of
energy. The units of power are kJ/s, kcal/s, W, kW, and MW.
2.1.2 Power plant engineering
Power plant is a machine or assemblage of equipment that produces and delivers a flow of
mechanical or electrical energy. The source of energy for power in a power plant can be fuels,
flowing streams of water, ocean tides and waves, winds, solar rays, terrestrial heat and atomic
nuclear.
Fuels currently provide more energy than any of the other sources initiated. The principal fuels are
coal, natural gas and petroleum products. Others include biomass such as wood, agricultural and
industrial residues etc. They are characterised by sufficient carbon or/and hydrogen, which during
combustion produces large quantities of heat. The combustion process therefore converts chemical
energy of the fuel into mechanical.
Flowing streams of water contains energy in the form of mechanical energy. It may exist as
kinetic energy of a moving stream or as a potential energy of water at some elevation with respect
to a lower datum level, e.g. the water held behind a dam.
MPE 571E: POWER PLANT ENGINEERING
, 10
Ocean tides and waves can be used for the generation of electrical energy and is practical in a
few favourably situated sites where the geography of an inlet or bay favours the construction of a
large-scale hydroelectric power plant. During high tide, water could be collected in the bay by
opening gates and closing them at low tide using the water collected to run a low-head hydraulic
turbine. There is an enormous amount of energy present in ocean waves, but it is so distributed
and variable that the development of it on a large industrial scale presents complexities that have
not yet been solved.
Kinetic energy of the wind can be converted into mechanical energy. The cost of installation and
the variability of operation have limited the use of wind power to electrical generation. There are
several wind energy farms in Europe whereas in developing countries small-scale applications of
wind energy are found in services such as water pumping and charging of storage batteries.
Other forms of energy for power plants include solar energy in which by using concentrators,
high temperature could be achieved for the production of steam electrical generation in a turbine,
terrestrial heats -natural steam escapes from surface units in many places with temperature high
enough and can be used for electrical generation. During the atomic fission of Nucleus Energy
thermal energy is released which is converted to electrical generation.
Power plant engineering is thus the art of selecting and placing the necessary power -
generating equipment over the working life of the plant and the operation of the completed plant
in a manner to provide cheap, reliable and continuous service.
2.2 Types of Power Plants
Based upon the various factors the power plants are classified as follows:
1. On the basis of fuel used
a. Steam Power Plants
i. Condensing Power plant
ii. Non-condensing Power plant
b. Diesel Power Plants
c. Nuclear power Plants
MPE 571E: POWER PLANT ENGINEERING
, 11
d. Hydroelectric power plants
e. Gas-Turbine power plants
2. On the basis of nature of Load
a. Base load Power Plant
b. Peak Load Power plant
3. On the basis of location
a. Central Power Station
b. Isolated Power Station
4. On the basis of Services rendered
a. Stationery
b. Locomotive
2.3 Principles of power plant design
While designing a power station the following factors need to be considered
1. Economy of expenditure i.e minimum
a. Capital Cost
b. Operating and maintenance costs
2. Safety of plant and personnel
3. Reliability
4. Efficiency
5. Low cost of energy generated
6. Reserve capacity to meet future power demand
7. Simplicity of design
8. Ease of maintenance
9. Good working conditions
10. Minimum transmission losses
These factors are greatly influenced by the site of the power plant, availability of raw materials,
availability of water, type of load, maximum power demand and the generating equipment
among other considerations
MPE 571E: POWER PLANT ENGINEERING
