MW Ocean Thermal Energy Conversion Research Articles

Economic Viability Analysis for an OTEC Power Plant at San Andrés Island

This paper presents the economic feasibility analysis of a 2 MW Ocean Thermal Energy Conversion (OTEC) power plant in the open cycle. The plant can supply 6.35% of the average annual consumption of the electricity demand located at San Andrés Island (Colombia). On the one hand, the work presents the selection of the place to locate an offshore facility considering the technical viability while, on the other hand, the economic viability analysis is performed. The latter considers two scenarios: one without desalinated water production and another one with desalinated water. In this way, it is intended to first determine its construction’s technical requirements to analyse its economic performance. This approach allows us to have a general idea of the implementation costs and the benefits obtained with this type of plant, for the particular case of San Andrés, an island in the Colombian Caribbean with sustained stress on electricity production and freshwater generation. The results obtained show that the technology is viable and that the investment can be recovered in an adequate time horizon.

Economic study on the construction of a 50 MW Ocean Thermal Energy Conversion (OTEC) facility in Banten Province, Indonesia

Electricity demand is increasing every year along with economic growth and population in Indonesia. Meanwhile, non-renewable fossil fuels are still the main source of electricity generation in Indonesia. Therefore, the development of an affordable and environ-mentally friendly renewable energy-based power plant is very necessary. Ocean thermal energy sources available in abundance and has great potential in meeting national energy needs. In this study, a design concept of the 50 MW Ocean Thermal Energy Conversion (OTEC) facility was developed for Banten Province. Capital costs and expenditures for OTEC facilities were identified based on location requirements. The cost analysis is then combined with the OTEC facility investment scheme to obtain the Levelized Cost of Energy (LCOE).

A study of OTEC application on deep-sea FPSOs

The limited petroleum resources available for mankind have led to the exploration and development of oil fields in the offshore deep-sea regions, especially in light of the rising oil prices. Different studies and projects on the ocean thermal energy conversion (OTEC) technology, which operates the power generation facilities using the temperature difference between the deep-sea water and the sea surface water, are currently being undertaken. In this study, various methods of applying the OTEC technology to a floating production storage and offloading (FPSO) facility installed in a deep-sea area were simulated and analyzed. In the closed cycle, a 1595.5 kW net power generation capacity was obtained. In the open cycle, a 863.5 kW generating capacity and 54.4 m3/h fresh water were obtained. In the hybrid cycle, a 643 kW generating capacity and 55.1 m3/h fresh water were obtained. In addition, the cooling water of the heating, ventilation, and air-conditioning systems (HVACs) obtained using deep-sea water cooling was also investigated. Ultimately, a 100 MW OTEC power plant was designed, and the required seawater amount and operating fluid capacity were confirmed. Considering the similarity of OTEC power generation facilities and FPSOs, the conversion of an FPSO in the deep-sea region to an OTEC power generation facility after the end of the life of the FPSO was proposed. It will be an alternative way of addressing two important issues: the need for petroleum resource development considering the limited petroleum resources that are currently available, and the need to ensure the sustainable development of countries.

Increasing efficiency of a 33 MW OTEC in Indonesia using flat-plate solar collector for the seawater heater

This paper presents a design concept of Ocean Thermal Energy Conversion (OTEC) plant built in Mamuju, West Sulawesi, with 33 MWe and 7.1% of the power capacity and efficiency, respectively. The generated electrical power and the efficiency of OTEC plant are enhanced by a simulation of a number of derived formulas. Enhancement of efficiency is performed by increasing the temperature of the warm seawater toward the evaporator from 26˚C up to 33.5˚C using a flat-plate solar collector. The simulation results show that by increasing these a water temperature up to 33.5˚C, the generated power will increase up to 144.155 MWe with the OTEC efficiency up to 9.54%, respectively. The required area of flat-plate solar collector to achieve the results is around 6.023 x 106 m2.

Conceptual design of a 5 MW OTEC power plant in the Oman Sea

ABSTRACTDeveloping ocean energy extraction, including ocean thermal energy conversion (OTEC), has been of interest to researchers for many decades. OTEC is a free fuel technology and could be used as a baseline power generation. These advantages plus the engineering challenge have resulted in researchers striving to design and construct prototype devices. Making use of worldwide experience, all sections of a conceptual design including site selection, technical specifications and cost estimation were carried out for an Iranian OTEC power plant. A 5 MW closed cycle floating plant with an annual average temperature difference of 22°C was chosen at a 33 km distance from Chabahar harbour. Deep seawater would be extracted from 1000 m depth and would result in 3.52 MW of net power. According to cost calculations, the levelised cost of electricity of the plant has been estimated to be approximately 0.117 $/kWh, which is an acceptable level compared to other renewables. The conceptual OTEC design presented in this paper demonstrates a thermal potential in the Oman Sea which could assist with meeting the power demand for the southern coast of Iran.

