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- ItemOptimal planning of hybrid power generation system towards low carbon development(Universiti Teknologi Malaysia, 2014) Ab. Muis, ZarinaIn 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
- ItemOptimal planning for landfill gas utilisation as a renewable energy source for environmental sustainability(Universiti Teknologi Malaysia, 2015) Ahmed, Saeed IsaThe 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
- ItemKinetic studies and mathematical modelling of imperata cylindrica flash pyrolysis(Universiti Teknologi Malaysia, 2017) Oladokun, Olagoke AbimbolaBiomass 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
- ItemNew power pinch analysis techniques for optimal design of hybrid power systems(Universiti Teknologi Malaysia, 2014) Mohammad Rozali, Nor ErnizaThe 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
- ItemDesign and operation of renewable energy based distributed energy generation system(Universiti Teknologi Malaysia, 2014) Ho, Wai ShinConcerns 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