ENERGY RESOURCES

Renewable sources of energy:

Energy resources are sources of energy that are naturally
replenished on a human timescale or are practically inexhaustible.
These resources include solar energy, wind energy, hydroelectric
energy, biomass energy, and geothermal energy.

• Solar Energy: Generated from sunlight using solar panels or

concentrated solar power systems.
• Wind Energy: Captured using wind turbines to convert wind kinetic
energy into electricity.
• Hydroelectric Power: Generated from flowing or falling water,
typically using dams or run-of-the-river systems.
• Biomass Energy: Produced from organic materials such as wood,
agricultural residues, or waste.
• Geothermal Energy: Derived from the heat of the Earth's crust,
typically accessed through geothermal power plants or heat
pumps. Tidal Energy: Generated from the kinetic energy of tidal
flows or the potential energy of tides.
Non - renewable energy resources : Non-renewable energy is
energy sources that exist in finite quantities and takes a very long
time for replenishment or regeneration.
• Fossil Fuels: Coal, oil, and natural gas are derived from
ancient organic matter. Due to their formation process
spanning millions of years, they are classified as non-
renewable resources, unable to be naturally replenished within
human timeframes.
• Nuclear Energy: Nuclear power relies on the process of
nuclear fission, splitting uranium atoms to generate energy.
Although uranium is abundant, the creation of nuclear energy
produces radioactive waste, which remains hazardous for
thousands of years. As such, despite uranium's prevalence,
nuclear energy is deemed non-renewable due to the long-term
environmental implications of its waste.
SOLAR ENERGY
Solar power plants use one of two technologies:
❑ Photovoltaic (PV) systems use solar panels, either on rooftops or in ground-
mounted solar farms, converting sunlight directly into electric power. The solar
panels are made up of photovoltaic (PV) cells, which convert sunlight into direct
current (DC) electricity throughout the day. This device converts the DC electricity
generated by the solar panels into the alternating current (AC) electricity.
❑ Concentrated solar power (CSP, also known as "concentrated solar thermal") plants
use solar thermal energy to make steam, that is thereafter converted into electricity
by a turbine.

Merits of solar energy –

• Renewable Energy Source
• Reduces Electricity Bills
• Low Maintenance Costs
• Constant improvement and advancement in technology

Demerits of solar energy –

• Initial cost of purchase of the solar panels and installation is high
• Solar panels are dependent on the on sunlight to effectively gather solar energy. So
the efficiency of the solar energy system drops considerably.
• Solar energy storage is expensive
• Require a lot of space for installing the solar panels
WIND ENERGY
Generation of wind energy –
The terms "wind energy" or "wind power" describe the process by which the
wind is used to generate mechanical power or electricity. Wind turbines
convert the kinetic energy in the wind into mechanical power. This mechanical
power can be used for specific tasks (such as grinding grain or pumping water)
or a generator can convert this mechanical power into electricity.

Merits of wind energy –

➢ renewable energy source
➢ Low operational costs
➢ Eco – friendly and it is classified as a green source of energy
➢ Minimizes overdependence on traditional sources of electricity
➢ wind energy is space efficient
➢ Creation of green jobs and revitalizes rural economies
Demerits of wind energy –
❑ Wind is inconsistent. The strength of the wind is not constant and it varies from zero to
storm force. This means that wind turbines do not produce the same amount of
electricity all the time and there will be times when they produce no electricity at all.
❑ Involves high upfront capital investment
❑ Wind turbines can reduce the local bird population
❑ Many people feel that the countryside should be left untouched, without these large
structures being built. The landscape should left in its natural form for everyone to
enjoy.
❑ Wind energy is suited to particular region. Wind turbines are suited to the coastal
regions which receive wind throughout the year to generate power.
❑ Wind turbines are noisy.
❑ Many people see large wind turbines as unsightly structures and not pleasant or
interesting to look at. They disfigure the countryside and are generally ugly.
The term geothermal originates from the
Greek words; Geo, which means earth and
Thermal, which means heat. It is the energy
harnessed from the heat of the earth deep
beneath the ground.

