Ilkka Mellin

Clustering of Connection Points and Load Modeling in Distribution Systems

The lifetime of transmission and distribution power systems is long and thus, long-term plans are needed for their successful development. In generating long-term scenarios, the starting point is the analysis of the present electricity consumption. The data of electricity consumption will become more exact by the end of 2013, when hourly based automated meter reading (AMR) consumption data will be received from each customer in Finland. The amount of data is huge and powerful analysis methods are needed. This paper presents a method for clustering the electricity consumptions using principal component analysis (PCA) and K-means clustering. AMR data of 18 098 customers from two city districts of Helsinki, Finland is applied for a case study reported in this paper. A multiple regression analysis is also carried out on the two largest clusters to find the most important explanatory factors for the load modeling. The interpretations of the clusters and the plausibility of the regression coefficients are considered very important. Five distinct and meaningful clusters are found. The regression models give interesting insights into the explanatory factors behind electricity consumption. The models of the main customer groups assist the distribution system operator (DSO) in the long-term development of the power system.

Statistical analysis of large scale wind power generation using Monte Carlo Simulations

As more wind power generation is installed, the effect of wind power on the electric power system is becoming increasingly important. This paper presents two time series models that can be used in Monte Carlo simulations to assess the risk of very high or low wind speeds occurring contemporaneously in multiple locations. The suitability of the models is assessed for existing measured locations and new non-measured locations. The simulation results are verified against measurements from 19 locations from Finland. Also, an example scenario is given to show the effect of geographical spread on the aggregate power generation of multiple wind power generation units.

A Statistical Model for Hourly Large-Scale Wind and Photovoltaic Generation in New Locations

The analysis of large-scale wind and photovoltaic (PV) energy generation is of vital importance in power systems, where their penetration is high. This paper presents a modular methodology to assess the power generation and volatility of a system consisting of both PV plants (PVPs) and wind power plants (WPPs) in new locations. The methodology is based on statistical modeling of PV and WPP locations with a vector autoregressive model, which takes into account both the temporal correlations in individual plants and the spatial correlations between the plants. The spatial correlations are linked through distances between the locations, which allow the methodology to be used to assess scenarios with PVPs and WPPs in multiple locations without actual measurement data. The methodology can be applied by the transmission and distribution system operators when analyzing the effects and feasibility of new PVPs and WPPs in system planning. The model is verified against hourly measured wind speed and solar irradiance data from Finland. A case study assessing the impact of the geographical distribution of the PVPs and WPPs on aggregate power generation and its variability is presented.

How to Leave the Eurozone: The Case of Finland

This article provides thoughts and guidelines on how a country could exit from the Economic and Monetary Union (EMU) and its currency the euro. We take the hypothetical exit of Finland as a concrete example. Although there is a way out of the euro for Finland and other member countries, exit would not be easy, nor would its short-term costs be known beforehand with any clear margin. We find the lack of a domestic payments system and uncertainty concerning the redenomination costs to be the biggest risks associated with the cost of Finland’s exit. Still, the costs of Finland’s exit need not be very large, around 10 billion euros in the best-case scenario, but we also acknowledge a very costly scenario for the exit. Any member country considering exit from the euro should weigh the short-term costs of an exit against the possible long-run benefits of having a domestic currency.

How to Abandon the Common Currency in Exchange for a New National Currency

The question how to leave a currency union has become an important economic issue during last few years. Asymmetric shocks, low growth and increasing federalism have left several countries of the Eurozone more open to considering whether the economic and political costs associated with euro membership have become too high. Having an individual currency can produce benefits to a country compared to a common currency of a monetary union, particularly if the single monetary policy proves unsuitable for the macroeconomic development of the country in question. However, uncertainty relating to the costs of an exit can discourage political leaders from taking decisive steps towards an exit. This article provides thoughts on how an exit from a modern currency union can be managed. We will show that the costs related to the exit can be controlled, but also that the process includes many uncertainties that the exiting country needs to be prepared for since they cannot be reduced.