Dissertation

1
Feasibility study and design of a
hybrid hydro-wind power
generation for the Treforest area
Author: Kieran Williams
1st Supervisor: Dr Ali Roula
2nd Supervisor: Dr Eurfyl Davies
Course: Bsc (Hons) Electrical and
Electronic Engineering
Venue: University of South Wales
2014/2015

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Chapter 1 - Abstract
The main aim of the project is to simulate and determine the feasibility of developing
an off grid hybrid network consisting of wind and hydro power generation for the
town of Treforest. For the simulation the software package
Simulink/SimPowerSystems within the Matlab software will be utilised. Matlab is a
high-level language and interactive environment used by millions of engineers and
scientists worldwide. It lets you explore and visualize ideas and collaborate across
disciplines including signal and image processing, communications, control systems,
and computational finance. (Matlab, 2015).

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Contents
Chapter 1 - Abstract........................................................................................................2
1.1 Aims and Objectives .............................................................................................7
1.2 Equipment/Tools Required ...................................................................................7
Chapter 2 - Introduction..................................................................................................8
Chapter 3 - Background ..................................................................................................9
3.1 Wind Power...........................................................................................................9
3.1.1 Components..................................................................................................15
3.1.2 Horizontal and Vertical-axis turbines...........................................................15
3.1.3 Capacity Factor.............................................................................................18
3.1.4 Betz’s law .....................................................................................................18
3.1.5 Financial Costs .............................................................................................19
3.2 Hydro-Electric Power..........................................................................................21
3.2.1 Turbines........................................................................................................24
3.2.2 Turbine Design .............................................................................................26
3.2.3 Financial Costs .............................................................................................31
3.3 Generator.............................................................................................................32
3.4 Matlab..................................................................................................................33
3.5 Treforest Area......................................................................................................34
3.5.1 Wind .............................................................................................................34
3.5.2 Hydro ............................................................................................................36
Chapter 4 - Case Study .................................................................................................38
Chapter 5 – Design........................................................................................................39
5.1 Hydro Simulation................................................................................................39
5.2 Wind Simulation .................................................................................................43
5.2.1 Calculations ..................................................................................................43
5.2.2 Wind Simulation Blocks...............................................................................44

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Chapter 6 – Simulation and Testing..............................................................................46
6.1 Wind Farm...........................................................................................................46
6.2 Hydro Plant .........................................................................................................53
Chapter 7 – Conclusion.................................................................................................60
7.1 Further Work .......................................................................................................62
Works Cited ..................................................................................................................63
Appendices....................................................................................................................65
Appendix 1- Interim Report......................................................................................65
References.....................................................................................................................78
Appendix – 2.................................................................................................................81
Project Plan ...............................................................................................................81

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Figure 1: Shows the inside of a typical horizontal axis wind turbine used to harness the
energy of the wind ..........................................................................................................9
Figure 2: This image shows how the flow of air hitting a wind turbine can be
interpreted. ....................................................................................................................11
Figure 3: An image to show how the angle of attack affects the drag produced..........14
Figure 4: This image shows a standard three-bladed Horizontal-axis wind turbine.....16
Figure 5: An image of a vertical-axis wind turbine ......................................................16
Figure 6: This image shows the structure of a hydroelectric facility............................21
Figure 7: Pumped Storage Hydroelectric Facility.........................................................22
Figure 8: This shows the general layout of a small hydroelectric facility ....................24
Figure 9: Cutaway view of a synchronous AC generator .............................................32
Figure 10: This image shows the average wind speeds in the Treforest area...............34
Figure 11: An image showing the approximate width of the River Taff at Treforest.
(Daft Logic, 2015) ........................................................................................................36
Figure 12: This figure shows the three components connected together......................39
Figure 13: Nonlinear system within the hydraulic turbine block .................................40
Figure 14: Second-order system within the gate servomotor .......................................40
Figure 15: Excitation System within the Matlab software............................................41
Figure 16: The input parameters for the Excitation Block............................................41
Figure 17: Synchronous machine block within Matlab ................................................42
Figure 18: Wind Turbine Block....................................................................................44
Figure 19: Variable Block Parameters of the Wind Turbine ........................................45
Figure 20: Circuit diagram of the simulated wind farm................................................46
Figure 21: Sub system built into the wind farm block..................................................47
Figure 22: Wind farm graph showing the results for all three turbines ........................48
Figure 23: Wind speed (m/s) against Time (s)..............................................................49
Figure 24: Output Power vs Time (s) ...........................................................................50
Figure 25: Reactance power (MW) vs Time (s) ...........................................................51
Figure 26: Pitch Angle (Deg) vs Time (s).....................................................................52
Figure 27: Hydro plant design within Matlab...............................................................53
Figure 28: Stator Current (pu) vs Time (s) ...................................................................55
Figure 29: Stator Current vs Time (s)...........................................................................56
Figure 30: Rotor Speed (wm) vs Time (s) ....................................................................57
Figure 31: Rotor Speed (wm) vs Time (s) ....................................................................58

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Figure 32: Output and Reactive Power vs Time (s)......................................................59
Figure 33: This image shows the movement of air as it passes over an increase in
height. As it moves it speeds up, resulting in the air molecules having more energy. .71
Figure 34: This figure shows the location of Treforest within the Taff valley.............73
Equation 1.....................................................................................................................10
Equation 2.....................................................................................................................12
Equation 3.....................................................................................................................12
Equation 4.....................................................................................................................12
Equation 5.....................................................................................................................12
Equation 6.....................................................................................................................13
Equation 7.....................................................................................................................13
Equation 8.....................................................................................................................13
Equation 9.....................................................................................................................23
Equation 10...................................................................................................................43
Equation 11...................................................................................................................43
Equation 12...................................................................................................................68
Equation 13...................................................................................................................68
Equation 14...................................................................................................................69
Equation 15...................................................................................................................69
Equation 16...................................................................................................................70
Table 1: Capital cost and payback period for each turbine size....................................19
Table 2: Characteristics of each hydro turbine .............................................................29
Table 3: Water Turbine Type vs Head Water Pressure ................................................30
Table 4: Synchronous Generator vs Asynchronous generator......................................32

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1.1 Aims and Objectives
The original aims and objectives for the project are as follows:
 Research into the local area to determine what renewable sources are readily
available. Also research into what is not readily available and would need
considerable construction work to be achievable.
 Create a possible questionnaire to determine the public’s view on renewable
energy and how they would like to see it implemented. (Include a list of
renewable sources available to the local area and determine which the public
would like to see being possibly implemented.)
 Research into the energy requirements of the local area and find methods of
reaching this requirement using readily available renewable sources. Various
methods can involve calculating the solar energy output when every house in
the local area if fitted with solar panels, a possible hydroelectric power facility
built on the river taff, and wind turbines build on top of the valley in which
Treforest is situated.
 Find and calculate the overall cost to implement an off grid network of this
description, including investment, interest and maintenance costs over multiple
years.
Since the time that these aims and objectives were created, other forms of work will
have to be carried out including:
 Developing and simulating both a hydro and wind generation facility within
Matlab. In some cases the facilities may have to be connected to the national
grid in order to have the suitable energy to allow start up. They will also need
variable input parameters if the software allows to work alongside their real
life counterparts which vary with the time of the year.
1.2 Equipment/Tools Required
The only equipment/tools required is access to the MATLAB (Simulink) software, and
any online articles or books.

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Chapter 2 - Introduction
The main outcome of this project is to determine whether or not a small town or
village can be self-sustaining when disconnected from the national grid. To be able to
reach this goal many different sources of renewable energy will have to be utilised in
order to obtain a suitable volume of power that is comparable to the energy
requirements of said town or village. In today’s society with the growing usage of
technology, backup plans may need to be put in place for the ever growing need for
power. As well as this the financial costs involved with developing the various
projects will have to be taken into consideration, to determine whether the entire
project would be worthwhile.
The main problem with current power generation is the volume of emissions released
from power stations worldwide. The main gas emitted from these stations is Carbon
dioxide (CO2), which contributes to global warming and eventual climate change. By
constructing hybrid renewable generation systems worldwide we can effectively cut
down on the volume of emissions that humans release into the atmosphere, and thusly
keep the planet as a safe place to live.
The only equipment that will be used is the computers within J block at the university
of South Wales, as they have access to the Simulink software within Matlab. Simulink
is a block diagram environment for multidomain simulation and model-based design.
It supports simulations, automatic code generation, and continuous test and
verification of embedded systems. Simulink provides a graphical editor, customizable
block libraries, and solvers for modelling and simulating dynamic systems. It is
integrated with Matlab, enabling you to incorporate Matlab algorithms into models
and export simulation results to Matlab for further analysis. (Simulink, 2015).

