Operating Strategies for Battery Storage Systems in Low-Voltage Grids to Limit the Feed-In Power of Solar Power Systems Using Fuzzy Control

Germany’s energy turnaround is leading to an increasing integration of photovoltaics (PVs) throughout its distribution grid. To ensure safe grid operation in times of high solar radiation, PV plants must either be throttled back to comply with the feed-in limitation or store a portion of their excess electricity in batteries. This paper presents a grid-optimized operating strategy for PV storage systems based on a Fuzzy Logic Controller that reduces peak feed-in and thus also PV curtailment losses. The Fuzzy Logic Controller uses data on PV power surplus and battery charge level as input variables. To obtain good results, the set of numerical parameters of the membership functions is enhanced by evolutionary programming.The energetic assessment shows that even small electrical storage capacities (<<5?kWh) reduce curtailment losses considerably when using the grid-optimized operating strategy. The economic assessment shows that, in 2016, investments in PV storage systems with large PV plants and small batteries have small (positive) Internal Rates of Return. The system efficiency of the battery storage has a small impact on the profitability of PV storage systems, whereas the cycle stability and the electricity purchase price have a large impact. Moreover, there is an economic benefit for plant operators to switch from the simple to the grid-optimized operating strategy. Solar forecast inaccuracies and variations in load and generation profiles have a negligible impact on the performance of the control algorithm.     

Öffentliches und Geheimes

In the second half of 2009, the entire media agenda in Germany was dominated by the swine flu, next to the German Federal Parliament elections. Criticism was voiced in the media against the pharmaceutical industry for lobbying the nationwide swine flu vaccination, which was widely considered nothing but a product of the industry’s lobbying power. In order to avoid the usual interviews with lobbyists, we attempted to apply a new methodological framework approach in analysing lobbying processes and key stakeholders in the public sphere—and outside. Crucial to the diversified approach, which involves quantitative content analysis of media coverage and press releases, are interviews with journalists, lobbyists’ network analysis and internet research on biographies. Although a conspiracy could not be conclusively proven, the results do indicate associations that validate the criticism of the industry’s lobbying activities.     

Do Customers Affect the Value Relevance of Sustainability Reporting? Empirical Evidence on Stakeholder Interdependence

In spite of the strategic importance of sustainability reporting in current business practice and the resulting increase in research on its value relevance, studies accounting for stakeholder interdependence are scarce. On the basis of the instrumental stakeholder theory, we investigate whether customers have an impact on the value relevance of sustainability reporting. Using a sample of US listed firms, we show that the value relevance of sustainability reporting is affected by customer profile differences, thereby confirming customer–shareholder interdependence. However, customer profile effects are only predominant if firms' profitability levels are low and disappear as profitability increases. Overall, our findings provide a more nuanced understanding of the value relevance of sustainability reporting. Therefore, we offer managers fine‐grained guidance for value relevant sustainability reporting. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment     

Asymptotics for Autocovariances and Integrated Periodograms for Linear Processes Observed at Lower Frequencies

One of the most frequently used class of processes in time series analysis is the one of linear processes. For many statistical quantities, among them sample autocovariances and sample autocorrelations, central limit theorems are available in the literature. We investigate classical linear processes under a nonstandard observation pattern; namely, we assume that we are only able to observe the linear process at a lower frequency. It is shown that such observation pattern destroys the linear structure of the observations and leads to substantially different asymptotic results for standard statistical quantities. Central limit theorems are given for sample autocovariances and sample autocorrelations as well as more general integrated periodograms and ratio statistics. Moreover, for specific autoregressive processes, the possibilities to estimate the parameters of the underlying autoregression from lower frequency observations are addressed. Finally, we suggest for autoregressions of order 2 a valid bootstrap procedure. A small simulation study demonstrates the performance of the bootstrap proposal for finite sample size.     

Übernivellierung der Einnahmen aus der Grunderwerbsteuer im künftigen Finanzausgleich

Fiscal Equalisation in Germany provides substantial fiscal redistribution between federal and state and among state governments. However, there is also a degree of tax autonomy for the individual German states. Since 2007, states can adjust their local rate of the Real Estate Transfer Tax. However, if they keep the rate low, they may suffer revenue losses due to fiscal redistribution. The paper considers whether this effect will also be present in the new rules for fiscal equalization which will come in to effect in 2020.     

LOGISTICS AND SUPPLY CHAIN MANAGEMENT APPLICATIONS WITHIN A GLOBAL CONTEXT: AN OVERVIEW

This paper reviews 726 academic research studies covering logistics and supply chain management (L'SCM) applications within a global context. Articles are analyzed according to their publication year and outlet, common themes, and countries or regions investigated. The sample was drawn from the ABI/INFORM Global database, which includes almost 1,800 journal titles. The review offers a starting point for researchers, graduate students, faculty members or practitioners examining international L'SCM applications. The article also draws attention to the wide array of global L'SCM studies conducted, their settings and viewpoints. Additionally, this paper highlights some of the most interesting works and draws attention to lesser‐researched countries and regions of the world. The overview also provides an introduction for practitioners and managers to what academic research has covered in the area of global L'SCM. Practitioners can use this review as a starting point for the identification of relevant and useful references for their particular task.     

Does one model fit all? Exploring factors influencing the use of blogs,social networks,and wikis in the enterprise

Enterprise social media (ESM) have become increasingly widespread, but many intranet communities barely survive, miss their initially planned targets, or are even terminated. Research on technology acceptance can be a useful approach to improve adoption rates, but more empirical research needs to be conducted to examine factors driving the adoption of enterprise social media. To address this gap, we develop a model of individual ESM adoption, including technological and individual factors based on findings from collaboration and knowledge-sharing research. Because different ESM tools, such as blogs, social networks, and wikis, can be employed for fundamentally different uses, we explain differences between individual adoptions of the three technologies by identifying their uses and gratifications from the perspective of employees. The model is tested in three parallel studies, one for blogs, social networks, and wikis each, among employees of an international technology company in the pre-implementation phase. We find substantial differences between the factors influencing the intention to adopt the three applications. This provides the basis to employ the applications in a more effective way by considering organizational and employee needs.     

Challenges for land system science

While considerable progress has been made in understanding land use change, land system science continues to face a number of grand challenges. This paper discusses these challenges with a focus on empirical land system studies, land system modelling and the analysis of future visions of land system change. Contemporary landscapes are contingent outcomes of past and present patterns, processes and decisions. Thus, empirical analysis of past and present land-use change has an important role in providing insights into the socio-economic and ecological processes that shape land use transitions. This is especially important with respect to gradual versus rapid land system dynamics and in understanding changes in land use intensity. Combining the strengths of empirical analysis with multi-scale modelling will lead to new insights into the processes driving land system change. New modelling methods that combine complex systems thinking at a local level with macro-level economic analysis of the land system would reconcile the multi-scale dynamics currently encapsulated in bottom-up and top-down modelling approaches. Developments in land use futures analysis could focus on integrating explorative scenarios that reflect possible outcomes with normative visions that identify desired outcomes. Such an approach would benefit from the broad and in-depth involvement of stakeholders in order to link scientific findings to political and societal decision-making culminating in a set of key choices and consequences. Land system models have an important role in supporting future land use policy, but model outputs require scientific interpretation rather than being presented as predictions. The future of land system science is strongly dependent on the research community's capacity to bring together the elements of research discussed in the paper, via empirical data collection and analysis of observed processes, computer simulation across scale levels and futures analysis of alternative, normative visions through stakeholder engagement.