Geothermal Energy Potential in Northern Appalachia

Introduction Rising domestic energy needs in the face of limited supplies have led to various estimates of total energy consumption through 1985 and beyond. Increases in domestic energy production sufficient to meet demand by 1985 appear unlikely if energy sources are limited to fossil or nuclear fuel. The intent of this discussion is to delineate and evaluate the geothermal resource base of northern Appalachia, which comprises portions of the states of New York, Pennsylvania, North Carolina, Maryland, Virginia, Ohio, and West Virginia. Total development of geothermal resources in this region could provide additional amounts of energy for electrical provide additional amounts of energy for electrical power, commercial and process heat, valuable power, commercial and process heat, valuable minerals, and desalinated water for the eastern U. S. Geothermal Resource Base Determination of the resource base is supported by the assignment of quantitative values to the following parameters:geothermal gradient,heat flow parameters:geothermal gradient,heat flow in the subsurface, andheat capacity of the rocks. It should be realized that even in the most intensely investigated geothermal areas but few of these values are known, and then often only within an order of magnitude. Geothermal Gradients Fig. 1 illustrates a re-evaluated distribution of geothermal gradient values for northern Appalachia. Unfortunately, these data show only a broad range in the variation of these values (0.7 degrees F/100 ft to 2.1 degrees F/100 ft). Localized high and low gradient values could readily occur within the contours of the map. Heat Flow In-situ heat transfer measurements provide information about the amount of geothermal energy available in the region. The global average measured heat flow is approximately 1.5 HFU (1 HFU = 1 cal/cm2-sec), whereas the average heat flux in the Appalachian system has been estimated to be 1.3 HFU. Local thermal resistivities were re-estimated for various lithological units in Appalachia. Horizontal heat transfer between adjoining rock bodies was ignored. Fig. 2 illustrates the variation of the regional heat flux, which ranges from 0.6 to 1.5 HFU. One area bordering southern West Virginia and western Virginia contains a mixture of anomalous high and low heat flux values. Further field work must be done to resolve the implied geological problem. Geothermal Energy Potential The sensible heat stored in the sedimentary rocks was calculated with the following equation: Q = C, (1) JPT P. 1005