Insights from BCC Research

Open Wide and Say Ahh: The Earth as an Alternative Energy Source

Posted by Clayton Luz on Nov 15, 2016 10:00:00 AM

The Iceland Deep Drilling Project (IDDP) endeavors to determine the feasibility of extracting energy and chemicals out of the hydrothermal systems at supercritical conditions.

 
That's fancy talk for finding out if the Earth's magma can be tapped as a geothermal energy source, perhaps as the ultimate alternative energy source.
 
It's happening now in southwest Iceland, on its rugged Reykjanes peninsula where lighthouses outnumber villages. Nowhere on earth is the junction in the earth's crust between the European and American tectonic plates as clearly visible as on this peninsula.
 
Here, three miles below the earth's crust, lies a conventional high-temperature hydrothermal system that produces water at supercritical conditions (meaning steam so hot it's neither liquid nor gas, but holds much more heat).
 
The Reykjanes geothermal system is unique in that its geothermal fluids are modified sea water, which will allow the researchers to use the well to investigate the deep, high temperature reaction zone of mid-ocean ridge hydrothermal environment.
 
The project aims to harness the mantle's heat and bring the water to the surface as 400-600°C superheated steam for use as efficient electricity production in steam turbines.
 
As reported by Fred Pearce in New Scientist, magma 3 miles down moves from below through volcanic activity to meet and heat seawater that has penetrated under the ocean bed.
 
“People have drilled into hard rock at this depth, but never before into a fluid system like this,” Albert Albertsson, assistant director of HS Orka, an Icelandic geothermal-energy company involved in the project tells Pearce.
 
THE IDDP-2
 
The IDDP, a consortium of the National Energy Authority of Iceland and the nation's leading energy companies, began drilling into the region's old lava flows last August. The well on Reykjanes peninsula, named IDDP-2, aims to exploit the heat of the hottest borehole in the world—hitting temperatures between 400 and 1000 °C.
 
"The success of this drilling and research is amazing to say the least, and could in the near future lead to a revolution in energy efficiency in high-temperature geothermal areas of the world," an IDDP spokesman states.
 
The IDDP-2 represents the potential development of new geothermal resources not only in Iceland, but also globally. The aqueous geo-fluids at supercritical condition hold more than five times the power-producing potential than hydrothermal liquid water 225°C. Also, modeling suggests that a supercritical well like IDDP-2 could have 10 times the power output of a conventional geothermal well.
 
THE EARTH'S LAYERS
 
Four concentric layers compose the Earth: inner core (the hottest layer with temperatures up to 5,500°C, about 750 miles thick), outer core (a liquid layer as hot as the inner core, about 1,400 miles thick), mantle (semi-molten rock, or magma, this layer's 1,800 miles thick), and crust (a layer of solid rock about 30 miles thick).
 
Reykjanes's basaltic crust comprises tectonic plates, which move constantly and are a primary spot for the occurrence of earthquakes and volcanoes.
 
The IDDP drilled its first well in Reykjanes back in 2004 (IDDP-1), but two years later the well was abandoned due to mechanical issues. The current drilling operation is deepening the existing well.
 
A well that can successfully tap into supercritical steam could unleash an energy capacity of 50 megawatts as compared to the 5 MW of a typical geothermal well, Pearce quotes Albertsson. A single well powers about homes, contrasted with some 50,000 homes that could be powered by the supercritical steam.
 
The drilling itself is expected to be completed by the end of 2016 and after that the project will enter a two-and-a-half-year test period.
 

Topics: Environment