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IEA-OES released a White Paper on Ocean Thermal Energy Conversion (OTEC) for policymakers and developers.

Posted 2021-10-19 in News

The paper provides an update on the potential of OTEC, its history, present state of development and future prospects.

IEA-OES discusses the importance of a widespread adoption of OTEC technology.


IEA-OES today released a White Paper on Ocean Thermal Energy Conversion (OTEC) describing worldwide projects, different options to explore the thermal resource, the present status of the technology and barriers for its development, concluding with key recommendations to move beyond small demonstration plants to pre-commercial prototype units. 

The tropical oceans act as incredibly large solar energy collectors and the OTEC process allows the production of electricity continuously, 24 hours a day, 365 days a year.  Additional benefits can be gained through key by-products generated by an OTEC plant, including fresh desalinated water. There is a well-established track record of infield performance at small scale. While relatively high capital estimates have hampered OTEC's commercial developments, another significant factor has been the lack of knowledge and understanding on the full potential of the technology and how much work has been done.

As a non-intermittent renewable energy that is widely available in the inter-tropical belt, OTEC has considerable development potential. Based on proven small-scale prototypes and well-considered investments, many communities should be able to adopt this sustainable energy source” said the IEA-OES Chairman Yann-Hervé De Roeck. “This white paper provides guidance to all stakeholders to engage in this process.”

Purnima Jalihal, Head of the Energy and Fresh Water Department at NIOT said “This White Paper presents several aspects of OTEC from history to the road ahead. It should enable policy makers and funding agencies to view OTEC as a potential energy source and encourage technology development towards scaling up.”

OTEC has the potential to make a major contribution to the energy transition process and worldwide decarbonisation. There is an urgent need for a larger scale demonstration project running for two years to provide reliable operational data. A land-based 2.5 MW plant is achievable today particularly for small islands in tropical oceans. The main challenge to scaling up to 100 MW is confidence in large diameter cold water intake pipes. Therefore, the experience gained from building and operating a 10 MW floating OTEC plant, as an intermediate step, would allow engineers to identify suitable designs for larger-scale plants. Considering the significant technical developments over the last 15 years in the oil and gas deep-water floating production market, a 10 MW net floating OTEC is considered technically feasible to build using present-day technology.
The report can be downloaded here.
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