Economic implications of open versus closed cycle cooling for new steam electric power plants : a national and regional survey

Originally published as the author's thesis (M.S.), M.I.T., Dept. of Civil Engineering, 1979.Current and anticipated thermal pollution regulations will prevent many new steam electric power plants from operating with once-through cooling. Alternative cooling systems acceptable from an environmental view fail to operate with the same efficiencies, in terms of resources consumed per Kwh of electricity produced, offered by once-through cooling systems. As a consequence there are clear conflicts between meeting environmental objectives and meeting minimum cost and minimum resource consumption objectives. This report examines, at both the regional and national level, the costs of satisfying environmental objec- tives through the existing thermal pollution regulations. This study forecasts the costs of operating those megawatts of new generating capacity to be installed between the years 1975 and 2000 which will be required to install closed cycle cooling solely to comply with thermal regulations. A regionally disaggregated approach is used in the forecasts in order to preserve as much of the anticipated inter-regional variation in future capacity growth rates and economic trends as possible. The net costs of closed cycle cooling over once- through cooling are based on comparisons of the costs of owning and operating optimal closed and open-cycle cooling configurations in separate regions, using computer codes to simulate joint power plant/ cooling system operation. The expected future costs of current thermal pollution regulations are determined for the mutually exclusive - collectively exhaustive eighteen Water Resources Council Regions within the contiguous U.S., and are expressed in terms of additional dollar expenditures, water losses and energy consumption. These costs are then compared with the expected resource commitments associated with the normal operation of the steam electric power industry. It is found that while energy losses appear to be small, the dollar costs could threaten the profitability of those utility systems which have historically used once-through cooling extensively throughout their system. In addition the additional water demands of closed cycle cooling are likely to disrupt the water supplies in those coastal areas having few untapped freshwater supplies available

Global Supply Chain Management at Digital Equipment Corporation

Interfaces, 25, pp. 69-93. (Nominated for the 1994 International Management Science Achievement Award.)Digital Equipment Corporation evaluates global supply chain alternatives and determines worldwide manufacturing and distribution strategy, using the Global Supply Chain Model (GSCM) which recommends a production, distribution, and vendor network,, GSCM minimizes cost or weighted cumulative production and distribution times or both subject to meeting estimated demand and restrictions on local content, offset trade, and joint capacity for multiple products, echelons, and time periods.Cost factors include fixed and variable production charges, inventory charges, distribution expenses via multiple modes, taxes, duties, and duty drawback. GSCM is a large mixed-integer linear program that incorporates a global, multiproduct bill of materials for supply chains with arbitrary echelon structure and comprehensive model of integrated global manufacturing and distribution decisions. The supply chain restructuring has saved over $100 million (US)