Ocean Renewable Energy

The ocean one of the most perpetual sources of energy andhas already been exploited on a small scale. Sometechnologies are being developed to exploit the largepotential of this energy source. This paper will focus onocean energy as an alternative source in Malaysia. Thecurrent development of various devices to extract theocean energy will be reviewed. Although technologies arecurrently being developed in the areas of tidal power, wavepower, thermal energy gradient, current energy, winds andsalinity gradient, not all of these are suitable for Malaysiansea areas. This paper surveys the available Malaysianoceanographic data and identifies the potential sources of energy.

Harvesting the energy from ocean waves is one of the greatest attractions for energy engineers and scientists. Till date, plenty of methods have been adopted to harvest the energy from the ocean waves. However, due to technological and economical complexity, it is intricate to involve the majority of these energy harvesters in the real ocean environment. Effective utilization and sustainability of any wave energy harvester depend upon its adaptability in the irregular seasonal waves, situation capability in maximum energy extraction and finally fulfilling the economic barriers. In this paper, the front end energy conversions are reviewed in detail which is positioned in the first stage of the wave energy converter among other stages such as power take off (PTO) and electrical energy conversion. If the recent development of these front end energy conversion is well known then developing wave energy converter with economic and commercial viability is possible. The aim of this review is to provide information on front end energy conversion of a point absorber and emphasize the strategies and calamity to be considered in designing such kinds of devices to improve the energy harvesting competence. This will be useful to the engineers for speeding up the development of a matured point absorbing type wave energy converter. Keywords wave energy converter, point absorbers, power take off (PTO), front end energy conversion

Research in different types of ocean energy including wave energy, tidal energy, ocean thermal, ocean currents, salinity gradients and ocean biomass has led to promising technologies and in some cases commercial deployment. Ocean energy extractors can be integrated into coastal structures: one of the device is the oscillating water column (OWC), which has so far been used on shore and proposed for floating plants. Oscillating water column wave energy conversion devices consist of a partially submerged chamber open to incident wave. The ocean waves cause the water column inside the chamber to rise and fall, driving the air in and out of the chamber which in turn drives a turbo-generator. In this paper, an analytical model was proposed for an OWC wave energy converter and formulas were proposed for its output power and overall efficiency. The optimum values were found for both the power and efficiency.

Indonesia merupakan salah satu negara yang mempunyai alam berlimpah
dan berpotensi untuk dimanfaatkan menjadi energi listrik terbarukan. Ironisnya,
kondisi listrik di Indonesia sangat mengkhawatirkan, masih banyak masyarakat
yang belum tersuplai listrik terutama di daerah Indonesia bagian timur. Sebagaian
besar dari mereka hanya menggunakan listrik yang dihasilkan dari diesel. Pada
saat ini, energi terbarukan yang sedang dikembangkan dan telah direalisasikan di
Indonesia adalah, energi bertenaga air dan angin skala mikro. Energi listrik
bertenaga air atau mikrohidro, pertama kali dikembangkan oleh Iskandar dan Tri
Mumpuni tahun 1987, dan pada tahun 1997 telah menghasilkan listrik di daerah
Gunung Halimun, Sukabumi, Jawa Barat. Sedangkan akhir-akhir ini, energi listrik
bertenaga angin telah dikembangkan oleh Ricky Elson di Ciheras, Jawa Barat
pada tahun 2012, dan tahun 2014 telah melistriki Desa Kalihi, Sumba Timur,
NTT. PT Lentera Angin Nusantara adalah, salah satu perusahaan hasil karya
tangan anak bangsa Indonesia yang didirikan oleh Ricky Elson. Dengan
mengembangkan energi terbarukan dengan memanfaatkan alam. Adapun alam
yang sudah dimanfaatkan adalah, angin dan matahari. Sebagai mahasiswa Jurusan
Teknik Kelautan Institut Teknologi Sepuluh Nopember, melalui kerja praktek ini
akan mendesain bilah Horizontal Axis Wind Turbine (HAWT) dengan
membandingkan jenis Air Foil Clark-Y, Naca 4412, Naca 3612, Naca 4418, Naca
0012 dan Naca 0018. Adapun jenis bilah yang dirancang adalah, Blade Tapper
yaitu bilah yang dapat berputar dikecepatan angin tinggi. Desain bilah itulah yang
akan dikembangkan untuk pembangkit listrik tenaga angin laut, yang mana
kecepatan angina laut lebih tinggi dibandingkan angina yang ada di daratan.
Kata kunci: Air Foil, Energi, Lentera Angin Nusantara, Listrik, Wind Turbine