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Chapter 3 - Background
3.1 Wind Power
Energy is playing an important role in human and economic development, with it
being a driving force for this development as well as being a basic demand by nearly
every nation worldwide. Every day energy use is produced by the conversion from one
form to another. During the industrial revolution between the years of 1760 and 1840,
the main method of producing energy was from the burning of wood and or coal.
Since then technology has
progressed to using natural gas
and oil to fill our energy
requirements. However, the use
of these fossil fuels has caused
an increase in the volume of
CO2 within the Earth’s
atmosphere. Between the years
1960 and 2010 alone, the ppmv
(parts per million by volume) of
carbon dioxide has increased
from 315, to 385. (gov.uk, 2015)
Over time, as our energy
requirements grow larger the
volume of CO2 or “greenhouse gases” being pumped into the atmosphere will carry on
increasing. The increase in greenhouse gases causes a blanket effect on the Earth,
resulting in the infrared radiation that should have been reflected back out into space
becoming trapped within the Earth’s atmosphere. This “blanket effect” causes the
climate to slowly increase in temperature, which thusly can cause wild and erratic
weather patterns. By developing a renewable off grid network, a small town could
potentially limit the volume of greenhouse gases they emit into the atmosphere to
0ppmv. It would allow them to only use the local area to produce energy, whether it is
by solar panels, wind turbines, geothermal, or even hydroelectric depending on
Figure 1: Shows the inside of a typical horizontal
axis wind turbine used to harness the energy of the
wind (Mehenni, 2015)

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location. For this project the local area (Treforest/Pontypridd) will be researched and
studied to determine the feasibility of developing an off grid network.
For this project wind power is going to be the main source of power for the Treforest
area, with a hydro facility acting as a backup for when the wind is insufficient for
power generation. Wind turbines are available in a wide range of types to suit different
needs. Wind direction is reported by the direction from which it originates. Since the
wind in the UK follows the jet stream, it is typically a western wind. Occasionally the
wind will change direction, but fortunately wind turbines are installed with a yaw
motor and wind vane to ensure that the maximum volume of energy is extracted from
the wind.
Remote sensing techniques for wind include SODAR, Doppler LIDARS and
RADARs, which work by measuring the electromagnetic radiation that has been
scattered or reflected off suspended aerosols or molecules, and radiometers, and radars
can be used to measure the surface roughness of the ocean from space or airplanes.
Ocean roughness can be used to estimate wind velocity close to the sea surface over
oceans. Geostationary satellite imagery can be used to estimate the winds throughout
the atmosphere base upon how far clouds move from one image to the next. (Mehenni,
2015)
A majority of turbine manufacturers rate their turbines by the amount of power they
can safely produce at a particular wind speed, which is typically found to be between
24 mph (10.5m/s) and 36mph (16m/s).
The formula below illustrates factors that are important to determine the overall
efficiency of a wind turbine:
Equation 1
𝑃 =
1
2
𝑘 𝐶 𝑝 𝜌𝐴𝑉3

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The rotor swept area is particularly important due
to the rotor being the part of the turbine that
captures the wind energy. Therefore, the larger the
rotor, the more energy it can capture. The air
density, p, can change slightly with air temperature
and elevation. Air density can be a particular
problem when calculating the energy that can be
extracted from wind. With cases such as high
altitudes, it must always be taken into account as
the overall energy could be considerably lower
than what is anticipated. Temperature generally
doesn’t need to be taken into account since it has
very little effect on the performance of a wind
turbine. Although the calculation of wind power
illustrates
important
features about wind turbines, the best measure of
wind turbine performance is annual energy output.
The difference between power and energy is that
power (kW) is the rate at which electricity is
consumed, while energy (kWh) is the quantity
consumed. An estimate of the annual energy output
from a wind turbine, kWh/year, is the best way to
determine whether a particular wind turbine and
tower will produce enough energy to meet a
particular need.
Where:
P = Power output, kilowatts
(kW)
Cp = Maximum power
coefficient, ranging from 0.25
to 0.45, dimension less
(theoretical maximum = 0.59)
p = Air density, kg/m3
A = Rotor swept area
V = Wind speed, mph
K = 0.000133, a constant to
yield power in kilowatts.
Figure 2: This image shows how the
flow of air hitting a wind turbine
can be interpreted. (Mehenni, 2015)

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In order to calculate the energy available in wind, knowledge of basic geometry and
the physics behind kinetic energy must be known. The kinetic energy (K.E.) of an
object with total mass (M) and velocity (V) is given by the expression:
Equation 2
𝐾. 𝐸. =
1
2
× 𝑀 × 𝑉2
Wind, which is essentially the kinetic energy of moving air molecules, must be
thought of as a single large object with a cross-sectional area (A), with thickness (D)
that passes through the plane of the wind turbine blades.
The volume (vol) of this object is determined by the objects area multiplied by its
thickness:
Equation 3
𝑉𝑜𝑙 = 𝐴 × 𝐷
In this instance ρ will represent the density of the air in the parcel. Density is
calculated as:
Equation 4
𝜌 =
𝑚
𝑉𝑜𝑙
Therefore, mass can be expressed as:
Equation 5
𝑚 = 𝜌 × 𝑉𝑜𝑙
When considering the velocity of the air parcel, a certain time (T) is given for the
thickness (D) to move through the plane of the wind turbine blades. This gives us the
expression V = D/T, to represent the velocity of the air parcel. This expression can be
rearranged to find the thickness of the parcel, with the expression showing D=V*T.

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The equations mentioned above can be combined together to find the overall power
that a wind turbine will generate. Below shows the process in which this takes place.
Equation 6
Substitute for m = ρ * Vol to obtain: KE = ½ * (ρ * Vol) * V2
And Vol can be replaced by A * D to give: KE = ½ * (ρ * A * D) * V2
And D can be replaced by V * T to give: KE = ½ * (ρ * A * V * T) * V2
Leaving us with: KE = ½ * ρ * V3
* A * T
Since power is just energy divided by time, the power available from an air parcel can
be expressed as:
Equation 7
Pwr = KE / T = (½ * ρ * V3
* A * T) / T = ½ * ρ * V3
* A
With this expression we can see that power is proportional to the cube of the wind
speed. If we were to rearrange the equation again to Pwr/A, we find something called
the ‘Wind Power Density’. Wind power density can be used as the following
expression:
Equation 8
𝑊𝑃𝐷 =
1
2
× 𝜌 × 𝑉3
Wind turbines are designed to exploit the wind energy that exists at a location.
Aerodynamic modelling is used to determine the optimum tower height, number of
blades, blade shape and control systems (pitch, stall).

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Wind turbine blades are shaped to generate the maximum power from the wind at the
minimum cost. Primarily the design is driven by the aerodynamic requirements, but
economics mean that the blade shape is a compromise to keep the cost of construction
reasonable. Since the previous equations showed that the power from wind is
approximately proportional to V3
, when wind speed is doubled, the power is
multiplied by eight.
Wind turbine blades work by generating lift due to their shape. The more curved side
generates low air pressure while high pressure air pushes on the other side of the
aerofoil. The net result is a lift force perpendicular to the direction of flow of the air.
The lift force increases as the blade is turned to present itself at a greater angle to the
wind. This is called the angle of attack, and at very large angles the blade will ‘stall’,
with the lift decreasing again. Therefore there is an optimum angle of attack to
generate the maximum lift.
There is a force known as drag which acts parallel to the wind flow and increases the
angle of attack. If the aerofoil shape is good, the lift force is much bigger that the drag,
but at very high angles of attack, especially when the blade stalls, the drag increases
dramatically. The best operating point for a wind turbine will be between the two
angles.
Figure 3: An image to show how the angle of attack affects the drag produced.
(Mehenni, 2015)

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3.1.1 Components
A wind turbine typically consists of three main components:
 The rotor component which includes the blades for converting wind
energy to low speed rotational energy.
 The generator component which includes the electrical generator, the
control electronics, and most likely a gearbox component for converting
the low speed incoming rotation to high speed rotation suitable for
generating electricity
 The support structure component which includes the tower and rotor yaw
mechanism.
Because so much power is generated by higher wind speed, much of the energy comes
in short bursts. In fact, half of the energy available from wind typically arrives in just
15% of the overall operating time. The consequence is that wind energy is not as
consistent as fuel-fired power plants. Thus, wind power is seen primarily as a fuel
saver rather than a base load plant.
3.1.2 Horizontal and Vertical-axis turbines
Wind turbines are typically found in two different varieties, Horizontal-axis and
Vertical-axis. Horizontal-axis wind turbines (HAWT) have the main rotor shaft and
electrical generator at the top of the tower, and must be pointed into the wind. Small
turbines are pointed by a simple wind vane, whilst large turbines however generally
use a wind sensor coupled with a servo motor. Most have a gearbox, which turns the
slow rotation of the blades into a quicker rotation that is more suitable to drive an
electrical generator.

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Since a tower produces turbulence behind it,
the turbine is usually pointed upwind of the
tower. The net result of this is that the turbine
blades are made stiff to prevent them from
being pushed into the tower by high winds.
Downwind machines have been built, despite
the problem of turbulence, because they don’t
need an additional mechanism for keeping
them in line with the wind. This allows the
blades to bend, thusly reducing their swept
area and their wind resistance. Over time
however, turbulence can lead to fatigue
failures, resulting in most HAWT’s being
upwind machines.
Turbines for commercial production of
electric power are usually, for optimum
inertia and stability, thinner three-bladed
and pointed into the wind by computer-
controlled motors. This results in them have
having high tip speeds, high efficiency, and
low torque ripple, which contribute to good
reliability. The blades are usually coloured
light grey to blend in with the clouds and
range in length from 20-40m or more. The
steel towers used to support the entire
structure range from 60-90m tall. A tall
tower base allows access to stronger wind in
sites with wind shear. In some wind shear sites, the
wind speed can increase by 20% and the power
output by 34% for every 10 meters in elevation.
Figure 4: This image shows a standard
three-bladed Horizontal-axis wind
turbine. (Mehenni, 2015)
Figure 5: An image of a
vertical-axis wind turbine
(Mehenni, 2015)

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A variable blade pitch can be used in HAWT’s to give the turbine blades the optimum
angle of attack. By allowing the angle of attack to be adjusted, greater control of the
turbine can be had, meaning the turbine can collect the maximum volume of wind
energy for the time of day and season.
Vertical-axis wind turbines (VAWT) have the main rotor shaft arranged vertically.
Key advantages of this arrangement are that the turbine does not need to be pointed
into the wind to be affective. This is an advantage on sites where the wind direction is
highly variable.
With a vertical-axis, the generator and gearbox can be placed near the ground, so the
tower doesn’t need to support it, and it is more accessible for maintenance. Drawbacks
are that some designs produce pulsating torque.
Air flow near the ground and other objects can create turbulent flow, which can
introduce issues of vibration, including noise and bearing wear which may increase the
maintenance of shorten the service life. However, when a turbine is mounted on a
rooftop, the building generally redirects wind over the roof with a doubling of the
wind speed at a turbine. This results in VAWT’s being very suitable for houses as they
can generate the most electricity.
VAWT’s also have a lower wind startup speed when compared to HAWT’s.
Typically, they start creating electricity at 10km/h.
The wind blows faster at higher altitudes because of the reduced influence of drag at
the surface or nearer the ground. The increase in velocity with altitude is most
dramatic away from the surface and is affected by topography, surface roughness, and
upwind obstacles such as tree, buildings or other wind turbines. Approximately 2% of

