27 research outputs found
Modelling the effects of nuclear fuel reservoir operation in a competitive electricity market
No full textIn many countries, the electricity systems are quitting the vertically integrated monopoly organization for an operation framed by competitive markets. In such a competitive regime one can ask what the optimal management of the nuclear generation set is. We place ourselves in a medium-term horizon of the management in order to take into account the seasonal variation of the demand level between winter (high demand) and summer (low demand). A flexible nuclear set is operated to follow a part of the demand variations. In this context, nuclear fuel stock can be analyzed like a reservoir since nuclear plants stop periodically (every 12 or 18 months) to reload their fuel. The operation of the reservoir allows different profiles of nuclear fuel uses during the different seasons of the year. We analyze it within a general deterministic dynamic framework with two types of generation: nuclear and non-nuclear thermal. We study the optimal management of the production in a perfectly competitive market. Then, we build a very simple numerical model (based on data from the French market) with nuclear plants being not operated strictly as base load power plants but within a flexible dispatch frame (like the French nuclear set). Our simulations explain why we must anticipate future demand to manage the current production of the nuclear set (myopia can not be total). Moreover, it is necessary in order to ensure the equilibrium supply-demand, to take into account the non-nuclear thermal capacities in the management of the nuclear set. They also suggest that non-nuclear thermal could stay marginal during most of the year including the months of low demand.Electricity Market; nuclear generation; optimal reservoir operation; electricity fuel mix; perfect competition with reservoir
An inter-temporal optimization of flexible nuclear plants operation in market based electricity systems : The case of competition with reservoir
No full textIn electricity markets where competition has been established for a long time, a nuclear operator familiar with the operation of such markets could be interested in the optimal long-term management of a flexible nuclear set (like the French) in a competitive market. To obtain a long vision of the optimal management of a nuclear set, we realize a full inter-temporal optimization of the production which results from the maximization of the value of generation over the whole game. Our model takes into consideration the periodical shut-down of nuclear units to reload their fuel, which permits to analyze the nuclear fuel as a stock behaving like a reservoir. A flexible nuclear reservoir permits different allocations of the nuclear fuel during the different demand seasons of the year. Our analysis is realized within a general deterministic dynamic framework where perfect competition is assumed and two flexible types of generation exist : nuclear and thermal non-nuclear. The marginal cost of nuclear production is (significantly) lower that the one of non-thermal production, which induces a discontinuity of producers' profit. In view of this price discontinuity, a "regularization" of the merit order price is achieved within our numerical model which leads to an alternative optimization problem (reglarized problem) that constitutes a good approximation of our initial problem. We also prove that in the absence of binding productions constraints, solutions are fully characterized by a constant nuclear production. However, such solutions do not exist within our numerical model because of production constraints that are active at the optimum. Finally, we study the maximization of social welfare in an identical framework. Similarly, we demonstrate that in the absence of binding production constraints a constant non-nuclear thermal production is a characteristic property of solutions of the social welfare maximization problem.Electricity market, nuclear generation, inter-temporal optimal reservoir operation, competition with reservoir, price discontinuity, social welfare.
La gestion optimale des centrales nucléaires flexibles dans des systèmes électriques concurrentiels : le cas de la concurrence avec réservoir
No full textL’énergie nucléaire, qui est une technologie de génération largement utilisée dans des systèmes électriques, est caractérisée par des coûts fixes élevés et des coûts variables bas. Pour amortir ses coûts fixes, le nucléaire est préférentiellement utilisé pour une opération en base inflexible, c’est-à-dire opérer à un niveau constant pour répondre à la partie non variable de la demande d’un système électrique et produire au maximum de sa propre capacité. En raison de cette spécificité, l’insertion de la production nucléaire dans les marchés concurrentiels d’électricité n’a pas été profondément étudiée jusqu’à présent. Par conséquent, même dans des marchés concurrentiels, la question de la gestion optimale d’un parc de production nucléaire n’a pas été soulevée parce que la production nucléaire est censée fonctionner en continu (pour couvrir la demande de base). Cependant, il y a des cas ou` la gestion de la production nucléaire semble plus complexe que ne le suggère cette vision simplifiée. En règle générale, lorsque la proportion de l’énergie nucléaire dans un parc de production est élevée, la production nucléaire doit s’adapter aux variations de la demande. Cela soulève la question de la façon optimale de gérer cette technologie de production dans ce contexte. Comme cette question n’a pas été étudiée jusqu’à présent, il est nécessaire de proposer un cadre théorique qui permet une analyse des situations comme celle de la France, avec un marché concurrentiel et où le nucléaire représente 80% de la production, c’est-à-dire beaucoup plus que ce qui serait nécessaire pour couvrir la demande de base. Nous nous plaçons dans un horizon à moyen terme de la gestion (1 à 3 ans) pour tenir compte de la variation saisonnière de la demande. A moyen terme, le gestionnaire d’un parc nucléaire très large (comme le parc français) doit ajuster sa production selon les variations saisonnières de la demande. Dans ce cadre, le stock de combustible nucléaire peut être analysé