Electrical power is essential in commercial and social investments like lighting, heating, communications, computers, industrial equipment, transport etc. Therefore hydropower energy is one of the most suitable and efficient source of renewable energy which depends on more than century of experience for this issue. The power capacity and facility are two criteria required for the classification of hydropower plant. The first one consists of five technologies: dammed reservoir, run of river, pumped storage, in stream technology and new technology gravitational vortex. The other one is classified according to power scale is Large, Small, Micro and Pico Hydropower. This paper is focusing on micro hydropower especially gravitational vortex power which increases the sustainability and health of the water as a whole. It presents an overview from both flow and power points of view by discussing the free surface vortex (FSV) and the suitable turbine systems which are used in micro hydropower

Researchers have shown growing interest in the development of traditional Savonius turbine due to their numerous benefits such as structural simplicity, self-start ability, relatively low operating speed, bi-directional rotational ability and lower environmental impact. However, Savonius turbines exhibits lower efficiency as compared to other similar marine current turbines. This paper proposes a novel design concept for the Savonius turbine. In addition, this work investigates flow and pressure distribution around the buckets of novel rotor with a two-dimensional unsteady numerical model. The proposed marine current turbine with novel design is named as Reza Turbine. Numerical model employed the Dynamic Mesh Method (DMM) for modelling mesh movement around the blades of rotor for different position with respect to computational domain. Developed numerical model solves the unsteady Reynolds averaged Navier-Stokes equations by using SIMPLE algorithm. In addition, we conducted an experiment in a low speed wind tunnel to obtain important performance parameters namely torque, power and performance for the proposed turbine. A set of flow speed were used as inlet boundary condition for both numerical and experimental model. A comparison between numerical and experimental results shows that the SST k-u turbulence model gives satisfactory results for the developed novel turbine. The developed ReT is showed 52% improvement in efficiency as compared conventional Savonious turbine. Since the peak of power coefficient obtained was 0.321 for ReT, while 0.21 was reported for conventional Savonius turbine.

With the diminishing supply of fossil-based energy, new renewableenergy sources including marine tidal current are being explored.In vertical axis marine current turbine applications, Savonius-type rotorhas been shown as suitable for low current speeds normally associatedwith Malaysia seas. However, the efficiency of the rotor is low and assuch efforts are being made to optimise the rotor in variousmanners. This paper describes a validation procedure preparation for aparametric study to obtain an optimised Savonius turbine rotor. Theresearch work results have been validated by comparison with theexisting published experiment data. The study was based on conductingtwo and three dimensional analyses using Computational FluidDynamics (CFD) RANSE code. Some parametric analysis has beensuggested to obtain an optimal configuration for the turbine

