Climate mitigating energy production

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Just as climate change is a man made problem, the conditions that brought about the waming hiatus can be replicated with technology that uses heat pipes (Figure 1) to move surface ocean heat to deep water.


The oceans are storing about 93 percent of the energy of climate change.  When water is heated it becomes less dense and rises thus the oceans are increasingly thermally stratified.  This stratification presents the opportunity to create work in accordance with the 2nd law of thermodynamics.


The 2nd law dictates that heat flows from warm to cold.  When this flow is through a heat engine (Figure 2) work is produced.


Heat pipes are sometimes described as thermal superconductors because they rapidly move heat through phase changes of a working fluid. They are a highly efficient way of conducting heat away from a region where it can do harm, as with the ocean's surface.  The heat pipe’s efficiency stems from the fact they have no moving parts yet they can transport heat at speeds approaching that of sound. They can move heat counter to the forces of gravity and when a turbine is situated in the vapor stream heat can be converted to work.


With enough of these devices the hiatus can be perpetuated while generating as much energy as is currently derived from fossil fuels.


Researchers from the University of Hawaii have estimated the oceans have the potential to produce 14 terawatts of energy this way - more than is derived from all of the world's fossil fuels - with ocean thermal energy conversion or OTEC.

The efficiency of this process is determined by the difference in absolute temperatures between the warm and cold heat sink.


OTEC systems only operate where surface temperatures are at least 20oC above the 4oC found almost universally in the oceans at a depth of 1000 meters.


The theoretical efficiency of these systems is about 7 percent but

realistically about 5 percent is the best that can be expected so 20 times more heat is moved through the heat engine than the energy produced.


What engineers perceive as a drawback to these systems is an environmental benefit in view of the recent finding that heat movement into the depths means a slower increase in atmospheric warming.


For every kilowatt of energy produced with these systems a 20 kilowatt (2000 percent)  environmental heat benefit is derived.


Scaling to the 14 terawatt maximum it is estimated the oceans can produce this way, 280 kilowatts of heat is moved to the ocean depths, which takes care of 89 percent of the 330 terawatts of heat/year NOAA determined in 2010 the oceans are taking up on account of global warming. 


No amount of new technology will magically solve the climate problem or even help much," unless there's broad consensus on the need for urgent action, says Harvard physicist David Keith.


By the same token, unless climate change is addressed in accordance with sound scientific principles the money spent nominally to address the problem would be wasted.





(Figure 1)




(Figure 2)