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energy can be lost when wind turbines are situated close together. This is known as the
‘wind park effect’.
Since wind speed is not constant, a wind farm’s annual energy production is never as
much as the sum of the generator nameplate ratings multiplied by the total hours in a
year. The ratio of actual productivity in a year to this theoretical maximum is called
the capacity factor.
3.1.3 Capacity Factor
Unlike fuelled generating plants, the capacity factor is limited by the inherent
properties of wind. Capacity factors of other types of power plant are based mostly on
fuel cost, with a small amount of downtime for maintenance. Nuclear plants have low
incremental fuel cost, and so are run at full output and achieve a 90% capacity factor.
Plants with higher fuel cost are throttled back to follow load. Gas turbine plants using
natural gas as fuel may be very expensive to operate and may be run only to meet peak
power demand. A gas turbine plant may have an annual capacity factor of 5-25% due
to relatively high energy production cost.
The capacity factor achieved by a wind turbine fleet is shown to be increasing as
technology improves. The capacity factor achieved by new wind turbines in 2004-
2005 reached 36%.
3.1.4 Betz’s law
Betz’s law calculates the maximum power that can be extracted from the wind,
independent of the design of a wind turbine in open flow. The Betz limit places an
upper bound on the annual energy that can be extracted at a particular site. Even if a
hypothetical wind blew consistently for a full year, no more than the Betz limit of the
energy contained in that year’s wind would be extracted. The annual capacity factor of
a wind site is generally found to vary between 25-60% of the energy that could be
generated with constant wind.

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3.1.5 Financial Costs
When determining the likelihood of developing a wind farm, the cost is a major factor
that needs to be taken into consideration. In most cases, “75% of the total cost of
energy for a wind turbine is related to upfront costs such as the cost of the turbine,
foundation, electrical equipment, grid-connection and so on. Obviously, fluctuating
fuel costs have no impact on power generation costs. Thus a wind turbine is capital-
intensive compared to conventional fossil fuel fired technologies such as a natural gas
power plant, where as much as 40-70% of costs are related to fuel, operation and
manufacture.” (European Wind Energy Association, 2009)
The cost of a wind energy development will vary depending on the site, scale and
installation requirements. With wind turbines being available in a wide array of sizes
and types, the costs involved can change from site to site. A rough turbine cost for
turbine size is shown below feed-in-tariff generation rate, as well as the approximate
payback period:
Turbine Size Capital cost per
turbine
Feed-in-Tariff
generation rate
(current, £/kWh)
Payback Period
Building-mounted
micro (2.5kW)
£10,000 £0.27 May not payback
within lifetime
Micro (6kW) £20,000-£28,000 £0.27 May not payback
within lifetime
Small (20-50kW) £50,000-£125,000 £0.24 8-15 years
Medium (100-
850kW)
£250,000 to £1.8
million
£0.09-£0.19 7-9 years
Large (1MW-
2.5MW)
£2 million to £3.3
million
£0.05-£0.09 Less than 1 year –
5 years
(Local Government) Table 1: Capital cost and payback period for each turbine
size.
Over time as gas prices increase and wind turbine cost decreases due to market
growth, wind energy will likely become more competitive with gas fired power

20
generation. According to RenewableUK, “the average cost of generating electricity
from large scale onshore wind is now around three to four pence per kilowatt hour,
competitive with new coal (2.5-4.5 pence) and cheaper than new nuclear (4-7 pence)”.
(RenewableUK)
There are multiple schemes in place to encourage the growth of wind technology
within the UK. Projects with a total capacity over 5MW will not be able to claim the
Feed-in Tariffs, however, larger wind projects will be able to qualify for one
Renewables Obligation Certificate (ROC) for every MWh of electricity they generate.
These schemes are particularly enticing as an owner of a 5MW wind farm could
potentially earn up £96 from the Feed-in Tariffs for generating enough electricity to
save a tonne of CO2.

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3.2 Hydro-Electric Power
Out of all of the renewable energy
sources currently open to us,
hydropower by far is the most widely
used form. Once a hydroelectric
complex is constructed, the project
produces no direct waste, and has a
considerably lower output level of the
greenhouse gas Carbon Dioxide (CO-
2) than fossil fuel powered energy
plants.
Hydropower, hydraulic power or
water power is derived from the force or energy of surging water. Hydroelectricity is
the term referring to electricity generated by hydropower; the production of electrical
power through the use of the gravitational force of falling or flowing (inland) water
from lakes, rivers, streams and oceans. As water flows thanks to gravity or wind and
tidal movements, the kinetic energy it carries increases. This kinetic energy can be
converted into mechanical energy – e.g. by turning a turbine – and from there into
electrical energy.
The water turbine is the heart of any hydro power plant. It consists of a number of
metal or plastic blades fitted to a central rotating shaft or plate. Water flowing through
the casing of the enclosed turbine, strikes the blades of the turbine producing torque
and making the shaft rotate due to the velocity and pressure of the water. As the water
pushes against the turbine blades, its velocity and pressure reduces (energy is lost) as it
rotates the turbine shaft.
As the turbine continues to rotate, the water becomes trapped in between the turbines
blades and is pushed along by the rotational movement of the turbine. At some point
along the rotational angle of the turbine blades, the water encounters and opening in
Figure 6: This image shows the structure of a
hydroelectric facility. (Mehenni, 2015)

22
the casing, usually located at the centre. Which allows the water to exit and return
back to the river or stream from where it originally came.
Most hydroelectric power comes from the potential energy of dammed water driving
the water turbine and generator. The power extracted from the water depends on the
volume and on the difference in height between the source and the water’s outflow.
This height difference is called the head. The amount of potential energy in water is
proportional to the head. To deliver water to a turbine while maintaining pressure
arising from the head, a large pipe called a penstock may be used. This type of power
station is used for baseload power.
Pupmed-storage hydroelectric facilities produce electricity when there is a high peak
in demand. They typically move water between reservoirs at different elevations. At
times of low electrical demand, excess generation capacity is used to pump water into
the higher reservoir. When there is higher demand, water is released back into the
lower reservoir through a turbine. Pumped-storage schemes currently provide the most
commercially important means of large-scale grid energy storage and improve the
daily capacity factor of the generation system. This particular system is known as
peakload power.
Figure 7: Pumped Storage Hydroelectric Facility (Tennessee Valley Authority)

23
Run-of-the-river hydroelectric stations are those with smaller reservoir capacities, thus
making it impossible to store water. They usually rely on the fast flow of the water on
its journey from higher to lower altitudes. This dynamic gives rise to kinetic energy
that is diverted using a special pipe called a Penstock inside which the water is
pressurized and directed to the blades of a water turbine. The turbine converts the
kinetic energy of the water into mechanical energy that is then used to turn the rotor of
a generator inside a powerhouse. Once completed, the water is then released back into
the river to continue its journey.
The volume of power generated by a hydroelectric facility can be calculated by using
the following formula:
Equation 9
𝑃 = 𝜌ℎ𝑟𝑔𝑘
Where:
 P is power in Watts,
 Ρ is the density of water (≈1000 kg/m3
),
 h (head) is height in meters,
 r is flow rate in cubic meters per second,
 g is acceleration due to gravity of 9.8 m/s2
,
 k is coefficient of efficiency ranging from 0 to 1. Efficiency is often higher
(that is, closer to 1) with larger and more modern turbines.
Since a water turbine is not perfect, some input power is lost due to friction and other
inefficiencies within a turbine. Most modern water turbines have an efficiency rating
of between 80-95%, depending upon the type used.

24
A typical small scale hydro power
scheme needs a stream, an intake system
to divert the water, a canal or channel
called a penstock to carry the diverted
water, a water turbine or water wheel to
convert the waters kinetic energy into a
rotational mechanical energy, and an
electrical generator to convert this
rotational energy from the wheel into
electricity.
As well as choosing a good location to develop a hydroelectric facility, the hardest part
to determine is using the correct generator. There are multiple type of generators to
use, all with their advantages and disadvantages, however the most popular choice by
far for a small scale system is a permanent magnet alternator.
3.2.1 Turbines
There are also multiple types of turbines that can be used to convert the kinetic energy
of the water into mechanical energy. From these there are two main designs that are
typically found:
 Impulse Turbine Design- in this type of water turbine design, the water flow
hits the turbine blades from one or more jets of water known as nozzles.
These nozzles convert the pressurised low velocity water into high speed jets
of water known as nozzles. These nozzles convert the pressurized low
velocity water into a high speed jet of water aimed directly at the turbine
curved spoon or bucket shaped blades generating maximum force on the
blades. The mechanical power output from an impulse turbine is derived from
the kinetic energy of the water flow.
 Reaction Turbine Design – in this type of water turbine design, the turbine
blades are totally submerged in the flow of the water and are enclosed within
a pressurised casing. A reaction turbine is powered mainly by the change in
Figure 8: This shows the general layout of
a small hydroelectric facility (Mehenni,
2015)

25
pressure, called a ‘pressure drop’ across the casings body as this reduction in
water pressure and velocity releases energy causing a reaction by moving the
turbine blades. The flow of water through a reaction turbine may be reversed
due to the angle of the internal blades, so a reaction turbine can also be used
to pump water and vice versa. (Mehenni, 2015)
Hydroelectric power generation is by far the most efficient method of large scale
electric power generation. The conversion process captures kinetic energy and
converts it directly into electrical energy. There are no inefficient intermediate
thermodynamic or chemical processes and no heat losses.
The conversion efficiency of a hydroelectric power plant depends mainly on the type
of water turbine employed and can be as high as 95% for large installations. Smaller
plants with output powers less than 5MW may have efficiencies between 80 and 85%.
The main problem associated with hydroelectric facilities is that it is difficult to extract
power from low flow rates.

