Endre søk
Begrens søket
1 - 11 of 11
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Moiseeva, Ekaterina
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Impact of High levels of Wind Penetration on the Exercise of Market Power in the Multi-Area Systems2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    New European energy policies have set a goal of a high share of renewable energy in electricity markets. In the presence of high levels of renewable generation, and especially wind, there is more uncertainty in the supply. It is natural, that volatility in energy production induces the volatility in energy prices. This can create incentives for the generators to exercise market power by traditional means: withholding the output by conventional generators, bidding not the true marginal costs, or using locational market power. In addition, a new type of market power has been recently observed: exercise of market power on ramp rate. This dissertation focuses on modeling the exercise of market power in power systems with high penetration of wind power. The models consider a single, or multiple profit-maximizing generators. Flexibility is identified as one of the major issues in wind-integrated power systems. Therefore, part of the research studies the behavior of strategic hydropower producers as main providers of flexibility in systems, where hydropower is available.Developed models are formulated as mathematical and equilibrium problems with equilibrium constraints (MPECs and EPECs). The models are recast as mixed-integer linear programs (MILPs) using discretization. Resulting MILPs can be solved directly by commercially-available MILP solvers, or by applying decomposition. Proposed Modified Benders Decomposition Algorithm (MBDA) significantly improves the computational efficiency.

  • 2.
    Moiseeva, Ekaterina
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Nash Equilibria in Hydro-Dominated Systems under Uncertainty: Modified Benders Approach2017Artikkel i tidsskrift (Fagfellevurdert)
  • 3.
    Moiseeva, Ekaterina
    et al.
    KTH.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Bayesian and Robust Nash Equilibria in Hydrodominated Systems Under Uncertainty2018Inngår i: IEEE Transactions on Sustainable Energy, ISSN 1949-3029, E-ISSN 1949-3037, Vol. 9, nr 2, s. 818-830Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we model strategic interaction of multiple producers in hydrodominated power systems under uncertainty as an equilibrium problem with equilibrium constraints (EPEC), reformulated as a stochastic mixed-integer linear program with disjunctive constraints. We model strategic hydropower producers who can affect the market price by submitting strategic bids in quantity, price, and ramp rate. The bids are submitted to the system operator who minimizes the dispatch cost. We take into account the hydrospecific constraints and uncertainty in the system. Solving the problem results in finding Nash equilibria. We discuss two types of Nash equilibria under uncertainty: Bayesian and robust Nash equilibria. Large EPEC instances can be solved using a decomposition method-Modified Benders Decomposition Approach. This method eliminates the problem of tuning the disjunctive parameter and reduces the memory requirements, resulting in improved computation time.

  • 4.
    Moiseeva, Ekaterina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Impact of energy storage devices on energy price in decentralized wind-diesel utilities2013Inngår i: 2013 10th International Conference on the European Energy Market (EEM), IEEE conference proceedings, 2013, s. 6607282-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The most widely spread method of supplying the customers in isolated areas is to use single or multiple diesel generators with constant or variable speed. The price of energy in such areas is highly influenced by the cost of fuel transportation to the place of consumption. We propose an approach to reduce this price by complementing the diesel generators with wind turbines and high-capacity energy storage devices. We create a model to define the proportion between the installed capacities and to provide the proper sizing of elements. The paper studies the case of an isolated area in central Russia, where the fuel transportation share of energy price reaches 65%. We propose a new energy supply system, which includes diesel generators, wind turbines and energy storage devices. We study the system statistically and model it in Homer software. To decrease the capital and operating costs, we introduce the specific algorithm: the diesel generator operates only when wind turbines are not covering the load and energy storage device is exhausted. We test the proposed algorithm using MATLAB to obtain both economic and technical operation results. The economic modeling then continues the system evaluation. We evaluate the investment criteria and define the new minimum price for electricity. The paper is concluded by a systematic analysis of the results and remarks towards the efficiency of investment into the new equipment.

