What is a National Grid System?

The National Grid is a transmission network that connects power stations to consumers, ensuring the distribution of electricity within a country. It has advantages such as flexibility in power generation and disadvantages such as wastage of power and the potential for cyber attacks.

1. What is a National Grid System?
National grid is a transmission network consisting of the high voltage electrical power that
covering a whole country or a national by connection of power stations as well as the power
substations by ensuring the power generated is transmitted to consumer to satisfy the consumer
demands. The National grid majorly is for the distribution of the electricity within the country. It
connects the generating stations to factories, homes and commercial centers country wide. It is
composed of the overhead power transmission lines, pylons and underground cables. The system
is in use of bulk electrical energy transfer from the power stations to substations then to the
consumer.1
Advantages of the National grid
i. Electricity can be consumed from any power generating station in order to cater for the
demand anywhere in the country
ii. The power plants can be constructed near the available natural resources as well as far
away from urban centers.
iii. Extra electrical power can be used in generation of Hydro electrical power by pumping
water up hill
iv. If on power station may failure or switched for maintenance the consumer can continue
receiving electricity from the supplier.
v. Keeping of pollution far from the cities
Disadvantages of the national Grid
i. Some of the power is wasted due to the heating the cables
ii. It costly to build the national grid infrastructure system for the whole country if the
underground cable connection is used.
iii. The national grid system promotes monopoly, which may lead to laxity of quality service
delivery to the consumer.
iv. The overhead as well as their electrical supporting towers may bring an eyesore in some
areas.
v. The national grid system if connected to the internet and the system is hacked, it can
bring the whole national into a total electrical blackout for instance when Turkish
national grid was hacked the whole country was put into an electrical black out.
2. What is alternating current and how it is produced?
Alternating current is usually produced as a result of the change of the charges flow direction
periodically. Due this effect, the levels of voltage also reverse with current along the line. The
alternating current is generated using a device known as the alternator. An alternator is a special
device that designed to generate alternating current by the spurning a loop wire inside of the
1 Godfrey Boyle Renewable electricity and the grid: the challenge of variability ( 1. edn Earthscan 2012 ) 144.

magnetic field, that causes inducement of the current along a wire. This is usually done though
the rotation of the magnetic field at around stationary set coils of wire by the turning of the shaft.
Advantages of alternating current
i. Alternating current can be transmitted over a long distance.
ii. The alternating current can be easily produced
iii. It is cheaply generated when compared to dc.
iv. The generators of ac have higher efficiency than dc.
v. The alternating current can be easily stepped up or down by transformers.
vi. The value of the alternating current can be easily decreased without excess loss of
energy.
vii. It produces better lighting
viii. It can easily generate a waveform
Disadvantages of alternating current
i. It can cause heat and spark which can result electric fires or shocks.
ii. It can create impractical in transmission in undersea cables for it needs a substation
nearly after every four hundred miles. In underwater, the substations cannot be built
there.
iii. The need of insulation at high power makes it difficult to handle it because it can result
electrocution to the operator if not well handled.
iv. It is expensive when used in cars because of its impracticability in cost terms.
v. It needs more cables to transport making it expensive when compared to dc.
3. What is Hydropower?
Hydropower is the generation of electricity due to water moving which is harvested in a reservoir
or dam and falls due to gravity to rotate turbines. The water flow creates energy that can be
harnessed and used. The widely used method is of a dam constructed on the river channel to keep
water in the reservoir. The stored water at the reservoir is released to cause rotation of the
turbines which in turn rotates the magnetic magnets to induce current along the coils of the
wires. The power generated is the harnessed and connected to the step up transformers for
stepping up for transmission.
Advantages of Hydropower
i. It is a form of renewable energy
ii. It is a source of alternative and environmental friendly energy
iii. Hydropower is reliable and stable provided there rivers available.
iv. It needs a low operating cost
v. It easily matches with the current demands dep2ending the river regime.
2 James Kirtley Electric power principles: sources, conversion, distribution and use ( 1. edn Wiley 2011 ) 10-80.

