How The Marshall Hydrothermal Recovery System Works

As soon as the existence of the first hydrothermal vent was confirmed in 1977, every observer understood the enormous energy potential they contained, but utilizing it seemed an impossible task. Located at average depths of 2,300 m or about 7,500 ft, no one had the slightest idea of what kind of system could be placed at the bottom of the ocean to generate electricity. Although the promise was there, the reality has remained unattainable in the 30 years since their presence became known.

The Marshall Hydrothermal Recovery System is a deceptively simple leap of logic. Instead of trying to work with the vents at the bottom of the ocean, the vents are capped, and their flow is fed into a continuous, highly insulated pipe, which leads 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 teperature 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.

Another embodiment of the system uses a closed loop. Rather than bringing the hydrothermal fluid from the depths to the surface, clean working fluid recirculated within a closed loop is heated by the vent through a heat exchanger. The vent's heat is transferred to the fluid, which is then utilized directly to drive turbines on the surface. The cooled fluid is then sent back to be reheated by the vent again and again, but the hydrothermal fluid itself is never actually brought to the surface.