  • 5.
    Moiseeva, Ekaterina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Modeling the Hedging Decisions in Electricity Markets Using Two-stage Games2013Inngår i: 2013 4th IEEE/PES Innovative Smart Grid Technologies Europe, ISGT Europe 2013, IEEE conference proceedings, 2013, s. 6695462-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The electricity market structure aims to provide effective competition among producers. However, the exercise of market power considerably affects energy prices and induces the wealth transfer from consumers to generators. It is widely recognized that the incentive of generator to exercise market power depends on its hedging decision. The hedged generator has very little or no tendency to exercise market power. However, existing approaches for forecasting market power typically take the hedge cover level as an external input to the model, providing an open-loop analysis. In practice, the level of hedge is chosen by a generating firm and treated confidentially. Omitting this assumption results in equilibrium constraints in the forward and spot stages of the trade period. This type of problem can be modelled as a two-stage game, where in the first stage the generator decides on the profit-maximizing level of hedging and in the second stage it takes part in Cournot game on output in spot market. We show that in the oligopoly case with no constraints on installed capacity and transmission limits there is no equilibrium in pure strategies, which corresponds to the "all-or-nothing" decision. In the case when transmission and capacity constraints are binding, we use a backward induction approach and closed-loop analysis to find a sub-game perfect Nash equilibrium (SPNE) on the level of hedging and a corresponding SPNE in spot market. We show that the solution in this constrained network is similar to the unconstrained one.

  • 6.
    Moiseeva, Ekaterina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Modeling the Unilateral Multi-part Strategic Withholding in Electricity Markets2015Inngår i: 2015 Australasian Universities Power Engineering Conference, IEEE conference proceedings, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Modeling and predicting the exercise of market power is an important problem for modern electricity markets. A change in the generation mix and an evolvement of bidding procedures give ascent to a variety of new types of strategic behavior involving elaborate strategies with unconventional strategic variables. In this paper we show how it is important to consider all parameters of the bid to perform a sound market power assessment. We propose a bi-level model of a profit-maximizing decision maker bidding to the electricity market. A company, owning a portfolio of generating units, can strategically choose a price offer, capacity and a ramp rate of its units. We show that withholding the flexibility of the sources causes considerable market power costs. The strategic decision of the company is followed by the optimal dispatch, where the market price is calculated. The problem is formulated as a mathematical program with equilibrium constraints (MPEC) and recast as a single-stage mixed-integer linear programming problem (MILP). Developed model is applied to a 24-node IEEE test system to highlight the withholding and demonstrate the cost of market power.

  • 7.
    Moiseeva, Ekaterina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Strategic bidding by a risk-averse firm with a portfolio of renewable resources2015Inngår i: 2015 IEEE Eindhoven PowerTech, PowerTech 2015, IEEE conference proceedings, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The possibility of market power abuse in the systems with a high amount of flexible power sources (hydro units and energy storage) is believed to be very low. However, in practice strategic owners of these resources may limit the ramping rate whenever the price spikes occur. This is particularly relevant for the power systems with a high penetration of wind power, due to the high levels of uncertainty. In this paper we propose a bilevel game-theoretic model to investigate the effect of this type of strategic bidding. The lower-level is a security-constrained economic dispatch carried out by the system operator. The upper-level is a profit-maximization problem solved by a risk-averse company owning a varied portfolio of energy sources: energy storage, hydro power units, wind generators, as well as traditional generators. We represent the uncertainty affecting the decision making by introducing a set of wind power scenarios and variable competitors' price bids. The resulting mathematical problem with equilibrium constraints (MPEC) is recast as a single-stage mixed-integer linear program (MILP) and solved with CPLEX. In the case study we demonstrate the effect of withholding the ramp-rate on the social welfare.

  • 8.
    Moiseeva, Ekaterina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Strategic Bidding of a Hydropower Producer under Uncertainty: Modified Benders Approach2018Inngår i: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 33, nr 1, s. 861-873Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper proposes a stochastic bilevel program for strategic bidding of a hydropower producer. The price, quantity and ramp-rate bids are considered. The uncertainty of wind power generation, variation of inflows for the hydropower producer, and demand variability are modeled through the moment-matching scenario generation technique. Using discretization the stochastic bilevel program is reformulated as a stochastic mixed-integer linear program (MILP) with disjunctive constraints. We propose a modified Benders decomposition algorithm (MBDA), which fully exploits the disjunctive structure of reformatted MILP model. More importantly, the MBDA does not require optimal tuning of disjunctive parameters and it can be efficiently parallelized. Through an illustrative 5-node example, we identify possible strategies (specific to a hydropower producer) for maximizing profit, which in turn leads to market insights. We also use the IEEE 24-node, 118-node, and 300-node case studies to show how our parallelized MBDA outperforms the standard benders decomposition algorithm. The parallelized MBDA is also compared to the state-of-the-art CPLEX solver.