Thermodynamic analysis and optimization of a 10 MW OTEC Rankine cycle in Reunion Island with the equivalent Gibbs system method and generic optimization program GenOpt

The ocean thermal energy conversion (OTEC) process uses the difference in temperature between the warm seawater on the ocean surface and the deep cold seawater to operate a Rankine cycle system for producing electrical power without consuming fossil fuel. This thermodynamic cycle uses a very low temperature gradient that limits its efficiency at 3–5%. Consequently every consumptions and losses of the system have to be optimized to increase the cost-effectiveness of this technology. This paper presents a thermodynamic analysis of a closed OTEC Rankine cycle. The model used in this paper is based on the work of Martins, using the concept of equivalent Gibbs systems. In an equivalent system, mass, energy and entropy are linked through the Gibbs equation, and the entropy production can easily be expressed in terms of fluxes and their related forces. Assuming linear phenomenological laws, the phenomenological coefficients are assessed from technical data. This method permits the study or design of a lot of process engineering. Moreover, a reliable analysis of the second principle can be realized, in order to compare several processes. This method will be used to analyze the cycle, to determine which components need to be optimized. Based on these results, sensitivity analysis are made on these components and the generic optimization program GenOpt is used to determine the optimized parameters of a 10MW OTEC plant that could be installed on Reunion Island.

Application on Solar, Wind and Hydrogen Energy - A Feasibility Review for an Optimised Hybrid Renewable Energy System

Present status of development of the energy systems, like solar, wind and of Hydrogen use as renewable energy sources, have been examined in ascertaining the scope of their application from techno-economic viability. Efficiency rating of different generations of PV cells with cost component and scope of their use, including practical application and economic fall outs thereby, were also spelt out from case study. Cost of PV module being shown to be the main contributor, deciding the economy of PV – based power generation scheme, the methodology of determining its total requirement could also be shown. Economy evaluation of solar PV and solar heating (solar cooker, solar pond, etc.) were also assessed stating their merits and demerits. Different aspects on evaluation of economy for off-shore and on-shore wind energy for developing a wind farm at a particular site were assessed. The scope of availing the wind energy value /sq. m. at a concerned site for a particular wind speed (measuring it at anemometer height and converting to its value at the hub height), could also be ascertained. Necessary study on the economy of hydrogen production by splitting water (electrolysis) was made and was noted that the OTEC (ocean thermal energy conversion system) generated electricity would be the best cost-effective method, mainly because of its prospect of earning huge royalty from its different by-products. On examination of H2-fuel cell combine as transport fuel, it could be shown that a single 100 MW OTEC can cater to 30 hydrogen refuelling stations, each with 250 vehicle movement/day. Feasibility study on optimised hybridization of the combination of PV-wind and H2, for uninterrupted power supply with methodology on resource assessment at concerned sites, particularly for PV and wind energy with economic fall outs, could be ascertained. Grey areas of research in exploring acoustic energy is also discussed.

Ocean thermal energy resources in Colombia

Colombia's exclusive location surrounded by the warm tropical waters of the Caribbean Sea and the eastern equatorial Pacific Ocean make it a suitable region for ocean thermal energy conversion (OTEC). These are systems that can produce significant amounts of renewable electricity. From the assessment of the temperature gradient and the bathymetric, environmental and socio-economical characteristics, the maritime area around the island of San Andres (in the northwestern Caribbean Sea) was found to be ideal for an OTEC facility since sea surface temperature varies only slightly during annual and interannual timescales. The thermal difference encountered from the surface to a depth of 1000 m is always around 22°–24 °C and cold waters are available for intake at around 450–750 m, within a short horizontal distance from the coast (less than 2.5 km). At these depths, the 20 °C thermal gradient required for OTEC operations is achieved. Furthermore, winds, waves and surface currents around the island are of relatively weak intensity. Presently, energy sources based entirely on Diesel generators are inducing negative impacts on the sustainable development of the region and on the fragile marine ecosystem. An environmentally friendly 10 MW OTEC facility could be part of future energy and water management solutions for the island. It would cover nearly 50% of total electricity demands and provide important additional advantages such as chilled soil agriculture, aquaculture, freshwater, mariculture and seawater air conditioning.

The Indian 1 MW Demonstration OTEC Plant and the Pre-Commissioning Tests

Ocean Thermal Energy Conversion (OTEC) utilizes the thermal gradient available in the ocean to operate a heat engine to produce work output. Even though the concept is simple and old for almost one century, recently it has gained momentum due to worldwide search for clean continuous energy sources to replace the fossil fuels. There are technological hurdles to overcome to tap the immense potential of OTEC. But still the technology is mature enough to establish commercial power plants. National Institute of Ocean Technology was involved in the design, development and demonstration of a 1 MW OTEC floating plant-the largest of its kind-in the Indian waters. This is to be commissioned 60 km south east of Tuticorin, South India where an ocean depth of 1200m available. The site surveys, computer analysis, model studies were done in 1999. The basic power cycle design Was completed within 4 months. The plant was integrated and stage qualification tests were carried out in 2000-02. The project is to be commissioned in January 2003. This paper is projecting the technological and economical aspects of the OTEC with an overview of the various pre-commissioning activities of the project.

Ocean thermal energy conversion (OTEC) system as a countermeasure for CO 2 problem. Energy balance and CO 2 reduction potential

We evaluated the energy balance of an ocean thermal energy conversion (OTEC) system that is one of the substitute energy sources. It was found that a 100 MW OTEC system reduces the amount of CO 2 emission by 140,000 t-C/year, as compared with a 100 MW coal fired power plant. Its energy pay back time was calculated to be 0.46 year. In addition, the synergistic CO 2 uptake effect by the compulsory circulation of the ocean was calculated to be 7,800 t-C/year for a 100 MW OTEC system on the basis of the difference between the present and pre-industrial CO 2 concentrations in the atmosphere.