26
3.2.2 Turbine Design
Since it is the turbine that defines the efficiency of a hydroelectric system, the turbine
designs below show the various turbines in use throughout industry today.
Types of Water Turbine Design Shape
Pelton Turbine Design
The Pelton Water Turbine is the most common open turbine
type. It is an impulse type circular turbine in which the
circumference of the wheels outer rim is surrounded by a
series of equally spaced small curved cups or buckets that
catch the waters energy. The waters energy is delivered to
these spoon shaped cups at a high pressure and velocity
through one or more nozzles arranged around the
circumference and aligned to produce a jet of water aimed
directly at the individual cups shaped into two halves so that
when the jet of water hits the middle of each cup in turn, the
quantity of water splits in half. Each half of the water flows
around its own curved shape of the cup where it is forced out
under pressure. As the nozzles propel the cups, the kinetic
energy from the water is converted to mechanical energy used
to drive the turbine. The speed of a Pelton Turbine can be
controlled by controlling the flow of water through the
nozzles. Thus, this type of turbine design is used in high
speed and is smooth running, making it suitable for high
head, low water volume conditions.
Turgo Turbine Design
The Turgo Water Turbine is another impulse type water
turbine in which a jet of water strikes th turbine blades. It is
similar to the Pelton Turbine Design, however the water jet

27
from the nozzles this time strike a series of curved or angled
blades from the side at a shallow angle, resulting in the water
entering one side of the blade and exiting through the other.
Due to its higher flow rate, the power output for a Turgo
turbine can be equivalent to a Pelton Turbine, even when a
smaller diameter wheel is used. The Turgo turbine is less
efficient however.
Cross-flow Turbine Design
The Cross-flow water turbine is another impulse type water
turbine design in which the water strikes the turbine blades
transversely across its blades. The cross-flow turbine uses a
cylindrical drum shaped rotor, similar to the waterwheel of an
old style steamboat, that has a number of blades or slats
called runners, installed lengthwise around the rotors
circumference depending upon the size of the turbine wheel,
which may be up to two meters in diameter. The water is fed
to these slats through a single or double vertical rectangular
nozzle to drive a jet of water along the full length of the
runner. These nozzles direct the water to the runners at the
optimum angle causing them to move converting the potential
energy of the water to kinetic energy.
The main advantage of the cross-flow turbine is that it
maintains its efficiency under varying load and water flow
conditions. Also due to their relatively easy construction,
good regulation, and can operate with a very low head of
water, cross-flow water turbines are ideal for use in mini and
micro hydropower systems.

28
Francis Turbine Design
The Francis Water Turbine is a radial flow reaction type of
water turbine in which the entire turbine wheel assembly is
immersed in water and surrounded by a pressurised spiral
casing. The water enters the casing under pressure and is
guided through a set of fixed or adjustable slots called guide
vanes around the casing which direct the flow of water to the
turbines blades at the correct angle.
The water impacts against a set of curved turbine blades
mounted on a shaft and glides over them, thereby changing
direction and producing pressure on the fixed blades due to
centrifugal force causing it to rotate. The water enters the
turbine radially nearly at a tangent but to increase efficiency,
the water changes direction inside the turbines wheel and
exits in parallel (axially) with the axis or rotation at a reduced
velocity.
The turbines internal blades are fixed and cannot be adjusted
so to maintain a constant turbine speed, the water flow rate is
adjusted by changing the angle of the casing’s guide vanes. It
is suitable for low to medium head applications but requires a
relatively large quantity of water.
Kaplan Turbine Design
The Kaplan Water Turbine is an axial flow reaction type of
water turbine that looks very similar to a ships propeller. As a
result, it is also referred to as a Propeller Turbine. The
Kaplan’s propeller shaped rotor has two or more fixed or
adjustable blades. It has a set of fixed or adjustable guide
vanes around the inlet of the turbine to control its rotational
speed.
Its operation is the reverse to that of a ships propeller. The
water enters the turbine passage in a radial direction via the

29
inlet vanes. The angle and position of these vanes causes the
water to swirl producing a vortex within the enclosed passage
applying a force onto the angular shaped propeller blades. As
the blades are fixed within this passage to a central shaft, the
force of the swirling water pushing against the blades
transfers’ energy to the blades producing rotation and torque.
One of the major advantages is that it can be used in very low
head applications, providing that there are sufficiently large
water flow rates through the turbine, without the need for
dams and weirs resulting in negligible impact on the
environment. Also, depending on the amount of variability in
the amount of water flowing through the turbine, the pitch
(angle of attack) of the propeller blades can be adjusted
allowing for greater control of the water flow and increasing
its efficiency.
Table 2: Characteristics of each hydro turbine (Mehenni, 2015)
Selecting the best type of water turbine design for your particular situation often
depends on the amount of head and flow rate that is available at a particular location
and whether it is at the side of a river or stream, or the water is to be channelled or
piped directly to a location. Other factors include whether to use an enclosed “reaction
turbine design” such as the Francis turbine or an open “impulse turbine design” such
as the Pelton turbine as well as the speed of rotation of the proposed electrical
generator.

30
When analysing all of these factors, the turbines mentioned above can be classed into
specific categories in which they would perform best, resulting in the highest
efficiency possible for a hydro system.
Water Turbine Type Head Water Pressure
High → Medium → Low
Impulse Type
Water Turbine Design
Multi-jet
Pelton,
Turgo
Pelton,
Turgo,
Cross flow
Cross flow
Reaction Type
Water Turbine Design
Francis Francis,
Kaplan
Kaplan
Table 3: Water Turbine Type vs Head Water Pressure (Mehenni, 2015)
Hydroelectricity from river can be produced from two different ways; damming, or
run-of-the-river. Run of the river is a type of hydroelectric generation whereby the
natural flow and elevation drop of a river are used to generate electricity. The main
advantage of this form of electric generation is that little to no flooding takes place
upstream of the hydroelectric facility. However, the output from the facility can vary
depending on the time of year, since a dry season may produce very little electricity.
Considerable time needs to be spent in order to determine a suitable location that
provides a consistent volume of water throughout the year, as well as a suitable
elevation drop to give a respectable output. Since no damming is taking place the
output cannot directly correlate to the need of electricity required by people using the
national grid. Therefore, the facility cannot act as a base load power station, unlike a
dammed facility which can vary the volume of water that flows through it in order to
produce a range of outputs when required.

31
3.2.3 Financial Costs
As mentioned with the various types of turbine designs, the costs involved to build a
hydroelectric facility vary depending on location and how technologically advanced it
needs to be.
When looking at the facility, the following assumptions can be made to provide an
estimate for costs per kW of capacity:
 The development of the site is associated with 85 to 90 percent of the cost.
This can be broken down into civil engineering works (65 to 75 percent f the
total costs) and meeting environmental and other criteria (15 to 20 percent of
the cost).
 The turbine, generator and control systems should account for only 10 percent
of the total cost. (Renewables First)
A high investment cost does not mean that a hydroelectric facility that produces a
large volume of kWh as its output will be more costly than others, due to annual basis
operating costs being extremely reduced. Calculation of units costs is typically
complicated to perform, as the extreme variability of the number of annual operating
hours of a power plant can gives different results.
When a hydro plant is connected to the national grid, a power producer can sell an
excess of the electricity production to electricity companies.
When finding a location to build a micro hydro facility, an initial survey will need to
take place to determine whether or not the site is suitable. In most cases this survey
could cost up to £300. Once the initial survey has taken place and the site is suitable
for a facility, the expected costs for a typical 5kW scheme would cost between £20-
£25,000 including installation. (Renewables First, 2015)
There is an economy of scale when designing of hydroelectric facility. As the energy
output increases the expected overall costs decreases. This could result in a 5kW
system only costing approximately 50% more than a 2kW system.

32
3.3 Generator
In electricity generation, a generator is a device that converts mechanical energy to
electrical energy for use in an external circuit. There are two types of AC machines
used as generators within a hydro-electric plant, one being an asynchronous
(induction) generator, and the other a synchronous generator. The following table
shows the differences between both types of generators.
Synchronous Generator Asynchronous Generator
Steady-state voltage rise Faster due to reactive
power support
Smaller and at certain level
of power generation the
voltage starts to decrease
Voltage Dip After voltage dip, the
voltage recovers close to
its initial value
The voltage does not
recover due to lack of
reactive power support
Static Voltage Stability Large impact due to its
capability of reactive
power exchange
Smaller impact because of
limited benefit due to the
demand of reactive power
Cost Higher cost Lower cost
Efficiency Higher efficiency Lower efficiency
Table 4: Synchronous Generator vs Asynchronous generator
Between the two generator types a synchronous generator is the ideal type to use for a
hydroelectric facility due to the good voltage stability and high efficiency. Both of
these factors far outweigh the overall cost.
Figure 9: Cutaway view of a synchronous AC
generator (Sedky)

33
3.4 Matlab
Matlab has multiple features available that provide a wide array of utilities to help
with research, simulation and testing. The key features for Matlab are:
 High-level language for numerical computation, visualization, and
application development.
 Interactive environment for iterative exploration, design, and problem
solving
 Mathematical functions for linear algebra, statistics, Fourier analysis,
filtering, optimization, numerical integration, and solving ordinary
differential equations
 Built-in graphics for visualizing data and tools for creating custom plots
 Development tools for improving code quality and maintainability and
maximizing performance
 Tools for building applications with custom graphical interfaces
 Functions for integrating MATLAB based algorithms with external
applications and languages such as C, Java, .Net, and Microsoft Excel.
(Matlab, 2015)
As mentioned earlier, Simulink is a block diagram environment for multidomain
simulation and Model-Based Design. The SimPowerSystems addon located within
Simulink provides component libraries and analysis tools for modelling and simulating
electrical power systems. These libraries offer a wide range of models of electrical
components, including AC transmission systems, three-phase synchronous and
asynchronous machines, and renewable energy systems. In addition to the traditional
input-output or signal flow connections used in Simulink, SimPowerSystems uses
physical connections that permit the flow of power in any direction.
In some cases it may be impossible to implement a system which allows for various
inputs. This is due to the software sometimes requiring specific values in order to run
the simulation. If this does occur, the simulation will have to either run as is, or a work
around would have to be created by creating your own components within the
software. This does however require sizeable knowledge of the software and the real
life equivalent component.

