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ABSTRACT: This paper reports on a case study for Ghana's thermal/hydroelectric generation system that evaluates the incremental cost of returning dam outflows to pre-dam or near pre-dam conditions. This mode of operation is termed Run of River (ROR) operation. It appears that two key factors - the availability of alternatives for economically expanding hydro generation and the existence of well developed markets for energy and electricity - have a large influence on the increase in cost of ROR operation relative to the least cost operating rules.
Power & Energy Society General Meeting, 2009. PES '09. IEEE; 08/2009
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ABSTRACT: This paper presents the strategy for development of a stochastic programming model of the operation and capacity additions to a large hydro/thermal electricity generation complex. The proposed model minimizes the incremental costs of operating the complex so as to return river flows to pre-dam patterns. The paper focuses on a representative year made up of wet and dry seasons far enough into the future to allow adjustment of thermal and hydro generating capacities and the initial level of the reservoir, but not the capacity of the reservoir itself. The model was run first to find the operating and investment strategies which minimize electricity costs, and then run so as to minimize cost subject to equating seasonal reservoir inflows to seasonal outflows - so called ldquorun of river, RORrdquo operation. Using data from Ghanapsilas Akosombo/Kpong complex, likely outcomes of the model are presented and compared, based on existing capacities of the system.
Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century, 2008 IEEE; 08/2008
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ABSTRACT: A unit commitment problem has long been known in the class of short-term functions and decisions, inherited from vertically integrated utility. In the competitive environment, the problem has become more complicated due to the fact that any action taken will now influence profitability of decision maker such as generation companies, load serving entities, and so forth. Thus, not only do economic agents face operational risks, but they also need to procure their operations against financial risks from volatility in fuel contract, and electricity prices. This leads to the evolution of stochastic unit commitment in this paper integrating risk management tools, ie., electricity derivatives, so as to reduce the impacts from both operational and financial risks in the short run. The planning model is structured of stochastic mixed-integer program with recourse cost A case study will be addressed with preliminary result presenting an improved solution.
Power Symposium, 2006. NAPS 2006. 38th North American; 10/2006
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ABSTRACT: Electricity suppliers are always confronted with demand uncertainty even though the state-of-the-art forecast and sophisticated control systems are employed to ensure both security and reliability. With the emergence of power market, the market participants such as generation companies, load serving entities, etc., even face higher degree of uncertainty in its operation planning. This is due to the unique characteristics of electricity which could result in unprecedented price spikes. A portfolio of supply contracts including forwards and options is a set of tools for reducing the impacts of both demand uncertainty and price volatility by increasing production flexibility. Thus, a procurement strategy can be implemented by providing more choices via contracting in addition to self generation and spot market transactions. In this framework, a two-stage planning model is developed for improving the short-term operation by incorporating risk hedging strategy in the planning problem so as to meet stochastic demand
Probabilistic Methods Applied to Power Systems, 2006. PMAPS 2006. International Conference on; 07/2006
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ABSTRACT: Vital new transmission lines are high on the agenda of energy planners in the various regions of Africa. These lines are identified within the power pools of Southern Africa and West Africa. The new Central Africa power pool is in the process of identifying these lines as also is the East Africa region. What are the economic gains from these new lines and what are the plans for a continent wide network? The power pool modeling at Purdue University is helping utilities across Africa to answer these questions. This paper outlines some of the transmission modeling issues that are being considered at Purdue and with colleagues across Africa.
Power Engineering Society General Meeting, 2005. IEEE; 07/2005
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ABSTRACT: This paper presents a safety and security constrained hydrothermal scheduling model system. Safety is defined as the measure to take for reducing the potential damage of huge upstream dams while security is defined as the consideration of transmission capacity. The modeling system consists of three submodels: a long-term maintenance model, a long-term stochastic scheduling model and a short-term scheduling model. The paper concentrate on the maintenance model and an application to a large hydrothermal system.
Power Engineering Society General Meeting, 2004. IEEE; 07/2004
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ABSTRACT: In those cases where load fluctuations are small, a utility or independent system operator (ISO) may not incur significant costs in meeting these loads. In contrast, a utility confronted with large load variations due to industrial customers can experience significant costs in order to maintain system parameters. Therefore, highly varying load (HVL), containing uncertain components which are observable in short-term and realtime operations, generally results in the incremental cost in order for the electric utility to meet its customer demand without compromising electric power quality and reliability. The purpose of this study is to present a framework for measuring costs of uncertainty by considering system control and financial market functions and decisions in parallel with any activity that a utility anticipates HVL. The methods for cost measurement are also provided in order to assess the impacts of HVL in terms of costs of uncertainty in short-term and real-time operations.
