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While the share of fluctuating renewable energy resources is constantly increasing, the centralized, hierarchical organization of the current energy system and markets cannot adequately accommodate such decentralized electricity generation. New ideas have been developed and discussed for improved integration, also in Germany, one of the lead markets. Examples in this context are virtual power plants and microgrids. This paper presents a new local reserve energy market design (applied to residential households), which can facilitate the operation and allow trading within these constructs. Emphasis is put on the regulatory options and current market framework, mainly from a European and a German perspective, which serve as a basis for implementing the local market. It can be shown that using existing regulatory structures, a local market with simple rules (comparable to an 'energy-eBay') can be easily installed. Keywords: local reserve energy market, balance group, prosumer, 1. INTRODUCTION Addressing the goal and the growing reality of an increasing share of distributed energy generation, many of the recent research efforts in the field concern possible ways of [...]

The morning train from Slavutych is packed with commuters playing cards, browsing e-readers, or watching the monotonous flood plains pass by. It looks like any other routine journey to work. [...]

Fundamental differences between the optimization strategies for power cycles used in 'traditional' and solar-thermal power plants are identified using principles of finite-time thermodynamics. Optimal operating efficiencies for the power cycles in traditional and solar-thermal power plants are derived. In solar-thermal power plants, the added capital cost of a collector field shifts the optimum power cycle operating point to a higher-cycle efficiency when compared to a traditional plant. A model and method for optimizing the thermoeconomic performance of solar-thermal power plants based on the finite-time analysis is presented. The method is demonstrated by optimizing an existing organic Rankine cycle design for use with solar-thermal input. The net investment ratio (capital cost to net power) is improved by 17%, indicating the presence of opportunities for further optimization in some current solar-thermal designs. [DOI: 10.1115/1.2769689] Keywords: finite-time thermodynamics, solar-thermal, powerplant, optimization

New Energy Capital has completed a $12 million project in Greenville, Maine, for refurbishing a 16 MW wood-fired electricity generating facility that is fueled by forestry debris and mill wastes. It is qualified as a renewable generation unit under the Massachusetts Renewable Portfolio Standard (RPS) thus earning one Renewable Energy Certificate (REC) for every megawatt of power generated.

Parabolic trough power plants with direct steam generation technology are a promising option for the production of electricity from renewable energy resources. For the layout of the collector field and the design of the control system the knowledge of the short-time dynamics is of essential importance. To study the dynamic behaviour a transient non-linear simulation tool is developed based on the Modelica language. The impact of over-all and local shadings of an 1000 m collector loop is simulated. Different feed water control systems are developed, implemented and evaluated. It turns out that in addition to the liquid level control of the buffer tank a fast feedback of the actual steam production is necessary for a good performance. For the case of steam temperature control by an injection cooler, it is shown that feedforward control significantly reduces the temperature deviations compared to a simple proportional integral controller. The reaction of the controlled loop is simulated under a varity of irradiation disturbances. A key finding is that the orientation of the collector field relative to the moving clouds has large impact on the peak values during transients. Keywords: Parabolic trough; Direct steam generation; Power plant; Feed water control; Modelica; Dynamic simulation

The development of modern power generation systems with higher thermal efficiency requires the use of constructional materials of higher strength and improved resistance to the aggressive service atmospheres. In this paper, the following examples are discussed. (i) The oxidation behavior of 9% Cr steels in simulated combustion gases: The effects of [O.sub.2] and [H.sub.2]O content on the oxidation behavior of 9% Cr steels in the temperature range 600-800[degrees]C showed that in dry oxygen a protective scale was formed with an oxidation rate controlled by diffusion. In contrast, that in the presence of water vapor, after an incubation period, the scale became nonprotective as a result of a change in the oxidation mechanism. (ii) The development of NiCrAlY alloys for corrosion-resistant coatings and thermal barrier coatings of gas turbine components: The increase of component surface temperature in modern gas turbines leads to an enhanced oxidation attack of the blade coating. Considerable efforts have been made in the improvement of the temperature properties of MCrAlY coatings by the additions of minor elements, such as yttrium, silicon, and titanium. The experimental results show the positive, but different influence of the oxidation behavior of the MCrAlY coatings by the addition of these minor elements. (iii) The development of lightweight intermetallics of TiAl-basis: TiAl-based intermetallics are promising materials for future turbine components because of the combination of high-temperature strength and low density. These alloys, however, possess poor oxidation resistance at temperatures above 700[degrees]C. The experimental results showed that the oxidation behavior of TiAl-based intermetallics can be strongly improved by minor additions of 1-2 at. % silver. (iv) The oxide-dispersion-strengthened (ODS) alloys provide excellent creep resistance up to much higher temperatures than can be achieved with conventional wrought or cast alloys in combination with suitable high-temperature oxidation/ corrosion resistance. The growth mechanisms of protective chromia and alumina scales were examined by a two-stage oxidation method with [sup.18]O tracer. The distribution of the oxygen isotopes in the oxide scale was determined by secondary ion-mass spectroscopy and SNMS. The results show the positive influence of a [Y.sub.2][O.sub.3] dispersion on the oxidation resistance of the ODS alloys and its effect on growth mechanisms. [DOI: 10.1115/1.2137769] Keywords: power stations, metallic high-temperature materials, corrosion layers, coatings, SNMS, SIMS, SEM, TEM, EPMA, RBS, LRS, XRD

