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The proper characterization of energy suppliers is one of the most important components in the modelling of the supply/demand relations of the electricity market. Power generation capacity i. e. power plants constitute the supply side of the relation in the electricity market. The supply of power stations develops as the power stations attempt to achieve the greatest profit possible with the given prices and other limitations. The cost of operation and the cost of load increment are thus the most important characteristics of their behaviour on the market. In most electricity market models, however, it is not taken into account that the efficiency of a power station also depends on the level of the load, on the type and age of the power plant, and on environmental considerations. The trade in electricity on the free market cannot rely on models where these essential parameters are omitted. Such an incomplete model could lead to a situation where a particular power station would be run either only at its full capacity or else be entirely deactivated depending on the prices prevailing on the free market. The reality is rather that the marginal cost of power generation might also be described by a function using the efficiency function. The derived marginal cost function gives the supply curve of the power station. The load level dependent efficiency function can be used not only for market modelling, but also for determining the pollutant and CO2 emissions of the power station, as well as shedding light on the conditions for successfully entering the market. Based on the measurement data our paper presents mathematical models that might be used for the determination of the load dependent efficiency functions of coal, oil, or gas fuelled power stations (steam turbine, gas turbine, combined cycle) and IC engine based combined heat and power stations. These efficiency functions could also contribute to modelling market conditions and determining the environmental impact of power stations.

Nowadays, while the energy prices are continuously growing, the dispositions which try to increase the energy efficiency are getting more and more important in all industrial areas. This is especially true for the energy-intensive industrial processes. Because of this, the producing companies pay more attention every year on suggesting and supporting projects, which aim to decrease the energy consumption of their own factory. One way of increasing the energy efficiency is to use the waste energy of the installations to redeem other energy sources.In our research, we analyse the usefulness of a waste heat recovery system based on gas-nitriding furnaces. These furnaces are operating on an industrial company's site in Győr, Hungary. During the investigation, our aim is to determine the economically and technologically optimal way to use this industrial waste heat. In our dissertation, we examine the different uses of the heat from the flue gas, starting with decreasing heat demand of the heating and domestic hot water (DHW) system, then decreasing the cooling of the building with an absorption chiller and finally decreasing the electric energy usage of the factory with an ORC (Organic Rankine Cycle). The data and the parameters, which are necessary to the calculations, are based on measurements on the site (temperature of the stack gas, flow volume, content, etc.) and on data, which were given by the operator and producer of the furnaces (schedule of the furnaces, technical parameters of it, etc.).The purpose of the investigation is to find, among the given constraints, the optimal way of utilizing the waste heat and to study the effects of this on the total energy-intake of the factory.

No abstract

According to the consensus view, central banks reached a high level of independence by the end of last century. This paper argues that as a result short-term political considerations applied during the appointment process of central bank decision-makers, their actual independence was at a lower level already that time. In most countries, de jure independence is higher than de facto. India is one of the very rare countries where the reverse is the case.