OTEC

Utilizing temperature gradients in deep oceans to generate electricity.

Ocean Thermal Energy Conversion

 

While solar energy warms the surface of the ocean, the deeper reaches of the ocean remain cool, protected by the upper layers of water. Due to this, ocean temperatures can vary as much as 20 to 25 °C between layers (the greatest differences are seen in the tropics). These temperature differentials can be used to drive a system of moving fluid that creates electricity, with three different designs:

 

  • Closed-cycle: A fluid with a low-boiling point such as ammonia is used to circulate through a closed system. Warm surface seawater is pumped through a heat exchanger where the ammonia is vaporized. As the ammonia vapor expands it passes through and turns a turbine generating electricity. Cold deep seawater is pumped through a second heat exchanger where the ammonia vapor condenses back into a liquid to be recycled through the system and the cycle is repeated.
  • Open-cycle: Warm surface seawater is placed in a low-pressure container that causes the water to boil, turning a turbine as the steam expands. The steam is then exposed to cold deep seawater where it condenses into almost pure fresh water (the salt gets left behind in the low-pressure container).
  • Hybrid: Warm surface seawater enters a vacuum chamber where it is flash-evaporated into steam. The steam is used to vaporize a low-boiling point fluid, such as ammonia, that then turns a turbine to produce electricity. Similar to an open-cycle system, fresh water is also created during this process.

 

A major environmental concern arises as cool, nutrient rich water is withdrawn from the deep ocean and discharged higher in the water column. The effects of this cooler water and transport of nutrients on the ecosystem could vary, but may affect the nearfield environment through temperature changes or increased biological growth. Screens will cover the intake tubes, but there is still a chance that marine organisms could be fatally pinned against the screen. In order to maintain the efficiency of the heat exchangers, the warm water will need to be treated with chlorine, which could affect the nearfield habitat. As with all electricity generation, there is a slight concern that electromagnetic fields generated by power cables and moving parts may affect animals that use Earth's natural magnetic field for orientation, navigation, and hunting.