34
3.5 Treforest Area
3.5.1 Wind
When determining a power generation project the local area needs to be taken into
consideration to ensure that the maximum volume of output can be achieved by a
specific complex. When viewing the Treforest area, the local topography results in the
town being situated in a valley, with the valley sides reaching a height up to 150m
above the town. This difference
in height contributes to the
difference in wind speeds shown
on the NOABL wind map.
(rensmart, 2015)
As shown, the wind speed at the
bottom of the valley is found to
be approximately 3m/s
depending on location. Since a
wind turbine would need a
larger and more consistent wind
speed, the best location to build
the wind farm would be in the
area to the North East of
Treforest, which would give
wind speeds up to 7m/s. Since
these speeds are not permanent,
they are subject o change over
time. This results in some days
where the power output of the
turbines may exceed the usage
of the local population. Ideally it would be a good opportunity to develop the wind
farm while still connected to the national grid as any excess power can then be brought
Figure 10: This image shows the average wind
speeds in the Treforest area. (rensmart, 2015)

35
to the rest of the UK population. This should also result in money being paid back into
the local community to help cover the costs of the initial investment.
Figure 9: A graph showing the wind speeds in Treforest (Weather2)
This graph shows that the wind speeds within the Treforest area reach their maximum
(74 km/h in January) during the autumn and winter months. Throughout Spring the
wind speeds gradually drop until they reach their lowest during July. (Weather2)
0
10
20
30
40
50
60
70
80
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
WindSpeed(km/h)
Month
Wind Speed km/h (Average)
Wind Speed km/h (Max)

36
3.5.2 Hydro
There are two types of hydro plants available to the Treforest area. A run-of the river
plant could be used and would provide consistent electricity all year round due to the
size and flow rate of the river Taff. However, because the river is situated on a valley
floor, there is a very small head height, resulting in a limitation of the output power
available.
The UK Hydrometric Register has values for the river Taff at various points
throughout its course. It has been noted that the peak flow of water at Merthyr Tydfil
has been found to be 258.2m3
s-1
. This can be slightly misleading as this is the highest
peak flow that the
river has ever
achieved. Over a
year, this value
would change
considerably,
resulting in the
potential output
power of a run-of the
river hydro plant to
change. The peak
flow at Pontypridd, a
town adjacent to
Treforest, has been
found to be 612.3m3
s-1
. This is much larger than Merthyr Tydfil, with the river having
a total width of approximately 33 metres. As Merthyr is closer to the source of the
River Taff, very little tributaries (small streams or rivers joining a larger river) have
connected to it. The fact that it is closer to the source is the reason why it has a much
smaller peak flow.
In most cases, the head height is the main variable to consider when building a
hydroelectric facility. As Treforest is situated in a valley, the possible head height
Figure 11: An image showing the approximate width of the
River Taff at Treforest. (Daft Logic, 2015)

37
from a run-of the river facility is too small to give a sizeable output. However, further
upstream where the elevation is steeper, either a run-of the river or a reservoir facility
could be developed. At Merthyr, the River Taff is formed by the convergence of two
other rivers, the Taf Fechan (Little Taff), and the Taf Fawr (Big Taff). Further
upstream both of these rivers come from dammed reservoirs built into two separate
valleys. The Pontsticill reservoir is connected to the Taf Fechan and produces a power
output of 375kW. (Association, 2002)

38
Chapter 4 - Case Study
The county that which Treforest resides in, Rhondda Cynon Taff, is filled with valleys
leading up to the Brecon Beacons National Park. The Brecon Beacons are a series of
mountains and moorlands being 42 miles wide with an approximate area of 520 square
miles. The highest peak in southern Britain, Pen y Fan, is located here with a height of
886 metres above sea level. (Brecon Beacons National Park) Only a small portion of
the national park is found within the county, however, there is a project taking place
within the county at this moment that could potentially use the Brecon Beacons to
generate power.
The Pen y Cymoedd Wind Energy Project is a 76 turbine development located on land
managed by Natural Resources Wales within Rhondda Cynon Taf and Neath Port
Talbot. Once operational the project will generate enough electricity to meet the
domestic need of 140,000 homes per annum. (Pen y Cymoedd Wind Energy Project )
The three year construction period for this project started in early 2014 and will
continue until early 2017.
A full timeline for the project has been laid out detailing every step towards the
project’s completion. The timeline of the project is as follows:
 February 2014-2016: Civil and electrical works, including construction of
the site welfare compound, site access tracks, turbine foundations, crane
pads, underground cabling and substation.
 Late 2015: Turbine deliveries, civil works continue
 Early 2016: Turbine installation expected to begin
 Late 2016: The wind farm is commissioned
 Early 2017: Project completion
Once finished, the entire project will provide a community fund of £1.8 million per
annum for more than 20 years, with more than 3000 residents of the local area
deciding on where the money should go in the area. (Pen y Cymoedd Wind Energy
Project )

39
Chapter 5 – Design
5.1 Hydro Simulation
When viewing the individual blocks within Matlab to use for the simulation, there are
a few that stand out and will need to be incorporated into the final design. The first is
the Hydraulic Turbine and Governor block. The entire block implements three
different circuit designs; a nonlinear hydraulic turbine model, a PID governor system,
and a servomotor.
Within the Simulink software, all values are
represented as pu, which is calculated as:
Equation 10
𝑏𝑎𝑠𝑒 𝑣𝑎𝑙𝑢𝑒 𝑖𝑛 𝑝. 𝑢 =
𝑞𝑢𝑎𝑛𝑡𝑖𝑡𝑦 𝑒𝑥𝑝𝑟𝑒𝑠𝑠𝑒𝑑 𝑖𝑛 𝑆𝐼 𝑢𝑛𝑖𝑡𝑠
𝑏𝑎𝑠𝑒 𝑣𝑎𝑙𝑢𝑒
Figure 12: This figure shows the three components
connected together.
The inputs for this block are shown
as:
Wref – Reference speed, in pu
Pref – Reference mechanical power
in pu
We – Machine actual speed, in pu
Pe0 – Machine actual electrical
power in pu
Dw – Speed deviation, in pu

40
The hydraulic turbine block within this system is modelled by the following nonlinear
system.
Figure 13: Nonlinear system within the hydraulic turbine block
The gate servomotor is then modelled by a second-order system,
Figure 14: Second-order system within the gate servomotor
When building the simulation within Matlab, some real life situations may have to be
implemented. Nearly every hydro plant worldwide is externally connected to an
electricity grid, to provide initial power for the plant to start. This initial power allows
the gate to open and water to flow through the turbine. This can be simulated within
the software by implementing a fault over the electricity network that takes place after
a specific volume of time has been reached.

41
The excitation block is used in conjunction with the
synchronous machine to regulate its terminal
voltage when in its generation mode. The excitation
block is a Simulink system implementing a DC
exciter without the exciter’s saturation function.
The basic elements that form the Excitation System
block are the voltage regulator and the exciter.
(Mathworks)
Figure 15 shows input parameters
that can be altered within the
excitation block. A majority of the
inputs of the excitation block will
come from the return signal after it
has passed through the synchronous
machine and bus network.
Figure 15: Excitation System
within the Matlab software.
Figure 16: The input parameters for the Excitation
Block

42
The synchronous machine block that will be
utilised for the simulation can operate in one of
two modes, as a generator or a motor. The
operating mode of the machine will be dictated
by the return signal of the circuit. The block has
a wide array of values that can be altered,
including the field and damping windings, which
incorporate resistances, leakage inductances, and
mutual inductances. Figure 17: Synchronous machine block
within Matlab

43
5.2 Wind Simulation
5.2.1 Calculations
When determining the model and size of which turbine to use, the approximate present
and yearly consumption of electricity is in Treforest must be found. According to
government census data taken in 2011, there are 4461 residents living in 1665 homes.
There are an extra 689 people in communal living, but because there is no data on the
size of their living space and yearly energy consumption, they will have to remain
absent from the following calculations. (UK Cencus Data) A high proportion of these
residents probably live in student accommodation at the University of South Wales,
which itself has built small hydropower facilities in the number of streams that run
through the campus.
When looking through the previous information regarding the different sizes of wind
turbines, a 1MW turbine farm looks probable and doable considering the elevation and
wind speeds in the area. When using a 1MW turbine as an example, the total output
over one year can be found as follows:
Equation 11
1.0 × 106
× 365 × 24 × 0.25 ≡ 2190 𝑀𝑊ℎ
A kWh (kilo-watt hour) is a unit of energy equivalent to one kilowatt of power
expended for one hour. In the above calculation the total energy produced from one
1MW turbine over one year has been found, when a capacity factor of 25% is taken
into account. However, due to the variability of the weather, this value could either
increase or decrease year on year.
According to government data, the UK electricity consumption in 2013 was 4192kWh
per household. When rounding this up to 4200kWh, we find that:
Equation 12
1665
521
= 3.2
This value corresponds to the minimum number of wind turbines required to power
Treforest over one year. Since there is no such thing as 0.2 turbines (unless smaller
output turbines are utilised), the value can be rounded up to give a minimum number

