Energy

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Superstructure optimization and forecasting of decentralized energy generation based on palm oil biomass
(Universiti Teknologi Malaysia, 2013) Bazmi, Aqeel Ahmed
Malaysia realizes the importance of addressing the concern of energy security to accomplish the nation’s policy objectives by mitigating the issues of security, energy efficiency and environmental impacts. To meet the rising demand for energy and incorporation of Green Technology in the national policy, Malaysian government during the last three decades has developed several strategies and policies. National Green Technology Policy was an initiative, which marked the firm determination of the government to incorporate Green Technology in the nation’s economy policy. Malaysia has abundant biomass resources, especially oil palm residues with power generation potential of about 2400 MW, which is promising for decentralized electricity generation (DEG). The aim of this study is to determine the best location to install appropriate biomass electricity generation plant in Johor and forecasting the electricity market (i.e. electricity demand) in order to provide a strategic assessment of measures for the local energy planners of Malaysia, as an optimization bottom-up model. A superstructure was developed and optimized to represent DEG system. The problem was formulated as Mixed Integer Nonlinear Programming (MINLP) and implemented in General Algebraic Modeling System (GAMS). Electricity demand was modeled using Adaptive Neuro Fuzzy Inference System (ANFIS). Based on GAMS and ANFIS models, palm oil biomass based DEG system and distribution network scenarios for current as well as next ten, twenty and thirty years have been proposed for State of Johor, Malaysia. Biomass from sixty six Palm Oil Mills (POMs) would be collected and transported to eight selected locations. Empirical findings of this study suggested that total production cost is minimized by placing biomass gasification based integrated combine cycle (BIGCC) power plant of 50MW at all eight locations. For 2020 Scenario, no additional infrastructure will be required. For 2030 Scenario, additional units of BIGCC of 50MW will be required at five out of eight locations. While for 2040 Scenario, again no additional infrastructure development will be needed. Total minimum cost varied from 6.31 M$/yr for current scenario to 22.63 M$/yr for 2040 scenario.
Design and operation of renewable energy based distributed energy generation system
(Universiti Teknologi Malaysia, 2014) Ho, Wai Shin
Concerns over sustainability of fossil fuels, escalating petroleum prices and increasing awareness for the environment have encouraged countries all over the world to shift from the heavy reliance on fossil fuel to renewable energy (RE) resources for electricity generation. The distributed energy generation (DEG) system that operates within the distribution network that fits the criteria of future needs of smart and efficient energy system could therefore be the best platform to implement RE. However, in order to achieve an optimal DEG system in terms of cost and efficiency, the designing and scheduling process could be rather difficult and complex. Among the factors taken into consideration during the planning stage include; i) intermittency and operation of RE especially for solar energy systems which are weather oriented; ii) manipulation of supply load through integration of energy storage (ES) system for peak shaving; and iii) manipulation of demand load through load shifting (LS) for peak shaving. Taking these factors into account, new optimisation methodologies are introduced in this thesis, specifically, a targeting technique based on Pinch Analysis known as the Electric System Cascade Analysis (ESCA). The technique was then expanded in to a mathematical model for a more holistic investigation. In Malaysia, developments of RE and DEG are currently focused on Iskandar Malaysia (IM) which is set with the goal to be developed as the low carbon city. Compared to many other countries which focus on wind energy as their main RE for low carbon development, IM which lacks of wind energy instead considers other RE resources such as biomass, biogas (both from palm oil resources) and solar energy, as they are the most promising RE resources to simultaneously reduce the dependency on fossil fuels as well as providence of environmental benefit in the region of IM. Palm oil mills (POM), being a biomass and biogas collection point, having sufficient land area for solar energy systems, and located distances away from a centralised grid system could therefore gain much benefits from a DEG system. Thus it was taken as the case study for the optimisation techniques developed in this thesis. The case study on the POM includes optimal DEG system design and operation (electricity and heat) of the mill as well as the local residential community. The application of the model on an eco-community and industrial case study has demonstrated the applicability of the model to design an optimal cost competitive DEG system. Through this study, it shows that implementation of DEG system within IM is indeed feasible
New power pinch analysis techniques for optimal design of hybrid power systems
(Universiti Teknologi Malaysia, 2014) Mohammad Rozali, Nor Erniza
The International Energy Agency has estimated a renewable power escalation of 40% in the next five years, and expected the renewable energy (RE) to make up almost a quarter of global power mix. Hybrid Power Systems (HPS) comprising RE sources can provide an effective safeguard while enhancing energy security and efficiency. Systematic methods to design and perform optimal power allocation in HPS are required in order to maximise power recovery as well as profitability. In this study, new algebraic and graphical Process Integration tools based on the Pinch Analysis concept have been developed for the optimal design as well as allocation of power for a HPS. The new Power Pinch Analysis (PoPA) techniques introduced in this study complement the modeling tools, particularly in offering visualisation advantages as well as vital insights on the network design, and providing designers with better control over the design decisions. Important decision variables during various design stages including the real-time amount of electricity transfer, stored and outsourced were established prior to the in-depth analysis. The new framework proposed in this research consisted of five key components. The first component introduced new systematic techniques to integrate the HPS both graphically and algebraically. Targets for first day and continuous 24 hours operations had been established to achieve 96.94% reduction in the conventional electricity requirement for the studied wind-solar system in Case Study 1. Consideration of energy losses during conversion, storage and transfer processes were incorporated into the second technique in order to reflect the actual HPS performance. Incorporation of the losses into the method leads to 31.26% reduction in the storage capacity as presented in the case study. The third technique presented a handy sizing method to achieve optimal configuration in a HPS with multiple generators. The studied system showed that the minimum payback period of 11.78 years was obtained for the optimal configuration. Effects of peak-off-peak electricity pricing were taken into account in the load shifting procedure as proposed in the fourth technique. Application on case study gave electricity cost savings of RM 80,881. The final component was developed to guide the designers to decide on the most cost-effective storage scheme for their HPS considering storage types, efficiencies, costs and power trends factor. The costeffective storage for the investigated household system was the superconducting magnetic storage with capacity of 26.12 kWh, while the Lead-Acid battery storage of 15.38 MWh capacity was best applied in the presented industrial case study
