Utilization of a Time Domain Simulator in the Technical and Economic Analysis of a Wind Turbine Electric Drive Train

The amount of installed wind power has been growing exponentially during the past ten years. As wind turbines have become a significant source of electrical energy, the interactions between the turbines and the electric power network need to be studied more thoroughly than before. Especially, the behavior of the turbines in fault situations is of prime importance; simply disconnecting all wind turbines from the network during a voltage drop is no longer acceptable, since this would contribute to a total network collapse. These requirements have been a contributor to the increased role of simulations in the study and design of the electric drive train of a wind turbine. When planning a wind power investment, the selection of the site and the turbine are crucial for the economic feasibility of the installation. Economic feasibility, on the other hand, is the factor that determines whether or not investment in wind power will continue, contributing to green electricity production and reduction of emissions. In the selection of the installation site and the turbine (siting and site matching), the properties of the electric drive train of the planned turbine have so far been generally not been taken into account. Additionally, although the loss minimization of some of the individual components of the drive train has been studied, the drive train as a whole has received less attention. Furthermore, as a wind turbine will typically operate at a power level lower than the nominal most of the time, efficiency analysis in the nominal operating point is not sufficient. This doctoral dissertation attempts to combine the two aforementioned areas of interest by studying the applicability of time domain simulations in the analysis of the economicfeasibility of a wind turbine. The utilization of a general-purpose time domain simulator, otherwise applied to the study of network interactions and control systems, in the economic analysis of the wind energy conversion system is studied. The main benefits of the simulation-based method over traditional methods based on analytic calculation of losses include the ability to reuse and recombine existing models, the ability to analyze interactions between the components and subsystems in the electric drive train (something which is impossible when considering different subsystems as independent blocks, as is commonly done in theanalytical calculation of efficiencies), the ability to analyze in a rather straightforward manner the effect of selections other than physical components, for example control algorithms, and the ability to verify assumptions of the effects of a particular design change on the efficiency of the whole system. Based on the work, it can be concluded that differences between two configurations can be seen in the economic performance with only minor modifications to the simulation models used in the network interaction and control method study. This eliminates the need ofdeveloping analytic expressions for losses and enables the study of the system as a whole instead of modeling it as series connection of independent blocks with no lossinterdependencies. Three example cases (site matching, component selection, control principle selection) are provided to illustrate the usage of the approach and analyze its performance.

Economic Geographical Analysis of The Finnish Paper Industry

The purpose of this academic economic geographical dissertation is to study and describe how competitiveness in the Finnish paper industry has developed during 2001–2008. During these years, the Finnish paper industry has faced economically challenging times. This dissertation attempts to fill the existing gap between theoretical and empirical discussions concerning economic geographical issues in the paper industry. The main research questions are: How have the supply chain costs and margins developed during 2001–2008? How do sales prices, transportation, and fixed and variable costs correlate with gross margins in a spatial context? The research object for this case study is a typical large Finnish paper mill that exports over 90 % of its production. The economic longitudinal research data were obtained from the case mill’s controlled economic system and, correlation (R2) analysis was used as the main research method. The time series data cover monthly economic and manufacturing observations from the mill from 2001 to 2008. The study reveals the development of prices, costs and transportation in the case mill, and it shows how economic variables correlate with the paper mills’ gross margins in various markets in Europe. The research methods of economic geography offer perspectives that pay attention to the spatial (market) heterogeneity. This type of research has been quite scarce in the research tradition of Finnish economic geography and supply chain management. This case study gives new insight into the research tradition of Finnish economic geography and supply chain management and its applications. As a concrete empirical result, this dissertation states that the competitive advantages of the Finnish paper industry were significantly weakened during 2001–2008 by low paper prices, costly manufacturing and expensive transportation. Statistical analysis expose that, in several important markets, transport costs lower gross margins as much as decreasing paper prices, which was a new finding. Paper companies should continuously pay attention to lowering manufacturing and transporting costs to achieve more profitable economic performance. The location of a mill being far from markets clearly has an economic impact on paper manufacturing, as paper demand is decreasing and oversupply is pressuring paper prices down. Therefore, market and economic forecasting in the paper industry is advantageous at the country and product levels while simultaneously taking into account the economic geographically specific dimensions.

Research framework for the connection between environmental collaboration and firm performance

This thesis focuses on collaborative activities with regard to environmental issues both within the firm and outside the firm with the key suppliers and customers, i.e. internal and external environmental collaboration. Integrating environmental thinking into supply chain management has received increasing interest in recent years. The relational view and the natural resource-based-view together suggest that environmental capabilities can be built jointly with supply chain partners and used to gain sustained competitive advantage. Several studies have been undertaken to analyse the connection between environmental activities and firm performance but most studies have taken only economic performance into account. This study pays attention also to two other dimensions of firm performance, intra-firm supply chain performance and environmental performance, and aims at presenting the linkages between them and environmental collaboration. This thesis creates a research framework for the connections between environmental collaboration and firm performance and suggests approaches to analyse these. In order to find out the key concepts and their relationship, an extensive literature review is conducted. The research framework proposes a positive connection between internal and external environmental collaboration and all three dimensions of firm performance. In addition, environmental performance and intra-firm supply chain performance are expected to contribute positively to economic performance. Hence, firms are suggested to benefit from environmental collaboration both within the firm and outside the firm. Empirical testing of the developed research framework is out of the scope of this study. However, this thesis proposes using a mixed methods research approach, including survey research and multiple case studies. Finland State of Logistics 2012 survey commissioned by the Finnish Ministry of Transport and Communications and conducted by Turku School of Economics is used as an example of data for the quantitative phase. The applicability of these two methods is discussed at a general level and with regard to analysing the research framework developed in the thesis. Future research will aim at the development of the research framework and the methods in order to confirm the connection between environmental collaboration and firm performance.

Economic and environmental evaluation of renewable energy systems

The main objective of this thesis is to evaluate the economic and environmental effectiveness of three different renewable energy systems: solar PV, wind energy and biomass energy systems. Financial methods such as Internal Rate of Return (IRR) and Modified Internal Rate of Return (MIRR) were used to evaluate economic competitiveness. Seasonal variability in power generation capability of different renewable systems were also taken into consideration. In order to evaluate the environmental effectiveness of different energy systems, default values in GaBi software were taken by defining the functional unit as 1kWh. The results show that solar PV systems are difficult to justify both in economic as well as environmental grounds. Wind energy performs better in both economic and environmental grounds and has the capability to compete with conventional energy systems. Biomass energy systems exhibit environmental and economic performance at the middle level. In each of these systems, results vary.

Sosioekonomisten tekijöiden yhteys terveyteen 75- ja 80-vuotiailla jyväskyläläisillä miehillä ja naisilla

Summary: Socio-economic factors and health among 75- and 80-year-old men and women