44
of 4 1MW turbines being required. However, since wind may be slow for a given
period of time, or there is a sudden increase in the volume of power required by the
residents of Treforest, it would be safer to have backup turbines in place for when
extra power is needed. In this case a total number of six turbines would be beneficial.
Any power produced from the two extra turbines can either be transferred to the
national grid, with the potential to bring some money into the local community, or be
used to transfer water back into a top reservoir if a pumped storage hydro facility is
utilised.
5.2.2 Wind Simulation Blocks
The Simulink software has an extension built into it called SimPowerSystems, which
provides various machinery and renewable
models to the software. Figure 18 is the wind
turbine block available within the software,
which uses various input parameters to
calculate the overall output power. The
generator speed works in correlation with the
wind speed, in that the wind moves the wind
turbines blades, which thusly spins the
generator. As wind speed increases, so should
the generator speed. Just like in real life, safety
precautions have been built into the software in case an unrealistic wind speed was to
enter the simulation. The simulation would effectively stop the generator from
spinning (i.e brake), and prevent any power from being produced.
Figure 18: Wind Turbine Block

45
This model is based on the
steady-state power
characteristics of the turbine.
The stiffness of the drive
train is infinite and the
friction factor and the inertia
of the turbine must be
combined with those of the
generator coupled to the
turbine.
Figure 19 shows the block
parameters that can be
changed within the software.
The base wind speed is the
minimum wind speed
required for the turbine to
reach a stable output.
Therefore, since the
minimum wind speed in
Treforest is 9m/s, (during the
summer months), this value will be set as the base wind speed within the simulation. If
the turbine was to exceed this speed, the pitch control will function to try and reduce
the output power of the generator. As mentioned earlier about the safety controls, if
the wind speed exceeds the parameters of the pitch control, the output power will
reduce to zero.
Figure 19: Variable Block Parameters of the Wind
Turbine

46
Chapter 6 – Simulation and Testing
6.1 Wind Farm
The initial testing began with a wind farm model consisting of six 1MW wind turbines
working in pairs. These are interconnected with transmission lines to provide power to
a local community or to feed excess power into the national grid. Each pair use
squirrel cage induction generators, with the pitch angle of the turbines not changing
until the wind speed is in excess of 9m/s. Built into each turbine is a protection system
which monitors the voltage, current and machine speed. In order for the system to
generate power, the induction generator speed must be greater than the synchronous
speed. In this simulation a 6MW wind farm consisting of six 1MW wind turbines is
connected to a 25kV distribution system which exports power to a 120kV grid through
a 25km, 25kV feeder.
Figure 20: Circuit diagram of the simulated wind farm

47
Figure 21 shows the sub-system built into the wind farm block in figure 20. The circuit
in figure 21 allows the user to alter the wind speeds for each turbine to determine how
it would affect the power output. The reactive power absorbed by the induction
generator is partly compensated by a 400kvar capacitor bank connected to each wind
turbines low voltage bus.
Figure 21: Sub system built into the wind farm block

48
The initial testing phase began with the wind farm model. Initially 40 seconds was
chosen to represent the simulation as it should be an adequate time for the simulation
to reach a steady state.
Figure 22: Wind farm graph showing the results for all three turbines
Figure 22 shows how the wind speed affects the power output for each turbine. Each
graph has been found individually to show in more detail how the wind turbines react
to a load.

49
This graph shows the wind speed affecting each turbine. The simulation was run over
40 seconds with the y-axis representing wind speed(m/s), and the x-axis representing
time (s). As the wind speed is remaining consistent through all three pairs of turbines,
they should all be subjected to the same load, albeit, with a time difference of 6
seconds between each pair of turbines. Initially, the wind speed is 0 m/s, until it starts
increasing at 2 seconds. Each turbine pair is then subjected to the same wind two
seconds apart. The wind speed reaches its maximum after 10 seconds. As there is no
change in speed until it reaches maximum, this wind farm is not subjected to any down
flow turbulence caused by the turbines.
Figure 23: Wind speed (m/s) against Time (s)

50
Figure 24 shows the output power of each turbine against time. Initially the turbines
are subjected to a large output power which stabilises itself after approximately 4
seconds. Even though it looks like it is only the third pair of turbines that is subjected
to this jump in power, the truth is that every turbine suffers from this. When looking at
figure 22, we notice that the reason this jump in power occurs is due to a large
reactance at the beginning of the simulation. This is done to ensure that the circuit
stabilises by the time the wind starts affecting each turbine. The sudden drop in power
output between 15 and 25 seconds is due to the pitch angle trying to stabilise the
circuit. This is a safety mechanism built into the software to ensure that the simulation
will reach a steady state and provide an adequate power output. Therefore, at a wind
speed of 15m/s, we can assume that the wind turbines will reach steady state and
provide their maximum output.
Figure 24: Output Power vs Time (s)

51
Initially the reactance power is high to allow the movement of the wind turbines as
soon as they are subjected to a load. Once the wind starts affecting each turbine pair in
succession the reactance quickly starts increasing. The reactance follows the same
pattern as the output power which in turn is affected by the pitch angle as the wind
speed increases.
Figure 25: Reactance power (MW) vs Time (s)

52
Figure 26 shows the pitch angle of the wind turbines against time. As the wind speed
increases as shown in figure 23, the pitch angle also increases to compensate for the
jump in output power. As the turbines start approaching their physical limits, the pitch
angle starts dropping to try and reach a steady state. The steady state occurs at
approximately 19 seconds after each turbine is initially subjected to the wind flow.
Figure 26: Pitch Angle (Deg) vs Time (s)

53
6.2 Hydro Plant
The design used for the hydro simulation is shown in Figure 27. The output (pm) of
the hydraulic turbine and governor block is connected to the Pm input of the
synchronous machine. This is used to drive the synchronous machine. A bus selector
block is connected to terminal m of the synchronous machine to allow the user to
choose which signals could be measured using a scope and which can be used to feed
back into the system. In this case the stator voltage (vq and vd) are fed back into the
excitation block, and the rotor speed, output active power and rotor speed deviation are
fed back into the hydraulic turbine and governor block to provide a closed loop
system.
The part of the circuit connected to ABC on the synchronous machine can be thought
of as a separate entity. The three phase fault is connected to a design that resembles the
transmission network of the national grid. In this scenario, the power from this could
potentially come from the wind farm simulated earlier. This is done as a hydro facility
requires start up power. A three-phase generator rated 200MVA, 13.8kV, 112.5 rpm is
Figure 27: Hydro plant design within Matlab

54
connected to a 230kV network through a 210MVA transformer. At t = 0.1s the three-
phase to ground fault occurs on this network, and resolves itself after six cycles, or
0.2s. This is done as the entire design does not initially start in steady state. Connected
to this network is a three phase breaker which is open at start up and closes at t=-0.4s.
By doing this at effectively 12 cycles we can safely assume that the 3-phase fault has
occurred and resolved itself, and the entire circuit is approaching a steady state.

55
Once the designing phase had finished the testing phase could begin. Initially the run
time for the simulation was chosen to be 60 seconds, as to allow the circuit to reach a
steady state. Figure 28 shows the stator current against time.
As shown the stator current requires approximately 5 seconds to reach a steady state.
This is perfectly reasonable as a sudden flow of water within a hydro facility needs a
period of time to make the rotation of the turbine maintain a consistent speed. From
this graph we can see that 60 seconds is far too long to accurately show the circuit
reaching steady state. Figure 29 shows the same stator current over a 5 second period.
Figure 28: Stator Current (pu) vs Time (s)

56
The current peak that occurs at t=0.2s is due to the 3-phase fault occurring. This causes
feedback into the system, resulting in the excitation block compensating to try and
reach steady state. Steady state within this circuit finally occurs after approximately
3.5 seconds.
Figure 29: Stator Current vs Time (s)

57
Figure 30 shows the rotor speed during the simulation over 60 seconds. The initial
jump in rotor speed is caused by the sudden influx of power from the transmission
system. This causes the rotor to start moving and thusly, a flow of water. As the
system becomes more stable, the rotor speed starts levelling out until it becomes
constant.
Figure 30: Rotor Speed (wm) vs Time (s)

58
Figure 31 shows the rotor speed once again over a shorter time frame. This allows a
clearer view to be seen of the circuit reaching and constant speed.
Figure 31: Rotor Speed (wm) vs Time (s)

59
The three phase breaker acts as a switch, so once the 3-phase fault has occurred the
output power can be transmitted. The scope labelled as PQ in figure 27 represents the
total power output of the circuit. Since the circuit reaches steady state in
approximately 5 seconds, there was no scientific reasoning to show the scope over a
60 second time period. The yellow line on figure 32 represents the total output power,
with the purple line representing the reactive power.
The initial jump in output power is caused by the 3-phase breaker becoming closed at
0.4s. Once this has occurred the output power quickly stabilises over 3.5 seconds to
give a total output of approximately 2.0MW. This stabilisation follows the rest of the
circuit as the excitation block works to get the entire circuit into a steady state. There
is very little reactive power in this part of the circuit as it does not deal with the
stabilisation of the signals.
Figure 32: Output and Reactive Power vs Time (s)

60
Chapter 7 – Conclusion
Overall the project seemed to be a success, with a majority of the initial aims and
objectives as specified within chapter 1 having been completed. The main aim was to
build two different models within the Matlab software to represent both a wind farm,
and a hydroelectric facility that could potentially be built within the Treforest area.
Even though a hybrid system with both designs working together was not possible
within the Matlab software, by developing two different models a clear idea on how
much output power can be generated within the Treforest area was given. The research
that had gone into the Treforest area has shown that a wind farm is a very liable option
for power generation within the area, however, a location upstream from Treforest
would be best suited for a hydro-electric facility. The wind speed on the valley top
adjacent to Treforest should be able to supply enough electricity to the town. The
valley top is a particularly large area, and since only the eastern side has been looked
at as a potential site, the western side could be just as viable depending on location.
Not all of the initial aims and objectives were achieved to the level that was wanted.
As already mentioned, the system that was simulated was originally meant to be a
hybrid system with both the wind and hydro facilities working together. However,
after more use and gaining more knowledge of the Matlab software, this was
impractical to do. By testing them individually it allows a user to still see how the
initial conditions for each system can affect its total output. A questionnaire was also
listed within the aims and objectives however, after working through and reviewing
the project it was decided that a questionnaire would not bring anything to the project
as a whole.
The results obtained showed that a hybrid renewable system built in the Treforest area
is a liable alternative to current fossil fuelled power generation systems. Under ideal
conditions it is possible to power the entire town using only the wind farm. When
taking into consideration that one 1MW turbine costs approximately £2 million, a
wind farm consisting of six of these turbines could be facing a rough cost of £12
million. Considering the fact that these turbines can be paid back within a couple of
years, it makes this a very enticing opportunity for developers around the world to start
expanding upon current wind power generation methods.