Optimal planning of hybrid power generation system towards low carbon development
(Universiti Teknologi Malaysia, 2014) Ab. Muis, Zarina
In Malaysia, the energy sector is identified as one of the major carbon dioxide (CO2) emitters. Electricity in Malaysia is primarily generated from coal, natural gas, diesel, oil and hydro. The government of Malaysia encourages power producers to shift towards the use of renewable energy (RE) and reduce their reliance on fossil fuels. There is a clear need for a systematic method to sustainably plan the fleet-wide electricity generation and capacity expansion towards fulfilling the forecasted electricity demand and simultaneously meet the emission reduction target. A comprehensive superstructure consisting o f all existing (i.e. Pulverized Coal (PC), Natural Gas Open Cycle (NGOC)) and new power generation technologies (i.e., Natural Gas Combined Cycle (NGCC), nuclear, solar, biom ass and M unicipal Solid W aste (M SW )) was constructed at the early stage of model development in this study. Towards this end, three different models have been developed and implemented in the General Algebraic Modeling System (GAMS) as follows: 1) Single period model for electricity generation mix that is designed to satisfy the electricity demand until the year 2020 for Peninsular Malaysia, 2) Multi period model for selection o f power generation technology that is designed to satisfy the forecasted electricity demand from year 2012 to 2025 in Iskandar Malaysia (IM) and 3) Multi-period optimization model that is developed to determine the optimal location o f new RE generation stations to reduce transmission losses and transportation cost in IM. Options are made available by models 1 and 2 to switch the coal plants to natural gas power plants and to increase the use o f renewable energy in order to meet CO2 target and to minimize cost. Model 3 is capable o f predicting the cost-optimal generation capacity, type o f biomass-energy conversion technology and location for the construction and operation of new biomass power plants. The models can provide vital tools to assist the government in policy making
Energy consumption behaviour assessment model for student accommodations in Malaysian public universities
(Universiti Teknologi Malaysia, 2015) Ishak, Mohd. Hafizal
In achieving towards sustainable campus of higher education institutions (HEIs), energy consumption behaviour assessment is one of the several issues that require attention by the facilities manager. Information on energy consumption behaviour is needed to determine potential energy savings. However, issues on the information of energy consumption behaviour such as 'direct' and 'indirect' data, pattern segregation, factors influence and modeling subsequently has inhibited the energy consumption behaviour assessment agenda. The purpose of this study is to assess energy consumption behaviour for student accommodations in Malaysian public universities. This study has two main objectives, first, to determine energy consumption patterns and analyse the factors that influence the pattern. Second, is to develop energy consumption behavioural models (ECBM) and assess the potential energy savings. The 'energy culture' framework consolidated with 'centrographic' approach and econometric analysis used to strengthen the development of ECBM. A self-administrated survey carried out involving 1,400 respondents in selected public HEIs. There are three types of energy use among students in public HEIs namely, 'high', 'low', and 'conserve'. The 'device', 'activities' and 'building regulation' are the influence factors on the pattern of energy use. The energy consumption behaviour model (ECBM) was developed at the final stage of the study. Through the model's application, there is a potential energy savings of 52 to 66 percent among the students. It is capable of assessing the energy consumption behaviour and potential energy savings
Optimal planning for landfill gas utilisation as a renewable energy source for environmental sustainability
(Universiti Teknologi Malaysia, 2015) Ahmed, Saeed Isa
The Malaysian government aims to secure 5.5 % of the total energy installed capacity from renewable energy (RE) sources by 2015 and 11 % by 2020, leading to 42.2 million tonnes of carbon dioxide (CO2) avoidance in 2020. Landfill gas (LFG) is one of the most promising RE sources and a major source of greenhouse gas (GHG) emission, if it is not efficiently utilised. Efficient LFG utilisation planning is therefore very important to achieve the nation’s goal and at the same time balancing the economic and environmental benefits, thus supporting the diversification of energy sources. The thesis evaluated the economic and environmental benefits of LFG in Malaysia and then developed four optimisation models (from simple to complex cases) to efficiently plan the utilisation of the biogas. Factors such as resources to be produced (such as electricity, steam), the equipment type to employ (gas engines, gas turbines, steam turbines), GHG emission reduction potentials of technologies, resources availability and several others, impose constraints to the models. The first model predicts the optimal products and equipment type. The second model, in addition to predicting optimal products and equipment type, also determined the optimal equipment size and cost and compares the performance of the current practice with the proposed one. The third and fourth models, besides possessing the capabilities of the first two models, considered multi-period and multi-grade LFG utilisation. That is, the models predict whether low, medium or high grade LFG should be utilised and gave a tim e-based profile for the economic and environmental benefits. The models were applied to Seelong landfill and Iskandar Malaysia as case studies, with positive outcomes in terms of profitability and GHG emission reduction. The models are significant beyond LFG utilisation because they contain tools, which make them generic, flexible and robust for application to other waste management options
Kinetic studies and mathematical modelling of imperata cylindrica flash pyrolysis
(Universiti Teknologi Malaysia, 2017) Oladokun, Olagoke Abimbola