Abstrak Energi merupakan kebutuhan pokok dan terpenting bagi setiap manusia yang tinggal di planet bumi. Kebutuhan energi yang semakin meningkat menyebabkan pasokan sumber energi di bumi semakin menipis. Hal tersebut dapat diketahui dari sumber utama energi di dunia yaitu, fosil yang semakin menipis setiap tahunnya. Sehingga, berbagai belahan dunia sedang berlomba-lomba untuk mengembangkan penerapan energi baru dan terbarukan sebagai pengganti energi fosil. Begitupun dengan negeri tercinta ini, Indonesia yang akhir-akhir ini telah mengeluarkan peraturam menteri (PERMEN) mengenai pengembangan energi baru dan terbarukan di Indonesia. Dari berbagai kasus energi baru dan terbarukan di Indonesia, yang membuat penulis tertarik adalah kasus energi air dan energi air laut. Hal tersebut melihat luas wilayah Indonesia sebagian besar adalah wilayah perairan, sehingga perlu dikaji lebih dalam potensi terbesar untuk pengembangan energi baru dan terbarukan di Indonesia, apakah bersumber dari aliran air di darat dalam hal ini adalah sungai, atau bersumber dari aliran air di laut. Sehingga, dibutuhkan metode pengambilan keputusan dalam penerapan energi air atau energi air laut di Indonesia. Game Theory merupakan salah satu metode pengambilan kepetusan yang dikembangkan oleh Emile Barel seorang ilmuan dari Prancis, metode tersebut bertujuan untuk menyelesaikan masalah. Dengan demikian, dengan menggunakan metode Game Theory diharapkan dapat terselesaikan permasalahan dalam pengembangan energi terbarukan di Indonesia yang akan fokus pada energi air atau energi air laut.

Renewable energy systems have much lower environmental impact than conventional energy technologies. Tidal energy is one of the most important forms of renewables which carry the electricity production capacity within its height differences and current flow. In this paper, a time-dependent mathematical model for electrical energy generation from a single-pool tidal system is developed. Using current model with available tidal data, the extracted energy from this system can be calculated. Model results have shown that such system has the capacity of producing 40.6 Megawatts electricity from tidal energy for a specific area.

Harvesting energy from the ocean waves has two significant advantages over other renewables: more attractive mean power density and integration into coastal structures. A commonly deployed device is the oscillating water column (OWC), which has so far been mounted on shore and proposed for floating plants. It is an inverted piston-in-cylinder which consists of an air chamber in contact with the sea so that the water column in the chamber oscillates with the waves and makes the air flow in and out of the chamber which turns a turbine. The objective of this study is to propose simple formulas for estimating the output power, efficiency and their maximum values of an inverted piston-in-cylinder converter based on the engine geometry and the most occurring sea state wavelength. Two mathematical models were developed for a floating inverted piston-in-cylinder wave engine based on the theoretical fluid dynamics and expressions were proposed for its output power and overall efficiency. The optimum values were found for both the power and efficiency. The relationship between two models is investigated and it is showed that however the second model is simpler than the first one but, it can be used when the wavelength is more than a specific value.

Due to the low current speeds associated with Malaysian tidal currents, Savonius turbine was
chosen as a device in extracting this energy. However, this turbine suffers from poor efficiency. The present paper describes some works carried out to improve the turbine. The effect of speeds on performance was found to be minimal while the use of deflectors improved flow into the rotor and contributes significantly to the coefficient of performance improvement. The use of ducts was also studied, indicating improved flow characteristics.

The Southeast Asian region (SEA) is surrounded by ocean space, from which there is a vast potential to harness energy. Wave, tidal energy, and ocean thermal energy conversion could be tapped, to provide alternative sources of clean and dependable energy in the region. This article contributes to the growing academic literature on ocean renewable energy (ORE) in SEA by improving understanding of the opportunities and challenges of ORE development in the region, beyond its technical aspects. It conducts a critical analysis of the socio-political aspects of ORE development at a regional scale, which have been less studied in the existing literature. Aside from providing a sustainable energy source, the development of the ORE sector could provide socioeconomic benefits to SEA countries through employment opportunities, inter-industry learning, inbound investments and improving economic resilience. However, these benefits can only be maximised if the costs of deployment, maintenance and ...

ABSTRACT: PhilSHORE tool is a web-based GIS (geographic information system) application which allows stakeholders, such as the government, academe and private institutions concerned with ocean renewable energy, to readily assess the potential and suitability of a particular location for ocean energy developments. This service provides data access to different site-suitability layers and device information. Also, it includes a raster calculation function, which can implement a weighted overlay analysis using the different site-suitability factors to create their own energy assessment map. The data available on the map were resource, site suitability and device layers. The resource layers contains power and velocity which was modelled using Delft3D and regional IHO tide stations. Device performance such as Availability and Capacity Factor and Potential Power, were derived from aforementioned resource layers. PhilSHORE tool was developed using different open-sourced libraries and frame...