Introduction of closed-cycle gas turbines with their capability of retaining combustion generated C[O.sub.2] can offer a valuable contribution to the Kyoto goal and to future power generation. Therefore, research and development at Graz University of Technology since the 1990s has lead to the Graz Cycle, a zero emission power cycle of highest efficiency. It burns fossil fuels with pure oxygen, which enables the cost-effective separation of the combustion C[O.sub.2] by condensation. The efforts for the oxygen supply in an air separation plant are partly compensated by cycle efficiencies far higher than 60%. In this work a further development, the S-Graz Cycle, which works with a cycle fluid of high steam content, is presented. Thermodynamic investigations show efficiencies up to 70% and a net efficiency of 60%, including the oxygen supply. For a 100 MW prototype plant the layout of the main turbomachinery is performed to show the feasibility of all components. Finally, an economic analysis of a S-Graz Cycle power plant is performed showing very low C[O.sub.2] mitigation costs in the range of $10/ton C[O.sub.2] captured, making this zero emission power plant a promising technology in the case of a future C[O.sub.2] tax. [DOI: 10.1115/1.1850944]

The heat rejected and water evaporated in mechanical and natural draft cooling towers are critically evaluated by employing the Merkel, Poppe, and e-number-of-transfer-units (e-NTU) methods of analysis, respectively, at different operating and ambient conditions. The importance of using a particular method of analysis when evaluating the performance characteristics of a certain fill material and subsequently employing the same analytical approach to predict cooling tower performance is stressed. The effect of ambient humidity and temperature on the performance of cooling towers employing the Merkel, e-NTU, and Poppe methods of analysis are evaluated. [DOI: 10.1115/1.1787504]

This paper summarizes achievements in the Siemens Westinghouse Advanced Turbine Systems (ATS) Program. The ATS Program, co-funded by the U.S. Department of Energy, Office of Fossil Energy, was a very successful multiyear (from 1992 to 2001) collaborative effort between government, industry, and participating universities. The program goals were to develop technologies necessary for achieving significant gains in natural gas-fired power generation plant efficiency, a reduction in emissions, and a decrease in cost of electricity, while maintaining current state-of-the-art electricity generation systems' reliability, availability, and maintainability levels. Siemens Westinghouse technology development concentrated on the following areas: aerodynamic design, combustion, heat transfer/cooling design, engine mechanical design, advanced alloys, advanced coating systems, and single crystal (SC) alloy casting development. Success was achieved in designing and full scale verification testing of a high-pressure high-efficiency, compressor, airfoil clocking concept verification on a two-stage turbine rig test, high-temperature bond coat/TBC system development, and demonstrating feasibility of large SC turbine airfoil castings. The ATS program included successful completion of W501G engine development testing. This engine is the first step in the W501ATS engine introduction and incorporates many ATS technologies, such as closed-loop steam cooling, advanced compressor design, advanced sealing, and high-temperature materials and coatings. [DOI: 10.1115/1.1719030]

The phenomenon of 'dwell sensitivity' in the [alpha]+[beta] and near a titanium alloys and the intrinsic relationship with quasi-cleavage facet formation is discussed. In the present paper, particular emphasis is placed upon the role of 'cold creep' and ambient temperature strain accumulation under cyclic loading. A process of stress redistribution between microstructurally distinct regions that demonstrate different strengths is proposed as the fundamental cause of facet development and subsequent dwell failures. A model to describe the redistribution process is validated through a matrix of fatigue testing designed to assess the effects of microstructural form, stress axiality, and periods of dwell loading at peak stress on cyclic strain accumulation. [DOI: 10.1115/1.1494094]