Biomass pyrolysis product offers great potentials in facilitating energy and environmental challenges. This is, however, yet to be realized due to some technological barriers that limit its economic potential. In this thesis, a flash pyrolysis of Imperata cylindrica in a transported bed reactor is investigated, aiming at improving its overall performances from both operation and design perspectives using a mathematical modelling approach. A macroscopic model of the process was used in estimating the kinetic parameters of I. cylindrica and in determining the optimal operating conditions of the reactor. A microscopic model using Computational Fluid Dynamics (CFD) was applied to study the reactor’s hydrodynamics and to determine optimal values for key design parameters, i.e., solid inlet positions, gas inlet position and height-width ratio. To facilitate more detailed analyses, a new algorithm was developed for determining cellulose, hemicellulose and lignin compositions from biomass devolatilization kinetic study. The results obtained confirmed that I. cylindrica has good fuel properties and decomposes easily in the presence of heat, thus making it a suitable feedstock for biofuel production in thermochemical processes. However, the laboratory scaled transported bed reactor was found inefficient and requires very high operating temperature in maximizing biooil yield. Based on the CFD study, the efficiency can be improved if the biomass and hot-sand inlets were positioned closer to the reactor wall and at opposite end. The results also indicated that a good hydrogen gas yield could be obtained from steam reforming of I. cylindrica biooil. In conclusion, the mathematical modelling approach carried out in this study has highlighted the potential of the proposed process and the use of I. cylindrica as a good biomass source for energy
Framework for multistage pre-treatment of anaerobic digestion for maximizing electrical energy production
(Universiti Teknologi Malaysia, 2018) Abdur Raheem
Anaerobic digestion (AD) is a complex process involving several dependent variables. Among critical factors are pH value, temperature and type of pre-treatment of raw material. The change in these parameters affects the overall performance of the system in terms of biogas and methane yield, resulting into varying power output. Different pre-treatments of biomass have different impact on the kinetics of AD. Therefore, the overall electrical output power varies with varying the type of pretreatment and to which extent it is used. In this regard, most of the existing approaches focused only on the multistage reactor design and economic evaluations with single pre-treatment technique. They did not consider the effect of multistage pre-treatment techniques on electrical power output. This research proposes a novel methodology of multistage pre-treatment of organic matters which has the potential to increase the power output from AD to its maximum. The modelling of most common pre-treatment techniques (chemical, mechanical and thermal pre-treatments) of organic matters is presented to calculate the effect of these treatments on the electrical energy production. A framework is developed to evaluate the whole process from pre-treatment to the power output. Multistage pre-treatment is proposed in this research to enhance the electrical energy production from AD. The first order kinetic model of AD is used to calculate the biogas and methane yields and electrical energy as existing literature illustrates that this model is a good choice acceptably for the solution of chemical reactions involved in AD. Three different pre-treatment scenarios, AD with single pretreatment (Case 1), AD with two stage pre-treatment (Case 2) and AD with three stage pre-treatment (Case 3) are considered for the application of the proposed methods. The proposed scenarios are simulated to use different possible number of combinations in all three pre-treatment cases. The highest production of electrical energy achieved was 0.62 kWh, 0.75 kWh and 0.87 kWh for 1 kg of animal wastes for Case 1, Case 2 and Case 3 respectively. The results are compared with the experimental results of pilot scale plant and Anaerobic Digestion Model No. 1 (ADM1). This shows that biogas, methane yield and electrical energy output can be enhanced to approximately two fold by using multistage pre-treatment. The proposed technique is useful for the prediction of bioenergy yield for different organic matters as well as for other bioenergy conversion routes.
Control of the photovoltaic emulator using fuzzy logic based resistance feedback and binary search
(Universiti Teknologi Malaysia, 2018) Ayop, Razman
Photovoltaic (PV) emulator is a power supply that produces similar currentvoltage (I-V) characteristics as the PV module. This device simplifies the testing phase of PV systems under various conditions. The essential part of the PV emulator (PVE) is the control strategy. Its main function is to determine the operating point based on the load of the PVE. The direct referencing method (DRM) is the widely used control strategy due to its simplicity. However, the main drawback of DRM is that the output voltage and current oscillate due to the inconsistent operating point under fixed load. This thesis proposes an improved and robust control strategy named resistance feedback method (RFM) that yields consistent operating point under fixed load, irradiance and temperature. The RFM uses the measured voltage and current to determine the load of the PVE in order to identify the accurate operating point instantaneously. The conventional PV models include the I-V and voltage-current PV model. These PV models are widely used in various control strategies of PVE. Nonetheless, the RFM requires a modified PV model, the current-resistance (I-R) PV model, where the mathematical equation is not available. The implementation of the I-R PV model using the look-up table (LUT) is feasible, but it requires a lot of memory to store the data. A mathematical equation based I-R PV model computed using the binary search method is proposed to overcome the drawback of the LUT. The RFM consists of the I-R PV model and the closed-loop buck converter. In this work, the RFM is investigated with two different controllers, namely the proportional-integral (PI) and fuzzy logic controllers. The RFM using the PI controller (RFMPI) and the RFM using the fuzzy logic controller (RFMF) are tested with resistive load and maximum power point tracking (MPPT) boost converter. The perturb and observe algorithm is selected for the MPPT boost converter. In order to properly design the boost converter for the MPPT application, the sizing of the passive components is proposed, derived and confirmed through simulation. This derivation allows adjustment on the output voltage and current ripple of the PVE when connected to the MPPT boost converter. The simulation results of the proposed control strategies are benchmarked with the conventional DRM. To validate the simulation results, all controllers are implemented using dSPACE ds1104 rapid prototyping hardware platform. The RFM computes an operating point of the PVE at 20% faster than the DRM. The generated output PVE voltage and current using RFMPI and the RFMF are up to 90% more accurate compared to the DRM. The efficiency of the PVE is beyond 90% when tested under locus of maximum power point. In transient analysis, the settling time of RFMF is faster than the RFMPI. In short, the proposed RFMF is robust, accurate, quick respond and compatible with the MPPT boost converter.
