Three decades ago, we did a program on what was then called Hot Dry Rock Geothermal Energy. The process is now called the Enhanced Geothermal Energy Systems. With us then and now: Dr. Jefferson Tester, today a professor of sustainable energy systems at Cornell University and principal scientist for Cornell’s work on an Enhanced Geothermal Energy System, its Earth Source Heat Project. Dr. Tester relates how Cornell has drilled a two-mile hole in the ground at its campus in Ithaca, New York in it work to use heat from below the Earth to provide heat at university buildings. And, he discusses the history of what started at the U.S. Department of Energy’s Hot Dry Rock pilot operation at Fenton Hill in New Mexico, featured in our earlier program. Dr. Tester has been a pioneer in geothermal energy, after beginning at the Fenton Hill project, as a professor at the Massachusetts Institute of Technology. He cites in this Enviro Close-Up a study done when he was at MIT stating that “in spite of its enormous potential, the geothermal option for the United States has been largely ignored.” The MIT team concluded that “while further advances are needed, none of the known technical and economic barriers…are considered insurmountable.”