[en] For quite a long time now, the total electro energy consumption in the electro energetic system of Macedonia has been stagnating at about 5,5 TWh in a year. In the last few years, exactly since the Republic of Macedonia's independence, the electro energetic system has been working with a great level of technological and economic autonomy. The greater part of the electric energy production has been realized in fossil fueled power stations which makes additional problems in the system management. This paper contains an analysis of hydroelectric power stations in such complex conditions.The proposed working regime includes the long- term-seasonal problems, as well as short- term-weekly-hourly problems. For all hydroelectric power stations the yearly-weekly situation of the water level in the accumulation has to be defined, as well as the weekly available quantity of water. With the hydroelectric power station parameters defined in this way, we can determine the hydroelectric and fossil fueled power station weekly-hourly involvement in the system. At the end, some activities are given, which can significantly improve the operation of the whole electro energetic system in a relatively short time. (author). 3 refs., 15 figs., 1 tab

[en] The physical and operational constraints of the network pose very specific problems to market power analysis in the oligopolistic electricity markets. This paper presents a direct analytical approach to find the market equilibrium based on a supply function game model. The model is exploited to undertake a sensitivity analysis of the producer surplus with reference to the line flow limits under a DC power flow model for network representation. Two different kinds of indices, that can capture the market power arising under network constraints, are proposed. The first set of indices is the location privilege (LP), that measure the effect of the generators positioning in the grid on their surplus under perfect competition. The second set is for the network market power (NMP) indices that take into account the strategic behaviors of the producers that may take advantage of the congestion of the transmission lines. The indices allow for a ranking of the lines in terms of the market power they can induce and, in this respect, they may help the market regulator to focus on the network weakness in terms of the possible market outcomes under the market power behaviors from the supply side. The application of the proposed indices is illustrated with reference to the IEEE 30-bus test system. (author)

[en] This article discusses how the opening-up of the European electricity market has led to the creation of more room for manoeuvre in the deployment of the generation capacity of dam and pumped-storage-based hydropower facilities and low-head power stations. Software tools for the optimisation of the operation of power generation facilities that can take care of complex hydraulic interdependencies are described. The use of the software for the assessment of new installations being planned or of older installations being extended is examined. The influence of climatic conditions, market prices for power, the general requirements placed on the system and other influences on financial gain are looked at. The article makes recommendations on those factors influencing the design of the software and for its optimal use in practice

[en] After a short introduction into the problems and questions surrounding the issue of external costs Chapter 2 presents the most important results of the studies under review and analysis in this work. Occasionally, minor discrepancies were found between the results given in the summary of a study and the data reported in the relevant chapters. Chapter 3 identifies and discusses differences in perspective between the studies under consideration. Chapter 4 analyses the most important premises and parameters adopted in the studies for the calculation of overall costs and net benefits of the different modes of electricity production. This serves to probe the reliability of the data, plausibility of the premises, and nature of the presupposed relationships. Chapter 5 examines the relationships of time assumed in the studies and gives a first comment on the more advanced Prognos study. Chapter 6, finally, offers a summarizing evaluation. (orig./UA)

[en] In the note a review of the present status and perspectives of hydroelectric power in the world is introduced. The present status regards, in chronological order, the last decade, as to say the works carried out in the 80ies whereas the perspectives regard the next twenty years as to say until 2010. The mentioned electric power potentiality refers to pure generation plants of great, middle and small size and to what could be achieved by already existing plants after changes and/or replacements and improvement of the machinery. Beside the figures regarding powers, great generation and pumping plants whose contribution has been and will be remarkable have been properly mentioned. The Italian contribution - civil works design, construction, and machinery supply - in the last hydroelectric development is briefly mentioned with particular reference to the developing countries

[en] In 1992 only 3.6% of the total german energy production was produced from hydropower, on grounds of the topographical structure. (orig./HP)

[en] According to Vedomosti journal Russian state energy company RAO JES Rossii paid for Georgian assets acquisition to American company AES only 23 million USD, what is less than a tenth of sum which AES had originally paid for it. Thus total transaction value including debts reached 80 millions USD. But internal documents of American AES confirm that Americans paid 260 millions USD for Georgian assets and they took besides over 60 millions USD of obligations. Russians bought Georgian AES assets through Finnish filial Nordic Oy. Thus they obtained 75 per cent share in Telasi company which operates distributive network in Tbilisi, two blocks of plant in Tbilisi and half share in AES-Transenergy company which exports electric energy from Georgia to Turkey. RAO JES besides got managerial laws on Hramesi company which owns two water plants. Russian company controls one fifth of production and 35 per cent of electric energy sale in Georgia by these assets

[en] A presentation of the environmental focus of the company and its goals to the professional as well as laic public can be presented very effectively also by educative paths. On one hand, they present natural and cultural and historical features of the area but since all the objects created by human activity are located directly in this area, the paths can be used also for stressing the purpose of these objects out, on the other hand. (author)

[en] This paper presents a design technique to control a low-head hydro power plant connected as a single machine to an infinite bus (SMIB) system. A state-space model with two-input and two-output variables is considered. The control action is performed through the excitation and governor subsystems. The approach used is based on optimal pole shift theory. The solution to optimal control is achieved without solving any non-linear algebraic Riccati equation. The discussed technique offers satisfactory damping effects on speed and load angle oscillations. It is observed that the system's satisfactory response remains unchanged for any variation in a plant parameter that may occur due to change in operating conditions of a plant. (authors)

[en] With the single exception of Chernobyl Unit 4, 1986 was another year of safe, reliable and economic operation for nuclear power plants. During 1986, the total installed nuclear capacity increased by about 10%, with 23 new nuclear reactors totaling more than 23,000 MW(e) coming on-line in eight countries. It was predicted that world nuclear electricity generation would increase from 1514 TW.h in 1986 to 3038 in 2000. To put the Chernobyl accident in perspective, the author compares its effects with those of catastrophic failures of hydroelectric dams