vi. The water used for Hydropower can be used for other applications such as irrigation.
vii. The dam constructed can be used for recreational activities such as canoeing
viii. The hydropower station can attract tourists.
Disadvantages of hydropower
i. It can lead to environmental damage due to water flow interruption.
ii. It is expensive to build it.
iii. The exploitation of hydropower may lead to droughts in some areas.
iv. It can lead to floods at lower regions of the water flow.
v. It can cause water supply shortages
vi. The site of constructing hydropower can result displacement of people and wild life from
their habitats.
vii. Accidents caused by dams are deadly to the lower regions of the dam.
viii. It does not provide consistent power due to drought sometimes.
4. What is Wind power?
It is the power produced by harvesting the wind energy to generate electricity or mechanical
power. The mechanical energy can be employed for grinding cereals or water pumping. The
Mechanical energy is convertible into electricity by use of a generator. The wind rotates the
turbines which are connected magnets, and then a rotating field is produced that leads to induced
current at the coils of the wires. Wind movement has kinetic energy. Thus, high velocity wind
will result high power produced by the wind power plant. So when there is slow wind velocity
small power is generated.
Advantages of wind power
i. Promotion of energy cost effectiveness
ii. It revitalizes the rural economies as it is built in rural areas.
iii. It reduces dependence on fossil fuels which are exhaustible in nature.
iv. It is environmental friendly because it does not pollute air and water.
v. It is a renewable energy resource.
vi. Wind is a free fuel to be exploited.
vii. Promotes price stability in energy sector.
viii. It promotes job creation.
ix. It discourages energy subsidies from the government.
x. It has negligible greenhouse effects on the environment.
Disadvantages of Wind power
i. It only when the wind is blowing a turbine can produce electricity.
ii. The aesthetic to people when seeing the wind power.
iii. The shadow flickering which may alter the light to residents near the wind farm.

iv. They can interfere with the radar operations
v. Movement of the turbines is noisy.
vi. It can cause loss of wild life.
vii. The construction of the wind farm can involve bulk transportation of equipment.
viii. The construction may lead to erosion at the site.
5. What is Solar power?
It is the harnessing of the light from, and converted into electricity either directly by use of solar
panels or indirectly using concentrated solar power or intergrated.Thev concentrated solar power
system uses the mirrors or lenses as well as tracking systems to bring into focus the wide
sunlight area into a small beam. While the photovoltaic cell converts light into electric current by
use of photovoltaic effect. The small consumers of electricity usually use photovoltaics cells for
the applications. The commercial concentrated sola power systems are constructed normal in a
wide area and connected to the national grid. The solar power system has a solar panel, a battery,
cables, inverters and diodes.
Advantages of solar power
i. Zero marginal generation cost in solar power
ii. It is an insurance against increasing power prices
iii. It is a form of renewable energy source.
iv. Solar power is environment friendly because it does not pollute air, land and water.
v. It is geographically available in a wide area on earth.
vi. It results electricity cost reduction.
vii. It is silent, means there is no noise.
viii. It requires little maintenance.
ix. It is technologically ever improving day by day.
x. There is financial support from the government in some countries.
xi. Solar radiation is freely available.
xii. The communal solar plant may be used in order to overcome solar installation problems.
Disadvantages of solar power
i. High initial capital cost due to the prices of the solar panels for large scale production of
solar power.
ii. It can be harnessed only the day time when there is sunlight.
iii. The storage of solar energy is expensive in large scale due to batter systems.
iv. It can be associated to pollution when the solar panels are manufactured, and nitrogen
triflouride and Sulphur hexafluoride is emitted which has greenhouse effect.
v. A certain solar panel types require exotic and rare material.
vi. Solar power needs a large space in large scale production.
vii. The solar power does not move a house.

viii. It is intermitted that in rainy, fog and cloud day the energy produced is small.
6. What is Tidal power?
It is a kind of hydropower which converts energy harnessed from tidal waves into electricity. The
tides are easily predicted than the sun and wind. The tides occur as the result of the sun and
moon gravitation effects on the ocean. This form of power is produced by use of tidal generators.
The tidal generator are underwater turbines which are positioned at areas with high tide
movements, as well as designed to harness kinetic motion of surging and ebbing ocean tides for
electricity production. When the tidal generators are rotated by the tides, electricity is produced.
Advantages of tidal power
i. It is a form of renewable energy source because the energy source is as a result of
gravitational fields of the moon and the sun, in combination of the earth’s rotation on its
own axis.
ii. It is friendly to the environment for it does not pollute air, water and land.
iii. It is easily predicable for the ocean tides when high and low for energy production.
iv. It is efficient even at low speeds
v. It is of the longer lifespan thus lowering the cost of operation of the tidal power station.
vi. It freely available resource to maritime countries.
Disadvantages of tidal power
i. The tidal barrages depend on the levels of the ocean and as potential results like
hydropower dams on the environment.
ii. Tidal power requires construction close to the land.
iii. It is very expensive to construct and design tidal plant because the technology used is
new.
iv. The barrages can bar access to open water.
v. Disruption of marine animal movements.
vi. It can disrupt tidal cycle rhythm
vii. It can lead to tidal level change of the surrounding area of tidal power station.
viii. It can decrease kinetic energy in the ocean.
ix. The sites of the power stations are remote regions.
7. What is geothermal power?
Geothermal power is a source power generated as a result of underground hot spring water or
steam, from its thermal energy is converted into electricity. The steam can be used directly for
mechanical and heating purposes.3 Usually a well is drilled to tap the steam which can be either
wet or dry and the directed to the turbine. The steam comes out of the earth crust with high
3 Paul Breeze Power generation technologies ( 1. edn Elsevier 2005 ) 20-50.