Design and fabrication of arc thermal plasma reactor for petroleum sludge treatment
(Universiti Teknologi Malaysia, 2019) Mohammed, Abubakar Ali
Over 130, 000 metric tonnes of toxic petroleum sludge are generated yearly in Malaysia. The traditional methods of disposing of petroleum sludge are short of providing the much-needed benign treatment. A more robust treatment technique is therefore desirable. The thermal plasma treatment technique is employed to bridge the gap. In this research, a 4.7 kW thermal plasma reactor was designed and fabricated. The output current and the plasma temperature range were 5 – 200 A and 356 – 1694 oC respectively. After the treatment, the morphology of the sludge transformed from jelly-like to crystalline solid. A mass reduction of 36.87 – 91.40% and a total organic compound reduction of 21.47 – 93.76% were achieved in a treatment period of 2 – 5 minutes. The leaching test indicates that the heavy metals were stabilized in the solid, and hence, the solid is safe for secure landfill. The product gas is a mixture of carbon monoxide (CO), carbon dioxide (CO2), hydrogen (H2), water (H2O), methane (CH4), acetylene (C2H2) and ethylene (C2H4). The concentrations of the greenhouse gases, CH4 and CO2, were small. The lower heating value and the cold gas efficiency of the gas were 7.40 – 7.86 MJ/Nm3 and 25.22 – 51.90% respectively. The efficiency is within the range of the efficiency of gasification of petroleum sludge in an updraft gasifier. Based on the operating cost estimation, a profit margin of RM 3.11/kg of sludge was achieved. Two quadratic models, one for cold gas efficiency and the other for CO/CO2 ratio were developed. The developed models, using response surface methodology, showed a good fit with correlation coefficients of 99.32% and 99.66% for cold gas efficiency and CO/CO2 ratio respectively. The optimum operating conditions for the treatment were arc current = 188.15 A, plasma gas flow-rate = 31.54 L/min and treatment time = 1.89 min. The optimum responses obtained from the optimization of the reaction system were 52.59% and 1.80 for cold gas efficiency and CO/CO2 ratio respectively with the desirability of 1. Thermal plasma technique is, therefore, an alternative method for treating petroleum sludge.
Characterization of carbon nanotube growth region in flame using wire-based macro-imaging method
(Universiti Teknologi Malaysia, 2019) Hamzah, Norikhwan
Carbon nanotube (CNT) synthesis in flame has enormous potential as an energy-efficient and economical production method compared to the conventional catalytic chemical vapor deposition (CCVD) synthesis process. However, synthesis control remains a great challenge for flame synthesis due to the limited understanding on the effect of flame inlet condition toward CNT growth region in a heterogeneous flame environment and premature catalyst surface encapsulation by the amorphous carbon layer. The present study formulates a simple, yet accurate method called wirebased macro image analysis (WMA) for thorough growth region identification. The WMA method is employed to investigate the effects of reactant composition and aerodynamics on the spatial distribution of CNT growth region. Besides that, bend wire method is developed to provide cross-sectional analysis of the CNT growth region with focus on the amorphous carbon layer thickness (ACLT) at variable reactant concentration including fuel from 50% to 100% and oxygen from 19% to 27%, with addition of water vapor up to 0.14 mg/sec mass flow rate within the fuel stream. The CNT is synthesized on a 0.4 mm diameter pure nickel wire within the methane diffusion flame with a stainless-steel wire mesh placed on top and water vapor is introduced in a fuel stream using a bubbler mechanism. The CNT growth region is confined within the flame sheet, gradually shifts from flame front to flame centreline as height above the burner increases. The growth region is more sensitive towards the change in the oxygen concentration compared to that of the fuel concentration due to the significant change of flame height caused by the former. A segregation of growth region temperature with temperature difference of 100 ? that is observed between the upstream and downstream growth region is governed by the proximity with respect to the flame sheet. The ACLT reduces in lean flame due to the reduction in excess carbon concentration and the addition of water vapor remarkably reduces ACLT by 17% on average in any combination of inlet conditions due to the water-induced etching and oxidation of amorphous carbon on the catalyst surface. Development of the WMA and bend wire method leads to deeper fundamental understanding of CNT flame synthesis and further enhance possibility of highly efficient and economical CNT production process in the future.
