Energy systems
and
Resources
Learning objectives
• Define energy
• Explain energy systems
• Discuss classification of energy sources
1.0 Energy Systems and Resources
1.1 Introduction
• Energy comes from an energy source also known
as resource.
• Each of these sources has a starting form and
has to be converted into different forms for our
convenient use by help of an energy system
1.0 Cont…
• Energy system is a set of processes involving production,
transformation, transport and distribution of energy
sources e.g. geothermal energy system shown below.
These systems are made
up of a sequence of
conversions with inputs
and outputs that
transform an energy
resource into a form
usable for human work
or heating.
1.0 Cont…
• Energy refers to the ability of a system to cause
external action and is calculated by:
Energy  E   Power  P   Time T 
SI units  Joules  J 
1.0 Cont…
1.2 Classification of Energy
Energy can be classified into two main categories:
1. Potential energy
 Potential energy is stored energy and the energy of position
(gravitational).
 It exists in various form such as elastic potential, gravitational
etc.
2. Kinetic energy
 Kinetic energy is energy in motion- the motion of waves,
electrons, atoms, molecules and substances.
 It also exists in various forms such as sound, mechanical,
thermal, electrical etc.
1.0 Cont…
1.3 Energy Resources
• Energy resource is a natural resource that can be
converted by humans into other forms of energy
in order to do useful work.
• There is a variety of resources that provide us
energy for different purposes which includes:
 Wind energy
 Biomass Energy
 Fossil fuel Energy
 Geothermal Energy
 Nuclear energy
 Ocean Tidal and Wave
energy
 Solar Energy
 Water Energy
1.0 Cont…
1.3.1 Classification of Energy Resources
• Based on usability energy resources may be classified into
primary and secondary resource:
Energy Resources
Primary resource
Secondary resource
(found or stored in nature )
Coal
Biomass
Natural gas
(derived from the transformation of primary energy)
wind
Nuclear fuels
Sun
Bio fuels
Steam
Electricity and Heat
1.0 Cont…
• Based on transaction, energy resources may be classified as
commercial and non-commercial energy resource:
Energy Resources
Commercial Energy
(available in the market for a definite price)
Coal
Electricity
Petroleum
products
Non-Commercial Energy
(not available in the commercial market for a price)
firewood
cattle dung
Agricultural wastes
1.0 Cont…
• Based on energy storage or cycling time involved, energy
resources may be classified as renewable and non-renewable
energy resouce:
Energy Resources
Renewable Energy
(Biomass based and replenishable)
solar energy
Geothermal
energy
wing energy
Water energy
Biomass
Non-Renewable Energy
(Available in limited amount)
Coal
Petroleum
fossil fuels
1.0 Cont…
1. Wind Energy Sources
 Wind energy is the oldest and cleanest forms of
energy and the most developed of the renewable
energy sources.
 Could be used without producing by-products that are
harmful to nature
ADVANTAGES
DISADVANTAGES
Renewable
Only practical in windy areas
Relatively
inexpensive to
generate
Produces less energy
Does not produce
air pollution
Wind mill is big, bulky and
inconvenient to use as
compared to other forms of
energy
1.0 Cont…
2. Fossil Fuels - Conventional Source of Energy
 A fossil fuel is a fuel formed by natural processes, such as
anaerobic decomposition of buried dead organisms,
containing energy originating in ancient photosynthesis
 Coal, crude oil and natural gas are examples of fossil fuels
ADVANTAGES
DISADVANTAGES
Easy to get & transport
Nonrenewable
Provide a large amount
of thermal energy
Costly
Can be used to
generate electrical
energy and make
products, such as
Plastic, paints etc.
Burning coal releases
substances that can cause
pollution
1.0 Cont…
3. Nuclear Energy
 Energy released from nuclear reactions is called nuclear
energy
1.0 Cont…
 In a nuclear power plant, thermal energy released from
splitting uranium atoms is transformed into electrical energy
ADVANTAGES
DISADVANTAGES
Very concentrated form
of energy
Produces radioactive
waste
Power plants do not
produce smog
Radioactive elements are
nonrenewable
1.0 Cont…
4. Solar Energy
 Solar energy is energy derived from the sun in form of solar
radiation
 It can be harnessed by either direct sources (like solar
cooker, solar steam systems, solar dryer, solar cells, etc.), or
indirect sources (biomass production, wind, tidal, etc.)
ADVANTAGES
DISADVANTAGES
Almost limitless source
of energy
Expensive to use for large
scale energy production
Does not produce air
pollution
Only practical in sunny
areas
Renewable
It is intermittent in nature
1.0 Cont…
5. Biomass Energy
 Biomass energy is energy obtained from organic material
made from plants and animals (micro-organisms)
 Biomass as a fuel consists of organic matter such as
industrial waste, agricultural waste, wood, and bark
ADVANTAGES
DISADVANTAGES
Cleaner burning than oil
It is dispersed and land
intensive source
Abundant
Produces smoke
Renewable
It has low energy density
1.0 Cont…
6. Geothermal Energy
 Geothermal energy is energy derived by tapping the heat of
the earth in form of steam from geothermal hotspots like
volcano, geysers, hot springs (etc.)
1.0 Cont…
 The heat from these geothermal hotspots is altered in the
form of steam which is used to run a steam turbine that can
generate electricity
ADVANTAGES
DISADVANTAGES
Reliable
High cost of investment
Abundant supply
Emission of greenhouse gases during
extraction
Sustainable
Non-renewable
1.0 Cont…
7. Ocean Tidal and Wave energy
 Tidal power or tidal energy is a form of hydropower that
converts the energy obtained from tides into useful forms of
power, mainly electricity
 Tides are the rise and fall of sea level caused by the
gravitational pull of the moon and the sun on the Earth
 Wave energy, also known as ocean energy is defined as
energy harnessed from oceanic waves
ADVANTAGES DISADVANTAGES
Running cost is Low efficiency
negligible
Continuous
power supply
High installation
cost
1.0 Cont…
8. Water energy/Hydro energy
 Water energy also known as hydro power, is the use of
falling or fast-running water stored in dams to produce
electricity or to power machines
ADVANTAGES
DISADVANTAGES
Renewable
Expensive to
build
Low emissions
Limited reserves
Reliable
Draught potential
Safe
Environmental
consequences
Acknowledgements
1. Boyle, Godfrey. 2004. Renewable energy. Oxford
University Press, 450 pages (ISBN: 0-19-926178-4).
2. Boyle, Godfrey, Bob Everett, and Jane Ramage 2004.
Energy systems and sustainability: Power for a
sustainable future. Oxford University Press, 619
pages (ISBN: 0-19-926179-2)
3. Sudheer, K.P, Sureshkumar, P.K, Sreekutty Suresh V,
and Greeshma, K. 2018. Lecture Notes of Renewable
Energy. Published by The Associate Dean, College of
Horticulture, Vellanikkara, Kerala Agricultural
University.
THE
END