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In the paper are presented and discussed the results of a more complex research of technology portfolio's competitiveness in power systems with high penetration of intermittent renewable energy sources (i-RES). Possible technology portfolios compositions are analyzed. The portfolios comprise very high participation of i-RES, as well as a certain participation of energy storage technologies, but also and other energy technologies like nuclear and fossil fueled power plants. Within the research are developed new competitiveness indicators i.e., dispatchability indicator and the technology portfolio's assured capacity. The latter is defined on the basis of recently published Ulrich's and Schiffer's paper. Obtained results point out that inclusion of pumped-hydro storage plants improves portfolio's dispatchability. However, within the researched interval up to PHS installed capacities relative to i-RES capacities of 0.3. Numerical values of the dispatchability indicators are still below their values for the portfolio without i-RES. Increased participation of nuclear power plants contribute to the improvement of numerical values of the dispatchability indicators. The sensitivity analysis for the case of two times smaller cost of pumped hydro storage capacities is also performed. Hypothetical change of power system's technology structure in sense of substitution hard coal and lignite fired power plants with wind generators or with nuclear power plants is also analyzed. The analysis points out that the substitution with nuclear power plants enables much better results regarding power system's ability to change the power on demand than substitution with wind generators, particularly in the countries with high participation of hard coal and/or lignite in electricity generation. [ABSTRACT FROM AUTHOR]

This paper presents the performance and economic analysis of the gas turbine with co-firing gas from corn cob gasification and natural gas. Adiabatic and non- -adiabatic expansion in the turbine is considered. The analysis is performed parametrically with corn cob gasification gas and natural gas ratio. The volumetric energy content of fuels with different share of gas from the corn cob gasification, therefore, with different calorific values, is compared by means of the Wobbe Index. In energy and economic analyses, the following configurations are dealt with: single manifold, dual manifold, and separate gas systems. [ABSTRACT FROM AUTHOR]

Technology development is a keystone within the efforts toward enabling longer duration of the world fossil energy resources. The past development and the technologies applied, cause huge emissions of CO2 that must be significantly reduced. Increased usage of renewable energy sources for electricity generation (RES-e) contributes essentially to the reduction of CO2, but on the other hand, under current conditions of feed-in priority reduces also the market for the electricity from fossil fuelled power plants. The other possibility for reduction of CO2 emissions is to apply carbon capture and storage technologies as a part of overall fossil fuelled power plants technologies. A hypothesis presented in this paper is that there is a marginal share of RES variable electricity in overall annual electricity supply after which further increase of RES-e participation produces higher average electricity generated cost, than in the case of CO2 emission reduction by applying carbon capture and storage technologies. The presented work confirms this hypothesis. Value of the marginal share depends to the price of RES-e feed-in. With the price span from 13.5 to 7.5 €c/kWh, the marginal share is under 50%. [ABSTRACT FROM AUTHOR]

The paper presents the mathematical model and the procedure for calculation of the resultant force acting on the air cooled gas turbine blade(s) based on the aerodynamic theory and computation of the circulation around the blade profile. In the conducted analysis was examined the influence of the cooling air mass flow expressed through the cooling air flow parameter λc, as well as, the values of the inlet and outlet angles β1 and β2, on the magnitude of the tangential and axial forces. The procedure and analysis were exemplified by the calculation of the tangential and axial forces magnitudes. [ABSTRACT FROM AUTHOR]

This paper presents a new approach in mathematical modeling of thermodynamic cycles and electric power of utility district-heating and co-generation steam turbines. The approach is based on the application of the dimensionless mass flows, which describe the thermodynamic cycle of a combined heat and power steam turbine. The mass flows are calculated relative to the mass flow to low pressure turbine. The procedure introduces the extraction mass flow load parameter ?h which clearly indicates the energy transformation process, as well as the co-generation turbine design features, but also its fitness for the electrical energy system requirements. The presented approach allows fast computations, as well as direct calculation of the selected energy efficiency indicators. The approach is exemplified with the calculation results of the district heat power to electric power ratio, as well as the cycle efficiency, vs. ?h. The influence of ?h on the conformity of a combined heat and power turbine to the grid requirements is also analyzed and discussed. [ABSTRACT FROM AUTHOR]