Optimal design and scheduling of an integrated centralized and decentralized energy generation system
(Universiti Teknologi Malaysia, 2019) Liu, Wen Hui
Most electricity worldwide is supplied from the established centralized energy generation (CEG) system network which mainly operates using fossil fuels. An alternative decentralized energy generation (DEG) system has emerged with the advantage of generating electricity from locally available resources (usually renewable energy) for local consumption. DEG systems could avoid significant power losses during transmission in the CEG network and reduce the reliance on fossil fuels. These DEGs however, are geographically scattered and their resources are intermittent. One notable problem is that, at one point of time, some DEGs may have excess electricity and some may have electricity deficits; depending on the resource availability and the electricity consumption pattern. Weather-depending resources such as solar and wind energy could also affect the system’s reliability. The energy gaps between one DEG to another can be solved, provided that the DEGs are integrated at the distribution level whereas the reliability issue can be overcome by integrating multiple DEGs to the existing CEG (which has a more stable electricity supply) at the transmission level. To deploy this complex integrated energy system, key decision parameters such as selection of technologies and their capacities, interactions between different units, overall system efficiency and costing at their optimum level have to be determined. There are limited studies in the literature regarding the wide-scale integration of DEGs with CEG and a lack of comprehensive optimization approach to solve for the system’s design and scheduling. To fill these gaps, this research aimed to develop a novel targeting and optimization methodology for the design and scheduling of the DEG-CEG integrated energy system. A new numerical DEG-CEG integration framework was developed based on two enhanced Power Pinch approaches: (i) Extended Power Pinch Analysis for on-grid DEG system, and (ii) Extended Electrical Power System Cascade Analysis for CEG system with generation flexibility. The numerical framework optimized only the system’s energy efficiency. A mixed integer nonlinear programming (MINLP) model was then developed to study the DEG-CEG system more holistically in terms of energy efficiency and costing, as well as to validate the optimal solutions resulted from the numerical framework. Both approaches were demonstrated using a hypothetical case study – an integrated energy system with multiple DEGs (operating using solar, wind and biomass energy) at different locations connected to one CEG (operating using natural gas) to fulfil power demand from residential, commercial and industrial sectors. From energy-efficient aspect, the numerical framework resulted in the system operating at an efficiency of 77 %, while the MINLP model showed 80.7 %. The difference of 3.7 % confirms the relevance of the numerical DEG-CEG integration framework as a systematic and effective energy planning tool in solving the design and scheduling problems of a power system. In term of costing, the MINLP model revealed that the system can achieve 77 % with a total cost of RM 936 million/y. Nevertheless, the numerical method is still an important analytical tool as the analysis provides visual insights that can be easily understood and appreciated by users like energy engineers and policymakers.
Robust approach for capacity benefit margin computation with wind energy consideration for large multi-area power systems
(Universiti Teknologi Malaysia, 2019) Mohammed, Olatunji Obalowu
Capacity benefit margin (CBM) represents the tie-lines transfer capability margin for power interchange between interconnected areas. Accurate evaluation of CBM is essential for available transfer capability (ATC) determination. Most of the existing methods for CBM computation rely on complex optimization techniques. In these techniques, for every step increase in power transfer, to improve supply reliability of the deficient areas, the reliability must be recalculated and checked through optimization. Thus, for a large number of interconnected areas, these techniques might not scale well. Another shortcoming of these techniques is the simplifying assumption of only one deficient area with a fully connected network (i.e., all the areas have a direct connection or tie line with each other). In this thesis, a robust graph-theoretic approach is proposed to calculate CBM in a multi-area network with multiple deficient non-directly connected areas. Unlike the existing approaches, multiple deficient areas are considered and some of the areas are not fully connected. From literature, previous techniques only considered conventional generating units in the loss of load expectation (LOLE) computation. A strategy for the incorporation of wind power generating unit is proposed using Weibull probability distribution. This is important since the supply reliability of an area is measured using LOLE of the area and considering the random nature of wind generating systems which has a great effect on the supply reliability. In addition, LOLE which is commonly used as an index for the CBM computation is usually evaluated by using the area peak load demand and the available reserve capacity. The system peak demand usually occurs within a few weeks in a year; therefore, the period of off-peak demand is not efficiently accounted for in the LOLE evaluation. Hence, demand side management (DSM) resources; peak clipping and valley filling are employed to modify the chronological load model of the system which subsequently enhances the CBM quantification. Finally, the results of the CBM are incorporated in ATC computation to study the influence on the ATC evaluation. The proposed technique has been evaluated using IEEE RTS-96 test system because the system has all the required reliability data for LOLE computation. The technique can evaluate and allocate CBM among multi-area systems consisting of two deficient areas. The influence of renewable energy on LOLE has been efficiently evaluated and the DSM technique was efficiently employed to improve three-area test system generation reliability. The generation reliability of the interconnected areas has been improved by an average of 35%. This improvement is very significant in terms of the generation facilities and the financial implication that may be required to be put in place if the proposed DSM technique was not applied. The results and the performance evaluation showed that the proposed technique is simple and robust compared to the existing methods. The technique can also be used as a feasibility tool by utilities to verify the possibility of wheeling power to a deficient area using maximum flow algorithm
Unsteady hydrodynamic effects on the dynamic performance of low speed vertical axis current turbine
(Universiti Teknologi Malaysia, 2020) Meftah Soufaljen, Atef Salem