Geothermal Energy Technologies:

❑ Geothermal Electricity Production -
Generating electricity from the earth's
heat.
❑ Geothermal Direct Use - Producing heat
directly from hot water within the earth.
❑ Geothermal Heat Pumps - Using the
shallow ground to heat and cool
buildings.
Formation of geothermal reservoir
Advantages –
➢ It is a reliable source of renewable energy
➢ Eco – friendly source of energy
➢ There is no wastage or generation of by-products.
➢ Little to no geothermal system maintenance
➢ Geothermal power plants don't occupy too much space and thus help in protecting
natural environment.
➢ Unlike solar energy, it is not dependent on the weather conditions.

Disadvantages –
✓ Only few sites have the potential of Geothermal Energy.
✓ Total generation potential of this source is too small.
✓ Most of the sites, where geothermal energy is produced, are far from markets or
cities, where it needs to be consumed.
✓ There is no guarantee that the amount of energy which is produced will justify the
capital expenditure and operations costs.
✓ There is always a danger of eruption of volcano.
✓ It may release some harmful, poisonous gases that can escape through the holes
drilled during construction.
✓ Installation cost of steam power plant is very high.
Biofuels are fuels produced directly or indirectly from organic
material – biomass – including plant materials and animal waste.
1st Generation Biofuels
Produced from food crops.Corn, wheat, and sugar cane are the most commonly used
first generation biofuel feed stock. Most common first-generation biofuels include:
❑ Biodiesel - extraction of vegetable oils, with or without esterification, from the seeds
of plants like soybean, rape (canola) and sunflower
❑ Ethanol - fermentation of simple sugars from sugar crops (sugarcane) or starch crops
(corn, wheat)
❑ Biogas - anaerobic fermentation of organic waste and crop residues as energy crops

2nd Generation Biofuels

Second (2nd)-generation biofuels are those biofuels produced from cellulose,
hemicellulose or lignin. What separates them from first generation biofuels the fact that
feedstock used in producing second generation biofuels are generally not food crops.
Second-generation non-food feed stocks include woody crops and agricultural residues
or waste, which are a little more difficult to extract. One well-known second-generation
technology is called lignocellulosic processing, which uses forest materials.

Third generation biofuels:

The Third Generation of biofuels is based on improvements in the production of
biomass. It takes advantage of specially engineered energy crops such as algae as its
energy source. The algae are cultured to act as a low-cost, high-energy and entirely
renewable feedstock and is predicted that algae will have the potential to produce more
energy per acre than conventional crops.
Advantages :
❑ Biofuels prices have been falling and have the potential to be significantly less expensive
than existing fossil fuels.
❑ It is a renewable source of energy. Most of the sources like manure, corn, switchgrass,
soyabeans, waste from crops and plants are renewable and are not likely to run out any
time soon.
❑ Biofuels can be manufactured from a wide range of materials including crop waste,
manure, and other byproducts which makes it an efficient step in recycling.
❑ When biofuels are burned, they produce significantly less carbon output and fewer
toxins, making them a safer alternative to preserve atmospheric quality and lower air
pollution.
❑ Biofuel production also increases the demand for suitable biofuel crops which in turn
provides economic stimulation to the agriculture industry

Disadvantages:
▪ Biofuels have a lower energy output than traditional fuels
▪ Refining biofuels to more efficient energy outputs and building the necessary
manufacturing plants to increase biofuel quantities, a high initial investment is required
which makes its production currently more expensive.
▪ Utilization of valuable croplands for growing fuel crops might cause food shortage.
Moreover, food crops used for biofuel production (like corn) raises the price of staple
food crop.
▪ Massive quantities of water are required for proper irrigation of biofuel crops as well as
to manufacture the fuel, which could strain local and regional water resources.
Tidal energy, is a form of hydropower
that converts the energy of tides into
useful forms of power – mainly
electricity.
Tidal energy or tidal power is a form of
renewable energy obtained due to
alternating sea levels. The kinetic
energy from the natural rise and fall of
tides is harnessed and converted into
electricity. Tides are caused by the
combined gravitational forces of the
moon, sun, and earth but they are
influenced most by the moon. The high
and low tides create tidal currents,
which are essential in generation of this
kind of energy mostly prevalent in
coastal areas.
Tidal barrage is a tidal power generation method that work similar
to hydropower and have sluices that control the tidal flow to drive turbines and
generate electricity.
Tidal barrages are among the oldest methods of tidal power generation, with projects
being developed as early as the 1960s.
Benefits:
❑ Such types of dams can be used not only to produce renewable energy, but also to
reduce flooding. They can be used to prevent flooding of low lying areas - areas that
already are at a high risk of flooding - by holding back or releasing water as necessary.
❑ High predictability as high and low tides can be predicted years in advance
Demerits:
o Tidal barrages alter the flow of saltwater in and out of estuaries, which can alter the
quality of the seawater and thus negatively impact and displace marine life in the
area.
o High development cost of tidal barrage
These are underwater windmills which are consistent source of kinetic
energy caused by regular tidal cycles influenced by the phases of the
moon.
Tidal turbines are installed on the seabed at locations with high tidal
current velocities, or strong continuous ocean currents where they extract
energy from the flowing water.
Tidal Fence is tidal stream generator design that uses the movement of the ocean’s
currents, flows and streams created by this constant ebbing and flowing of the tides to
generate electricity

