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Physical Science, Measurement and Instrumentation, Management and Education - Reviews, IEE Proceedings A

Issue 5 • Date May 1987

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Displaying Results 1 - 14 of 14
  • Alternative energy

    Page(s): 369 - 370
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    Freely Available from IEEE
  • Development of hot-dry-rock geothermal systems in the UK

    Page(s): 371 - 380
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    Geothermal developments in the UK are constrained by the stable nature of the local geological regime. However, underground temperatures of over 200°C have been predicted at 5000 m under parts of South-West England and, potentially, elsewhere in the country. Exploitation of this heat source as a possible means of power generation requires the development of a process to sweep water through the rock mass between an injection point and a pattern of recovery wells. This method of exploiting geothermal energy is known as the hot-dry-rock process. Work has been underway in Cornwall to study the geotechnical problems influencing the creation of a sufficiently large heat transfer system. A three-well system reaching a depth of 2600 m has been in operation for over 10000 h with a maximum downhole temperature of 100°C. The system has been changing throughout the experiments, and the trends show that the necessary targets for viable operation should be attained in the near future. The results have been extrapolated to full commerical scale and show that generation costs of 3¿4 p/k Wh are attainable with the current technology at favourable sites. Future developments to reduce costs substantially by reducing the number of wells needed for the operation, make hot-dry-rock worthy of serious attention as a potential source of power. View full abstract»

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  • Ocean thermal energy conversion ¿ past progress and future prospects

    Page(s): 381 - 391
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    An overview is provided of the current status of ocean thermal energy conversion, together with an historical perspective and the progress anticipated in the next ten years. The problems yet to be resolved are briefly described, and the importance of providing risk assessments is stressed so that funding agencies may be persuaded of the commercial prospects for this base-load generating system consisting predominantly of existing technology. It is concluded that a limited market exists for island developing nations, with prospects for substantial growth as OTEC plant efficiency improves or as oil prices increase. View full abstract»

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  • Tidal power

    Page(s): 392 - 398
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    The principal tidal power sites around the world are summarised, showing that the UK is fortunate in having three major potential sites. The first use of tidal power for generating electricity was a small scheme near Bristol built 56 years ago. Since then, the 240 MW Rance barrage and the recent 20 MW pilot `Straflo¿¿ turbine installed at Annapolis Royal in the Bay of Fundy are the main schemes built to date. These were built `in the dry¿¿. For an inlet off the White Sea, North Russia, a small tidal power plant was prefabricated complete and towed into position in the early 1960s. This method is favoured for the Severn barrage. An alternative method of in-situ construction has been proposed recently for the River Mersey estuary. Alternative methods of operation are discussed and the economics of tidal power compared with thermal stations. These show that, in the UK, forecasts of coal prices have dominated this aspect. Overall, the tides could be a highly predictable and substantial source of renewable energy whose development involves proven technology. View full abstract»

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  • Concept and operating experiences with Eurelios 1 MW helioelectric power plant of the European Communities

    Page(s): 399 - 406
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    The paper describes the design and operational results of Eurelios, the 1 MW (electrical) solar power plant of the mirror-field/central-receiver type, a project sponsored by the Commission of the European Communities. Construction of the plant was completed by the end of 1980 and was connected to the grid of the Italian National Electricity Generating Board, ENEL, at Adrano, Sicily (Italy), in April 1981. ENEL is the operator of the plant and its coproprietor, along with the Commission of the European Communities. A European Industrial Consortium, consisting of Ansaldo SpA and Ente Nazionale per l'Energia Elettrica (ENEL), Italy; Cethel (combining Renault, Five-Cail-Babcock, Saint-Gobain Pont-a-Mousson and Heurtey SA), France; Messerschmitt-Boelkow-Blohm (MBB), FRG, was set up for the design and construction of the plant. The operation experience gained proved the feasibility to produce electric energy, in connection with the grid, and to operate the plant by standard procedures like those for the conventional thermoelectric units. If the electrical energy production was rather disappointing, this was mainly due to mediocre quality and quantity of insolation at the site, together with inadequate design of the receiver and the thermal circuit. Because these factors are extraneous to proper engineering, the central receiver technology cannot, as such, be blamed. Solar thermal power generation is feasible today. No major scientific breakthroughs are required, but rather the development and cost reduction of more or less available components, as well as optimisation of the systems linking together those components: receiver, heliostat, prime mover, storage, heat cycle. View full abstract»

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  • Practical experience of a 50 kWp photovoltaic system supplying power to a dairy farm on Fota Island, Cork, Ireland