Electric Utility Deregulation, Restructuring and Power Technologies, 2004. (DRPT 2004). Proceedings of the 2004 IEEE International Conference on; 05/2004
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ABSTRACT: This paper investigates the impact of transmission networks on imperfect competition in deregulated electricity markets. Electricity producers are assumed to engage on a noncooperative gaming with complete but imperfect information. The problem is formulated as a vector profit optimization model. It shows that increasing wheeling charges can both increase market prices and reduce producers' profits, a phenomenon that cannot be explained by a nonspatial framework. Transmission limits have a significant impact on outcomes of market gaming, indicating that reducing transmission congestion would mitigate market power.
Power Engineering Society Winter Meeting, 2002. IEEE; 02/2002
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ABSTRACT: This paper evaluates the impact of mergers of electricity generation companies on wholesale electricity prices. A spatial gaming model, with the Cournot-Nash strategy, is used for the evaluation. The proposed merger evaluation method has certain advantages over the traditional HHI index for measuring potential market power of generators. Case studies are provided to illustrate the use of the model
Power Engineering, 2001. LESCOPE '01. 2001 Large Engineering Systems Conference on; 02/2001
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ABSTRACT: This paper presents a large spatial gaming model with price caps
for the Midwest electricity markets. Price caps are enforced in several
deregulated regional electricity markets in the USA, a logical step is
to reflect this reality in imperfect competition modeling.
Unfortunately, most current gaming models have not included any price
cap formulation. This paper is one of the first to address the issue. A
transportation formulation is used for representing the spatial nature
of an electrical network. An algorithm is proposed to find a Nash
equilibrium under the enforcement of price caps based on the Kuhn-Tucker
vector optimization theorem. Case studies show the successful
application of the model. The conclusion is that, given appropriate
price caps, market power impact can be reduced in the short run
Power Engineering Society Summer Meeting, 2001; 02/2001
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ABSTRACT: This paper presents a market power monitoring model for
electricity markets. It is a social welfare maximization model subject
to nonnegative short-term profit constraints. Traditional economics
claims that market power exists whenever the price is above the
corresponding marginal cost. However, this paper argues that a generator
cannot be considered to be exercising any market power if it earns zero
profit considering only variable cost
IEEE Power Engineering Review 08/2000;
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ABSTRACT: This paper presents a Stackelberg price leadership model for
simulating deregulated electricity markets consisting of one or a few
large producers and a larger number of fringe producers. It is assumed
that the large producer(s) would adopt oligopoly strategy using their
market power while the small producers would use Bertrand-like strategy.
The model is a multi-objective profit maximization program. The
multi-objectives are converted into the same number of partial
Lagrangian functions with power production and supply as the control
variables. A set of KKT conditions is then derived considering the game
strategies of the producers. Test results show that the model
successfully produces a total profit that is greater than that profit
from a welfare maximization model but is less than that from a collusion
model. Producers who adopt Cournot strategy are better off with higher
profits as compared with marginal cost pricing
Power Engineering Society Winter Meeting, 2000. IEEE; 02/2000
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ABSTRACT: This paper presents a gaming model with Cournot strategy considering cross-price elasticities over different time periods. The almost ideal demand system is explored which considers consumption with expenditure target. This means that the total consumption within certain time periods cannot be less than a lower bound. However, consumption can be shifted from peak demand time to nonpeak demand time. A small electricity market setting is used in a case study to demonstrate the model
Power Engineering Society Summer Meeting, 2000. IEEE; 02/2000
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ABSTRACT: This paper presents an optimal dispatch model for competitive
electricity markets where independent system operators (ISOs) dispatch
real power and ancillary services based on supply offers and demand
bids. The model maximizes the “net” societal benefit while
respecting various constraints. Zonal market clearing prices are
determined and DC power flow equations are used to capture the physics
of real power flows. In addition, integer decision variables are used to
capture unit's on/off status and automatic generator control (AGC)/load
following capability in a reliable way. Each producer is assigned a
power flow on each inter-zonal connection and this will be used for
accounting purposes. A six zone, 18-unit system is used as a case study
with satisfactory results
Power Engineering Society Summer Meeting, 2000. IEEE; 02/2000
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ABSTRACT: Water and energy are the key resources required for both economic and population growth, and yet both are increasingly scarce. The distribution of water takes large amounts of energy, while the production of energy requires large amounts of water in processes such as thermal plant cooling systems or raw materials extraction. This study analyzes the water needs for energy production in Spain according to the energy source sector (electricity, transportation or domestic) and process type (extraction and refining of raw materials or thermal plant use). Current and future water needs are quantified according to energy demand and technology mix evolution. Hypothetical scenarios that simulate the risks of promoting specific energy policies are also analyzed. Results show that the combination of energy resources used in Spain is projected to be more than 25% more water consumptive in 2030 than in 2005 under ceteris paribus conditions. Renewable energies are mixed in terms of their consequences on the water supply; wind power can reduce water withdrawal, while the biofuels production is a water-intensive process.