61
When simulated, the hydro system isn’t specifically built to resemble one type of
hydro system. Due to this the design that has been created could be a pumped storage,
reservoir or a run-of river facility. For the Treforest area a pumped storage system
would benefit the most, as it provides a storage of energy available for when the
residents need it. During the night, when very little power will be used from the wind
farm, any excess power can be used to pump water from a lower reservoir to a higher
one. This effectively uses the power produced from the wind farm. If for instance the
pumped storage facility does not need water to be pumped, any excess electricity
could be transferred to the national grid, and bring some money back into the
community to help pay back for the turbines.
Throughout winter it is expected that more power would be produced from the wind
farm as winds are higher. The simulation showed that a wind speed of 15m/s was more
than enough to reach the maximum power output from each turbine. When comparing
the wind speed graph to the power output, the maximum power from the turbines
(2MW) is achieved when the wind is approximately 10m/s. This shows that the
average wind speeds within Treforest should be more than adequate to power the
town. As the British weather can be quite erratic, on days where there is a surplus of
electricity generated, as mentioned, it can be transferred into the national grid.
As calculated in Chapter 3.5.1, a minimum of four 1MW turbines is required to power
Treforest. In cases when a large volume of power is required, such as someone having
a shower or using a kettle, the extra two turbines can be used contribute to the overall
power output of the wind farm.
The hydro system built within the Matlab software suffered complications in that it is
impossible to input a specific flow of water through the hydraulic turbine and governor
block. To compensate for this the parameters chosen for each block resembled a life
like counterpart to try and get an accurate reading for output power using just the
settings within the software.
Another complication with the project was time management. Even when using a
Gantt chart to follow a prepared layout, some tasks were either not started or were late
in finishing. The entire project was a month late to begin with due to problems in
determining a suitable project title.

62
7.1 Further Work
There are multiple ways in which the project could be improved; with one of the
biggest ways being to research and simulate other forms of renewable energy. As
shown in Appendix 1, solar power was a possible option with the Treforest area due to
the orientation of the buildings with the area. This was not carried on however as a
hybrid wind/hydro system made better use of the local area’s resources.
If a considerable more time was spent working on Matlab, it may have been possible
to integrate the wind and hydro models together. However, this would have still been
very difficult to perform.
As shown in the brief case study, development of 76 wind turbines within the Rhondda
Cynon Taff region is currently taking place. It may have been a wise idea to question
the local council as to where exactly these turbines are being constructed, to then be
able to compare that region to the Treforest area.
For simulating circuit designs, Matlab is not necessarily the best software to use. There
are other software development tools available that that give more control over input
parameters and are much more flexible when compared to Matlab. The software
WindFarm would have been particularly useful but unfortunately it was not available
at the time it was needed.

63
Works Cited
Association, B. H. (2002). Pontsticill WTW.
Brecon Beacons National Park. (n.d.). Retrieved 2015, from
http://www.breconbeacons.org/about
Daft Logic. (2015). Retrieved from http://www.daftlogic.com/projects-google-maps-
distance-calculator.htm
European Wind Energy Association. (2009). The Economics of Wind Energy. 8.
gov.uk. (2014). Climate Change. Retrieved November 26th, 2014, from gov.uk:
https://www.gov.uk/government/topics/climate-change
gov.uk. (2015). http://uk.mathworks.com/products/simulink/.
Jefferson, M. (2012). Capacity Concepts and Perceptions – Evidence from the UK
Wind Energy Sector. International Association for Energy Economics.
Latchways. (2012). A Specification Guide For Wind Turbines. Devizes, Wiltshire:
Mansafe.
Local Government. (n.d.). Retrieved 2015, from http://www.local.gov.uk/home/-
/journal_content/56/10180/3510194/ARTICLE
Mapmywalk. (2014). mapmywalk. Retrieved November 2014, from mapmywalk.com:
http://www.mapmywalk.com/gb/pontypridd-wls/
Mathworks. (n.d.). Retrieved 2015, from
http://uk.mathworks.com/help/physmod/sps/powersys/ref/excitationsystem.htm
l
Mathworks Inc. (2014). Overview. Retrieved November 25th, 2014, from Matlab:
http://uk.mathworks.com/products/matlab/
Matlab. (2015). http://uk.mathworks.com/products/matlab/.

64
Mehenni, B. (2015). Renewable Energy Systems.
Mitsubishi Electric Research Laboratories (MERL). (2010). Off-Grid Portable EV
Charging Network.
Pen y Cymoedd Wind Energy Project . (n.d.). Retrieved from
http://penycymoedd.vattenfall.co.uk/about-the-project/
Renewables First. (n.d.). Retrieved 2015, from
http://www.renewablesfirst.co.uk/hydro-learning-centre/how-much-do-
hydropower-systems-cost-to-build/
Renewables First. (2015). How much does a hydropower system cost? Retrieved from
http://www.renewablesfirst.co.uk/hydro-learning-centre/how-much-do-
hydropower-systems-cost-to-build/
RenewableUK. (n.d.). Retrieved 2015, from http://www.renewableuk.com/
rensmart. (2015). Retrieved from http://www.rensmart.com/Weather/BERR
REUK. (2014). REUK.co.uk. Retrieved November 2014, from
http://www.reuk.co.uk/Calculation-of-Hydro-Power.htm
Sedky, E. (n.d.). Retrieved from http://emadrlc.blogspot.co.uk/2009/01/cutaway-view-
of-synchronous-ac.html
Simulink, M. (2015). http://uk.mathworks.com/products/simulink/.
Tennessee Valley Authority. (n.d.). Raccoon Mountain Pumped-Storage Plant.
Retrieved from http://www.tva.gov/sites/raccoonmt.htm
UK Cencus Data. (n.d.).

65
Appendices
Appendix 1- Interim Report
The Simulation and Research into the feasibility
of developing an off grid renewable network for
the village of Treforest
Author: Kieran Williams
Supervisor: Ali Roula
Course: Bsc (Hons) Electrical and Electronic
Engineering
Venue: University Of South Wales 2014/2015

66
Introduction
The main outcome from this project is to determine whether or not a small town or
village can be self sustaining when disconnected from the national grid. To be able to
reach this goal many different sources of renewable energy will have to be utilised in
order to obtain a suitable volume of power that is comparable to the energy
requirements of said town or village. In today's society with the growing usage of
technology, backup plans may need to be put in place for the ever growing need for
power.
Since the industrial revolution the volume of Carbon Dioxide within the Earth’s
atmosphere has increased. (gov.uk, 2014) Between the years of 1960 and 2010 alone
the ppmv (parts per million by volume) of carbon dioxide has increased from 315, to
385. Over time, as our energy requirements grow larger the volume of CO2 or
“greenhouse gases” being pumped into the atmosphere will carry on increasing. The
increase in greenhouse gases causes a blanket effect on the Earth, resulting in the
Infrared radiation that should have been reflected back out into space becoming
trapped within the Earth’s atmosphere. This “blanket effect” causes the climate to
slowly increase in temperature, which thusly can cause wild and erratic weather
patterns. By developing a renewable off grid network, a small town could potentially
limit the volume of greenhouse gases they emit into the atmosphere to 0ppmv. It
would allow them to only use the local area to produce energy, whether it is by solar
panels, wind turbines, geothermal, or even hydroelectric depending on location. For
this project the local area (Treforest/Pontypridd) will be researched and studied to
determine the feasibility of developing an off grid network.
The main aims and objectives for the project are as follows:

67
 Research into the local area to determine what renewable sources are readily
available. Also research into what is not readily available and would need
considerable construction work to be achievable.
 Create a possible questionnaire to determine the public’s view on renewable
energy and how they would like to see it implemented. (Include a list of the
renewable sources available to the local area and determine which the public
would like to see being possibly implemented.)
 Research into the energy requirements of the local area and find methods of
reaching this requirement using readily available renewable sources. Various
methods can involve calculating the solar energy output when every house in
the local area is fitted with solar panels, a possible hydroelectric power facility
built on the river taff, and wind turbines built on top of the valley in which
treforest is situated.
 Find and calculate the overall cost to implement an off grid network of this
description, including investment, interest and maintenance costs over multiple
years.
Background research
MATLAB
The software known as MATLAB is a high-level language and interactive
environment for numerical computation, visualization, and programming. Using
MATLAB, you can analyse data, develop algorithms, and create models and
applications. The modelling aspect has a simulation called SimPowerSystems, which
provides component libraries and analysis tools for modelling and simulating electrical
power systems. The libraries offer models of electrical power components, including
three-phase machines, electric drives, and components for applications such as flexible
AC transmission systems and renewable energy systems. If any components aren’t
included in MATLAB, they can be created and integrated into the software.
(Mathworks Inc, 2014)

