Elsevier

Renewable Energy

Volume 51, March 2013, Pages 36-45
Renewable Energy

Optimal green energy management for island resorts in Malaysia

https://doi.org/10.1016/j.renene.2012.08.056Get rights and content

Abstract

This paper proposes optimum green energy systems for electricity generation of island resorts in Malaysia. A combination of solar energy and wind energy as intermittent renewable energy sources with a fuel cell (FC) system and a battery storage energy system as a backup to the green energy system is introduced for this study. This system is eco-friendly, economical over the long-term, highly sustainable and reliable. In addition, a diesel-based energy system as a non-green system is compared with the proposed green system. National Renewable Energy Laboratory's (NREL) HOMER software is used to determine and compare the optimal configuration green energy system with the diesel-based energy system in terms of net present cost, sensitivity analysis and pollutant gas emission. The feasibility and assessment of the proposed system is evaluated by utilizing the load profile and considering the geographical condition of a village (Juara village in Tioman Island) with approximately 30 chalets located in southern Malaysia. HOMER uses two types of load profiles for each given year. The first load profile is used during the presence of tourists, and the second profile is used when the locals are the main inhabitants of the island. The optimization management for the green energy system is performed through unit sizing to find the optimum power management analysis and to perform cost analysis of the system.

The potential of renewable energy as well as a diesel-based energy system to meet the power demand for such a stand-alone system is considered. Technically feasible and economically viable green energy systems as prospective plans are explored in this study.

Highlights

► This configuration is a novel idea and practical for island resorts in Malaysia. ► Optimal configuration for green energy generation system can be used by less price. ► Less worry about reliability, disconnecting, reconnecting and distortion of system. ► Less worry about environmental problems and shortage of fossil fuel.

Introduction

Energy consumption is a main factor in defining development of any society and has been identified as a major input parameter for national economic development. Global primary energy demand was only 7228 million tons of oil equivalent in 1980, whereas the demand was approximately double this amount in 2005 [1]. After the first decade of the 21st century, energy demands are still met by huge amounts of fossil fuels such as coal, oil and natural gas. According to [2], [3], the reserve of coal, oil and natural gas will be consumed in approximately 60 years given to current rate of energy consumption. Future scarcity, air pollution, fresh water pollution, coastal pollution, deforestation, biodiversity loss and global climate deterioration from gases (mainly CO2) produced by burning fossil fuels around the world are all negative aspects fossil fuels consumption. In addition to these concerns, the current increase in global fuel price encourages nations to find other resources for supplying energy. All of these drawbacks, as has been indicated previously, can be overcome by an economically feasible autonomous system operating with non- or less-polluting sustainable energy. The selection of sustainable energy must be in accordance with climate conditions [4]. Energy experts expect that in the year 2050, over 50% of all electricity could be generated by renewable energy such as sunlight, wind, rain, tides and geothermal heat.

The power generation capacity in Malaysia is 19,023 MW, with a maximum demand of 13,340 MW [5]. The energy sources are 62.6% gas, 20.9% coal, 9.5% hydro-power and 7% other forms of fuel [6]. According to the macroeconomic indicators obtained from official publications of the Malaysian government, primary energy consumption is expected to grow on average 4.3% annually from 2004 to 2030. In 2030, the total primary energy consumption is expected to be 3 times that of 2004 [7]. On the Malaysian islands, many areas lack electricity supply. While some of these regions have access to electricity supplied by local diesel generators, most of the remaining residents lack electricity resources. However, a state-of-art energy solution based on renewable resources could guarantee the provision of reliable, secure, optimal cost energy and green energy supplies throughout the developing island regions with no access to electricity. In pursue it of this goal, the Malaysian government has enacted a renewable energy policy that seeks to increase the development of renewable energy. This goal of this policy has been expanded to supplying electricity by a small renewable energy program that supports the connections of small renewable resources to the island grid. In pursuit of this policy, the State Government and TNB-Energy Services Bhd in 2007 implemented the project of installing a hybrid renewable energy system at the Perhentian Island, Malaysia [8].

In total, over 200 km2 the islands are connected to the national power grid of Malaysia. While Malaysia has over 3500 km2 islands, the majority of them are located on the east and south east of Malaysia. The Malaysian islands, known as “Green Islands”, have a good potential to generate renewable energy. The high average annual rainfall of the Malaysian islands encourages experts to install hydro-power station on these islands; in addition, geothermal energy is another possible renewable energy source. The majority of the developments on the islands have been dedicated to vacation resort facilities. The local population, mostly villagers and fishermen, often rely on their own diesel generators for energy. For example, the inhabitants of Pulau Perhentian (the smallest island in Malaysia) rely on the 200 kW diesel generators. Southeast Asian countries have abundant sunlight, which, along with lengthy duration days and a small angle of daylight deflection, is favorable to the development of solar energy. The Malaysian Metrological Department [9] reported that the solar radiation for the more remote area is estimated to be in the range of 4.8–6.1 kWh/m2/day. Thus, for every resort building with 5 square meters of useful roof extent, 24–30.5 kW/day can be generated. Another green power technology that has only a minor impact on the resort islands of Malaysia is wind energy, a power source that produces no air pollutant or greenhouse gases. The northeast monsoon, which is from September to March, benefits wind technology in this region where the strongest wind comes from the South China Sea and blows the East Coast of Malaysia. The wind speed in Malaysia is light and varies from season to season in the range of 2 m/s to 13 m/s. In 2005, a 150 kW wind turbine generator was used to supply electricity to the villagers on Terumbu Layang.

