Journal of Energy & Environment
Journal homepage: www.uniten.edu.my/jee
Simulation Studies on the Electrical Power Potential Harnessed by Tidal Current
Turbines
K.S. Lee1*, L.Y. Seng1
1
Tunku Abdul Rahman University, Faculty of Engineering & Science, Department of Electrical & Electronic Engineering, UTAR
Compleks, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur, MALAYSIA
KEYWORDS
ABSTRACT
Computational Energy
Fluid Generation
Malaysia Tidal
Malaysia depends heavily on fossil fuel for electricity generation and transportation.
However, its fuel reserve is expected to diminish very rapidly over the next 10 years. It is
therefore very important to increase the use of renewable energy, particularly bio-fuel and
solar energy. The potential of harnessing ocean energy in Malaysia, such as tidal energy,
needs to be investigated thoroughly. Ocean energy could be a promising form of
renewable energy because of the cyclic, reliable and predictable nature and the vast energy
contained within it. According to UK Department of Trade and Industry, 10% of the
United Kingdom’s electricity needs could be met by tidal power. Philippine has installed
tidal fences stretching across the straits of San Bernardino. Being a neighboring country,
Malaysia may also have a huge potential for tidal energy. This paper provides the details
of the investigations carried out to explore the potential of electricity generation using tidal
energy at the ocean around Malaysia.
© 2009 Universiti Tenaga Nasional. All rights reserved.
1. INTRODUCTION
Malaysia is heavily dependent on the fossil fuel to satisfy
its energy requirements. However, it is reported that the oil
reserve in Malaysia will be depleted by 2015 and gas by 2048
[1]. With the growing negative environmental impact of fossil
fuels, Malaysian Government has started to explore the use of
renewable energy.
The potential of harnessing energy from the ocean in
Malaysia is being investigated since a little effort has
been put to initiate such studies. Based on the literature
studies, the common categories of energy available are (a)
Tidal Energy (b) Current Energy (c) Wave Energy and (d)
Thermal Energy [2-3]. This paper provides a general view on
the potential of harnessing tidal energy in Malaysia for
electricity generation. It is identified that there are a number of
sites with great potential for tidal energy conversion, which
could supplement the energy needs of Malaysia as well as
reduce the greenhouse gas generation [4-6]. The findings on
this study can form a foundation for further investigation on
the viability by actual measurement of tidal data at the
identified sites, development of innovative and suitable tidal
energy technologies as well as prototyping of the selected
technology.
*Corresponding author
E-mail address: K.S. Lee <[email protected]>.
As the tidal cycle is highly predictable, it has the potential
to be a very reliable renewable energy source. Two main
approaches are being researched internationally to harness the
energy from tides: (a) Barrage Approach (b) Tidal Stream
Approach [7-11].
For the Barrage Approach, a physical barrier, namely the
Barrage is created within the sea with Sluice Gates to control
the flow of sea water. The Sluice Gates are to be closed at
high tide so that the water level inside the barrage is held at its
highest level. As the tide recedes, a difference in water level in
between the barrage and the sea is created. The potential
energy from the water level difference can then drive turbines
to generate electricity, similar to the way that a hydroelectric
plant generates electricity.
In the Tidal Stream Approach, horizontal axis turbines are
placed in the path of tidal currents to generate electricity,
similar to the operation of wind turbine.
This paper presents the findings on the preliminary
studies undertaken to identify the potential of harnessing tidal
energy in Malaysia for electricity production. Section 3
provides the flow velocity, power output, availability of power
supply and monthly yield of turbines using the Barrage
Approach and Section 4 presents the same set of results using
the Tidal Stream Approach.