Utilities Policy 01/1999; 8(3):183-197. · 0.80 Impact Factor
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ABSTRACT: The paper presents a new long-term, large-scale hydrothermal
production scheduling method. The proposed method uses both composite
hydro and composite thermal representations, based on the monthly or
weekly energy requirement. The method can minimise the thermal
production cost and maximise the hydro production profit. The advantage
of this method is that it uses a more precise cost objective function
considering unit commitment effect. The method can be used by the owners
of independent hydro plants in a region for long-term hydroelectric
scheduling under both deregulation and competition. A case study shows
that the model allocates successfully and efficiently the hydroelectric
resources to the peak demand periods with negligible computation time
IEE Proceedings - Generation Transmission and Distribution 04/1998; · 0.48 Impact Factor
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ABSTRACT: This paper presents a new long-term hydrothermal production
scheduling method. The proposed method maximizes the profit of
hydroelectric plants, based on the monthly energy requirement of the
system, instead of minimizing the production cost of thermal units. It
is shown that different forms of composite thermal marginal costs will
lead to the same hydro production schedule. Thus a linear marginal cost,
the simplest form, is sufficient for long-term hydrothermal scheduling.
A linear hydro marginal profit is also sufficient for this purpose. An
immediate conclusion is that an actual composite thermal cost function,
which is complicated by thermal unit availability, may not be needed for
the long-term optimal hydrothermal scheduling. Due to this
simplification, traditional long and mid-term hydrothermal scheduling, a
complicated problem, becomes easier to solve. The method can be used by
the owners of independent hydro plants in a region for long-term
hydroelectric scheduling under both deregulation and competition. A case
study shows that the model allocates successfully and efficiently the
hydroelectric resources to peak demand periods with negligible
computation time
IEEE Transactions on Power Systems 03/1998; · 2.68 Impact Factor
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ABSTRACT: Military base closures will affect more than 100 communities across the United States during the next five years. The potential for economic hardship is significant. However, the experience of communities where military bases have closed suggests that the efforts of individual communities during the transition can significantly affect the economic outcome. A PERT simulation model is developed in SLAMSYSTEM to provide a tool for communities that illustrates recovery, takes the impact of job loss into account and gives insight into the implications for a manufacturing organization. An engineering analysis is applied to a problem that has previously been modeled strictly by economists. The PERT simulation model combines the network modeling and continuous modeling concepts in SLAM. It allows the initial conditions and activity times in the base transition process model to control the governing equation for jobs created at a site. Data is collected through a survey of community representatives in communities where the transition is already completed. It is determined that simulation modeling is a reliable method of understanding community influences on successful military base transitions.
Simulation Conference Proceedings, 1994. Winter; 01/1995
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ABSTRACT: Market gaming is a daily routine in a deregulated electricity market. It has been reported extensively that producers have been gaming in the England and Wales power market ever since the market was deregulated. In June 1998, wholesale electricity prices settled at $7000/MWh in the Midwest US market. The replacement power prices settled at $9999/MWh on July 13, 1998 in the newly formulated California Power Exchange. Market power abuses have caught the concern and attention of the Federal Energy Regulatory Commission, state regulatory commissions, and consumer groups. This paper examines different forms of electricity market power abuses and suggests mitigation strategies to minimize the effect of market power on the fledgling competitive markets in the US.
Power Engineering Society 1999 Winter Meeting, IEEE;
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ABSTRACT: The benefits from a centralized and competitive dispatch, compared with existing bilateral electricity trade agreements are determined to be about $100 million per year in the 12-nation Southern African Power Pool (SAPP). Generation, transmission, and costing variables are uniquely incorporated into a short-term cost minimizing mixed integer linear programming model, to determine the optimal unit commitment and dispatch across this 12-nation pool of the Southern African Development Community (SADC) region of Africa. Costs are minimized from increasing the use of existing hydropower facilities in the Democratic Republic of Congo (DRC), Zambia, and Mozambique and reducing fuel costs primarily in South Africa.
Utilities Policy.
