Hot Prospects

The granite of New Hampshire has been a p'art of Dartmouth lore since Richard Hovey discovered it in the muscles and the brains of Dartmouth men. Following in this tradition, John W. Foster '45 is looking deeper into the granite of New Hampshire in fact, some three and a half miles deep where the Conway-Osceola granite has been dubbed "hot dry rock" and reaches temperatures of up to 500 degrees F.

After graduation from Dartmouth, John earned his M.S. in geology and mining engineering from Ohio State University and is presently senior vice president of HDR Energy Development Corp. of Augusta, Ga. HDR is proposing to establish in the town of Bartlett in the White Mountains the nation's first commercial venture into geothermal production of electricity. The president of HDR has testified before the U.S. House of Representatives Subcommittee on Energy Development that geothermal resources in the United States have a greater potential than the combined energy of all the oil, gas, coal, and uranium in the entire world. He went on to say that some of the "hottest rock east of the Rockies" lies beneath New Hampshire and that the proposed plant could provide "an environmentally pure and virtually infinite source of energy" for electric power production.

John, whose profession led him to Kuwait and Saudi Arabia before joining HDR, outlined the technology for utilizing subterranean heat in an article published in the September 1980 issue of Petroleum Engineer Inter-national. The viable commercial plant, he explained, will consist of three loops of two wells each, reaching 18,000-20,000 feet below the surface. The injection well and the production (extraction) well, each 15 inches in diameter, will be drilled 300 feet apart at the surface and down through thousands of feet of granite, using advanced turbo-and-hammer drilling methods. Between the 16,000 and the 20,000 foot levels, complex fracturing technology will be applied to create 18 fissures in the hot dry rock, thereby connecting the wells and providing 36 heat-transfer surfaces. Water injected at 4,000 p.s.i. will be recovered at the production wellhead at 600 p.s.i., sufficient to maintain liquid phase at temperatures in excess of 400 degrees. Resulting from this geothermal recovery will be 62-66 megawatts of electricity, which approximates the peak load of the New Hampshire Electric Cooperative, and which John estimates can be sold for a price of 3.2 cents per kilowatt hours.

In an interview for The Union Leader (Manchester, N.H.), John stated that geothermal power "is considered by the Los Almos (New Mexico) lab as being the most innocous form of energy known to man." He also stated that "from its nationwide site investigation conducted in 1980 the corporation determined that among the many optional states New Hampshire ranks number one and remains the corporate preference for its $8O million prototype electric plant."