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K.S. Lee & L.Y. Seng/ Journal of Energy & Environment, Vol. 1 (2009), No. 1, 18-23
19
2. CHARACTERISTICS OF TIDES IN MALAYSIA
Tides are generated by the rotation of the earth and
gravitational fields of the moon and sun. The gravitation
creates tidal two “bulges” in the earth’s ocean envelope: one
on the side of the earth facing the moon and the other on the
opposite side. Depending on the location relative to the axis of
the earth rotation, a maximum of two tides can be observed
[2]. The spring tides, whose ranges are greater than the
average, occur at the time of new and full moon, when the
earth, moon and sun lie approximately on the same line. The
neap tides, with the ranges less than the average, occur when
the sun’s gravitation act at right angles to the moon on the
earth.
A tidal phenomenon is periodic. The exact nature of
periodic response varies according to the interaction between
lunar and solar gravitation effects, respective movements of
the moon and sun, and other geographical peculiarities. There
are three main types of tide phenomena at different locations
on the earth.
1. Semi-diurnal Tides: This type of tide has a period that
matches the fundamental period of the moon (12 hour 25
min). Any ocean with such tide will have two high tides
per day. The amplitude of the tide varies through the lunar
month, with tidal range being greatest at full moon or new
moon (spring tides) when moon, earth, and sun are
aligned. Resonance phenomena in relation to the 12 hr 25
min period characterize tidal range.
Fig. 1. Types of tides available in Malaysia
3. POTENTIAL OF TIDAL ENERGY
MALAYSIA – BARRAGE APPROACH
AROUND
3.1 Measured Tidal Range
Tide data are obtained from the Tidal Observation
Records 2005 [15] and tabulated in Fig. 2. The tidal range is
calculated by taking the difference between the Mean High
Water Springs (MHWS) and the Mean Low Water Springs
(MLWS). The MHWS is the average height of two successive
high waters during a day when the range of the tide is the
greatest throughout a year. MLWS is the average of two
successive low waters during the same period. It can be seen
that Sejingkat has the highest tidal range of 4.38 m.
2. Diurnal Tides: This type of tide has a period corresponds to
a full revolution of the moon relative to the earth (24 hr 50
min). Such a tide has one high tide per day. Semi-diurnal
tides are subject to variations arising from the axis of
rotation of the earth being inclined to the planes of orbit of
the moon around the earth and the earth around the sun.
3. Mixed tides combine the characteristics of semi-diumal
and diumal tides. They may also display monthly and
bimonthly variation.
The recorded annual data on the tidal heights were
analyzed and decomposed into 60 harmonic components.
These recorded data, together with the statistical results and
extracted harmonic components are recorded in the Tidal
Records [15]. The 4 most significant harmonic components,
namely the M2, S2, K1 and O1, are used to study the
characteristics of tides around Malaysia as shown in Fig. 1.
In Peninsular Malaysia, the tides are semi-diurnal and
mixed tide with dominant semi-diurnal, except Terengganu
which has mixed tide with dominant diurnal. On the other
hand, the tide in East Malaysia is mixed tide with either
dominant semi-diurnal or diurnal. There is no diurnal tide
available in Malaysia.
Fig. 2. Tidal range (MHWS - MLWS) of year 2005 for 20 tide
stations in Malaysia
Fig. 3 shows the locations of six sites with the highest
tidal range around Malaysia, based on [12]. Using the
Computation software, Fluent [16], the flow velocity is
obtained. Using the Computational Fluid Dynamic technique,
Fluent is able to simulate fluid flow, heat and mass transfer,
and a host of related phenomena involving turbulence,
reactions, and multiphase flow. Fig. 4 shows the flow velocity
for one tidal cycle for the six sites, based on MHWS and
MLWS.
K.S. Lee & L.Y. Seng/ Journal of Energy & Environment, Vol. 1 (2009), No. 1, 18-23
Fig. 3. Six Sites Around Malaysia with the Highest Tidal
Range - (a) Sejingkat; (b) Pelabuhan Kelang; (c) Pulau
Langkawi; (d) Tawau; (e) Kukup; and (f) Johor Baru
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Fig. 4. Flow velocity over one tidal cycle for the six sites in
Malaysia with the highest tidal range, using MHWS and
MLWS.
The electrical power of a turbine in one tidal cycle is
calculated as in Fig. 5, using Eq. (1) below.