comme un réservoir puisque les centrales nucléaires s’arrêtent périodiquement (tous les 12 ou 18 mois) pour recharger leur combustible. La gestion de ce réservoir permet de profils différents d’usages de combustible nucléaire au cours des différentes saisons de l’année. Ainsi, nous nous pencherons sur cette question comme une analyse économique rationnelle de l’opération d’un “réservoir” de combustible nucléaire. Nous allons ensuite l’analyser dans un cadre général déterministe dynamique avec deux types de production : nucléaire et thermique non-nucléaire. Nous étudions la gestion optimale de la production dans un marché parfaitement concurrentiel. Ensuite, nous établissons un modèle numérique (basé sur les données du marché français) où les centrales nucléaires ne sont pas opérées à production constante, mais dans un cadre de placement flexible (comme le parc nucléaire français). […]Nuclear power as a generation technology that is widely used in electricity production systems is characterized by high fixed costs and low variable costs. To amortize its fixed costs, nuclear is preferentially used for inflexible baseload operation, i.e. operate at a constant level to meet the non variable part of electricity demand of a system and produce at its maximum capacity. Because of this specificity, the insertion of nuclear production in competitive electricity markets has not been deeply studied so far. Therefore, even in competitive markets, the question of the optimal management of a nuclear generation set has not been raised because nuclear production is supposed to operate continuously (to cover baseline demand). However, there are cases where the management of nuclear generation seems more complex than suggested by this simplified view. Typically, when the proportion of nuclear energy in a production set is high, the nuclear generation output has to adjust to the variations in demand. This raises the question of the optimal way to manage this production technology in that kind of setting. As this question has not been studied so far, there is a need for a theoretical framework that enables an analysis of situations like the French one, with a competitive market and where nuclear represents 80% of generation, i.e. much more that what would be necessary to cover the baseload demand. We place ourselves in a medium-term horizon of the management (1 to 3 years) to take into account the seasonal variation of the demand level. In the medium-term, the manager of a large nuclear set (like the French set) has to set its seasonal variation of output according to the demand level. Since nuclear units have to stop periodically (from 12 to 18 months) to reload their fuel, we can analyze the nuclear fuel as a stock behaving like a reservoir. The operation of the reservoir allows different profiles of nuclear fuel use during the different demand seasons of the year. Thus, we will look at this question as a rational economic analysis of the operation of a nuclear fuel “reservoir”. We then analyze it within a general deterministic dynamic framework with two types of generation: nuclear and thermal non-nuclear. We study the optimal management of the production in a perfectly competitive market. Then, we establish a numerical model (based on data from the French market) with nuclear plants being not operated strictly as base load power plants but within a flexible dispatch frame (like the French nuclear set). [...
The optimal short-term management of flexible nuclear plants in a competitive electricity market as a case of competition with reservoir
No full textThe optimal short-term management of flexible nuclear plants in a competitive electricity market as a case of competition with reservoir / Maria Lykidi, Jean-Michel Glachant & Pascal Gourdel. Paris : Centre d'Economie de la Sorbonne, octobre 2012, 47 p. (CES working papers ; 2012.58) http://halshs.archives-ouvertes.fr/halshs-00747386 In many countries, the electricity systems are quitting the vertically integrated monopoly organization for an operation framed by competitive markets. It there..
The optimal short-term management of flexible nuclear plants in a competitive electricity system as a case of competition with reservoir
No full textURL des Documents de travail : http://centredeconomiesorbonne.univ-paris1.fr/documents-de-travail/Documents de travail du Centre d'Economie de la Sorbonne 2014.57 - ISSN : 1955-611XIn many countries, the electricity systems are quitting the vertically integrated monopoly organization for an operation framed by competitive markets. It therefore questions how flexible nuclear plants capable of load-following should be operated in an open market framework. A number of technico-economical features of the operation of flexible nuclear plants drive our modelling complex which makes difficult to determine the optimal management of the nuclear production within our model. In order to examine the existence of an equilibrium and calculate it, we focus on a short-term (monthly) management horizon of the fuel of nuclear reactors. The marginal cost of nuclear production being (significantly) lower than that of thermal production induces a discontinuity of producer's short-term profit. The problem of discontinuity makes the resolution of the optimal short-term production problem extremely complicated and even leads to a lack of solutions. That is why it is necessary to study an approximate problem (continuous problem) that constitutes a “regularization” of our economical problem (discontinuous problem). Its resolution provides us with an equilibrium which proves the existence of an optimal production trajectory
Optimal production allocation of load-following nuclear units in an electricity market in the early stages of competition
No full textInternational audienceElectricity systems are quitting monopoly for an operation framed by competitive markets. It therefore questions how the operation of nuclear plants capable of load-following is expected to change at the transition stage in a challenging economic environment for nuclear producers given the high penetration of renewables and the increase of nuclear production costs for renovation and safety reasons. To answer this question, we are focusing on a month-by-month management horizon of the nuclear fuel given the technico-economical features of the operation of flexible nuclear plants. The resolution of the month-by-month profit maximization problem contributes to identify potential difficulties and limits of production optimization and provides us with an equilibrium which proves the existence of an optimal production path. This benchmark could serve as a reference providing valuable insight on the resolution of more complex optimisation problems