Malaysia’s rivers and ocean energy can be the best resource for green marine renewable energy. The generation of electricity by the burning of fossil fuels are expensive and produce undesirable greenhouse gases. Malaysia’s sea has average speed of 1 m/s, which is twice less than the minimum speed that can operate the conventional turbines. Low-Speed Vertical Axis Turbine (LS-VACT) as a drag device represents a promising technology to exploit marine currents. It can be applied to harness current energy in rivers, coastal area and ocean due to their relative simplicity with reduced installation and maintenance costs. The purpose of this research is to investigate performance of the turbine and the influence of added mass, damping and arm-length to its performance at low current velocities. To achieve that, numerical simulation was conducted using MATLAB program by utilizing the hydrodynamic coefficients and derivatives of the hydrodynamic forces and moments acting on the turbine buckets. The simulation program was validated through the experiments of the LS-VACT. This developed simulation program can be used as a fast and useful tool to achieve design improvements for this turbine at several speeds and various loads. This computer programming can match and integrate the full-scale turbine to a suitable generator with different powers and loads efficiently. The simulation results showed that the performance of LS-VACT agreed within 10% with the experiment results and having the same trend at various flow speeds. A parametric study was performed to analyse the effects of added mass and arm-length at several current speeds. LS-VACT has the highest power coefficient of 0.196 at 0.32 m/s. Also, the peak power (8.6W) and the maximum torque (19.4N.m) values were recorded at a flow velocity of 0.64 m/s. At low water flow speed of 0.17 m/s and 0.32 m/s, the added mass has a significant influence on the LS-VACT performance. At this condition, the inertia forces were dominant at low Keulegan-Carpenter number (K-C) of 3 to 9. The torque and the power magnitudes of the turbine decreased about 18 % and 52.7% respectively. At K-C number above 10, the boundary layer separated with formation of vortex shedding occur. The drag forces were found to be dominant in this situation. At the current speed of 0.32 m/s and arm-length of 0.27 m, the maximum torque of 10.11 N.m and corresponding power of 1.75 W was achieved. However, further increase of the arm-length results in decreasing torque and power. The dynamic performance of LS-VACT was carried out and it can facilitate improvements in its design at low current speed.
Simulation and experimental design of thermoacoustic heat engine
(Universiti Teknologi Malaysia, 2020) Abd. Rahim, Irfan
Renewable energy is an important field in providing reliable and sustainable energy to the world. Wasted heat is found to be a good source of renewable energy. This wasted energy can be found almost in all types of production processes, including the heat exchanger. The heat energy dissipated from these processes is unutilized leading to inefficiency in the system. The need to harvest the wasted heat is essential in making sure the energy can be further utilized for other applications. Previous research works conducted on harvesting heat into sound in the system is still lacking and there is no specific standard can be employed. This research focused on analysing and developing a reference method of harvesting sound from a thermoacoustic heat engine system. A simulation approach was employed to investigate the performance of heat flow on the heat exchanger and related components. A standard test rig was designed to evaluate the performance of heat transfer experimentally. A comprehensive laboratory work was set-up to collect ample data to obtain the correlation of acoustic sound pressure-volume due to heat transfer performance by the oscillatory flow on the thermoacoustic system. The design of the developed thermoacoustic engine was able to produce waste heat in the range between 200?C and 700?C, and the harvested sound frequency ranged from 20 Hz to 2 kHz. From the experimental study, the sound level started at 4 s to 8 s and reaches a steady-state at 10 s. The temperature gradient on stack performance was 8.45°C/mm with a temperature difference at the steady-state point of 300°C. The spectrum analysis amplitude reached 133.5 dB with the frequency value of 397.5 Hz. The pressurevolume analysis has proved the existence of both isochoric and isothermal process through the gas bucket brigade phenomenon as the lead compression and expansion happened at the stack wall between the sound pressures of 12.94 Pa and 20.15 Pa. The finding confirmed that the sound energy from the heat oscillation can be harvested and a standard method has been developed. This study also confirmed the presence of a thermoacoustic cycle on the stack wall. This finding is significant as it provides a new standard in harvesting sound from the thermoacoustic heat engine. The efficiency of the system was successfully improved by 40% and the wasted energy was successfully harvested for further applications.
Performance of gravitational water vortex energy system
(Universiti Teknologi Malaysia, 2020) Shabara, Hosam
An essential part of a mini-hydropower system is the conversion of low-head potential energy into kinetic energy to drive power turbines. One way of converting low-head potential energy is using a gravitational water vortex power plant (GWVPP). However, the eciency at this very low-head is still low. Therefore, this research focused on two fronts: (1) to optimize the vortex pool so as to increase the eciency of transfer of potential energy to kinetic energy by using the natural vortex and articially augmented vortex and, (2) to design a turbine to obtain maximum power from such low kinetic and potential energy. This work dealt with the optimization of the vortex pool to improve energy conversion and hence, generate electricity from a very low operating head of 0.2 m to 0.3 m. For this purpose, a numerical and experimental studies were carried out to investigate the vortex ow characteristics in a gravitational water vortex system in the absence and presence of a water turbine. The commercial Computational Fluid Dynamics (CFD) software ANSYS Fluent was used to investigate the optimum conguration of the vortex pool system. Moreover, an experimental test rig was set up to validate CFD results. The results of the validation demonstrated that ANSYS Fluent can model the system correctly. The Reynolds Stress model showed better results than K ?? " and K ?? ! models in predicting the vortex ow structure. A parametric study was carried out using the software to determine the main parameters aecting the eciency of energy conversion. Two dierent turbines were tested experimentally, revealing that the curved blade turbine was more ecient than the crooked blade turbine by 18%. Finally, six rectangular vanes were used to guide the ow for enhancing system eciency. Hence, a 50% increment in system eciency was recorded. The maximum eciency of the cylindrical pool system with six vanes was about 54%. This system has broad applications in low-head cases such as streams, small rivers, irrigation canals, wastewater, and rainwater harvesting systems. This system can provide rural and remote communities with an economical green source of energy.
