Monday, January 09, 2012

Front Row Seat

Marathon, Florida
24 42.40 081 N 05.68 W

Friday night sunset looking West.

Friday night sunset, looking Southeast.

Saturday morning sunrise, looking Southeast.

Friday and Saturday have been mostly cloudless days.  Why then the heavy bank of clouds seen in the above two photos looking Southeast?   The answer is that it is a nearly perpetual bank of clouds directly over the Gulf Stream.  That's how close we are here in Marathon.  

I'm a power engineer by background.  Therefore, I love it having a front row center street watching the biggest power engine in the world.   What I'm talking about is the Gulf Stream.  

The Gulf Stream moves 30 million cubic feet (850 thousand cubic meters)  of water per second past me here in Boot Key Harbor.  Off the coast of Newfoundland, the flow is five times larger. Compare that with 0.6 million cusec as the total flow of all rivers emptying into the Atlantic Ocean.     

The water is also warm, so energy in the form of heat is also transported.  Energy transport per unit of time is defined as power.  The Gulf Stream carries lots of power.  Lots and lots.  The total power in the Gulf Stream is 1.4 petawatts.  That's the equivalent of the power generating capacity of 1.4 million of the largest nuclear power plants.  It is 100 times more than the total power demand of men on the whole planet.  Wow that's a lot of power.

That much power is enough to give renewable energy enthusiasts wet dreams.  However, the power is not so easy to exploit for our own purposes.   The water in the Gulf Stream is only a few degrees warmer than the ambient water or air temperatures.  Therefore the Carnot efficiency of a heat engine using that temperature difference would be so low, that such a heat engine would be impractical to make.  (For the benefit of those who never had a course in thermodynamics or who slept through their course, the Carnot efficiency is the maximum theoretical efficiency.  Any real life engine is necessarily worse than a Carnot engine.)

There could be another problem.  If we extracted a large fraction of the Gulf Stream's power, or if we disrupted the flow it would cause global climate changes so big as to make the current greenhouse gas caused changes seem like child's play.  Actually the Gulf Stream is only part of a global circulation pattern of ocean currents that transport heat and salt through all the world's oceans.  Especially in the Northern Hemisphere, all the coastal climates in all countries are heavily dependent on those currents.  

Anyhow, if we did have a practical way of extracting even 1% of that power, we could replace all other energy sources.   If we could do it, we would, but we don't, therefore we can't.  (Ugh what an ugly sentence, but it speaks precisely to my point.)

But for me, as a power engineer, it is a wonderful privilege to be able to sit here and see the visible evidence of nature's colossal power plant at work.  The word awesome is much overused in today's world, but it applies here.


  1. There you go making me think again. I enjoyed your post.


  2. Dick - thought of you and the constant refining to attain an energy balance while aboard -

    This week is the CES and there will be plenty of ideas to address alternative energy for consumer electronics there -
    As always, enjoying the blog.


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