Utilization of geothermal energy

Abstract

Fluid is introduced to one or more underground fluid passages in thermal contact with a hot rock formation. Kinetic energy of the fluid being introduced is converted into electrical energy. The introduced fluid absorbs heat from the hot rock formation. That absorbed heat is extracted from the heated fluid for use in connection with a domestic or industrial application.

1 . A method comprising:
 introducing fluid to one or more underground fluid passages in thermal contact with a hot rock formation;   converting kinetic energy of the fluid being introduced to the one or more underground fluid passages into electrical energy;   absorbing heat from the hot rock formation into the introduced fluid; and   extracting the absorbed heat from the heated fluid for use in connection with a domestic or industrial application.   
   
   
       2 . The method of  claim 1  wherein the hot rock formation is an underground hot dry rock formation. 
   
   
       3 . The method of  claim 1  wherein converting the kinetic energy of the fluid being introduced comprises directing the fluid through a turbine-generator. 
   
   
       4 . The method of  claim 3  wherein the fluid flows through the turbine-generator at least partially under the influence of gravity. 
   
   
       5 . The method of  claim 3  wherein the fluid flows through the turbine-generator entirely under the influence of gravity. 
   
   
       6 . The method of  claim 3  wherein the turbine-generator is positioned as near as possible to the hot rock formation without undue risk that static fluid may accumulate above the hot rock formation to a level that will unduly impede fluid flow through the turbine-generator. 
   
   
       7 . The method of  claim 1  further comprising:
 prior to extracting the absorbed heat from the heated fluid, removing the heated fluid from thermal contact with the hot rock formation.   
   
   
       8 . The method of  claim 7  wherein the heated fluid is removed from thermal contact with the hot rock formation with a pump. 
   
   
       9 . The method of  claim 7  wherein the heated fluid is a vapor that is removed from thermal contact with the hot rock formation by naturally flowing upward. 
   
   
       10 . The method of  claim 1  wherein the fluid is introduced through a fluid injection well that extends from the earth's surface to the hot rock formation and
 wherein the fluid is removed through a fluid production well that extends from the earth's surface to the hot dry rock formation.   
   
   
       11 . The method of  claim 10  wherein the one or more underground passages comprise a horizontal borehole in the hot rock formation,
 wherein the horizontal borehole extends between the fluid injection well and the fluid production well.   
   
   
       12 . The method of  claim 10  wherein the one of more underground passages comprise a plurality of fractures formed in the hot rock formation,
 wherein the plurality of fractures extend between the fluid injection well and the fluid production well.   
   
   
       13 . The method of  claim 1  wherein heat is extracted from the heated fluid for use in connection with a domestic or industrial application by a heat exchanger located above the hot rock formation. 
   
   
       14 . The method of  claim 1  further comprising using the extracted heat in connection with a domestic or industrial application. 
   
   
       15 . The method of  claim 1  further comprising:
 after extracting the absorbed heat from the heated fluid, returning the fluid to be reintroduced to the one or more underground fluid passages.   
   
   
       16 . A system comprising:
 an underground hot rock formation;   a fluid injection well that facilitates introducing fluid to one or more underground fluid passages in thermal contact with the underground hot rock formation; and   a turbine-generator arranged to convert kinetic energy of the fluid being introduced into electrical energy;   wherein the system is arranged so that introduced fluid absorbs heat from the hot rock formation and wherein the absorbed heat is extracted for use in connection with a domestic or industrial application.   
   
   
       17 . The system of  claim 16  wherein the hot rock formation is an underground hot dry rock formation. 
   
   
       18 . The system of  claim 16  wherein the system is arranged so that fluid introduction occurs at least partially under the influence of gravity. 
   
   
       19 . The system of  claim 16  wherein the system is arranged so that fluid introduction occurs entirely under the influence of gravity. 
   
   
       20 . The system of  claim 16  wherein the turbine-generator is positioned as near as possible to the hot rock formation without undue risk that static fluid may accumulate above the hot rock formation to a level that will unduly impede fluid flow through the turbine-generator. 
   
   
       21 . The system of  claim 16  further comprising a fluid production well to facilitate removing heated fluid from the one or more underground passages. 
   
   
       22 . The system of  claim 21  further comprising a pump beneath a static fluid level in the fluid production well to remove fluid from thermal contact with the hot rock formation. 
   
   
       23 . The system of  claim 21  arranged so that the heated fluid is a vapor that is removed from thermal contact with the hot rock formation by naturally flowing upward through the fluid production well. 
   
   
       24 . The system of  claim 16  wherein the one or more underground passages comprise a horizontal borehole in the hot rock formation, wherein the horizontal borehole extends between the fluid injection well and a fluid production well arranged to facilitate removal of the heated fluid from the horizontal borehole. 
   
   
       25 . The system of  claim 16  wherein the one of more underground passages comprise a plurality of fractures formed in the hot rock formation, wherein the fractures extend between the fluid injection well and a fluid production well arranged to facilitate removal of the heated fluid from the plurality of fractures. 
   
   
       26 . The system of  claim 16  further comprising a heat exchanger to extract the absorbed heat from heated fluid for use in connection with a domestic or industrial application. 
   
   
       27 . The system of  claim 26  further comprising:
 a pipe extending from the heat exchanger to the fluid injection well to return fluid, after the absorbed heat is extracted, to be reintroduced to the one or more underground fluid passages.   
   
   
       28 . A system comprising:
 an underground hot rock formation having one or more surfaces that define one or more underground fluid passages in thermal contact with a hot dry rock formation;   a fluid injection well arranged to facilitate introducing fluid to the one or more underground fluid passages, wherein the introduced fluid absorbs heat from the hot rock formation;   a fluid production well arranged to facilitate removing fluid from the one or more underground fluid passages;   a turbine-generator arranged in the fluid introduction well to convert kinetic energy of the fluid being introduced into electrical energy; and   a heat exchanger to extract the absorbed heat for use in connection with a domestic or industrial application.