Optimization of Thermal Energy Storage Systems in Distributed Generation Systems

The distributed generation as well as the combined production of electrical energy and heat for domestic use in order to increase the energy efficiency becomes more important and both technically and financially feasible. However, feasibility and efficiency can be significantly increased by decoupling the production of heat or power or the referring demand in order to operate the production units in the most efficient way. Thermal storage systems connected to combined heat and power units offer the opportunity of such a decoupling of production and demand for heat in domestic or industrial use. In this article, based on an analysis of different thermal storage technologies, a model is introduced for optimal operation of thermal storage connected to combined heat and power units in terms of the generation costs or contribution margin as extension of an energy generation planning and trading optimization method. Moreover, the application, coordinated operation and participation in spot markets of such plant-storage-combinations are evaluated.     

Impact of Modeling Approaches on Dispatch Optimization of Combined Cycle Gas Turbines

Due to the age structure of the German generation system and the nuclear phase out, a significant amount of older power plants will be substituted during the coming years by newly built generation units. Such projects are frequently realized as combined gas and steam turbines, so-called Combined Cycle Power Plants or Combined Cycle Gas Turbines (CCGT). These power plants, mostly fired by natural gas, possess high efficiency factors combined with low specific CO₂-emissions compared to other conventional power plants, e.g. fired by coal and moreover provide a high operational flexibility. As they represent a combination of several thermal processes, their generation planning and optimized dispatch are more demanding than those of existing steam or gas turbines. Therefore, a new formulation of the unit commitment problem is required, including all relevant technical and economic restrictions for scheduling CCGT. In this paper, the relevant characteristics of the different types of CCGT are analyzed. This especially includes part load efficiency and the permitted modes of operation. For modeling of these characteristics and for optimizing the CCGT dispatch, a decomposition approach as well as a linearized closed-loop formulation is introduced. In the decomposition the optimization problem is split into sub problems, which can be solved with specialized algorithms. As the recombination of these sub problems may result in a limitation of the overall solution quality, the closed-loop approach considers the entire problem, but has to linearize the formulation to ensure solvability. By applying both methods on an exemplary case the advantages and shortcomings of both approaches can be analyzed in detail. This comprises model accuracy, overall solution quality and a detailed schedule analysis and comparison. The paper??s results will also show the deviations caused by the different modeling approaches. Finally, the results show the added value of the adequate modeling of combined cycle power plants towards gas or steam turbines.     

Measuring income elasticity for Swiss money demand: What do the cantons say about financial innovation?

Recent time-series evidence has re-confirmed the forecasting ability of Swiss broad money. The same money demand studies and others, however, find that the income elasticity is greater than one. Such parameter estimates are difficult to reconcile with transactions demand theory. This study re-examines the estimates for income elasticity in money demand based on cross-regional evidence for Switzerland. Particular attention is given to the influence of regional financial sophistication. The cross-cantonal results find that the income elasticity lies between 0.4 and 0.6. This discrepancy between the two empirical methodologies has important consequences for the conduct of Swiss monetary policy.     

A simple test for regression specification with non-nested alternatives

In this paper, I introduce a simple test for the presence of the data-generating process among several non-nested alternatives. The test is an extension of the classical J test for non-nested regression models. I also provide a bootstrap version of the test that avoids possible size distortions inherited from the J test.     

Accounting for labor demand effects in structural labor supply models

When assessing the effects of policy reforms on the labor market, most studies only focus on labor supply. The interaction of supply and demand is not explicitly modeled, which might lead to biased estimates of potential labor market outcomes. This paper proposes a straightforward method to remedy this shortcoming. We use information on firms' labor demand behavior and feed them into a structural labor supply model, completing the partial analysis of the labor market on the microdata level. We show the performance and relevance of our extension by introducing a pure labor supply side reform, the workfare concept, in Germany and simulating the labor market outcome of the reform. We find that demand effects offset about 25% of the positive labor supply effect of the policy reform.     

Pollution Control and Foreign Direct Investment in Mexico: An Industry-Level Analysis

Foreign direct investment (FDI) flows into developing countries have been increasing dramatically over the past decade. At the same time, there has been widespread concern that lax environmental standards are in part responsible for this surge. This paper revisits the question of the existence of a pollution haven effect by examining the extent to which the pollution intensity of production helps explain FDI in Mexico. We focus on pollution intensities, which are directly related to emission regulations, rather than unobservable pollution taxes and allow for substitution between capital and pollution. Examining several different pollutants, we find a positive correlation between FDI and pollution that is statistically and economically significant in the case of the highly regulated sulfur dioxide emissions. Industries for which the estimated relationship between FDI and pollution is positive receive up to 30% of total FDI and 30% of manufacturing output. Although we confirm the importance of Mexico’s comparative advantage in labor-intensive production processes, consistent with the previous literature, our results suggest that environmental considerations may matter as well for firms’ investment decisions.      

More on parametric characterizations of risk aversion and prudence

Summary. This note provides an alternative proof for the equivalence of decreasing absolute prudence (DAP) in the expected utility framework and in a two-parametric approach where utility is a function of the mean and the standard deviation. In addition, we elucidate that the equivalence of DAP and the concavity of utility as a function of mean and variance, which was shown to hold for normally distributed stochastics in Lajeri and Nielsen [4], cannot be generalized. Received: November 27, 2000; revised version: November 26, 2001 Correspondence to: T. Eichner     

Jahresinhaltsverzeichnis 2010

Jahresinhaltsverzeichnis

Jahresinhaltsverzeichnis 2010     

On risk and cost in global sourcing

The benefits of global sourcing as part of a firm’s purchasing strategy have been widely discussed in the academic literature, yet so there are few models that provide a comprehensive risk and cost assessment to guide managerial decision-making. In particular, few models capture the dynamic nature of many cost drivers, such as transportation and energy cost, labour cost inflation, or carbon offset costs, in their calculations. In this paper, we define three basic cost elements in global sourcing: static, dynamic and hidden cost, and use this framework to assess the costs and risks inherent in global sourcing scenarios from three different points of view: conceptually, analytically and empirically. We highlight the key learning points from each perspective and propose a total cost model of how to make informed global sourcing decisions, which we test by applying it to three exploratory case studies of global sourcing arrangements.