P 1
 U 3
A 2
(1)
where A is Cross-sectional area of turbine;  is density of
fluid (1,025 kg/m3 for seawater); and U is current speed (m/s).
Fluent simulation is subsequently run for one year period
based on year 2005 data [15] for the six sites. From the
simulation results, the monthly power availability and the
yields are summarized in Tables 1 and 2.
Table 1 shows that the Sejingkat has the highest power
availability, with an average of 76.15%. The lowest is 74.97%
which happened in June. The highest is 77.61% happening in
December. The average monthly yield per meter square of
turbine sweeping area is 476.51 kWh/m2. If the length of a
turbine’s blade is 5 m, then the sweeping area of the blades is
31.5 m2 and therefore the monthly yield of a single tidal
turbine installed in Sejingat is 14,970 kWH. The single tidal
turbine is able to provide energy to about 75 households for a
month, assuming that the monthly power consumption of an
average household is 220 kWh. The number of households
that can be powered by the tidal power plant depends upon the
number of Sluice Gates and the turbines. With the 10m
diameter turbine, an one kilometer long barrage can easily
accommodate 20 turbines, which will be sufficient to supply
to 1500 households.
Johor Baru is the site with the average power availability
of 63.33%. The average monthly yield per meter square of the
turbine sweeping area is 183.76 kWh/m2. If the length of a
turbine’s blade is 5 m2 and the monthly power consumption of
a household is 220 kWh, then a single tidal turbine is able to
provide energy to about 26 households.
Fig. 5. Electrical power output (kw/m2) of a turbine installed
on the selected sites of Malaysia, assuming that the sweeping
area of the turbine’s blades is 1 m2
Table 1. Power availability for six sites using barrage
approach
K.S. Lee & L.Y. Seng/ Journal of Energy & Environment, Vol. 1 (2009), No. 1, 18-23
Table 2. Monthly yields for six sites using barrage approach
It is identified that all the potential sites are evenly
spread around the whole country, providing the opportunity to
various states throughout the country to capture and utilize the
tidal energy for development purposes. For example, the
ocean of Pulau Langkawi is identified as one of the potential
sites and is near to the Northern part of Peninsular Malaysia. If
a tidal power plant is installed on the site, it can provide
energy to the states of Perlis and Kedah. The ocean of
Pelabuhan Kelang is close to the capital of Malaysia and
identified to be the site of the second highest yield. A tidal
power plant in the ocean of Pelabuhan Kelang can supplement
the energy needs of the capital. The sea of Johor Baru and
Kukup are close to the South of Peninsular Malaysia and any
tidal power plant on the site can provide energy to Johor state.
The ocean of Sejingat is close to Kuching, which is the capital
of Sarawak state. The ocean is identified as the site of the
highest yield in the country. Any tidal power plant in the site
will bring benefit to the capital of Sarawak. Tawau is the third
biggest city in Sabah state. Any tidal power plants on the
ocean of Tawau will certainly bring benefit to the
development of the city.
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and Eq. (1) with efficiency as in Eqs. (2) and (3) below, the
power output of a tidal turbine installed in the ocean of these
four sites is calculated as in Fig. 8. The tidal currents (m/s) of
the four sites are plotted as in Fig. 7.
Fig. 6. Four sites with the highest tidal stream velocity
around Malaysia: (a) Sandakan; (b) Pulau Pangkor;
(c) Melaka; and (d) Kelang (captured from Google earth [12])
Fig. 7. The tidal stream velocity on the day with the highest
amplitude in year 2007 at the four sites around Malaysia
4. TIDAL STREAM APPROACH
For tidal power generation using the Tidal Stream
Approach, the available power is directly proportional to the
velocity U3 as in Eq. (1) above.
4.1 TPXO Software by Oregon State University, USA
The TPXO software [13-14] is used to identify the sites
with the higher stream current velocity around Malaysia. The
software is based on the Oregon State University Tidal
Inversion Software and the TOPEX/POSEIDON satellite
imaging data to predict the tidal heights and tidal current.