With the rising concerns over fossil fuel, adverse environmental impacts and its diminishing supply, efforts are turned ontorenewable energy. One potential source for renewable energy is the ocean. The challenge is how to extract its vast supply of energy in the waves, current, thermal differences, salinity gradient and tides. This paper presents a survey of the potential of marine renewable energy (MRE) sources in Malaysia. Whilst most proponents of MRE tend to paint an exaggerated positiveview of MRE, this paper will give a more realistic look at its potential. Based on presently available data on the resources aswell as current state of the art of the technology, it will provide an honest assessment of MRE as a contributor to the nationalrenewable energy requirements. Among others, it will describe the limitations posed by many practical and technical hurdlesin harnessing the energy potential.

spring, and the spring constants are denoted by k u , k l , k w , and k s , respectively. The downward force on the piston in equilibrium is denoted by F 0 . The main features of the transmission line and load are presented in . Here, resistance, inductance, and capacitance of the cable are denoted by R c , L c , and C c , and the load resistance is denoted by R load .

Wave energy, tidal energy and thermal energy are the three main categories of the ocean energy. The stored thermal energy in the ocean acts as a heat source and can be used to run a thermodynamic cycle. The paper presented here investigates the potential temperature gradient in southern Caspian Sea during summertime in Iran. The variation of extracted net power, heat rejection rate and efficiency of an ocean thermal energy conversion power plant are analyzed with different possible turbine inlet temperature. The analysis is performed by two popular Rankine cycle working fluids (ammonia and R-134a) for a 15MW OTEC power plant where the turbine inlet temperature varies between 17℃ and 23℃. The results showed that for the same power generation at turbine, R-134a requires more working fluid mass flow rate but the rejected heat at condenser is essentially remains constant. It is also concluded that increasing inlet temperature for 6℃ will cause the efficiency to change by factor of 2.

With the rising concerns over fossil fuel, adverse environmental impacts and its diminishing supply, efforts are turned onto renewable energy. One potential source for renewable energy is the ocean. The challenge is how to extract its vast supply of energy in the waves, current, thermal differences, salinity gradient and tides. This paper presents a survey of the potential of marine renewable energy (MRE) sources in Malaysia. Whilst most proponents of MRE tend to paint an exaggerated positive view of MRE, this paper will give a more realistic look at its potential. Based on presently available data on the resources as well as current state of the art of the technology, it will provide an honest assessment of MRE as a contributor to the national renewable energy requirements. Among others, it will describe the limitations posed by many practical and technical hurdles in harnessing the energy potential.

The Southeast Asian region (SEA) is surrounded by ocean space, from which there is a vast potential to harness energy. Wave, tidal energy, and ocean thermal energy conversion could be tapped, to provide alternative sources of clean and dependable energy in the region. This article contributes to the growing academic literature on ocean renewable energy (ORE) in SEA by improving understanding of the opportunities and challenges of ORE development in the region, beyond its technical aspects. It conducts a critical analysis of the socio-political aspects of ORE development at a regional scale, which have been less studied in the existing literature. Aside from providing a sustainable energy source, the development of the ORE sector could provide socioeconomic benefits to SEA countries through employment opportunities, inter-industry learning, inbound investments and improving economic resilience. However, these benefits can only be maximised if the costs of deployment, maintenance and repair are reduced, the impact to the marine environment is taken into consideration and issues of public acceptance are addressed. Beyond a cost-benefit analysis, this study critically assesses the unintended risks and consequences of ORE technologies and activities in the region and recommends different policy strategies to mitigate them. It concludes that for the region to reap the benefits of ORE, a coordinated approach among different stakeholders (technology developers, policymakers, and end-users) is needed to minimise the risks and unintended consequences.

