Dowsing is the controversial practice of locating underground water using a divining rod. Researchers at the Lawrence Berkeley National Laboratory may have just created a scientific version of the dowsing rod for locating ideal underground sources of geothermal energy. Geochemist Mack Kennedy defines that "a good geothermal energy source has three basic requirements: a high thermal gradient - which means accessible hot rock - plus a rechargeable reservoir fluid, usually water, and finally, deep permeable pathways for the fluid to circulate through the hot rock." Helium 3 isotopes exist in space and around volcanic mantle. Kennedy's findings show that prime geothermal sources are ripe with Helium 3 isotopes, making them easier to find and allowing equipment to perform under the most optimal conditions. Geothermal energy in North America has the potential to provide 90 quadrillion kilowatt hours of power, more than 3000 times the amount of energy used by Americans today.