Multiobjective Robust Optimal Design of a Gas Turbine Cogeneration Plant Under Uncertain Energy Demands

2001 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito
Keyword(s):  
Optimal Design ◽  
Energy Saving ◽  
Gas Turbine ◽  
Energy Supply ◽  
Design Method ◽  
Primary Energy ◽  
Weighted Sum ◽  
Cogeneration Plant ◽  
Energy Demands ◽  
Robust Optimal Design

A multiobjective robust optimal design method based on the minimax regret criterion is proposed for sizing equipment of energy supply plants so that they are robust in economic and energy saving characteristics under uncertain energy demands. Equipment capacities and utility contract demands as well as energy flow rates are determined to minimize a weighted sum of the maximum regrets in the annual total cost and primary energy consumption, and satisfy all the possible energy demands. This optimization problem is formulated as a kind of multilevel linear programming one, and its solution is derived by repeatedly evaluating lower and upper bounds for the optimal value of the weighted sum of the maximum regrets. Through a case study on a gas turbine cogeneration plant for district energy supply, the trade-off relationship between the robustness in economic and energy saving characteristics is clarified.

Robust Optimal Design in Multistage Expansion of a Gas Turbine Cogeneration Plant Under Uncertain Energy Demands

2003 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito ◽  
Tatsuhiro Murata
Keyword(s):  
Optimal Design ◽  
Gas Turbine ◽  
Energy Supply ◽  
Design Method ◽  
Design Stage ◽  
Cogeneration Plant ◽  
District Energy ◽  
Expansion Planning ◽  
Energy Demands ◽  
Robust Optimal Design

In designing cogeneration plants, the estimation of energy demands is an important work. However, many conditions under which energy demands are estimated have some uncertainty at the design stage. Therefore, designers should consider that energy demands have some uncertainty, evaluate the robustness in the performance under uncertain energy demands, and design plants rationally in consideration of the robustness. The authors have developed a robust optimal design method based on the minimax regret criterion for the single-stage planning of energy supply plants. In this paper, the method is extended for the multistage expansion planning. Under uncertain energy demands increasing stepwise, equipment capacities and utility contract demands as well as energy flow rates for each expansion period are determined in consideration of their sequential relationships to minimize the maximum regret in the annual total cost and satisfy all the possible energy demands for all the expansion periods. Through a case study on a gas turbine cogeneration plant for district energy supply, features of the economic robustness and the robust optimal design are clarified in relation to the uncertainty in energy demands and the numbers of years for the expansion periods.

Robust Optimal Design in Multistage Expansion of a Gas Turbine Cogeneration Plant Under Uncertain Energy Demands

2004 ◽  
Vol 126 (4) ◽  
pp. 823-830 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito ◽  
Tatsuhiro Murata
Keyword(s):  
Optimal Design ◽  
Gas Turbine ◽  
Energy Supply ◽  
Design Method ◽  
Design Stage ◽  
Cogeneration Plant ◽  
District Energy ◽  
Expansion Planning ◽  
Energy Demands ◽  
Robust Optimal Design

In designing cogeneration plants, the estimation of energy demands is an important work. However, many conditions under which energy demands are estimated have some uncertainty at the design stage. Therefore, designers should consider that energy demands have some uncertainty, evaluate the robustness in the performance under uncertain energy demands, and design plants rationally in consideration of the robustness. The authors have developed a robust optimal design method based on the minimax regret criterion for the single-stage planning of energy supply plants. In this paper, the method is extended for the multistage expansion planning. Under uncertain energy demands increasing stepwise, equipment capacities and utility contract demands as well as energy flow rates for each expansion period are determined in consideration of their sequential relationships to minimize the maximum regret in the annual total cost and satisfy all the possible energy demands for all the expansion periods. Through a case study on a gas turbine cogeneration plant for district energy supply, features of the economic robustness and the robust optimal design are clarified in relation to the uncertainty in energy demands and the numbers of years for the expansion periods.

Robust Optimal Design of a Gas Turbine Cogeneration Plant Under Uncertain Energy Demands and Costs

2015 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Masashi Ohkura ◽  
Tetsuya Wakui
Keyword(s):  
Optimal Design ◽  
Gas Turbine ◽  
Energy Supply ◽  
Design Method ◽  
Performance Comparison ◽  
Energy Demands ◽  
Robust Optimal Design ◽  
Optimal Design Method ◽  
Supply Systems ◽  
Energy Supply Systems

In designing energy supply systems, designers should consider that energy demands and costs as parameters have some uncertainties, evaluate the robustness in system performances against the uncertainties, and design the systems rationally to heighten the robustness. A robust optimal design method of energy supply systems under only uncertain energy demands was revised so that it can be applied to systems with complex configurations and large numbers of periods for variations in energy demands. In addition, a method of comparing performances of two energy supply systems under only uncertain energy demands was proposed by utilizing a part of the revised robust optimal design method. In this paper, the revised robust optimal design method as well as the proposed performance comparison method are extended so that they can be applied to the robust optimal design and the performance comparison of energy supply systems under not only uncertain energy demands but also uncertain energy costs. Through a case study on a gas turbine cogeneration system for district energy supply, the validity and effectiveness of the extended optimal design method and features of the robust optimal design are clarified. In addition, the gas turbine cogeneration system is compared with a conventional energy supply system using the extended performance comparison method.

