Showing papers on "Power station published in 2002"

A technical, economic, and environmental assessment of amine-based CO2 capture technology for power plant greenhouse gas control

Abstract: Capture and sequestration of CO2 from fossil fuel power plants is gaining widespread interest as a potential method of controlling greenhouse gas emissions. Performance and cost models of an amine (MEA)-based CO2 absorption system for postcombustion flue gas applications have been developed and integrated with an existing power plant modeling framework that includes multipollutant control technologies for other regulated emissions. The integrated model has been applied to study the feasibility and cost of carbon capture and sequestration at both new and existing coal-burning power plants. The cost of carbon avoidance was shown to depend strongly on assumptions about the reference plant design, details of the CO2 capture system design, interactions with other pollution control systems, and method of CO2 storage. The CO2 avoidance cost for retrofit systems was found to be generally higher than for new plants, mainly because of the higher energy penalty resulting from less efficient heat integration as well ...

Advances in Parabolic Trough Solar Power Technology

Abstract: Parabolic trough solar technology is the most proven and lowest cost large-scale solar power technology available today, primarily because of the nine large commercial-scale solar power plants that are operating in the California Mojave Desert. These plants, developed by Luz International Limited and referred to as Solar Electric Generating Systems (SEGS), range in size from 14-80 MW and represent 354 MW of installed electric generating capacity. More than 2,000,000 m 2 of parabolic trough collector technology has been operating daily for up to 18 years, and as the year 2001 ended, these plants had accumulated 127 years of operational experience. The Luz collector technology has demonstrated its ability to operate in a commercial power plant environment like no other solar technology in the world. Although no new plants have been built since 1990, significant advancements in collector and plant design have been made possible by the efforts of the SEGS plants operators, the parabolic trough industry, and solar research laboratories around the world. This paper reviews the current state of the art of parabolic trough solar power technology and describes the R&D efforts that are in progress to enhance this technology. The paper also shows how the economics of future parabolic trough solar power plants are expected to improve.

A techno-economic comparison of power production by biomass fast pyrolysis with gasification and combustion

Abstract: This paper presents an assessment of the technical and economic performance of thermal processes to generate electricity from a wood chip feedstock by combustion, gasification and fast pyrolysis. The scope of the work begins with the delivery of a wood chip feedstock at a conversion plant and ends with the supply of electricity to the grid, incorporating wood chip preparation, thermal conversion, and electricity generation in dual fuel diesel engines. Net generating capacities of 1–20 MWe are evaluated. The techno-economic assessment is achieved through the development of a suite of models that are combined to give cost and performance data for the integrated system. The models include feed pretreatment, combustion, atmospheric and pressure gasification, fast pyrolysis with pyrolysis liquid storage and transport (an optional step in de-coupled systems) and diesel engine or turbine power generation. The models calculate system efficiencies, capital costs and production costs. An identical methodology is applied in the development of all the models so that all of the results are directly comparable. The electricity production costs have been calculated for 10th plant systems, indicating the costs that are achievable in the medium term after the high initial costs associated with novel technologies have reduced. The costs converge at the larger scale with the mean electricity price paid in the EU by a large consumer, and there is therefore potential for fast pyrolysis and diesel engine systems to sell electricity directly to large consumers or for on-site generation. However, competition will be fierce at all capacities since electricity production costs vary only slightly between the four biomass to electricity systems that are evaluated. Systems de-coupling is one way that the fast pyrolysis and diesel engine system can distinguish itself from the other conversion technologies. Evaluations in this work show that situations requiring several remote generators are much better served by a large fast pyrolysis plant that supplies fuel to de-coupled diesel engines than by constructing an entire close-coupled system at each generating site. Another advantage of de-coupling is that the fast pyrolysis conversion step and the diesel engine generation step can operate independently, with intermediate storage of the fast pyrolysis liquid fuel, increasing overall reliability. Peak load or seasonal power requirements would also benefit from de-coupling since a small fast pyrolysis plant could operate continuously to produce fuel that is stored for use in the engine on demand. Current electricity production costs for a fast pyrolysis and diesel engine system are 0.091/kWh at 1 MWe when learning effects are included. These systems are handicapped by the typical characteristics of a novel technology: high capital cost, high labour, and low reliability. As such the more established combustion and steam cycle produces lower cost electricity under current conditions. The fast pyrolysis and diesel engine system is a low capital cost option but it also suffers from relatively low system efficiency particularly at high capacities. This low efficiency is the result of a low conversion efficiency of feed energy into the pyrolysis liquid, because of the energy in the char by-product. A sensitivity analysis has highlighted the high impact on electricity production costs of the fast pyrolysis liquids yield. The liquids yield should be set realistically during design, and it should be maintained in practice by careful attention to plant operation and feed quality. Another problem is the high power consumption during feedstock grinding. Efficiencies may be enhanced in ablative fast pyrolysis which can tolerate a chipped feedstock. This has yet to be demonstrated at commercial scale. In summary, the fast pyrolysis and diesel engine system has great potential to generate electricity at a profit in the long term, and at a lower cost than any other biomass to electricity system at small scale. This future viability can only be achieved through the construction of early plant that could, in the short term, be more expensive than the combustion alternative. Profitability in the short term can best be achieved by exploiting niches in the market place and specific features of fast pyrolysis. These include: •countries or regions with fiscal incentives for renewable energy such as premium electricity prices or capital grants; •locations with high electricity prices so that electricity can be sold direct to large consumers or generated on-site by companies who wish to reduce their consumption from the grid; •waste disposal opportunities where feedstocks can attract a gate fee rather than incur a cost; •the ability to store fast pyrolysis liquids as a buffer against shutdowns or as a fuel for peak-load generating plant; •de-coupling opportunities where a large, single pyrolysis plant supplies fuel to several small and remote generators; •small-scale combined heat and power opportunities; •sales of the excess char, although a market has yet to be established for this by-product; and •potential co-production of speciality chemicals and fuel for power generation in fast pyrolysis systems.

Survey of Thermal Energy Storage for Parabolic Trough Power Plants

Abstract: A literature review was carried out to critically evaluate the state of the art of thermal energy storage applied to parabolic trough power plants. This survey briefly describes the work done before 1990 followed by a more detailed discussion of later efforts. The most advanced system is a 2-tank-storage system where the heat transfer fluid (HTF) also serves as storage medium. This concept was successfully demonstrated in a commercial trough plant (13.8 MW e SEGS I plant; 120 MWh t storage capacity) and a demonstration tower plant (10 MW e Solar Two; 105 MWh t storage capacity). However, the HTF used in state-of-the-art parabolic trough power plants (30-80 MW e ) is expensive, dramatically increasing the cost of larger HTF storage systems. Other promising storage concepts are under development, such as concrete storage, phase change material storage, and chemical storage. These concepts promise a considerable cost reduction compared to the direct 2-tank system, but some additional R&D is required before those systems can be used in commercial solar power plants. An interesting and likely cost-effective near-term option for thermal energy storage for parabolic trough power plants is the use of an indirect 2-tank-storage, where another (less expensive) liquid medium such as molten salt is utilized rather than the HTF itself.

Method for operating a wind park

Abstract: The invention relates to a method for operating a wind park; consisting of several wind power plants. The wind part is connected to an electric supply network into which the power produced by the wind park is fed and the wind park and/or at least one of the wind power plants of the wind park is provided with a control input which is used to adjust the electric power of the wind park or one or several individual wind plants within a range of 0-100 % of the respectively provided power, especially the nominal output thereof. A data processing device is connected to the control input and is used to adjust the control value within a range of 0-100 % according to the amount of power available from the entire wind part at the output where it is fed into the power network. The operator (EVU) of the electric power supply network to which the wind park is connected can adjust the power provided by the wind park via the control input.

Concentrating photovoltaic cavity converters for extreme solar-to-electric conversion efficiencies

Abstract: A concentrating photovoltaic module is provided which provides a concentration in the range of about 500 to over 1,000 suns and a power range of a few kW to 50 kW. A plurality of such modules may be combined to form a power plant capable of generating over several hundred megaWatts. The concentrating photovoltaic module is based on a Photovoltaic Cavity Converter (PVCC) as an enabling technology for very high solar-to-electricity conversions. The use of a cavity containing a plurality of single junction solar cells of different energy bandgaps and simultaneous spectral splitting of the solar spectrum employs a lateral geometry in the spherical cavity (where the cell strings made of the single junction cells operate next to each other without mutual interference). The purpose of the cavity with a small aperture for the pre-focused solar radiation is to confine (trap) the photons so that they can be recycled effectively and used by the proper cells. Passive or active cooling mechanisms may be employed to cool the solar cells.

System for providing assured power to a critical load

Abstract: A first AC power source comprising a fuel cell power plant (18), and a second power source, typically grid (10), are normally connected via a high speed isolation switching means (19) to provide sufficient AC power to a critical load (14).

Greenhouse Gas Emissions from Building and Operating Electric Power Plants in the Upper Colorado River Basin

Abstract: As demand for electricity increases, investments into new generation capacity from renewable and nonrenewable sources should include assessment of global (climate) change consequences not just of the operational phase of the power plants but construction effects as well. In this paper, the global warming effect (GWE) associated with construction and operation of comparable hydroelectric, wind, solar, coal, and natural gas power plants is estimated for four time periods after construction. The assessment includes greenhouse gas emissions from construction, burning of fuels, flooded biomass decay in the reservoir, loss of net ecosystem production, and land use. The results indicate that a wind farm and a hydroelectric plant in an arid zone (such as the Glen Canyon in the Upper Colorado River Basin) appear to have lower GWE than other power plants. For the Glen Canyon hydroelectric plant, the upgrade 20 yr after the beginning of operation increased power capacity by 39% but resulted in a mere 1% of the CO2 e...

Power transmission of a desk with a cord-free power supply

Abstract: The battery is an indispensable component of portable electronic equipment, but charging is often inconvenient. A contactless electric power supply, such as the desk-type contactless power station (CLPS) we propose, significantly improves the ease of charging such equipment. In this system, primary coils are embedded into the desk surface to efficiently supply electrical power to portable equipment placed on the desk. Only the primary and the secondary coils facing each other work as a power transmitter. We have confirmed that electric power transmission with efficiency of 85 /spl plusmn/ 5% can be attained anywhere on the desk. This examination reveals the effectiveness of using several primary coils.

Review paper An economic analysis of biomass gasification and power generation in China

Abstract: With vast territory and abundant biomass resources China appears to have suitable conditions to develop biomass utilization technologies. As an important decentralized power technology, biomass gasification and power generation (BGPG) has a potential market in making use of biomass wastes. In spite of the relatively high cost for controlling secondary pollution by wastewater, BGPG is economically feasible and can give a financial return owing to the low price of biomass wastes and insufficient power supply at present in some regions of China. In this work, experimental data from 1 MW-scale circulating fluidized bed (CFB) BGPG plants constructed recently in China were analyzed; and it was found that the unit capital cost of BGPG is only 60–70% of coal power station and its operation cost is much lower than that of conventional power plants. However, due to the relatively low efficiency of small-scale plant, the current BGPG technology will lose its economic attraction when its capacity is smaller than 160 kW or the price of biomass is higher than 200 Yuan RMB/ton. The development of medium-scale BGPG plants, with capacity ranging from 1000 to 5000 kW, is recommended; as is the demonstration of BGPG technology in suitable enterprises (e.g. rice mill and timber mill) in developing countries where large amounts of biomass wastes are available so that biomass collection and transportation can be avoided and the operation cost can be lowered. 2002 Elsevier Science Ltd. All rights reserved.

Mobile wind and solar energy aggregate

Abstract: The present invention relates to a mobile power station. The power station has a transportable housing (1). This housing is provided with a wind turbine (2, 3, 4) and/or a solar cell panel (10) containing solar cells and storage means for storing electrical energy and supplying electrical energy. The wind turbine and the solar panel, respectively, are actively connected to the storage means for supplying thereto electrical energy generated by the wind turbine and the solar panel, respectively. The storage means comprise a battery as well as a hydrogen system. The hydrogen system comprises a hydrogen generator, a hydrogen tank and a hydrogen cell for generating electrical energy by combustion of hydrogen. The mobile power station in particular also has a solar collector panel that is actively connected to a boiler for hot water.

Solar power enhanced combustion turbine power plants and methods

Abstract: Combustion turbine power plants and methods of operating the same are provided in which air is cooled using solar energy and supplied to an air inlet of the power plant to support combustion. Also, combustion turbine power plants and methods of operating the same are provided in which steam is produced using solar energy and injected into a turbine of the power plant.

Wind powered hydroelectric power plant and method of operation thereof

Abstract: A hydroelectric power plant uses a plurality of windmills connected to compressed air generators to produce pressurized air. Pressurized air is used to drive water through a turbine to produce electrical power. The water is recycled and the power plant includes reserve pressurized air tanks to allow the plant to continue to operate when the wind levels are not sufficient to produce high pressure air. The power plant is designed to be operated on a continuous basis based on wind power. When the wind subsides and the reserve capacity has been exhausted, electricity can be drawn from the local utility supplier. When excess power is generated by the power plant, electricity from the power plant can be added to the grid of the local electricity supplier.

Method for operating a wind farm

Abstract: The method involves setting the electrical power of the wind park or one or more wind power systems in a range of 0 to 100 per cent of the available power by means of a data processing device connected to at least one wind power system control input. The demanded power is set depending on the total available power of the wind park. The controller of the supply system can set the power output by the wind park. An independent claim is also included for the following: a wind park and a wind power system.

The European efforts in material development for 650°C USC Power plants: COST522

Abstract: Advanced Steam Power Plant is one of three working groups within the frame of European COST 522 with the aim of developing and evaluating ferritic steels for steam conditions up to 650°C. Today's state-of-the-art large fossil-fired steam turbines comprise live steam conditions of up to 610°C/ 300 bar and re-heat temperatures of up to 630°C. These ultra super critical steam parameters significantly increase plant efficiency and reduce fuel consumption and emissions of CO 2 . Ferritic materials should be used for thick-walled components to maintain high operational flexibility of such large plants. Rotors, casings, bolts, tubes/pipes and waterwalls are the critical components under current investigation. The class of the 9-12 % Cr steels offers the highest potential to meet the required property level for critical components. Therefore a significant effort to increase the application temperature of these steels was the focus of study within the European COST 501 programme and has led to improved materials for 600°C application of forged and cast components and for pipework. These 600°C materials are already being successfully utilised in a number of advanced European power plants. Further potential for improvement in creep strength seems possible after taking into account the oxidation resistance for T> 600°C. A large number of new ferritic-martensitic compositions, which have been designed on the basis of the positive outcomes attained in previous studies as well as on the results obtained with advanced thermodynamic calculation tools are under investigation in the new COST 522 programme. Full-size cast and forged components have been manufactured from the most promising compositions and now are being evaluated by intensive mechanical testing.

Control of grid-connected fuel cell power plant for transient stability enhancement

Abstract: This paper describes a dynamic model of a SOFC fuel cell, which can be used in transient stability studies. The model is applied to a distributed utility grid that uses a fuel cell and a gas turbine as distributed generators (DGs). Transient stability of the system is investigated for different DGs power outputs using a software developed based on the commercial Power System ToolBox and SIMULINK in MATLAB. A method for interfacing the fuel cell to the grid is presented. Transient stability is enhanced through a control design of the firing angle of the fuel cell inverter.