The optimal short-term management of flexible nuclear plants in a competitive electricity system as a case of competition with reservoir
No full textURL des Documents de travail : http://centredeconomiesorbonne.univ-paris1.fr/documents-de-travail/Documents de travail du Centre d'Economie de la Sorbonne 2014.57 - ISSN : 1955-611XIn many countries, the electricity systems are quitting the vertically integrated monopoly organization for an operation framed by competitive markets. It therefore questions how flexible nuclear plants capable of load-following should be operated in an open market framework. A number of technico-economical features of the operation of flexible nuclear plants drive our modelling complex which makes difficult to determine the optimal management of the nuclear production within our model. In order to examine the existence of an equilibrium and calculate it, we focus on a short-term (monthly) management horizon of the fuel of nuclear reactors. The marginal cost of nuclear production being (significantly) lower than that of thermal production induces a discontinuity of producer's short-term profit. The problem of discontinuity makes the resolution of the optimal short-term production problem extremely complicated and even leads to a lack of solutions. That is why it is necessary to study an approximate problem (continuous problem) that constitutes a “regularization” of our economical problem (discontinuous problem). Its resolution provides us with an equilibrium which proves the existence of an optimal production trajectory
How to manage a large and flexible nuclear set in a deregulated electricity market from the point of view of social welfare?
No full textURL des Documents de travail : http://centredeconomiesorbonne.univ-paris1.fr/documents-de-travail/Documents de travail du Centre d'Economie de la Sorbonne 2014.59 - ISSN : 1955-611XIn the case of a large nuclear set (like the French set), nuclear production needs to be flexible to adjust to the predicted evolutions of the energy demmand. Consequently, the dominant position of nuclear in the national energy mix makes it responsible for the overall equilibrium of the electricity system which is directly intertwined with social welfare. In a previous work, we looked at producers own profits (short-term, inter-temporal) considering the equality between supply and demand. Here, we proceed with a full optimization of the social welfare in an identical framework. Theoretically, the optimal production behaviour that maximizes social welfare is characterized by a constant thermal production and a totally flexible nuclear production given that the nuclear capacity is sufficient. Numerically, the significant amount of nuclear capacities compared with thermal capacities in the French electricity market leads to the same “paradoxical” production behaviour. Therefore, we conclude that social optimum is ensured within our model by investing sufficiently in nuclear capacity. The optimal production scheduling determined by the social welfare maximization problem and the optimal inter-temporal production problem are totally opposite
The inter-temporal optimization of the operation of the nuclear fuel reservoir in a liberalized electricity market dominated by the nuclear generation
No full textURL des Documents de travail : http://centredeconomiesorbonne.univ-paris1.fr/documents-de-travail/Documents de travail du Centre d'Economie de la Sorbonne 2014.58 - ISSN : 1955-611XWe look at the optimal inter-temporal management of the fuel reservoir of nuclear units in a liberalized electricity market. We use the assumption that nuclear fuel works as a “reservoir” of energy due to the periodical shutdown of nuclear units to reload their fuel. In the medium-term, how a producer sets the nuclear fuel of the reservoir to respond to the variations of seasonal demand in order to maximize its production value on a multi-annual basis? The dynamic nature of the nuclear fuel reservoir highlighted the discontinuity of the price which complicates the resolution of the optimal inter-temporal production problem and even leads to a lack of solutions. Theoretically, at the optimum, nuclear is used to serve baseload and thermal follows demand's variations. Numerically, both nuclear and thermal units operate in load-following mode. Solutions characterized by a constant nuclear production do not exist which shows that the significant share of nuclear in the energy mix does not permit to produce at a constant rate unless further investments in thermal capacity are done. Inter-temporal optimization shows the role of nuclear for ensuring the equilibrium between supply and demand
How to manage flexible nuclear power plants in a deregulated electricity market from the point of view of social welfare?
No full textInternational audienceFlexible nuclear power plants can adjust their electricity production to the predicted evolution of demand. Under certain conditions, flexible operation is necessary to ensure the stability of the electricity system. However, despite the potential advantages of nuclear energy including the flexibility of nuclear reactors, the social acceptance of nuclear has reduced after the Fukushima accident, leading some countries to reduce or even phase out nuclear (e.g. Germany). So, a question that arises is how flexible nuclear power plants have to be operated in order to maximize social welfare. The French nuclear fleet gives an illustration of flexible management while social acceptance of nuclear is questioned; this was reflected in the new French Energy Transition law. Theoretically and numerically, we found that the production behavior that maximizes social welfare is characterized by a constant thermal production and a totally flexible nuclear production given sufficient nuclear capacity.Energ
