Geothermal Startup Testing CO2

I admit that I am a bit skepticalwith this protocol but it certainly solves the problems encountered with a watersteam system.  The negatives can beovercome with simple volume methods and in the end; heat is transferred up tothe surface and converted to brake horsepower. Except those hot rocks are never dry and injecting water helps pushpresently live water into the system.

You will be dealing with steamregardless and you will be leaving salts down well.

Let us hope they know somethingthat we do not know about this exercise that makes it a barnburner.

If the working fluid sheds heatdown to ambient temperature easily, then maybe we are onto something.  The right set up would allow us to pull heatfrom much shallower rocks and that would be beneficial  It is possible to tap power a couple hundredfeet away from molten lava, but the cost is likely to be a bitch.

Innovative Geothermal Startup Will Put Carbon Dioxide To Good Use

Submitted by JoAnn Milliken on March 17, 2011 - 2:09pm

http://blog.energy.gov/blog/2011/03/17/innovative-geothermal-startup-will-put-carbon-dioxide-good-use

Geothermal power holds enormous opportunities to provide affordable,clean energy that avoids greenhouse gases like carbon dioxide (CO2). That’sbecause geothermal technologies rely on heat found under the earth’s surface togenerate uninterrupted, low-cost renewable energy that is virtuallyemissions-free. Now, one Utah-based startup is working on an innovative projectthat could make geothermal power even more beneficial.

Just last month, GreenFire Energy began work to demonstrate a processthat would use CO2 to harness geothermal energy to make electricity. What ismore, the technology has the potential to add carbon sequestration – not tomention reduced water consumption – to the benefits already associated withgeothermal power. The idea originally emerged several years ago from the workof geoscientist Donald Brown at the Department of Energy's Los Alamos NationalLab. Karsten Preuss and others at the Department’s Lawrence Berkeley NationalLab have since advanced the theory.

A basic overview of GreenFire's process to convert CO2 intoelectricity. | Photo courtesy of GreenFire.

Now GreenFire plans to test that theory on (and under) Arizona soil. InSeptember 2010, the Office of Energy Efficiency and Renewable Energy’sGeothermal Technologies Program awarded GreenFire Energy a $2 millioncost-share award to conduct the first field demonstration of a CO2-basedgeothermal system. This pilot project will rely on local geothermal resourcesand naturally-occurring carbon dioxide from the St. John’sDome formation near Springerville, AZ.

Greenfire’s planned demonstration facility will work much likeconventional geothermal power plants, which send a “geothermal fluid” – usuallywater – to be heated by underground rock formations and returned to the surfaceas steam, powering turbines that produce electricity. Instead of water,GreenFire will test CO2 as its geothermal fluid. Carbon dioxide from St. John’s Dome – the productof past volcanic activity – will be tapped, pressurized to a “supercritical”state and injected underground. When this CO2 returns to the surface, it willcycle through a power conversion system, creating power. After each cycle, theCO2 will be recompressed and reinjected underground. During this process, aportion of the CO2 will be permanently trapped in porous underground rocks.Thus, the process emits no carbon – and may actually store some of it deepunderground.

Getting geothermal power with CO2 instead of water would beparticularly beneficial in the arid Southwestern U.S.,where water is scarce. Moreover, supercritical CO2 may actually be a bettergeothermal fluid than water in key ways. Studies suggest that CO2 may havehigher heat recovery rates, lower pumping costs due to buoyancy effects, andfewer problems with rock alteration and surface equipment problems.

Pending suitable results from geological testing that is now underway,the company is scheduled to drill its first geothermal well later this year.

Should the project demonstrate the technical and economic feasibilityof this unconventional geothermal energy technology, GreenFire would ultimatelylook to build several 50MW geothermal plants, supplementing naturally occurringCO2 from the St. John’s Dome formation with emissions from conventional powerplants in the region. Six coal-fired power plants in the area account fornearly 100 million tons of CO2 each year, much of which could be stored orchanneled through the geothermal formation, sequestering emissions andgenerating clean, renewable energy in the process.

The Department of Energy is working with innovative startups likeGreenFire Energy to provide promising technologies with the funding and supportthey need, ensuring that lessons learned from demonstrations like this one willhelp us better understand how geothermal energy and carbon sequestration cancontribute to meeting long-term clean energy goals.

JoAnn Milliken is the Acting Program Manager for the Geothermal TechnologiesProgram