Robust Optimal Operation of a Gas Turbine Cogeneration Plant Under Uncertain Energy Demands

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Ryohei Yokoyama ◽  
Masashi Ohkura ◽  
Tetsuya Wakui
Keyword(s):  
Gas Turbine ◽  
Energy Supply ◽  
Numerical Study ◽  
Optimization Method ◽  
Optimal Operation ◽  
Mixed Integer ◽  
Cogeneration Plant ◽  
Co2 Emission Reduction ◽  
Operational Strategy ◽  
Energy Demands

Some optimal operation methods based on the mixed-integer linear programming (MILP) have been proposed to operate energy supply plants properly from the viewpoints of economics, energy saving, and CO2 emission reduction. However, most of the methods are effective only under certain energy demands. In operating an energy supply plant actually, it is necessary to determine the operational strategy properly based on predicted energy demands. In this case, realized energy demands may differ from the predicted ones. Therefore, it is necessary to determine the operational strategy so that it is robust against the uncertainty in energy demands. In this paper, an optimization method based on the MILP is proposed to conduct the robust optimal operation of energy supply plants under uncertain energy demands. The uncertainty in energy demands is expressed by their intervals. The operational strategy is determined to minimize the maximum regret in the operational cost under the uncertainty. In addition, a hierarchical relationship among operation modes and on/off states of equipment, energy demands, and energy flow rates of equipment is taken into account. First, a general formulation of a robust optimal operation problem is presented, which is followed by a general solution procedure. Then, in a numerical study, the proposed method is applied to a gas turbine cogeneration plant for district energy supply. Through the study, some features of the robust optimal operation are clarified, and the validity and effectiveness of the proposed method are ascertained.

Robust Optimal Design of a Gas Turbine Cogeneration Plant Based on Minimax Regret Criterion

1999 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito
Keyword(s):  
Energy Supply ◽  
Minimax Regret ◽  
Cogeneration Plant ◽  
Total Cost ◽  
Energy Demands ◽  
Robust Optimal Design ◽  
Annual Total ◽  
Minimax Regret Criterion ◽  
Maximum Regret ◽  
Annual Total Cost

A robust optimal design method based on the minimax regret criterion is proposed for unit sizing of energy supply plants so that they are robust economically against the uncertainty in energy demands. Equipment capacities and utility contract demands as well as energy flow rates are determined to minimize the maximum regret in the annual total cost and to satisfy all the possible energy demands. This optimization problem is formulated as a kind of multilevel linear programming one, and its solution is derived by repeatedly evaluating lower and upper bounds for the optimal value of the maximum regret in the annual total cost. Through a case study on a gas turbine cogeneration plant for district energy supply, it is shown that determining equipment capacities appropriately is more important under uncertain energy demands rather than certain ones. It is also shown that the ratio of power generating capacity to total power supply capacity decreases with an increase of the uncertainty in energy demands.

Robust Optimal Operation of a Gas Turbine Cogeneration Plant Under Uncertain Energy Demands

2014 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Masashi Ohkura ◽  
Tetsuya Wakui
Keyword(s):  
Linear Programming ◽  
Gas Turbine ◽  
Integer Linear Programming ◽  
Mixed Integer Linear Programming ◽  
Energy Supply ◽  
Optimal Operation ◽  
Mixed Integer ◽  
Cogeneration Plant ◽  
Operational Strategy ◽  
Energy Demands

Some optimal operation methods based on the mixed-integer linear programming have been proposed to operate energy supply plants properly from the viewpoints of economics, energy saving, and CO2 emission reduction. However, most of the methods are effective only under certain energy demands. In operating an energy supply plant actually, it is necessary to determine the operational strategy properly based on predicted energy demands. In this case, realized energy demands may differ from the predicted ones. Therefore, it is necessary to determine the operational strategy so that it is robust against the uncertainty in energy demands. In this paper, an optimization method based on the mixed-integer linear programming is proposed to conduct the robust optimal operation of energy supply plants under uncertain energy demands. The uncertainty in energy demands is expressed by their intervals. The operational strategy is determined to minimize the maximum regret in the operational cost under the uncertainty. In addition, a hierarchical relationships among operation modes and on/off states of equipment, energy demands, and energy flow rates of equipment are taken into account. First, a general formulation of a robust optimal operation problem is presented, which is followed by a general solution procedure. Then, in a numerical study, the proposed method is applied to a gas turbine cogeneration plant for district energy supply. Through the study, some features of the robust optimal operation are clarified, and the validity and effectiveness of the proposed method are ascertained.

Sign in / Sign up

Export Citation Format

Share Document