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Ocean Thermal Energy Conversion: National Security Implications

ocean thermal energy conversionThe Department of the Navy states, “Seafarers have always respected the power of wind and water. This is especially the case during storms at sea, where ships run the risk of damage or sinking from strong winds and high seas. Large and powerful storms, referred to as “closed cyclonic circulations,” are especially dangerous and have caused massive destruction throughout all of recorded history.”

The Department lists 55 U.S. warships and 2474 men lost or missing due to weather related incidents over the span 1781 to 1949.  

No losses are listed subsequent to 1949 presumably due to the Navy’s acknowledgement, that although cyclonic storms continue to effect Navy operations to this day, advances in satellite imagery, radar mapping, and communications have reduced the risks to ships at sea.

According to the Niels Bohr Institute the Navy can expect 10 times the current impact from storms on its operations should the climate become two degrees Celsius warmer, which it is almost certain to do by the end of the century according to all IPCC projections but for the one where CO2 levels are fixed at 2000 levels.

Not a great likelihood.  

Naval infrastructure is also under threat from sea level rise and all the more so when combined with storm surge.

Navy Admiral Samuel J. Locklear III, head of the U.S. Navy Pacific command, said earlier this month, “climate change is the biggest long-term security threat in the Pacific region”.

Ocean thermal energy conversion addresses the threats to naval operations and the security stressors of sea level rise and weather Admiral Locklear identifies by helping to reduce thermal expansion of the oceans and the movement of heat towards the poles and by sapping the energy of cyclonic circulations.

Since 2009, the U.S. Naval Facilities Engineering Command has awarded Lockheed Martin $12.5 million to develop critical OTEC system components and advance the design for an OTEC pilot plant, an essential step in developing large-scale utility plants.

In the humble opinion of this writer, this is an asymmetrically low response to the threat which can be mitigated by massive deployment of OTEC, which in turn has the potential to produce nearly twice the output from current primary energy sources.

The cost and environmental drawbacks of conventional OTEC are overcome by using a heat pipe, as much as 1/10th the size of a conventional cold water pipe, which transfers heat by circulating the working fluid in a closed loop between the hot and cold reservoirs.

The crushing problem associated with circulating a low pressure gas within a small pipe surrounded by high pressure is addressed by a coiled and pressurized counter-current heat flow system that recaptures the latent heat of condensation of the working fluid and returns it to the surface, as shown below.

With OTEC the navy can become energy self-sufficient in its own domain and can be relieved of a heavy burden in the Middle East.

A win for the navy.

A win for the planet.

Jim Baird's picture

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Discussions

Roger Faulkner's picture
Roger Faulkner on March 29, 2013

There is no chance for OTEC to affect the global circulation of heat in the oceans. Heat pipes are not capable of improving OTEC; these devices are good at transfering heat dozens of meters at best. OTEC typically is powered by temperature differentials that are on the order of 20 degrees C over 1000 meters of depth. OTEC generators rely on boilng/condensing a working fluid like butane (Rankine cyle), so the cycle is intrinsically similar to a heat pipe anyhow, except with a turbine inserted. This post makes no sense to me…it looks like a case of a flawed understanding of thermodynamics, something I hoped the moderators would filter out when I joined this site.

OTEC is indeed very promising technology, though.

Edward Kerr's picture
Edward Kerr on March 30, 2013

While this could, in theory, reduce the oceans temperature I can’t see how it would address the acidification issue which is as much a threat to the planet as is sea level rise and stronger storms.

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