velocity, and directed to turbine connected to magnets which are rotated to induce current at the
coils of the wires to generate electricity.
Advantages of Geothermal power
i. It emits nearly zero carbon dioxide and methane which are greenhouse gases.
ii. It has minimal environmental effects.
iii. The source of geothermal energy is in exhaustible due to abundant supply from the earths
crust.
iv. It can be consistently operating all times in the year.
v. It has price stability because it is not a fossil fuel which has fluctuating prices.
vi. It requires small land footprints to construct it compared to other forms of energy.
vii. There is a continuous innovation in this sector.
viii. It is a form of renewable energy source.
Disadvantages of geothermal power.
i. It is only suitable to certain areas
ii. It has high initial capital for constructions.
iii. The powering cost of the pump: it requires electricity for the pump to operate.
iv. It can lead to surface instability that causes tremors and earthquakes.
v. It can cause reduction of water in the aquifers it is being exploited.
vi. Some emissions from the underground have gases like hydrogen sulphide which can
cause air pollution.
vii. It needs high temperatures to turn the turbine.
viii. It may run out of steam during operation.
8. Ohm’s law?
It a law which states that electric current is proportional to voltage across two points as well
as inversely proportional to its resistance provided the temperature of the conductor is
constant. So when voltage is increasing current will increase at constant temperature, and if
current decreases also the voltage will decrease. However, if the voltage is increased the
resistance of the conductor will decrease. But if the resistance is increased the voltage will
reduce. In this case voltage is force causing flow of charges (current) from one point to
another while resistance is the quantity that opposes flow of the charges in a conductor. If the
resistance or temperature will vary, hence VI relation will change with temperature.
Furthermore the law is not applicable to nonlinear resistor. For instances LDR, varistors,
semiconductors and ionic liquids. This law creates a formula which links current and voltage
with conductor properties in the circuit. The mathematic formula:
Voltage V = current I x Resistance R
Advantages of Ohm’s law

i. It applicable to linear resistors for calculation voltage, current or resistance. Also it
can be used to calculate power or energy in the circuit.
ii. Works at constant temperature.
Disadvantages of Ohm’s law
i. It cannot be applied at the terminals of a battery
ii. It only applicable at constant temperature and surrounding conditions are consistent.
iii. Only applicable on linear devices
9. Series Parallel Circuit?
Series Circuits are the type of the circuit all the components are end to end connected to create
one path for flow of current through the circuit. In parallel circuits, components are linked
between two sets of common electrical points to create multiple ways or paths for flow of current
from one end to another. In every circuit there are rules which describe current, voltage and
resistance relationships.4
Circuits in series:
 The total voltage is equal to voltage drops added.
 All devices/components have equal current sharing.
 Total resistance equal to all added resistances.
Parallel circuits
 All devices share the same voltage
 Branch currents sum up to equal total currents
 Resistance diminish to equally same total resistance
Advantages of parallel circuits
i. Every component connected receives equal voltage.
ii. It is easy to connect or disconnect a device without affect another.
iii. If any fault occurs the current can use another path.
Disadvantages of Parallel circuits
i. It needs a lot of wires
ii. No multiplication of voltage in series.
iii. It fails when it is supposed to pass equal current in the circuit.
4 Suresh Kumar Electric circuits and networks ( 1. edn Pearson 2009 ) 1-112.

Advantages of series connection
i. The circuit in series does not overheat quickly.
ii. The series circuits are easy analyzed.
iii. Many more devices can be added to increase output power in terms of voltage.
iv. Current flowing in the circuit is the same.

References
Boyle G. Renewable electricity and the grid: the challenge of variability ( 1. edn Earthscan 2012 ) 144.
Kirtley J. Electric power principles: sources, conversion, distribution and use ( 1. edn Wiley 2011 ) 10-80.
Breeze P. Power generation technologies ( 1. edn Elsevier 2005 ) 20-50.
Kumar S. Electric circuits and networks ( 1. edn Pearson 2009 ) 1-112.