Co-researcher:  Mr Koh Siong Lee

Designation  :  UTAR Masters'Student

Faculty      :  Faculty of Engineering & Science

Department   :  Dept of Physical Science, Electrical &Electronic Engineering

Introduction

Malaysia is heavily dependent on the fossil fuels to satisfy its energy demand. The energy demand will increase from 82,000 GWh in 2005 to 190,000 GWh in 2020.  This would cause the greenhouse gas emissions to grow extensively from 43 million tones in 2005 to 110 million tones in 2010.  Such rapid growth of greenhouse gas emissions would have adverse effects on the country due to climate changes.  For example, the floods in the state of Johore in Peninsular Malaysia from December 2006 to Jan 2007 were the worst in the past 100 years. These floods killed 17 people and forced 90,000 people to evacuate their homes. Also, they caused financial losses of about RM 6 billion (=US$1.38 billion).  Apart from that, the oil and gas reserves in Malaysia will be depleted by 2015 and 2048 respectively. As a result, Malaysia would be facing more and more social and economic problems.  Therefore, it is imperative that the Malaysian government put greater efforts into seeking alternative sources of energy such ocean energy.

Figure 1.  Rapid growth in energy demand

Ocean energy is a form of renewable energy available on the earth. In the past, the potential and commercial viability of harnessing ocean energy in Malaysia have not been studied thoroughly. Only recently, a preliminary study was carried out to explore the potential of harnessing ocean energy for electricity generation in Malaysia.  Ocean energy can be categorized into (a) wave energy,  (b) thermal energy and (c) tidal energy.  Research findings indicate that there is little potential to harness wave energy because the wave power density of Malaysia?s ocean is less than 50 kW/m². However, wave energy conversion technology requires an average annual wave power density of greater than 50 kW/m² in order for it to be commercially viable. As for thermal energy, it would be commercially viable if the temperature gradient is greater than 20⁰C across the depth of at least 1000 m. The depth of Malaysia?s ocean is less than 1000 m. Hence, thermal energy is not commercially viable in Malaysia.  As for tidal energy, since the tidal cycle is highly predictable, it therefore has the potential of being a reliable renewable energy source.

Two main approaches are  being  researched  internationally  to  harness  the  energy  from  tides:

(a)Barrage Approach and (b) Tidal Stream Approach. 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. For the Tidal Stream Approach, horizontal axis turbines are placed in the path of tidal currents to generate electricity.

Figure 2.  Tidal technologies

Scope of Research

The Princeton Ocean Model (POM) was used to simulate ocean phenomena around Malaysia. A three-dimensional ocean model of Malaysia was created in POM and calibrated against measurement by means of adjoint data assimilation approach without the need of reducing the model into 2-dimensional.  An optimization code, an enhanced method for the formulation of the tidal boundary conditions was incorporated into POM to improve the convergence of the system. By using the POM software with the added on features, a set of reliable tidal speed and elevation data was generated to assess technical, economical and environmental aspects of installing marine current turbines (MCT) in Malaysia. This assessment was aided with established methodologies for designing the configuration of MCT, the capacity and the diameters of turbines for each potential location in Malaysia.

Outcome Of Research

Analytical assessment has been carried out to estimate the amount of electricity to be generated by MCTs and also to evaluate the economical viability and environmental benefits of installing MCTs in Malaysia. It was identified that Pulau Jambongan, Kota Belud, and Sibu are the locations with great potential for tidal energy extraction. The total amount of electricity that can be generated by MCTs on those locations is about 14.5 GWh/year. This amount is much higher than the amount of electricity of PV systems which is aimed to be generated in 2010. The government or utility company can save about RM 1.1 billions of natural gas and avoid a total greenhouse emission of 4,552,512 tonnes per year. Owners of MCTs may be able to recover the cost of the system after 10 years and can make profits after that. They can create additional income streams by selling CERs to developed countries. In addition, the characteristics of power supply by MCTs can be predicted using the types of tides available on the sites. For example, the types of tides in Pulau Jambongan, Kota Belud and Sibu are mixed tides with dominant in diurnal. Hence, maximum power supply from MCTs on those locations occurs at the extreme declination of the moon and lowest current at the zero declination.

Figure 3.  Energy density of tidal current

Conclusion

Tidal energy is a promising renewable energy source available in Malaysia. The results of this assessment should encourage the government to provide additional research funding for design, development, erection and installation of marine current turbine prototypes. On the other hand, there are several environmental issues that need to be investigated and resolved. The environmental issues are the threat of MCTs on marine wildlife, conflicts with other users of the sea as well as pollution. Therefore, additional research work is necessary to resolve several advanced technical and environmental issues before tidal energy can become a realistic renewable energy source in the future.