Green energy systems can be defined as the utilization of renewable energy resources such as solar energy, wind energy, biomass, and geothermal energy. A green energy system is resource-efficient and utilizes an integrated approach to design and operation [10]. The role of a planned green energy system for resort islands is not only to achieve real, long-term reductions in carbon dioxide and other emissions for the islands but also to promote highly sustainable and reliable electrical power. In addition to these benefits, the use of green energy systems will make the island's villagers and tourists less affected by the increase in fuel price while traveling, dwelling and working. It should be taken into account that the selected green energy system for this study is the combination of a photovoltaic (PV) system and wind turbines as main renewable resources and batteries and fuel cells as backup systems.

As the energy demand of many Malaysian resort islands for tourism and local living are similar. Juara village in Tioman Island, which is located in the East coast of Peninsular Malaysia (+2° 47′ 32.74″N, +104° 12′ 9.89″E), has been chosen for this study. It is estimated that 30 well-maintained, comfortably furnished chalets exist for both local inhabitants and visitors. It should be noted that most chalets are less often rented from November until February due to the weather conditions, which bring strong winds and rough seas. However, Juara's inhabitants stay in the village during this period. The highest mountain in Tioman is located in this region [11]. Fig. 1 shows the location of Juara village in Tioman Island.

To meet the renewable energy system analysis and optimization needs, we use HOMER, a computer model that simplifies the task of evaluating design options for both off-grid and grid-connected power systems for remote, stand-alone and distributed generation (DG) applications. HOMER's optimization and sensitivity analysis algorithms allow the user to evaluate the economic and technical feasibility of a large number of technology options and to account for uncertainties in technology costs, energy resource availability, and other variables [12].

The remaining part of this paper is structured as follows. Section 2 provides all the data needed to assess and analyze hybrid renewable-based and diesel-based systems. In Section 3, the design specification for each of the components is provided to meet the selected AC load demand. In Section 4, the optimization management for the hybrid renewable system is performed through unit sizing with power management analysis and a cost analysis of the system. Because this study is focused on green energy system, the optimization management for diesel-based systems is not discussed here. A complete description of this aim is described in [13]. In Section 5, the results are discussed and two types of systems, the green energy system and diesel-based system, are proposed. Finally, the sensitivity analysis for diesel price and pollutant gas emission for the diesel-based energy system are discussed in Sections 6 Sensitivity analysis for diesel price, 7 Pollutant gas emission, respectively.

Section snippets

Data collection

All of the data used to assess and analyze the hybrid renewable-based and diesel-based energy systems are collected as follows.

Design specification

The analysis has been performed for two separate renewable-based and diesel-based systems. The renewable-based system, which is called the “green” system, is a hybrid PV/wind/FC energy system. Wind and solar energy are irregular phenomena that require an energy storage device or some other generation source to form a hybrid system. In a hybrid energy system, photovoltaic arrays, wind turbines, and fuel cells are used as energy resources and an FC-electrolyzer system is used as a backup and

Optimization system management for renewable systems

The optimization management for the hybrid renewable system is performed through unit sizing with power management analysis and cost analysis. In the hybrid renewable system, the wind and PV power are introduced as the primary source reserve to guard against random decreases in the renewable power supply. The combination of FC and electrolyzer is used as a backup system. The battery bank will support transient power to load transient, ripples, and spikes. Unit sizing is used to minimize the

Results and discussion

Two models are simulated by HOMER. The first model is a green energy system with PV/wind/FC sources, and the second is a diesel-based energy system, powered by 2 diesel generators. The purpose of the simulation is to evaluate and compare two models in terms of efficiency and capital cost and to predict future fuel price. The results are for a 25-year period of projection and a 6% real annual interest rate in Juara village, considering Tioman Island's weather, diesel price and transportation

Sensitivity analysis for diesel price

To show the consequence of increasing diesel price, a sensitivity analysis has been perfumed. As previously discussed, the current diesel price is $1.50 (which is equal to RM 4.65) for Juara. Table 6 shows the sensitivity analysis for diesel prices ranging from $1.30/L to $2.20/L. The total NPC increases with the growth of diesel price at $2.20/L with an NPC of $2,608,481, the diesel-based system becomes more expensive than the green energy system, which has an NPC of $2,554,228. Thus green

Pollutant gas emission

Although the diesel-based energy system is currently more economical than the green energy system, the environmental aspects of the energy source should be considered because the use of diesel generally causes air pollution. As shown in Table 7, for the diesel base system, the total emissions of pollutants are 213,938 kg/year while the green energy system creates no emissions.

Conclusion

The future economic development trajectory for fossil fuels in the world is likely to result in an increasing diesel price. Due to the predominance of diesel generators in the energy mix, there are negative environmental aspects for resort islands in Malaysia. In this paper, simulation and optimization of the green energy management for an island resort in Malaysia has been performed using the HOMER software. From the HOMER software simulation, it has been proven that the green system with

Acknowledgments

The authors would like to thank Universiti Teknologi Malaysia for the support and the funds provided to the research team. This project is supported by Universiti Teknologi Malaysia (UTM) and the Ministry of Higher Education (MOHE), Malaysia under FRGS vote No. 78589.

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