Combining hydro-generation and wind energy biddings and operation on electricity spot markets

Wind generation is growing rapidly in all the world, especially in Europe. The power produced by this kind of generation is difficult to predict and the predictions are not very accurate. In most systems these imbalances are costly. These penalties reduce the revenue for the wind generation company (WGENCOs). An option to solve this problem would be to work together with another agent. In this paper, a combined strategy for bidding and operating in a power exchange is presented. It considers the combination of a WGENCO and a hydro-generation company (HGENCO). The mathematical formulation for the optimal bids and for the optimal operation is presented, as well as results from realistic cases.Publicad

Bidding wind energy under uncertainty

The integration of wind energy into electricity markets implies that the wind energy must commit their production for a given time period. This requires the use of short term wind power prediction tools to prepare the bids for the spot market. The output of these tools have a limited accuracy, and, therefore, these predictions are uncertain. Optimal bids must take into account this uncertainty in order to get the maximum revenue from the sell of energy, minimizing losses due to imbalance costs. The consequence is that the optimal bids sent to the market do not coincide with the best predictions. Regulatory authorities must consider if this situation is good for the system operation, and encourage TSOs to have their own prediction tools and have results independent of bidding strategies.International Conference on Clean Electrical Power, ICCEP '07 (Capri, 21-23 May 2007). P. 754-759Publicad

Matroid toric ideals: complete intersection, minors and minimal systems of generators

In this paper, we investigate three problems concerning the toric ideal associated to a matroid. Firstly, we list all matroids $\mathcal M$ such that its corresponding toric ideal $I_{\mathcal M}$ is a complete intersection. Secondly, we handle with the problem of detecting minors of a matroid $\mathcal M$ from a minimal set of binomial generators of $I_{\mathcal M}$. In particular, given a minimal set of binomial generators of $I_{\mathcal M}$ we provide a necessary condition for $\mathcal M$ to have a minor isomorphic to $\mathcal U_{d,2d}$ for $d \geq 2$. This condition is proved to be sufficient for $d = 2$ (leading to a criterion for determining whether $\mathcal M$ is binary) and for $d = 3$. Finally, we characterize all matroids $\mathcal M$ such that $I_{\mathcal M}$ has a unique minimal set of binomial generators.Comment: 9 page

Combined hydro-wind generation bids in a pool-based electricity market

Present regulatory trends are promoting the irect participation of wind energy in electricity markets. The final result of these markets sets the production scheduling for the operation time, including a power commitment from the wind generators. However, wind resources are uncertain, and the final power delivered usually differs from the initial power committed. This imbalance produces an overcost in the system, which must be paid by those who produce it, e.g., wind generators among others. As a result, wind farm revenue decreases, but it could increase by allowing wind farms to submit their bids to the markets together with a hydro generating unit, which may easily modify its production according to the expected imbalance. This paper presents a stochastic optimization technique that maximizes the joint profit of hydro and wind generators in a pool-based electricity market, taking into account the uncertainty of wind power prediction.En prens

Propuesta de indicadores de sostenibilidad para empresas cooperativas.

El presente trabajo se desarrolló en cuatro empresas cooperativas las cuales se encuentran ubicadas en la llanura sur de la provincia Pinar del Río. Se tomaron como muestra las unidades Rafael Ferro, La Majagua, La Sombrilla y Sumalacara para el año 2004 Los indicadores de sostenibilidad se definen atendiendo a las experiencias y marcos teóricos desarrollados para las condiciones de América Latina y el Caribe y sus posibilidades para el modelo político- social y económico cubano ( Hunnemeyer, de Camino y Muller, 1996). La metodología utilizada articuló diferentes técnicas y procedimiento de gestión del conocimiento y de la información, información geográfica, estadística y visualización, lo cual permitió: Construcción y definición de indicadores de sostenibilidad. Agregación de indicadores de sostenibilidad para el cálculo de: •Índice de sostenibilidad social. •Índice de sostenibilidad económico. •Índice de sostenibilidad ecológico. •Índice de sostenibilidad total. Se grafican los resultados de cada índice y se representan espacialmente con el empleo del Mapinfo 10.

A single-world consistent interpretation of quantum mechanics from fundamental time and length uncertainties

Within ordinary ---unitary--- quantum mechanics there exist global protocols that allow to verify that no definite event ---an outcome to which a probability can be associated--- occurs. Instead, states that start in a coherent superposition over possible outcomes always remain as a superposition. We show that, when taking into account fundamental errors in measuring length and time intervals, that have been put forward as a consequence of a conjunction of quantum mechanical and general relativity arguments, there are instances in which such global protocols no longer allow to distinguish whether the state is in a superposition or not. All predictions become identical as if one of the outcomes occurs, with probability determined by the state. We use this as a criteria to define events, as put forward in the Montevideo Interpretation of Quantum Mechanics. We analyze in detail the occurrence of events in the paradigmatic case of a particle in a superposition of two different locations. We argue that our approach provides a consistent (C) single-world (S) picture of the universe, thus allowing an economical way out of the limitations imposed by a recent theorem by Frauchiger and Renner showing that having a self-consistent single-world description of the universe is incompatible with quantum theory. In fact, the main observation of this paper may be stated as follows: If quantum mechanics is extended to include gravitational effects to a QG theory, then QG, S, and C are satisfied.Comment: thoughts and comments more than welcom

Interbank Rate and the Liquidity of the Market.

In this paper we study the dynamics of the interbank rate in Chile, with special attention to the role of liquidity provided by private depositors and by the central bank’s open market operations on a daily basis. The main aim of this paper is the use of disaggregated and high frequency data on such variables. The most relevant findings are related to the statistical and economic significance of speed of convergence, calendar effects and repos operations. The Central Bank plays a more important role injecting than draining liquidity through discretionary operations. However, there are not asymmetries in terms of the effectiveness of the discretionary injections and drainages operations depending on the liquidity market status. In terms of effect by class of bank, large- and medium-size banks are less receptive to monetary operations; by contrast small-size banks are the most responsive, which is consistent with its traditional position as a liquidity demander. Finally, private deposits do not play an important role on the dynamics of the interbank rate during the sample period.

M\"obius function of semigroup posets through Hilbert series

In this paper, we investigate the M{\"o}bius function $\mu\_{\mathcal{S}}$ associated to a (locally finite) poset arising from a semigroup $\mathcal{S}$ of $\mathbb{Z}^m$. We introduce and develop a new approach to study $\mu\_{\mathcal{S}}$ by using the Hilbert series of $\mathcal{S}$. The latter enables us to provide formulas for $\mu\_{\mathcal{S}}$ when $\mathcal{S}$ belongs to certain families of semigroups. Finally, a characterization for a locally finite poset to be isomorphic to a semigroup poset is given.Comment: 11 page