Now showing items 1-13 of 13

  • Agent-based Optimization to Estimate Nash Equilibrium in Power Markets 

    Authors:Yücekaya, Ahmet; Valenzuela, Jorge
    Publisher and Date:(Taylor & Francis Inc, 2013)
    In most deregulated power markets firms bid daily into a day-ahead power market. The auction mechanism supply and demand determine the equilibrium at each hour. In this environment firms aim to maximize their revenues by carefully determining their bids. This requires the development of effective computational methods that help them estimate their competitors' behaviors under incomplete information. In this article an agent-based method that uses particle swarm optimization is described to simulate ...

  • An analysis of price spikes and deviations in the deregulated Turkish power market 

    Authors:Gayretli, Gizem; Yücekaya, Ahmet; Bilge, Ayşe Hümeyra
    Publisher and Date:(Elsevier, 2019)
    The successful operation of a real time market is related to the planning in the day ahead market. We analyze the day ahead and real time market data for the Turkish power market for the period 2012-2015 to classify price spikes and their causes. We also focus on the levels of deviation between the day ahead market values and the real time market values. We define price deviation and load deviation ratios to measure the level of deviation both in price and demand. The analysis for the load is based ...

  • Bidding of price taker power generators in the deregulated Turkish power market 

    Authors:Yücekaya, Ahmet
    Publisher and Date:(Pergamon-Elsevier Science Ltd, 2013)
    In deregulated power markets power firms bid into the day-ahead power market either with buy offers or sell offers. The auction mechanism and competition determine the equilibrium price and quantity for each hour. If the bid price of a company is below the market clearing price then the offer of the company is accepted and rewarded with the market price. A company can be a price maker or price taker depending on the capacity it offers to the market. A price-taker unit must determine the right offer ...

  • Energy Storage with Pumped Hydrostorage Systems Under Uncertainty 

    Authors:Yücekaya, Ahmet
    Publisher and Date:(Springer International Publishing Ag, 2015)
    Energy storage is becoming an important problem as the difference between supply and demand becomes sharper and the availability of energy resources is not possible all the time. A pumped hydrostorage system (PHSS) which is a special type of hydroelectric power plant can be used to store energy and to use the water more efficiently. When the energy demand and the energy price are high (peak hours) the water at upper reservoir is used to generate electricity and the water is stored in the lower ...

  • A Fuzzy ANP-Based GRA Approach to Evaluate ERP Packages 

    Authors:Ayağ, Zeki; Yücekaya, Ahmet
    Publisher and Date:(IGI Global, 2019)
    One of the major problems that most companies face with during the implementation of an ERP system is to determine the best satisfying ERP software based on their needs and expectations. Because an improperly selected ERP software might lead to time loss and increased costs, and in the long run, a loss of market share. Therefore, the ERP evaluation process for companies becomes to a vital point. On the other hand, evaluating ERP software alternatives under a set of criteria leads us to a ...

  • Hourly electricity demand forecasting using Fourier analysis with feedback 

    Whether it be long-term, like year-ahead, or short-term, such as hour-ahead or day-ahead, forecasting of electricity demand is crucial for the success of deregulated electricity markets. The stochastic nature of the demand for electricity, along with parameters such as temperature, humidity, and work habits, eventually causes deviations from expected demand. In this paper, we propose a feedback-based forecasting methodology in which the hourly prediction by a Fourier series expansion is updated ...

  • Landfill Gas to the Energy Potential of Turkey: A Scenario-based Multi-period Simulation 

    Authors:Yücekaya, Ahmet
    Publisher and Date:(Taylor & Francis Inc, 2013)
    Turkey is a developing country with increasing power demands and limited energy sources. Municipal solid waste processing landfilling and utilization of the gas to generate electric power and lower emissions has been used in developed countries for decades however it is relatively new in Turkey. The new regulations force municipalities in the country to build landfills to safely store the waste and secure the emission gases. The landfill gas can be utilized to produce energy and heat or if the ...

  • Managing Fuel Coal Supply Chains With Multiple Objectives and Multimode Transportation 

    Authors:Yücekaya, Ahmet
    Publisher and Date:(AMER SOC ENGINEERING MANAGEMENT, 2013)
    Power companies require sophisticated tools to manage fuel-coal supply chains which include multiple suppliers coal contracts and multimode transportation routes. In this article a multi-objective model which is integrated with multi-attribute decision-making for the selection of suppliers transportation routes and coal orders is developed. The model simultaneously optimizes multiple objectives such as minimizing purchase costs transportation costs and ash output and it also presents a decision ...

  • Managing natural gas demand for free consumers under uncertainty and limited storage capacity 

    Demand for energy sources depends on several factors such as population growth, urbanization, industrialization, and climate. Among fundamental energy sources, natural gas is characterized by storage limitations and take-or-pay contracts, which makes it especially critical to forecast the demand accurately for cost management policies. Suppliers of natural gas require take-or-pay contracts to ensure that consumers pay for any unused amount up front; and if the demand exceeds the agreed amount, ...

  • Multi-objective Fuel Supply for Coal-fired Power Plants Under Emission Transportation and Operational Constraints 

    Authors:Yücekaya, Ahmet
    Publisher and Date:(Taylor & Francis Inc, 2013)
    Coal-fired power plants need to decrease their generation cost in deregulated power markets so as to be selected dispatched and compete with other cheaper resources. On the other hand coal prices have risen significantly and extra costs for SO2 and NOx emission outputs are imposed that force power companies to lower the costs for the fuel-coal supply process. In this article a multi-objective model for supplier transportation and coal order selection is developed for the coal supply of electric ...

  • Nutrient Dynamics in Flooded Wetlands. I: Model Development 

    Wetlands are rich ecosystems recognized for ameliorating floods improving water quality and providing other ecosystem benefits. This part of a two-paper series presents a relatively detailed process-based model for nitrogen and phosphorus retention cycling and removal in flooded wetlands. The model captures salient features of nutrient dynamics and accounts for complex interactions among various physical biogeochemical and physiological processes. The model simulates oxygen dynamics and the impact ...

  • Nutrient Dynamics in Flooded Wetlands. II: Model Application 

    In this paper the authors applied and evaluated the wetland nutrient model that was described in Paper I. Hydrologic and water quality data from a small restored wetland located on Kent Island Maryland which is part of the Delmarva Peninsula on the eastern shores of the Chesapeake Bay was used for this purpose. The model was assessed through various methods against the observed data in simulating nitrogen (N) phosphorus (P) and total suspended sediment (TSS) dynamics. Time series plots of observed ...

  • The operational economics of compressed air energy storage systems under uncertainty 

    Authors:Yücekaya, Ahmet
    Publisher and Date:(Pergamon-Elsevier Science Ltd, 2013)
    A Compressed Air Energy Storage System is a means of storing energy which can then be used when the demand for energy increases. In this system air is compressed in a cavern when power prices are low and this air is used to run a natural gas-fired turbine to generate power when prices go up with the aim of profiting from the price difference. This type of system can independently compress air generate electricity or do both. However the prices of electricity and natural gas fluctuate which directly ...