❑ All the electrical generators, machinery and cabling can be kept high and dry above the
water line where they can be easily accessed for maintenance and repair.
❑ Unlike tidal barrage, a tidal fence can be used in open tidal channels between the
mainland and a nearby island, or between two islands with sufficient tidal stream.
❑ They are also able to generate electricity as individual modules connected together,
rather than just one complete installation as in the case of tidal barrage schemes.
❑ Tidal Fence has much less impact on the environment than other forms of oceanic tidal
generation.
❑ They are cheaper to install than tidal barrages
Advantages of tidal energy
➢ It is a renewable energy resource because the energy it produces is
free and clean as no fuel is needed and no waste bi-products are
produced.
➢ It is not expensive to operate and maintain compared to other forms
of renewable energies.
➢ It has the potential to produce a great deal of free and green energy.
➢ It causes low noise pollution as any sound generated is transmitted
through the water.
➢ High predictability as high and low tides can be predicted years in
advance, unlike wind.
➢ Tidal barrages provide protection against flooding and land damage.
➢ Large tidal reservoirs have multiple uses and can create recreational
lakes and areas where before there were none.
➢ Low visual impact as the tidal turbines are mainly if not totally
submerged beneath the water.
Disadvantages of tidal energy:
❖ It requires a suitable site, where the tides and tidal streams are consistently strong
❖ It is not always a constant energy source as it depends on the strength and flow of
the tides which themselves are effected by the gravitational effects of the moon and
the sun.
❖ High power distribution costs to send the generated power from the submerged
devices to the land using long underwater cables.
❖ Danger to fish and other sea-life as they get stuck in the barrage or sucked through
the tidal turbine blades.
❖ Intermittent power generation, only generates power ten hours a day during the
ebb and flow of the tides
❖ Must be able to withstand forces of nature resulting in high capital, construction
and maintenance costs
❖ Changes to estuary ecosystem and an increase in coastal erosion where the tides
are concentrated.
Ocean thermal energy conversion (OTEC) is a process or
technology for producing energy by harnessing the temperature
differences (thermal gradients) between ocean surface waters
and deep ocean waters.
Solar energy warms the surface water of the ocean, particularly in
tropical regions, creating a temperature contrast between the
surface and deeper layers. This temperature gradient can be
harnessed to generate electricity and desalinate seawater. Ocean
Thermal Energy Conversion (OTEC) systems utilize this
temperature difference, typically exceeding 20°C (36°F), to drive a
turbine for electricity production. In this process, warm surface
water passes through an evaporator where a working fluid
vaporizes, powering a turbine and generator. The vaporized fluid
then condenses back into a liquid in a condenser cooled by cold
seawater pumped from deeper ocean layers. OTEC systems can
also use the condensed water to produce desalinated water,
offering a sustainable solution for both energy production and
water desalination.
Hydroelectricity is the form of energy
which is produced when moving water rotates a
turbine shaft and this movement is converted
to electricity with an electrical generator.
A typical hydro plant is a system with three parts:
▪ an electric plant where the electricity is produced,
▪ a dam that can be opened or closed to control water flow, and
▪ a reservoir where water can be stored.
The water behind the dam flows through an intake and pushes against blades in a
turbine, causing them to turn. The turbine spins a generator to produce electricity. The
electricity can be transported through long-distance electric lines to homes, factories,
and businesses.
Advantages:

❑ t is a clean and renewable source of energy.The generation of

hydroelectricity from flowing water does not pollute or add
greenhouse gases to the atmosphere.
❑ It is widely considered both a reliable and efficient electricity
source.
❑ Hydropower is also readily available and flexible in nature as
engineers can control the flow of water through the turbines to
produce electricity on demand
❑ Once a dam has been built and the equipment installed, the
energy source i.e. flowing water, is free. So it is a very cheap
source of energy
❑ reservoirs may offer recreational opportunities, such as
swimming, boating etc.
Disadvantages:
➢ The environmental consequences of hydropower are related to
interventions in nature due to damming of water, changed water
flow and the construction of roads and power lines. Construction of
dam might cause disastrous consequences for wildlife, fish and
even plants.
➢ The flooding of ecosystems upstream from hydroelectric facilities
also impacts human communities, local cultures and historical sites.
They may be damaged by flooding, and many local communities
may be displaced and be forced to relocate.
➢ Building power plants in general is expensive.
➢ Hydroelectric power generation is impacted by drought. Because
the generation of hydroelectricity is dependent upon river water
flow, a regional drought that significantly reduces river water flow
will negatively impact the ability of a facility to continue to produce
electricity.
➢ Construction of a hydroelectric facility may disrupt the water flow
to communities that are downstream from the plant and reduce
their access to water from the river which might lead to conflicts.
Small hydropower (SHP) facilities offer a clean, renewable, and
cost-effective energy source suitable for deployment in
virtually any location with sufficient water resources.
Particularly beneficial for electrifying remote rural areas, their
advantages are evident, yet their full potential remains largely
unexploited.
Small hydro projects may be built in isolated areas that
would be uneconomic to serve from a national electricity
grid, or in areas where a national grid does not exist.
Nuclear energy is the energy in the nucleus of an atom .
This energy can be obtained in two ways:
❑ Nuclear fusion. In nuclear fusion, energy is released when atoms are
combined or fused together to form a larger atom. The sun produces
energy like this.
❑ Nuclear fission : In nuclear fission, atoms are split into smaller atoms,
releasing energy.
In nuclear power plants, nuclear fission is used to produce electricity. Nuclear
energy comes from splitting atoms in a reactor to heat water into steam, turn
a turbine and generate electricity
Advantages:
❑ Nuclear energy is a clean energy source in terms of carbon emissions released. Rapid
development of nuclear power can be regarded as a means of combating global
warming.
❑ Uranium-235 is not fully burnt up in the reactor and can be re-used after
regeneration which makes it a reusable fuel.
❑ It is very efficient source of energy
❑ Nuclear energy is a reliable source of power

Disadvantages:
➢ Nuclear power produces nuclear waste that is very hazardous for the environment and
for any living being.
➢ Disposing nuclear waste is a very expensive activity
➢ Nuclear power has already produced several radioactive disasters that affected both
human life and the environment
 Chernobyl Disaster
On April 26, 1986, a sudden surge of power
during a reactor systems test destroyed Unit
4 of the nuclear power station at Chernobyl,
Ukraine, in the former Soviet Union. The
accident and the fire that followed released
massive amounts of radioactive material into
the environment.
As per the report of Soviet
scientists, Chernobyl 4 reactor
contained about 190 metric tons of
uranium dioxide fuel and fission
products. Estimates are that 13%
to 30 % of this escaped into the
atmosphere.
The Chernobyl accident caused a
large regional release of
radionuclides into the atmosphere
and subsequent radioactive
contamination of the atmospheric,
aquatic, terrestrial and urban
environment.
 Three Mile Island disaster
In March 1979, a series of mechanical and
human errors at the plant caused the worst
commercial nuclear accident in Three Mile
Island, Pennsylvania in U.S. history,
resulting in a partial meltdown that
released dangerous radioactive gasses into
the atmosphere. Water pumps that helped
to cool the radioactive fuel in the reactor
core malfunctioned.
 Fukushima Daiichi disaster

The Great East Japan Earthquake and the following

tsunami disabled the power supply and cooling of
three Fukushima Daiichi reactors, causing a nuclear
accident on 11 March 2011. All three cores largely
melted in the first three days.
The Fukushima disaster was the most significant
nuclear incident since the April 26, 1986 Chernobyl
disaster and the second disaster to be given the
Level 7 event classification of the International
Nuclear Event Scale (INES).