The most important factors affecting the economics of geothermal electricity production are the wellhead temperature or enthalpy, the well flow rate, and the cost of the wells. The capital cost of the powerplant is significant, but not highly sensitive to these resource characteristics. The optimum geothermal plant size will remain small, usually in the 50-100 MWe range. Therefore, the opportunities for achieving significant cost reductions through ''economies of scale'' are small. The steam and binary power cycles are closely competitive; the binary cycle appears better when the brine temperature is below 200-230/sup 0/C, and the flashed steam cycle appears better above this range. Geothermal electricity production is capital intensive; over 75 percent of the generation costs are fixed costs related to capital investment. Technological advances are needed to reduce costs from marginal geothermal resources and thus to stimulate geothermal energy development. Significant reduction in power costs would be achieved by reducing well drilling costs, stimulating well flow rates, reducing powerplant capital costs, increasing powerplant efficiency and utilization, and developing more effective exploration techniques for locating and assessing high-quality resources. (auth)

The following topics are covered: construction status, system operation, other start-up activities, and task force modifications. (MHR)

A unique and relatively simple method is described for modifying a 1965-vintage hardwired numerical control (N/C) for a machine tool so that it can operate in the SI (Metric) as well as the Inch mode. The modification procedure will be valuable during the transition from Inch to SI measurements, as it allows a numerically-controlled machine tool originally designed to operate only in the Inch mode to be ''recycled'' for SI use. The system digital logic of a Hughes N/C Model 2000 Control on an EE Monarch lathe was modified by changing the modulus of the Command Phase and Reference counters so that the control system has a SI modulus as well as an Inch modulus. The modified system thus allows selection of either the SI operating mode or the Inch mode by a front panel switch.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, John L. Hill, regarding a legal question submitted for clarification: Contractors’ performance and payment bonds required under articles 5160 and 5472a, V.T.C.S.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.