Ocean Thermal Energy Conversion (OTEC) is a promising renewable energy resource from the ocean near equator that had been neglected for decades due to its enormous capital cost. The technologies that are developed for oil and gas industry for deep water applications could be adopted into OTEC power plant and the capital cost could be reduced by fifty percent than the estimation using conventional OTEC technology. This paper addresses a new OTEC technology for the OTEC power plant. Design and workability of the individual components of the new OTEC engine is shown. The global architecture of the power plant is illustrated. The engineering analyses studied show that the new OTEC power plant is feasible to construct and the cost analysis studied shows that the new OTEC power plant is viable for applications.

Ocean Thermal Energy Conversion (OTEC) is a promising renewable energy resource from the ocean near equator that had been neglected for decades due to its enormous capital cost. The technologies that are developed for oil and gas industry for deep water applications could be adopted into OTEC power plant and the capital cost could be reduced by fifty percent than the estimation using conventional OTEC technology. This paper addresses a new OTEC technology for the OTEC power plant. Design and workability of the individual components of the new OTEC engine is shown. The global architecture of the power plant is illustrated. The engineering analyses studied show that the new OTEC power plant is feasible to construct and the cost analysis studied shows that the new OTEC power plant is viable for applications. Introduction Clean renewable energy is a necessity of today that more and more people are aware of. Countries all over the world support this effort, considering that there is no carbon dioxide emission and no environmental impact. Ocean Thermal Energy Conversion (OTEC), as one of the renewable energy source, is very attractive because no fossil fuel needed and is available with unlimited large quantity. USA is now spending several billion dollars for various renewable energy source projects. The operating cost of most of the renewable energy is very low but the capital cost is enormous. Because of the environmental nature, OTEC is very stable and reliable energy resource for tropical islands like Hawaii. The main challenge is to make the OTEC electric power generation cost-effective and comparable to the nuclear energy source. OTEC OTEC is a method for generating electricity utilizing the source of stored solar energy available in the ocean near the equator, where the surface water temperature is about 25 degree C or more due to heat from sunlight and at 3000 ft depth the water temperature is about 4 degree C. A thermodynamic heat transfer method is used to convert the thermal energy to run the gas turbine. Ammonia gas is used as working fluid for the OTEC engine. Heat transfer is the major engineering task to be involved on the success of any efficient OTEC power plant. Conventional OTEC does the heat transfer effort on the top of the platform deck. The amount of water needed to cool the working fluid, ammonia, is enormous. There is a cold water pipe in the conventional OTEC that is used to bring the cold water from 3000 ft down to the free surface. Similarly the gas heating process, where the surface warm water is used in the evaporator, faces the similar problem. Enormous amount of heavy equipment for handling large volumes of water on the surface of floating vessel has increased the vessel size and consequently the capital cost was very high in the conventional OTEC. This technology is addressed in Reference 1. New OTEC This paper addresses an OTEC engine that uses new technologies like sub-sea condenser, sub-sea pump, submerged evaporator and independent floating-pipe buoy platform to transport working fluid from turbine outlet to the subsea condenser. Oil and gas field has offered innovative and cost effective solutions for deepwater applications. The technologies developed for deepwater are well proven and are working in water depth over 6,000 ft. OTEC water depth is only 1,500 ft, which is much smaller than the depth capabilities of today oil and gas field operations. The new OTEC design uses subsea solutions for the heat conduction problem. The condenser is located subsea area where the enormous cold water is available without the need of storage. The condenser is directly exposed to the underwater environment with 4 degree C. The condenser is designed for 1,500 psi water depth pressure for its structural strength integrity. Subsea condenser is tested for flow simulation and heat conduction problem for workability by using modern ANSYS Computational Flow Dynamic (CFD) engineering software. The equipments and the piping are tested for 1,500 psi water pressure to work at 3,000 ft depth.

The purpose of this paper is to introduce various offshore platform concepts that can be employed in ice infested waters, particularly shallow waters, depths varying from 65 ft to 500 ft. The paper illustrates five innovative platform concepts that for arctic drilling. The proposed platform concepts would have ability to withstand extreme ice, wind, wave and temperature conditions to extend the drilling seasons either near to winter sever storm or for round the year operation. The platforms are designed to operate in different water depths in different part of the arctic by accommodating the drilling structures and equipment on the deck. The emphasis is on the efficient of breaking, moving ice sheets around the structure and withholding the topside loads. Some of the platform concepts are fixed and others are developed from the floating solution and the technical details are presented in this paper.

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The deep water development in the Gulf of Mexico (GOM) harsh environment could potentially reduce the capital cost with the self-contained drilling unit on the production floater. This paper studies the technical feasibility of a complete drilling package; an independent pipe deck combined drilling support structure on top of the ultra deepwater production floater. A dry-tree support semi-submersible is used for this study for water depths from 7000 to 9000 ft. The objective of the paper is to reduce the drilling costs with the use of an onboard platform rigs over dry trees. In this design, a 2.5 million hook load drilling rig in association with the drilling support modules on a box-on-box concept structure type is considered.The substructure skids are over the strong back in the transverse direction and the strong back skids are over the platform capping beam in the longitudinal direction. The substructure contains a trip tank and an independent mud separate system. The larger mud process system and the power units are isolated from the substructure that allows the substructure to be lighter and easy to move both longitudinal and transverse to cover the matrix of the well pattern. A bridge type structure communicates between the drill floor and the drilling support structure by transporting the pipe to and fro from the pipe deck to the drill floor. The bridge is also used to make up and break up the pipes in addition to the pipe-conveyer work. The substructure is designed as a box-on-box type thus easing the fabrication, transportation and rig-up. This paper conceptually engineers the drilling structure with the selection of major equipment accordingly, to meet the proposed platform requirement for the dry-tree support semi-submersible with production unit.The merits are the reduction in the overall drilling, operating and well enhancement cost. Additionally, the advantages are early production with accelerated production revenues leading to a reduction in the overall development capital requirement. Also the ease of well intervention field requirements to enhance the well performance is feasible. This paper also defines and illustrates a suitable dry tree vessel for ultra deepwater harsh environment to make the GOM ultra deepwater development reliable, feasible and cost effective.