Households energy consumption and carbon dioxide emissions of Mahabad City, Iran
(Universiti Teknologi Malaysia, 2020) Soltani, Mohammad
This study seeks to find a method to identify the dominant pattern of energy choice and consumption in households, centring on demographic factors affecting the use of home appliances. To this aim, this research dealt with a variety of energy sources that were widely used by households, namely LPG, electricity, and kerosene for cooking, heating and cooling, lighting, and home appliances. Additionally, significant associations for household energy choice and consumption were identified for demographic variables, including household size, gender, age of household head, educational level, and income group. A binary logistic regression was performed to obtain quantitative data provided by a survey from 821 households across residential districts of urban and rural areas in Mahabad Region, northwest of Iran. Collected data were analyzed within a proposed three-energy dimensions model (3-ED). The results showed that if the other variables remain constant, income may lead to variation in LPG and electricity consumption. Unlike other independent variables, the household-head age failed to have a significant impact. The findings can contribute to a better understanding of effective factors on household energy choice and consumption in other cities and be useful for the support of policymakers in their consumption patterns. This research explores the impact of different household demographic characteristics on energy-saving behaviours and carbon dioxide (CO2) emissions in Mahabad city located in the northwest of Iran. The structural model adopted was composed of six variables, including household age, household size, educational qualification, income quintile, gender, and energy conservation behaviour concerning demographic features, energy sources, and consumptions. To compare the predictability power of these variables' effects on households' energy conservation and CO2 emissions, a crisp instruction on how to evolve a statistical technique for analyzing data was provided by Partial Least Squares Structural Equation Modelling (PLS-SEM). It was revealed that households consume approximately 89.71% on liquefied petroleum gas (LPG), 9.87% on electricity, and the rest 0.43% on kerosene, petrol, and diesel on a monthly basis. Eventually, the results of this research showed that age, family size, and carbon dioxide emissions, except education background and income level, are significantly correlated with energy-saving behaviour.
Multi-omics and taxonomic analyses of empty fruit bunch adapted mangrove microbial communities with lignocellulolytic abilities
(Universiti Teknologi Malaysia, 2020) Lam, Ming Quan
Current demand for energy drives the rapid progress of second-generation biofuel development. Use of lignocellulosic biomass, such as oil palm empty fruit bunch (EFB) in second-generation biofuels production resolved the limitation of firstgeneration biofuels which compete with food source. Lignocellulosic pre-treatment and saccharification are two crucial steps in second-generation biofuel production. These steps require synergistic action of lignocellulolytic enzymes. The use of large volume of freshwater in biofuel industry is a major concern as it creates competition between biofuel industry and human consumption. Seawater, which cover 96.5% of the biosphere could be an alternative to freshwater in biological pre-treatment and saccharification of lignocellulosic biomass. Therefore, the discovery of novel salttolerant microorganisms and their halophilic enzymes is an important aspect of lignocellulosic waste deconstruction using seawater. In this study, halophilic microbial community was collected from mangrove soil at Tanjung Piai National Park, Johor. Their ability to degrade lignocellulose was explored using culture independent and culture dependent approaches. The mangrove soil was used as inoculum and incubated with EFB in artificial seawater medium for 10 weeks. Total DNA, RNA and proteins were extracted (culture independent). 16S rRNA and 18S rRNA gene fragments were amplified from total DNA and composition of microbial community was analyzed based on amplicon metagenome sequencing. Taxonomic analysis showed that phyla Proteobacteria and Bacteroidetes were predominant prokaryotic population. Metatranscriptomic analysis revealed a total of 9,953 open reading frames (ORFs) related to lignocellulose degradation: 3,867 glycosyl hydrolases (GHs), 2,485 carbohydrate binding modules (CBMs), 2,156 carbohydrate esterases (CEs), 947 auxiliary activities (AAs) and 498 polysaccharide lyases (PLs). The highly expressed enzyme families were GH74, CE1, GH5, AA2, GH43, CE3, GH3, CE15, GH10 and GH6. Metaproteomic analysis identified a total of 87 lignocellulolytic enzymes in bound fraction of EFB and culture supernatant. Synergistic action of different lignocellulolytic enzymes from diverse microbial origin was observed with mostly affiliated to phyla Proteobacteria and Bacteroidetes. In addition, bacteria from the mangrove microbial community were isolated and their lignocellulolytic abilities were assessed (culture dependent). Two halophilic bacteria from the phylum Bacteroidetes, namely Meridianimaribacter sp. CL38 and Robertkochia sp. CL23 were selected for genomic analyses. A total of 30 and 89 lignocellulolytic enzymes were encoded in the genomes of strain CL38 and CL23, respectively. Furthermore, both strains demonstrated their abilities to degrade EFB. Genomic analyses of these two strains are the first genomic information from their respective genera. Due to the low similarity of 16S rRNA gene with closely related member, strain CL23 was further taxonomically characterized via polyphasic approach. Based on phenotypic, chemotaxonomic and genomic evidences, the strain CL23 is proposed as a new species with the name Robertkochia solimangrovi sp. nov. Multi-omics and taxonomic analyses in this study identified new halophilic microorganisms from mangrove with a wide array of new lignocellulolytic enzymes that are able to degrade EFB. These enzymes could be further investigated for development of enzyme cocktails which will be useful for seawater based lignocellulosic biorefining.
