Robust decisions in power system investments
The Turkish electrical system has been studied, particularly for the near term investment programme. The objective of the study was to determine the most likely investment alternatives for the next ten-year period, from a cost effectiveness point of view. A dynamic linear programming model was used in representing the national energy system, with special emphasis on the electricity sector. Hydro, coal, nuclear and oil-fired power plants as well as their interconnection investments were modelled. A 27-year planning horizon was defined. The scenario approach was utilized in establishing the effects of different factors, such as foreign currency requirements of projects, nuclear plant costs and nuclear fuel costs, demand growth rates for electricity as well as other fuels, availability of foreign currency and skilled manpower, and the development rates of coal mines, coal power plants and nuclear power plants. After analyzing the results of 24 different scenarios, robust plans for developing the power system are suggested. Other investments that are subject to the realization of certain conditions are also indicated.
Robust contingency plans for transportation investment planning
A multistage decision process for transportation investment planning is described. Most transportation investment problems inherently involve multiple criteria and uncertainty. To deal with the variations arising from changes in external environments, robust contingency plans should be integrated in the planning process-not after plans are developed-to account for uncertainty. With the proposed decision process, a multiple criteria decision-making (MCDM) method is first used to select a set of good potential designs (or potential solutions). Corresponding optimal contingency plans for each design under uncertainty are then prepared. Robustness considerations are used in making the final selection among contingency plans. To demonstrate the proposed decision-making process, a scenario approach is applied to develop a multistage decision-making process for transportation investment planning problems. Finally, an example of regional transportation investment is presented to illustrate the method. >
Flow in a branching open channel: a review
Branching channel flow refers to any side water withdrawals from rivers or main channels. Branching channels have wide application in many practical projects, such as irrigation and drainage network systems, water and waste water treatment plants, and many water resources projects. In the last decades, extensive theoretical and experimental investigations of the branching open channels have been carried out to understand the characteristics of this branching flow, varying from case studies to theoretical and experimental investigations. The objectives of this paper are to review and summarise the relevant literatures regarding branching channel flow. These literatures were reviewed based on flow characteristics, physical characteristics, and modeling of the branching flow. Investigations of the flow into branching channel show that the branching discharge depends on many interlinked parameters. It increases with the decreasing of the main channel flow velocity and Froude number at the upstream of the branch channel junction. Also it increases with the increasing of the branch channel bed slope. In subcritical flow, water depth in the branch channel is always lower than the main channel water depth. The flow diversion to the branch channel leads to an increase of water depth at the downstream of the main channel. From the review, it is important to highlight that most of the study concentrated on flow characteristics in a right angle branch channel with a rigid boundary. Investigations on different branching angles with movable bed have still to be explored.