Electrical power is essential in commercial and social investments like lighting, heating, communications, computers, industrial equipment, transport etc. Therefore hydropower energy is one of the most suitable and efficient source of renewable energy which depends on more than century of experience for this issue. The power capacity and facility are two criteria required for the classification of hydropower plant. The first one consists of five technologies: dammed reservoir, run of river, pumped storage, in stream technology and new technology gravitational vortex. The other one is classified according to power scale is Large, Small, Micro and Pico Hydropower. This paper is focusing on micro hydropower especially gravitational vortex power which increases the sustainability and health of the water as a whole. It presents an overview from both flow and power points of view by discussing the free surface vortex (FSV) and the suitable turbine systems which are used in micro hydropower. 

The Philippines is an archipelagic country with hundreds of off-grid islands. Due to technical and financial barriers, connecting these islands to the national power grid may not be realized. Off-grid communities remain energy poor, lacking access to modern energy facilities and services. Their dependence on fossil fuels for their power supply has precipitated significant social and environmental issues. To improve the energy situation and energy access in off-grid areas, the government seeks private sector participation (PSP) to encourage private investments in power generation and electrification in offgrid areas. This is an opportunity for innovative ocean energy developers to come in and explore off-grid areas with tidal in stream energy (TISE) resources. It is estimated that a total of 6,272 MW of TISE could potentially be harnessed in off-grid areas without significant impact to flow (SIF) and to the environment. Twenty provinces are identified with TISE potential and 81 diesel power plants (DPPs), all of which are suitable for privatization with replacement of the DPP with TISE. When considering provinces with high TISE potential and high energy sales, Dinagat Islands, Palawan, and Northern Samar emerge as the top three candidates. Further assessing DPPs open for privatization in these provinces, Dinagat DPP, El Nido DPP, Cuyo DPP, Taytay DPP, and Culion DPP have the highest annual energy sales ranging from ~ 1.4-6.4 million USD. These findings will help innovative ocean energy technology development and deployment for off-grid areas in the Philippines.

This document presents the experimentally determined power generation efficiency for the drive-train and motor of a 20 kW experimental ocean current turbine. This efficiency assessment was performed using a custom designed dynamometer and covered much of the generator's expected operating range. These measurements are used with numerically modeled rotor performance to predict the overall efficiency of the ocean current turbine when converting kinetic energy flux to electric power.

Due to the low current speeds associated with Malaysian tidal currents, Savonius turbine was chosen as a device in extracting this energy. However, this turbine suffers from poor efficiency. The present paper describes some works carried out to improve the turbine. The effect of speeds on performance was found to be minimal while the use of deflectors improved flow into the rotor and contributes significantly to the coefficient of performance improvement. The use of ducts was also studied, indicating improved flow characteristics.

As the ocean energy industry approaches commercial readiness, there will be a greater focus on integration of ocean energy devices (OEDs) into the electrical power system network. Device developers will be required to provide dynamic models of their device for grid connection, and ensure their device operates within the limits laid out in the grid code. Project developers will need to assess the impact of different wavefarm configurations, ratings for the electrical equipment, power losses, and performance during a fault. Grid operators will require dynamic models to investigate the impact an OED will have on the grid and also for future grid planning studies. The SEAGRID dynamic modelling tool attempts to address each of these issues using its generic modelling approach. The SEAGRID model is capable of producing a scalable time domain power system dynamic model using empirical test data and component specifications, bypassing the need for a full hydrodynamic study of the device.

Due to the limited of fossil fuel and environmental concerns, development of renewable energy including ocean energy is becoming more important. This study on a specific type of vertical axis turbine, which is called Savonius, appropriate for shallow water and low current velocity applications. Considering the low efficiency of Savonius, this study to render some for enhancing the performance of Savonius utilization. Powerful computational fluid dynamic software was used to analyze and compare two types of turbines conventional turbine and helical turbine. The simulation results showed that the performance of helical Savonius rotor significantly higher than conventional ones. © IDOSI Publications, 2013.