Integrated framework for synthesising energy-efficient distillation column sequence
(Universiti Teknologi Malaysia, 2020) Zubir, Muhammad Afiq
This thesis presents and describes the development and application of an integrated framework for the synthesis of energy-efficient distillation column sequences. The framework is generic and applicable to various types of distillation columns. It is unique in the sense that it integrates distillation column sequencing, selection and design with the graphical representation of the driving force method. The existing driving force method was improved to include the effect of feed composition and also several concepts from existing methods, which can improve the capability of the method in finding optimal solutions that are feasible, economical, energy-efficient and material-efficient. The framework consists of five stages: 1) energy analysis of the existing sequence, 2) determination of the driving force sequence, 3) design of the driving force sequence, 4) feasibility, energy intensity and material intensity analyses and 5) economic analysis. In Stage 1, an existing distillation column sequence was simulated using the Aspen HYSYS process simulator to obtain its energy usage. In Stage 2, the graph of the improved driving force method was used to determine an energy-efficient distillation column sequence, which was also simulated to obtain energy usage. Then, by using a similar graph, suitable unit operations (flash columns, ordinary distillation columns, or extractive distillation columns) for the sequence were selected and designed in Stage 3. This post-design driving force sequence was also simulated for the same purpose as in Stage 1. The analyses began in Stage 4, where the feasibility, energy intensity and material intensity of the distillation column sequences obtained in Stages 1, 2 and 3 were compared. Feasibility was determined based on the reflux ratio range, distillation column height and product purity whilst energy and material intensities were based on mass, water and energy indexes. Finally, in Stage 5, an economic comparison based on capital, operation and total annual costs was employed. The framework was successfully tested on five different case studies with different objectives to test and verify the methodologies used in the framework. The application of the overall framework showed that energy savings of up to 32.94% could be achieved whilst operating within the feasible range. The energy and material intensities were also reduced by up to 59.31%, indicating lesser amount of energy and material used for the framework’s sequence. The capital and operation costs were also reduced, as much as 35.05% and 30.88%, respectively, which led to 31.71% lower total annual cost, compared with the sequences obtained by previous studies.
Policy enhancement framework for energy generation from palm oil mill effluent using life cycle multi criteria analysis
(Universiti Teknologi Malaysia, 2020) Siva Raman, Sharvini
One of the most challenging problems in palm oil industry in Malaysia is the management of palm oil mill effluent (POME). Majority of the palm oil mills treat POME using anaerobic ponding system, which is not environmentally friendly as large amount of generated greenhouse gases is not captured but released to the atmosphere. Therefore, it is crucial to ensure a sustainable practise of closed anaerobic digestion system in the palm oil industry. This study was mainly aimed to provide evidence-based policy enhancement for POME treatment to energy generation. For this, life cycle assessment (LCA) was carried out to assess environmental impacts and life cycle cost-benefit analysis to assess the economic aspects focusing on two commercially available POME treatment technologies which are covered lagoon bio-digester (CLB, representing 36 palm oil mills with covered lagoon system) and continuous stirred tank reactor (CSTR, representing majority of the 54 palm oil mills employing closed tank system). Based on the output of life cycle analysis and interviews with palm oil mill management, thirteen possible solutions for policy enhancement were suggested. Possible solutions were ranked by experts and weighting were assigned to the possible solutions by using analytical hierarchy process, which were then used for policy enhancement. In terms of LCA, the global warming potential and acidification potential for CSTR were -4.48 kg CO2 eq/kWh and -2.21 kg SO2 eq/kWh, respectively, while for CLB the values were -4.09 kg CO2 eq/kWh and -0.15 kg SO2 eq/kWh. Both technologies produced a negative result, which equates to a net environmental benefit. However, both systems had a negative impact in terms of eutrophication potential. The CSTR nevertheless achieved a better eutrophication potential result of 0.048 kg PO43-eq/kWh than the CLB with 0.054 kg PO43-eq/kWh. With respect to life cycle cost (LCC), CSTR has a higher LCC of RM 2.60 million/year compared to CLB with LCC value of RM 2.29 million/year. In terms of cost-benefit, CSTR has a higher net present value (NPV) of RM 2.21 million/year, higher return on investment (ROI) of 11.80% and shorter payback period (PP) of 8.5 years compared to the CLB system with NPV of RM 0.91 million/year, ROI of 7.79% and PP of 12.8 years. ‘Provide detailed environmental guidelines’ followed by ‘standardise technical guidelines for biogas installation’ and ‘cover open pond wall using lining’ were the top three possible solutions to be considered in order to improve the existing policy for the POME treatment for energy generation. Future researchers may wish to consider social aspects related to job creation, safety and health of workers besides environmental and economic aspects. As a whole, this study allows policy makers to understand the current situation faced by palm oil mill managers and the rankings of possible solutions, offering important inputs for consideration in policy development for the treatment of POME for energy generation.

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