Mining Hydrothermal Vents For Renewable Electricity, Drinking Water + Valuable Minerals

September 4th, 2009 by Susan Kraemer

Only after I snoozed my way through high school science class did science become more compelling than science fiction.

Back then, there was just no compelling reason to pay attention. Just a browzy fly buzzing in a smelly boring lab full of long agreed-upon dull principles that were really neither here nor there. In those days there were no colliding continents or hydrothermal vents or extremophile lifeforms. We looked to sci-fi for that.

Who knew that our planet would soon be busting at the seams with 7 billion of us. That our fossil fuel use would threaten our survival with climate changes — on a level unseen on the planet since Cyanobacteria made it safe it for oxygen-breathers 4 billion years ago.

Or that we would not only discover vast strange heat sources under the ocean but that we’d actually consider mining these hydrothermal vents for renewable energy: That was the sort of story you’d only find in science fiction back then.

But yet, here we are. This is not science fiction: The energy potential is staggering. In the Gigawatt range per vent.

The Marshall Hydrothermal Recovery System would use the heat from hydrothermal vents 7,000 feet under the sea to make electricity. Its temperature is incredibly high, 750 degrees Fahrenheit; hot enough to melt lead, but it does not boil because of the intense pressures at the depths where the vents are located.

Superheated fluid would be propelled up through a through a (well insulated!) pipe to an oil platform located on the surface above the vent. The superheated fluid is carried by means of flow velocity, convection, conduction, and flash steam pressure as it rises and the ambient pressure is decreased.

Once delivered to the platform, the heat energy contained in the fluid can be extracted to generate electricity. Since the amount of energy available from any thermal system is dependent on the difference in temperature between two points, the system also includes a Thermal Enhancement Pipe.

This is simply an open pipe, like a large drinking straw, which extends down below the layer of relatively warm water on the surface to the permanently frigid waters below. By withdrawing water from that pipe and using it as the cold side of any heat reaction, much more energy can be extracted from the process than could be delivered without it.

But what about those extremophile lifeforms down there at the vent? This has got to be ecologically disruptive!









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