  • 9.
    Moiseeva, Ekaterina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Biggar, Darryl
    Exercise of Market Power on Ramp Rate in Wind-Integrated Power Systems2015Inngår i: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 30, nr 3, s. 1614-1623Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With an increasing penetration of wind power, there is likely to be an increasing need for fast-ramping generating units. These generators ensure that no load is lost if supply drops due to the uncertainties in wind power generation. However, it is observed in practice that, in a presence of network constraints, fast-ramping generating units are prone to act strategically and exercise market power by withholding their ramp rates. In this paper we model this gaming behavior on ramp rates. We assume a market operator who collects bids in form of marginal costs, quantities, and ramp rates. He runs a ramp-constrained economic dispatch given the generators' bids, forecasted demand, and contingencies. Following the game-theoretic concepts, we set up a multi-level optimization problem. The lower-level problem is the ramp-constrained economic dispatch and the higher-level represents the profit maximization problems solved by strategic generators. The whole problem is formulated as an equilibrium problem with equilibrium constraints (EPEC). The outcome of the EPEC problem is a set of Nash equilibria. To tackle the multiple Nash equilibria problem, the concept of the extremal-Nash equilibria is defined and formulated. We model the concept of extremal-Nash equilibria as a single-stage mixed-integer linear programming problem (MILP) and demonstrate the application of this mathematical framework on an illustrative case and on a more realistic case study with tractable results.

  • 10.
    Moiseeva, Ekaterina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Dimoulkas, Ilias
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Tacit Collusion with Imperfect Information: Ex-Ante Detection2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The liberalization of electricity markets had a significant impact on the whole process of optimal dispatch. The positive effect of competition is partly canceled out by profit-maximizing behavior of market participants. Strategic generators can exercise market power or collude tacitly with other participants to ensure higher electricity price and therefore higher profits. In this paper we study the generators' possibility to come to a tacit collusion by distributed computations. Due to the strategic nature of market interactions, the information corresponding to the power production by generating companies is often fully confidential outside the generating unit. Such information includes the data about planned and emergency outages, capacity constraints, ramping rates specific to the units, probability of failures, etc. Under certain assumptions the constraint set of a generating unit can be represented as a convex set. Using a novel multi-agent distributed constrained optimization algorithm we show how market participants with confidential constraint sets can reach the collusion on the production share, while maximizing their own profit. We compare this outcome to the outcome of Nash equilibrium over specified time horizon and conclude, if both generators find it profitable to collude. This modeling is important for early detection and prevention of tacit collusion.

  • 11.
    Moiseeva, Ekaterina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Wogrin, Sonja
    Universidad Pontificia Comillas.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Generation Flexibility in Ramp Rates: Strategic Behavior and Lessons for Electricity Market Design2017Inngår i: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 261, nr 2, s. 755-771Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A ramp rate usually defines the speed at which an electric power producer can decrease or increase its production in limited time. The availability of fast-ramping generators significantly affects the economic dispatch, especially in the systems with high penetration of intermittent energy sources, e.g. wind power, since the fluctuations in supply are common and sometimes unpredictable. One of the regulatory practices of how to impel generators to provide their true ramp rates is to separate the stages of submitting the bids on ramp rate and production. In this paper we distinguish two types of market structures: one-stage – when electric power producers are deciding their production and ramp rate at the same time, or two-stage – when generators decide their ramp rate first, and choose their production levels at the second stage. We employ one-stage and two-stage equilibrium models respectively to represent these market setups and use a conjectured price response parameter ranging from perfect competition to the Cournot oligopoly to investigate the effect of the market competition structure on the strategic decisions of the generators. We compare these two market setups in a symmetric duopoly case with two time periods and prove that in the two-stage market setup the level of ramp rate is independent of the strategic behavior in the spot market and generally lower than the one offered in the one-stage setup. We also show that the ramp-rate levels in one- and two-stage models coincide at the Cournot oligopoly. We extend the model to asymmetry, several load periods, portfolio bidding, and uncertainty, and show that withholding the ramp rate still occurs in both models. Our findings prove that market regulators cannot rely on only separating the decision stages as an effective measure to mitigate market power and in certain cases it may lead to an adverse effect.

1 - 11 of 11
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf