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Power Stations (power + stations)

Distribution by Scientific Domains

Engineering	57%
Business, Economics, Finance and Accounting	28%

Selected Abstracts

CAN A NEW NUCLEAR PROGRAMME BE JUSTIFIED?

ECONOMIC AFFAIRS, Issue 2 2006
Colin Robinson
The moratorium on the building of new nuclear power stations in the UK that has existed since the 1980s may be ended as a result of government concerns about the security of energy provision and the environmental impact of fossil-fuel-based energy supply. This viewpoint argues that the case for nuclear power on both counts is unproven. Moreover, renewed government support for a civil nuclear power programme may be a case of government attempting to pick winners, when the evidence suggests that such decisions are best taken by energy suppliers, producers and consumers. [source]

Transient stability simulation of wind generator expressed by two-mass model

ELECTRICAL ENGINEERING IN JAPAN, Issue 3 2008
Yoshikazu Shima
Abstract Recently, wind power generation is increasing worldwide. In wind power stations, induction machines are mostly used as generators. Since induction generators have a stability problem similar to the transient stability of synchronous machines, it is important to analyze the transient stability of power systems including wind generators. Although there have been some reports analyzing the transient stability problem, wind turbine and wind generator are, in most cases, modeled as a one-mass shaft system having total inertia constant. This paper presents simulation analyses of transient stability of power system including induction generator which is expressed by a two-mass shaft model and analyzes an effect of shaft system modeling on the transient stability characteristics. Simulations are performed by PSCAD/EMTDC in this study. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(3): 27,37, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20394 [source]

Reliability of power stations: Stochastic versus derated power approach

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 2 2004
Kris R. Voorspools
Abstract Consideration of the eventual forced outage of individual power stations leads to a large number of possible states of the power generating system, all with their own probability. It is possible to design a stochastic method to properly take into account all of these possibilities and to weigh them accordingly. In broader energy models, instead of these stochastic techniques that require a considerable amount of calculation time, mostly approximative static simplified methods are applied. Up till now, these simplified techniques have not been validated. The scope of this paper is to check their validity. Therefore, two approaches are compared: a complete stochastic approach and a method based on the derated power (which is the nominal power multiplied with the average availability) of the individual plants. The conclusion of this comparison is that derated power may be used in energy modelling instead of the complicated stochastic approach. The error made is very small and the correlation between the unserved load probability functions obtained by both methods is excellent. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Emission of trace toxic metals during pulverized fuel combustion of Czech coals

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 13 2003
P. Danihelka
Abstract A study of the trace elements emission (As, Se, Cd, Co, Cr, Cu, Zn, Hg, Tl, Pb, Ni, Sn, Sb, V, Mn and Fe) from pulverized coal combustion has been made at six heating and power stations situated in the Czech Republic. The amount of chlorine in coal has considerable influence on volatilization of some elements such as Zn, Cu, Pb, Hg and Tl, which is explained by the formation of thermodynamically stable compounds of these elements with chlorine. Generally, the affinities for Cl follows the order Tl > Cu > Zn > Pb > Co > Mn > Sn > Hg. The experimental data indicates enrichment of some of the trace toxic elements in the emissions (Cu, Zn, As, Se, Cd, Sn, Sb, Hg and Pb) and good agreement was obtained by thermodynamic equilibrium calculations with a few exceptions. In the case of Fe, Mn, Co, Cr and Sn calculated values are overestimated in the bottom ash and there are zero predicted amounts of these elements in the fly ash. In comparison, the results from experiments show up to 80% of these elements retained in fly ash. This implies that there exist additional steps leading to the enrichment by Fe, Mn, Co, Cr and Sn of small particles. Such mechanisms could include the ejection during devolatilization of small inorganic particles from the coal of bottom ash particles, or disintegration of the char containing these metals to small particles of fly ash. On the other hand, there are slightly overestimated or similar values of relative enrichment factors for As, V, Cu, Cd, Sb, Tl and Pb in the fly ashes and zero predicted values for bottom ashes. Our experimental results show about 5% or less of these elements are retained in bottom ashes, so they probably remain in the bottom ash inside unburned parts of coal. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Advanced oxidation processes for destruction of cyanide from thermoelectric power station waste waters

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2004
José M Monteagudo
Abstract Several advanced oxidation processes for the destruction of cyanide contained in waste waters from thermoelectric power stations of combined-cycle were studied. Thus, oxidation processes involving ozonation at basic pH, ozone/hydrogen peroxide, ozone/ultraviolet radiation and ozone/hydrogen peroxide/ultraviolet radiation have been carried out in a semi-batch reactor. All these methods showed that total cyanide can be successfully degraded but with different reaction rates, and the decrease in the total cyanide concentration can be described by pseudo-first order kinetics. The influence of pH and initial concentration of hydrogen peroxide was studied to find the optimal conditions of the oxidation process. Experimental results of the single ozone treatment indicated that total cyanide is destroyed more rapidly at higher pH (12), while ozonation combined with H2O2 and/or UV is faster at pH 9.5. The optimum concentration of H2O2 was 20.58 × 10,2M because an excess of peroxide decreases the reaction rate, acting as a radical scavenger. The total cyanide degradation rate in the O3/H2O2(20.58 × 10,2M) treatment was the highest among all the combinations studied. However, COD reduction, in the processes using UV radiation such as O3/UV or O3/H2O2/UV was about 75%, while in the processes with H2O2 and/or O3/H2O2 was lower than 57% and was insignificant, when using ozone alone. Copyright © 2003 Society of Chemical Industry [source]

Sensor architecture for the robotic control of large flexible space structures

JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 4 2007
Amy Bilton
The future construction and maintenance of very large space structures such as orbital solar power stations and telescopes will require teams of free-flying space robots. For robots to effectively perform these tasks, they will require knowledge of the structure's vibrations. Here, a robotic based sensor architecture for the vibration estimation of very large structures is presented. It is shown that this information can be effectively estimated by combining data provided by free-flying remote robot "observers" equipped with range sensors with structure-mounted acceleration sensors. A modified Kalman filter fuses low-bandwidth vision data from the remote sensing robots with the high bandwidth, but spatially sparse structure-mounted acceleration sensors. Results from experimental studies are presented that confirm the effectiveness of this approach. 2007 Wiley Periodicals, Inc. [source]

West Africa plans ambitious gas-to-power program

OIL AND ENERGY TRENDS, Issue 11 2006
Article first published online: 9 NOV 200
For several years, Nigeria produced more natural gas than it could sell. The result was high levels of flaring. Recently, it has tried to reduce the amount flared, leaving it with potentially more gas to sell. A large, new, local market is now beginning to emerge in the form of gas-fired power stations across West Africa. Nigeria is planning a large number, as are many of its neighbours, and an export pipeline linking Nigeria with its western neighbours is already under construction. [source]