WHAT IS OTEC
Did you know that we can use the natural temperature difference in the tropical area of the ocean to create electricity day and night all year round?
Ocean Thermal Energy Conversion (OTEC) harnesses the power of the ocean to provide a continuous, cost-effective supply of clean energy. It possesses significant environmental advantages over fossil fuels and nuclear power; requires less land than renewable energy technologies such as solar, wind, biomass and hydroelectric power; and has the potential to produce far more useful and affordable energy than could be generated from other renewable sources.
Watch the video below to learn more:
- Using animation and motion graphics, this video highlights how OTEC will change the energy scenery in tropical islands. Currently powered by fossil fuels, these nations also face the highest electricity costs compared to the rest of the world. OTEC surges as a great alternative for their renewable energy transition.
- This educational video is the result of a cooperation between Global OTEC, environmentalist Kane Baker, of the George F. Baker Trust Foundation and Schoolyard Films.
How does it work?
Ocean Thermal Energy Technology (OTEC) provides a baseload power source that works day and night, year-round; offering a clean alternative to diesel that can be used alongside peak load solar or wind. It works by using warm surface seawater to produce electricity:
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The barge draws in warm surface seawater (of around 26°C) which has been heated by the sun’s rays
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This warm water is used to evaporate a working fluid with a low boiling point
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This produces a vapour which spins a turbine to produce electricity using a generator
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At the same time, cold deep water (of around 4°C) is drawn up through a pipe from the depths of the ocean
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The cold water cools the vapour, turning it back into a liquid which can then be immediately reused
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The cycle runs continuously whilst the power generated is transmitted to the grid using a sub-sea cable
Electricity grids use two types of power: baseload (the unchanging amount of energy needed throughout the day and night) and peak load (shorter periods when more energy is needed). Renewable energy sources like solar panels provide peak load power during the daytime when the energy from the sun can be captured. But most tropical nations require oil imports for constant baseload power the rest of the time. Because the tropical ocean is always warm whatever the weather, time of day or year, OTEC can continuously generate electricity 24 hours a day, 365 days a year. Check here where in the world OTEC is viable.
History of OTEC
The idea of creating energy from the temperature differences between the surface and deeper levels of the ocean isn’t new. In fact, the idea is over 140 years old. Decades of research and development in the lab have already been undertaken.
1881 to 1930:
THE CONCEPT
If using the ocean’s temperature to create energy sounds like fiction, you might not be far off. Jules Vernes’ famous novel Twenty Thousand Leagues Under the Sea – first published around 1870 – includes a fictional character – Captain Nemo – thinking about how to make electricity using temperature differences in the ocean. Perhaps this inspired the French physicist Jacques-Arsène d’Arsonval who proposed it was possible to harness the ocean’s energy to create power in 1881. In 1930 an entrepreneurial student of d’Arsonval, called Georges Claude, tested the idea. He built an Ocean Thermal Energy Conversion plant in Cuba but it was destroyed by a storm. Low-level research into OTEC continued through the 1940s and ‘50s but, by this time, the world’s focus was on cheaper energy sources such as nuclear and fossil fuels.
1970s to 90s
It wasn’t until the 1970s that OTEC returned to the spotlight. With the energy crisis causing oil prices to skyrocket, the USA and Japan decided to revisit OTEC as a source of clean, reliable energy. In 1974, the Natural Energy Laboratory of Hawaii Authority (NELHA) was founded to conduct research into clean energy technologies. In 1979, former President Jimmy Carter passed the Ocean Thermal Energy Conversion Act to ensure the USA had a wide range of energy sources. This led US researchers to develop two OTEC plants based off the coast of Hawaii, (mini-OTEC and OTEC-1) which successfully generated net power. Then, around 1981, Japanese companies tested an OTEC system off the coast of Nauru, in the Pacific, which generated 35 kilowatts of net power before being destroyed by a storm. By 1999, one of NEHLA’s plants could generate 250 kilowatts of energy.
2013 to date
After another lull in the progression of OTEC, the pace picked up again in the 2000s as people became more concerned about climate change. At this point, the OTEC energy pioneers of the 1980s were coming to the end of their careers. They had spent decades testing how to create the most efficient cycle and permanent projects in Hawaii, Japan and South Korea had proven that, alongside wind and solar, OTEC can provide a viable, clean energy solution to help the world move away from diesel. Despite this, OTEC hasn’t yet been commercially successful. Most plans to upscale have struggled to secure funding. Huge 100-megawatt plants needed billions in investment to get off the ground and failed because they tried to grow too quickly. Global OTEC plans to change this. We have designed the first small-scale commercial Ocean Thermal Energy Conversion system to transform the energy landscape for tropical islands.
The Future
Global OTEC’s goal is to transform the global renewable energy landscape by harnessing the ocean. Through a different range of projects, concepts and designs, our team is advancing OTEC to make it more cost-effective, viable and resilient to all tropical areas of the world. This effort supports Small Island Developing States (SIDS), Least Developed Countries (LDCs), coastal nations, and offshore industries in achieving zero carbon emissions with reliable, clean baseload power.
OTec is viable in over 100 territories around the globe
The OTEC technology is viable primarily in the tropical, equatorial regions of the world, where the year-round ocean temperature difference is at least 20 degrees Celsius. This area comprises over a hundred territories, with a resource estimated to be equivalent to more than 7 terawatts.
Check our special map feature to view all areas where OTEC works by clicking the button below:
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