To identify the accuracy of the results generated by the
TPXO software, the measurement data of tidal current in the
waters of two locations, namely Raleigh Shoal and Fathom
Bank, was collected from the Department of Meteorology
Malaysia [15]. TPXO was used to identify which sites in
Malaysia can have high tidal current. It was found that there
are four locations which have the highest tidal current: (a) The
ocean of Sandakan; (b) Pulau Pangkor; (c) Melaka; and (d)
Kelang, as shown in Fig. 6. Using the tidal current velocity
The electrical power output from the generator is
Pe  At  P t  p
(2)
where:
 p   d  g  c
(3)
Where P is the power density of the water passing through the
area swept by the turbine as in Eq. (1) At is the area swept by
the turbine rotor.
Typical values for component efficiencies as below are
used in the calculation:
•  t = 45% for turbine efficiency;
•  d = 96% for drive-train efficiency;
.
•  g = 95% for generator efficiency; and
•
 c = 98% for efficiency of the power conditioning
component [4].
K.S. Lee & L.Y. Seng/ Journal of Energy & Environment, Vol. 1 (2009), No. 1, 18-23
22
For the Melaka site, it has an average power availability
of 43% or 316 hours per month. The highest of 46% occurs in
the months of August whereas the lowest of 41% in June and
December. The average monthly yield per square meter of
turbine sweeping area is 83 kWh, translated to 997 kWh per
year.
For the Kelang site, it has an average power availability
of 19% or 134 hours per month. The highest of 24% occurs in
the months of September whereas the lowest of 13% in June
and December. The average monthly yield per square meter of
turbine sweeping area is 18 kWh, translated to 213 kWh per
year.
5. CONCLUSION
Fig. 8. The power output based on the velocity in Fig. 7
(assuming that the turbine sweeping area is 1 m2)
Fig. 8 shows that a tidal turbine in the ocean of Sandakan
is able to deliver power for about 22 hours every day and the
peak power output of 3.22kW/m2, which is the rated electrical
output power of the selected turbine for this analysis. At the
Pulau Pangkor site, the tidal turbine can deliver for 19 hours
per day and the peak power of 2.34 kW/m2. At the Kelang site,
the highest power availability happens is 14 hours or 59% of
the time. The peak power output per square meter of turbine
sweeping area is 0.32 kW.
The monthly power availability and monthly yields for
the year 2007 are tabulated in Tables 3 and 4. Tables 3 and 4
show that the Sandakan site has high power availability, with
an average of 584 hours per month, or 80% of the time. The
lowest is 79% which happened in January and February. For
the months of March, August, September, October and
December, the power availability is as high as 81% of the
time. The average monthly yield per square meter of turbine
sweeping area is 1,209 kWh, translated to 14,502 kWh per
year.
Table 3 Power Availability at 4 Sites around Malaysia,
Using the Tidal Stream Approach
With the predictable nature of the tides coupled with the
high availability and environmental benefits of the power
based on the above study, the tidal energy will be a source of
renewable energy with great potential in Malaysia.
For the Barrage approach, there are 6 sites distributed
across east and west Malaysia, which give power availability
between 76.16% and 63.33% of the time. With a single turbine
of 5m long blade installed at the site with the highest potential,
Sejingkat, 14,970 kWh of energy can be generated monthly.
This is sufficient to supply to 75 households.
Using the Tidal Stream approach, the study at Sandakan
and Pulau Pangkor shows equally promising results of 80%
and 57% power availability. However, the results at Melaka
and Kelang are less optimistic, with an average power
availability of 43% and 19%.
Further site measurements shall be carried out at the
potential sites to validate the software simulation results prior
to identifying the suitable technology and prototyping at the
sites to confirm the viability.
ACKNOWLEDGEMENT
The authors gratefully acknowledge the contributions of
the Department of Survey and Mapping, Malaysia for
providing the Tidal Observation Records 2005.
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