68
Power and Efficiency calculations
Solar cell efficiency is the ratio of the electrical output of a solar cell to the incident
energy in the form of sunlight. In order to calculate the efficiency of a solar panel the
following calculation must be used:
Equation 13
𝒏 =
𝑷 𝒎
𝑬 × 𝑨 𝒄
Where Pm = maximum power point (W), E= Input light (W/m2
) and Ac = the surface
area of the solar cell (m2
).
Solar cell efficiencies are measured under standard test conditions, with a temperature
of 25o
C and an irradiance of 1000 W/m2
with an air mass of 1.5. On a standard day in
the UK these conditions are very rarely met, resulting in the overall efficiency being
much lower when compared to standard test conditions. Under standard conditions a
solar cell with an efficiency of 20% and a surface area of 100cm2
would produce an
output of 2.0W. Due to the angle at which the Earth goes around the sun, the output
varies with latitude and climate. Countries closer to the equator would benefit most as
they have the most predictable climates and incoming solar radiation. In central
Colorado a solar panel can be expected to produce 440 kWh of energy per year. At
more northerly latitudes, such as the south of England, annual energy yield could be
expected to be around 175kWh.
For a wind turbine the kinetic energy of the moving air molecules can be calculated by
using the equation:
Equation 14
𝑲. 𝑬. =
𝟏
𝟐
𝒎𝒗 𝟐

69
Where m = mass (kg) and v = velocity (m/s). At sea level air has a known density of
around 1.23kg/m3
, therefore the mass of air hitting a wind turbine (sweep area) each
second is given by the following equation:
Equation 15
𝑴𝒂𝒔𝒔 𝒑𝒆𝒓 𝒔𝒆𝒄𝒐𝒏𝒅 = 𝑽𝒆𝒍𝒐𝒄𝒊𝒕𝒚 × 𝑨𝒓𝒆𝒂 × 𝑫𝒆𝒏𝒔𝒊𝒕𝒚
Where mass per second is measured in kg/s, velocity in m/s, area in m2
, and density in
kg/m3
.
Therefore, in order to calculate the power (W) of the wind hitting a wind turbine, the
mass/sec calculation is inserted into the kinetic energy calculation to give:
Equation 16
𝑷𝒐𝒘𝒆𝒓 (𝑾) =
𝟏
𝟐
× 𝒔𝒘𝒆𝒆𝒑 𝒂𝒓𝒆𝒂 × 𝒂𝒊𝒓 𝒅𝒆𝒏𝒔𝒊𝒕𝒚 × 𝒗𝒆𝒍𝒐𝒄𝒊𝒕𝒚 𝟑
The above calculation gives us the theoretical maximum energy that a wind turbine
could produce, however, there is a law in place called Betz’s law which limits the
overall energy that can be extracted and used from the wind. The Betz limit places an
upper bound on the annual energy that can be extracted at any given site. Even if a
hypothetical wind blew consistently for a full year, no more than the Betz limit of the
energy contained in that year’s wind could be extracted. In practice, the annual
capacity factor of a wind site varies around 25-60% of the energy that could be
generated with constant wind. (Jefferson, 2012)

70
The valley in which Treforest is located holds the river Taff. The river is fairly large
with a large volume of water moving every second, allowing for the possibility of a
hydroelectric facility being built on it. In order to find the maximum power that can be
obtained from a hydroelectric facility, the flow rate of a river will have to be measured
and calculated. From here the power can then be calculated from the following
equation:
Equation 17
𝑷𝒐𝒘𝒆𝒓 = 𝑯𝒆𝒂𝒅 × 𝑭𝒍𝒐𝒘 × 𝑮𝒓𝒂𝒗𝒊𝒕𝒚
Where power is measured in Watts, head in metres, flow in litres per second, and
acceleration due to gravity in metres per second per second.
As expected, it is not possible to extract all of this power, as nothing is 100% efficient.
However, hydro power turbine generators are very efficient when compared to wind
turbines and solar panels, with efficiencies in the region of 70%. This 70% efficiency
refers to the hydraulic energy of the flowing water that can be converted into
mechanical energy to spin the turbine generator. Unfortunately around 30% of the
energy is lost. A small portion of energy is once again lost from the conversion of
mechanical to electrical energy, resulting in a complete system efficiency of around
50-60%.
For example, if the above calculation showed that 13.6kW of power was
available, we can therefore expect to generate around 8.5-9.1kW of electricity.
(REUK, 2014)

71
Background
Figure 33: This image shows the movement of air as it passes over an increase in
height. As it moves it speeds up, resulting in the air molecules having more
energy.
Treforest is a village in the south-east of Pontypridd in the county borough of Rhondda
Cynon Taf, Wales. Treforest runs along the west banks of the River Taff, while
Glyntaff runs along its east banks. Both banks are moderately steep sided, with the
western bank reaching a height of 200m above sea level, and the eastern bank reaching
a height of 300m above sea level. (Mapmywalk, 2014) Both are much higher than the
100m elevation in which Treforest resides. Also, the eastern bank has mainly tree
cover, whereas the western bank has little to no trees, with multiple farmers’ fields in
the area. In this case the local area can be considered to be a mountain, due to the
steepness of the valley, and how the incoming wind will interact with it. Over elevated
surfaces, heating of the ground exceeds the heating of the surrounding air at the same
altitude, creating an associated thermal low over the terrain and changing the wind
circulation of the region. Hills and valleys, as with the Treforest area, can substantially
distort the airflow by increasing friction between the atmosphere and landmass by
acting as a physical block to the flow, deflecting the wind parallel to the range just
upstream of the topography. [6] This jet of air, known as a ‘barrier jet’ can increase the
low level wind by 45 percent.

72
Wind turbines can exist in a variety of different forms. Modern wind turbines used for
commercial production of electric power are usually thin three-bladed turbines that are
pointed into the wind by computer controlled monitors for optimum inertia and
stability. These have high tip speeds, high efficiency, and low torque ripple, which
contribute to good reliability. The steel towers that hold the turbines can range from
60-90m tall, depending on the location and needs. Generally, as you ascend in altitude,
wind speeds increase and are more reliable, resulting in taller wind turbines possessing
a better efficiency when compared to their lower level counterparts. The blades range
in length from 20-40m or more, and typically rotate at 10-22rpm. At 22rpm, the tip
speed exceeds 91m/s. A gearbox may well be used in order to step up the speed of the
generator to rpms of 1500-3000 rpm. Fortunately, due to the erratic behaviour of
Britain’s weather, all turbines are equipped with protective features to avoid damage at
high wind speeds, by feathering the blades into the wind which ceases their rotation,
supplemented by brakes. (Latchways, 2012)
Standard wind turbines used in wind farms are typically of the Horizontal axis variety.
Horizontal-axis wind turbines (HAWT) have the main rotor shaft and electrical
generator at the top of a tower, and thus must be pointed into the wind. Nearly all wind
turbines are fitted with a gearbox which ‘stepsup’ the slow rotation of the blades to a
speed that is more suitable to drive and electrical generator. The direction of wind is a
major factor when building a wind turbine, as the turbine must be pointed upwind of
the tower in order to experience a smaller amount of turbulence. The blades of a
turbine are made stiff to ensure that at high wind they are not pushed into the tower.

73
Due to the orientation of the Taff valley, Treforest runs from south to north, with the
sun rising from the eastern valley side and setting in the west. The following image
shows the layout and direction that Treforest faces.
The red outline on the map shows the Treforest area with the river taff running through
the valley from the North-west to the South-East (orange outline). A majority of the
houses in Treforest run parallel to one another, allowing for the possibility solar panel
connections between them. Since the sun rises in the east, solar panels installed on the
eastern side of each housing roof would benefit from the most energy generation
during the day. Some partial generation could be produced from panels on the western
side, however, due to the steepness of the valley the sun would quickly be setting,
resulting in a very short time of energy generation. The blue outlines on the map
represent what could be the best positions for wind turbines to be installed. One of the
main problems that the public has with wind turbines is that they see them as an
eyesore on the local scenery. Unfortunately, even though the eastern outline would
probably benefit the most due to the valley side having a larger amplitude, resulting in
EastWest
[2]
Figure 34: This figure shows the location of Treforest within the Taff valley

74
greater generation, it is also open to being seen by the general public and could suffer
criticism. The western side however has partial woodland on it, which would result in
partial, if not full cover of the wind turbines. The trees would also act as a sound
barrier, by preventing the volume of noise generated by the turbines that would reach
the public in the Treforest area.
Off grid networks are typically found in rural areas or developing countries. This is
done as it would be very expensive and time consuming to connect them up to the rest
of the country. Off grid networks can be classified into three different categories:
 Small scale renewables
 Micro-Grids
 Hybrid Applications
By developing an off grid network, you can potentially ‘future proof’ a small
community. By doing this you can ensure that no one is tied into a ‘big energy seller’,
and the energy that they require will be free of charge. Depending on the initial
production and construction costs, the greenhouse gases involved in the entire process
of setting up the off grid network should be moderate, as transportation costs alone
represent a large portion of the carbon dioxide emitted. However, if manageable, the
entire off grid network would have a greenhouse gas emission of zero, resulting in the
carbon dioxide emissions becoming negligible with time. There is also the potential
that for any energy generation that is more than the requirement by the local
community, could be fed into the grid to possibility bring an investment back to the
people. (Mitsubishi Electric Research Laboratories (MERL), 2010)

77
Risk Assessment
Since a majority of this report is going to be simulated on a computer, the chances of
any potential risks are very low.
Work Carried Out
So far, the only work that has been carried out has been the research that has been
implemented into this report. The research for the entire project is an ongoing process,
and thus will not stop until the final submission date has been reached.

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