Total Results: 40
Title Author Datesort ascending Type of Content Technology Type Stressor Receptor
Progress in Renewable Energies Offshore Soares, C. October 2016 Book Marine Energy general, OTEC, Tidal, Wave, Wind Energy general, Offshore Wind Socio-economics, Life Cycle Assessment
Reviews of Power Supply and Environmental Energy Conversions for Artificial Upwelling Zhang, D., et al. April 2016 Journal Article Marine Energy general, OTEC, Wave Nearfield Habitat
Environmental Impact Assessment for an OTEC Plant in Martinique Island Auvray, C., et al. April 2015 Journal Article Marine Energy general, OTEC
An Economic and Environmental Assessment of Transporting Bulk Energy from a Grazing Ocean Thermal Energy Conversion Facility Gilmore, E., Blohm, A., Sinsabaugh, S. November 2014 Journal Article Marine Energy general, OTEC Farfield Environment, Socio-economics
INORE: Sharing is Knowing Cameron McNatt and Michele Martini October 2014 Blog Article OTEC, Tidal, Wave, Offshore Wind
Potential Environmental Consequences of Enhanced Ocean Upwelling Karl, D., et al. September 2013 Presentation Marine Energy general, OTEC Energy Removal Ecosystem, Nearfield Habitat
Effect of OTEC Thermal Effluent on the Kosrae Coastal Waters of the Micronesia Kim, J., Mun, J., Kim, H. September 2013 Presentation Marine Energy general, OTEC Energy Removal, Static Device Nearfield Habitat
Observing Ocean Changes at the Nation's First SWAC System Comfort, C., et al. September 2013 Presentation Marine Energy general, OTEC Ecosystem
Effects of Ocean Thermal Energy Conversion Systems on Near and Far Field Seawater Properties - A Case Study for Hawaii Jia, Y., Nihous, G., Richards, K. November 2012 Journal Article Marine Energy general, OTEC Energy Removal Farfield Environment, Nearfield Habitat
Modeling the Physical and Biochemical Influence of Ocean Thermal Energy Conversion Plant Grandelli, P., et al. September 2012 Report Marine Energy general, OTEC Chemicals Nearfield Habitat
Assessment of Ocean Thermal Energy Conversion Muralidharan, S. February 2012 Thesis Marine Energy general, OTEC Chemicals, Energy Removal, Static Device Benthic Invertebrates, Nearfield Habitat, Socio-economics
Electricity Generation by the Ocean Thermal Energy Etemadi, A., et al. December 2011 Journal Article Marine Energy general, OTEC Chemicals, Energy Removal, Static Device Ecosystem, Farfield Environment, Nearfield Habitat
Physical and Biological Modeling of a 100 Megawatt Ocean Thermal Energy Conversion Discharge Plume Rocheleau, G., Grandelli, P. September 2011 Conference Paper Marine Energy general, OTEC Static Device
Environmental Assessment for Ocean Thermal Energy Conversion in Hawaii Comfort, C., Vega, L. September 2011 Conference Paper Marine Energy general, OTEC Nearfield Habitat
Research and Developments on Ocean Thermal Energy Conversion Wang, C., et al. February 2011 Journal Article Marine Energy general, OTEC Chemicals, Static Device Benthic Invertebrates, Ecosystem
Bringing OTEC Environmental Assessments of the 1980s Up To 21st Century Oceanographic Standards Sansone, F., Comfort, C., Weng, K. December 2010 Conference Paper Marine Energy general, OTEC Chemicals, EMF, Energy Removal, Noise, Static Device Benthic Invertebrates, Ecosystem
Ocean Thermal Energy Conversion: Assessing Potential Physical, Chemical and Biological Impacts and Risks Coastal Response Research Center June 2010 Report Marine Energy general, OTEC Chemicals, EMF, Noise, Static Device Benthic Invertebrates, Ecosystem, Fish, Marine Mammals, Sea Turtles
An Overview Of Ocean Renewable Energy Technologies Bedard, R., et al. June 2010 Magazine Article Marine Energy general, OTEC, Tidal, Wave, Wind Energy general, Offshore Wind
Environmental and Ecological Effects of Ocean Renewable Energy Development: A Current Synthesis Boehlert, G., Gill, A. June 2010 Journal Article Marine Energy general, OTEC, Tidal, Wave, Wind Energy general, Offshore Wind Static Device Nearfield Habitat
Potential Environmental Effects of Ocean Thermal Energy Conversion Sound and Sea Technologies April 2010 Presentation Marine Energy general, OTEC Chemicals, Noise, Static Device Benthic Invertebrates, Farfield Environment, Fish, Nearfield Habitat
Ocean Thermal Energy Conversion (OTEC) Environmental Impacts NOAA Office of Ocean & Coastal Resource Management January 2010 Report Marine Energy general, OTEC Chemicals, EMF Ecosystem, Nearfield Habitat
Potential OTEC Impacts in the Hawaiian Marine Environment Parke, M. January 2010 Presentation Marine Energy general, OTEC Chemicals, EMF, Noise, Static Device Benthic Invertebrates, Ecosystem, Farfield Environment, Fish, Nearfield Habitat
Worldwide Synthesis and Analysis of Existing Information Regarding Environmental Effects of Alternative Energy Uses on the Outer Continental Shelf Michel, J., et al. July 2007 Report Marine Energy general, Ocean Current, OTEC, Wave, Wind Energy general, Offshore Wind Dynamic Device, Static Device Benthic Invertebrates, Birds, Farfield Environment, Fish, Marine Mammals, Sea Turtles, Socio-economics
Overview of Environmental Effects: OTEC vs Other Power Generation Methods Martí, J. May 2007 Presentation Marine Energy general, OTEC Static Device
Review and Analysis of Ocean Energy Systems Development and Supporting Policies AEA Energy & Environment June 2006 Report Marine Energy general, OTEC, Tidal, Wave Socio-economics
Environmental Issues of Natural Temperature Differences Utilization Gauthier, M. August 2005 Book Chapter Marine Energy general, OTEC Energy Removal, Static Device Ecosystem, Farfield Environment, Nearfield Habitat
Renewable Energy Resources: Environmental Impact Chapter Tiwari, G., Ghosal, M. January 2005 Book Chapter Marine Energy general, OTEC, Tidal, Wave Chemicals, Dynamic Device, EMF, Energy Removal, Noise, Static Device
Potential and Future Prospects for Ocean Thermal Energy Conversion (OTEC) In Small Islands Developing States (SIDS) Binger, A. January 2004 Report Marine Energy general, OTEC Socio-economics
Renewable Energy From the Ocean: A Guide to OTEC Avery, W., Wu, C. January 1994 Book Marine Energy general, OTEC Chemicals, Static Device Ecosystem, Farfield Environment, Nearfield Habitat, Socio-economics
Potential Environmental Impacts of Closed-Cycle Ocean Thermal Energy Conversion Quinby-Hunt, M., Sloan, D., Wilde, P. June 1987 Journal Article Marine Energy general, OTEC Chemicals, Energy Removal
The 40 MWe OTEC Plant at Kahe Point, Oahu, Hawaii: A Case Study of Potential Biological Impacts Harrison, J. February 1987 Report Marine Energy general, OTEC
The Potential Impact of Ocean Thermal Energy Conversion (OTEC) on Fisheries Myers, E., et al. June 1986 Report Marine Energy general, OTEC Energy Removal Fish
Potential Environmental Impacts of Open-Cycle Thermal Energy Conversion Quinby-Hunt, M., Wilde, P., Dengler, A. January 1986 Journal Article Marine Energy general, OTEC Chemicals, Energy Removal
Potential Impacts from OTEC-Generated Underwater Sounds Rucker, J., Friedl, W. November 1985 Conference Paper Marine Energy general, OTEC Noise
Waterborne Noise Due to Ocean Thermal Energy Conversion Plants Janota, C., Thompson, D. July 1983 Journal Article Marine Energy general, OTEC Noise
Ocean Thermal Energy Conversion: Environmental Effects Assessment Program Plan, 1981-85 NOAA Office of Ocean Minerals and Energy June 1982 Report Marine Energy general, OTEC Chemicals, Energy Removal, Static Device
Ocean Thermal Energy Conversion Final Environmental Impact Statement National Oceanic and Atmospheric Administration July 1981 Report Marine Energy general, OTEC Chemicals, Noise, Static Device Farfield Environment, Nearfield Habitat
Environmental Impact Assessment for Operational OTEC Platforms Sands, M. September 1979 Conference Paper Marine Energy general, OTEC Nearfield Habitat, Socio-economics
Assessment and Control of OTEC Ecological Impacts Wilde, P., Sandusky, J., Jassby, A. December 1978 Report Marine Energy general, OTEC Chemicals, Static Device Socio-economics, Legal and Policy
Assessment and Control of OTEC Physical Environmental Impacts Ditmars, J. November 1978 Conference Paper Marine Energy general, OTEC Nearfield Habitat
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