The choice between multipurpose and multiple specialized offshore port facilities requires many decisions which may be more effectively made using system analysis and simulation methods recently developed and discussed in this paper. Optimization of investment and other costs by allocating resources and developing utilization strategies are also presented.
Decisions on offshore port location, type, and investment are a function of many economic, operational, technological, ecological, and environmental factors. Many of the questions relating to these decisions concern the relative advantage of one or more facilities to serve a projected commodity flow from assumed origins to defined destinations. These facilities may be of various types and capacities, as well as established in different alternative locations. Each type, capacity and location combination of an offshore facility system influences costs and transportation effectiveness. Other questions concern the advantages of single versus multipurpose offshore port facilities, where purpose is defined by the type and or form of commodities handled through it. A number of analytical and simulation methods or models have recently been developed which address these problems from a total transportation systems point of view.
The purpose of this paper is to summarize a description of these methods and discuss their potential application. The discussion is divided into:
Methods for determining effects of number, location, capacity, use, investment and other costs of offshore port facilities to meet a given demand, and
Methods for analyzing or simulating port design, use and policy decision as they effect multi versus single purpose ports.
It is recognized that these two types of decision problems are interrelated and both types of analysis are usually required to converge on an effective set of decisions.
The multiple offshore port problem consists of determining the number, location, capacity, use, investment and cost of a system of one or more offshore ports to meet the demand for commodity flow from other origin ports to inland destinations or vice versa. This problem, discussed in Ref. 1, can be presented as a transportation network or a linear programming model. Various solution techniques recently developed at M.I.T. (Ref. 3-6) are presented.
The basic problem of offshore port selection can also be formulated as a mixed integer programming problem in which we minimize an objective function such as:
(Mathematical equation available in full paper)
Aj = quantity required at inlandpoint j (per unit time) N = the number of trade routes of interest to offshore port development.
The second constraint guarantees that if port i is closed all trade routes to the port are closed and if port i is open that at least one trade route to the port is open.