    Page(s): 407 - 412
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    The Fotavoltaic Project is a 50 kWp photovoltaic system used to supply electrical energy to a 250-head dairy farm on Fota Island in Cork Harbour, Ireland. It is one of the fifteen pilot projects, ranging from 30¿¿300 kWp, which have been built throughout Europe under the auspices of the Solar Energy Research and Development Programme of the EEC. The dairy farm was selected because its energy demand has the same seasonal variation as the output of a solar generator. The system consists of a 50 kW solar generator, a 600 Ah lead-acid battery, three 10 kVA self-commutated inverters which supply the dairy farm loads and a 50 kVA line-commutated inverter which delivers excess energy to the utility grid. The system operates automatically and is controlled by a microcomputer, which, in addition, monitors and records data for analysis. A VAX 11/780 computer at the National Microelectronics Research Centre continually displays the system's operation on a graphics terminal using data transmitted from Fota via a telephone link. The system began operating in June 1983 and data recording began in January 1984. During the peak milking period between March and August 1984, the PV array generated 20.52 MWh, 4.643 MWh was supplied to the dairy farm and 9.676 MWh was supplied to the utility grid. The paper describes the design of the system, the practical experiences gained and improvements which have been implemented since the system was installed. View full abstract»

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  • Operating experience of the Fair Isle wind turbine

    Page(s): 413 - 426
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    The paper describes the combined wind-turbine and diesel generation scheme installed on Fair Isle in June 1982. The reasons for the choice of the system in use and the preferred mode of operation are given. The main features of the wind turbine and its control system are described in some detail. Some of the problems encountered in service are described as well as the solutions adopted. Three years of system operation are reported and the contribution of community participation in the successful operation of the scheme is emphasised. In addition to extended hours of supply at lower cost, by producing some 90% of the energy requirement from the wind turbine, diesel fuel consumption has been reduced by two thirds and extra savings for the community are reflected in a reduction of coal and heating oil imports by 40% and 34%, respectively. View full abstract»

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  • Performance of the CEGB Howden-WTG wind turbine at Carmarthen Bay Power Station

    Page(s): 427 - 430
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    A 24 m 3-bladed wind turbine was installed for the CEGB at Carmarthen Bay Power Station in 1982. The machine had a high-solidity slow-running rotor which was stall regulated at about 300 kW. Adjustable blade tips were provided for control purposes. Monitoring of the performance of the machine was undertaken using sensors on the wind turbine, in conjunction with anemometers on masts 50 m from the rotor. The power/wind-speed curve was found to be consistent with predicted values, although the power was limited to 200 kW during most of the operating period. This limitation was imposed to restrict large peak torques produced by a poorly damped drive-train torsional mode. Analysis of the aerodynamic design showed that the energy yield at the chosen site could have been improved with a different rotational speed. A theoretical modelling of the drive train yielded a power spectrum generally in line with measurements and clearly showed that the lightly damped first torsional mode was the source of most of the energy in the power swings. View full abstract»

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  • Operational experiences from WTS-3 wind turbine, Maglarp, Sweden

    Page(s): 431 - 434
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    Operational experiences with a 3 MW wind turbine are described in the paper, covering two years of successful operation after commissioning. The total operation time covered by the paper is 7500 h, and total power production 11 500 MWh, including operation during precommissioning tests. Availability has been 63%. View full abstract»

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  • Power quality measurements on a 24 m windmill

    Page(s): 435 - 440
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    The 24 m diameter horizontal-axis windmill installed by the CEGB at Carmarthen Bay has exhibited severe power-output fluctuations due to a poorly damped torsional resonance in the drive train. The paper describes measurements undertaken to investigate this behaviour. A simple model is developed which reproduces the important low-frequency features of the power-output autospectrum. View full abstract»

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  • WEG's operational experience with two medium-sized wind turbines

    Page(s): 441 - 449
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    The Wind Energy Group has been responsible for the design, construction, commissioning and operation of two medium-sized wind-turbine generators. The first of these on Burgar Hill, Orkney, was commissioned in September 1983, and has since operated synchronously with the grid for more than 9700 h (as of January 1987). The machine has a 20 m diameter, 2-bladed horizontal-axis rotor and is rated at 250 kW. It was designed as a test bed in that its rotor can be operated with a teeter hinge, or locked solid with the main shaft, and at fixed or varying rotational speed. The 200 sensors on this machine include strain gauges, crack-detection systems, displacement transducers and accelerometers. They are connected via fibre-optic cable to a computer-based data-handling system. The second machine was commissioned at its site near Ilfracombe, in Devon, during December 1984. It differs substantially from the Orkney machine in that it has been designed to meet the market requirement with respect to cost and specification. It has a 25 m diameter, 3-bladed horizontal-axis rotor of wood-epoxy construction, rigidly mounted to the low-speed shaft. Twenty of these machines were installed in Altamont Pass, California, in December 1986. The paper gives brief specifications of the two wind turbines and describes the operational experience gained. Experimental data is presented and, where appropriate, compared with theoretical predictions resulting from the use of specially developed computer codes. View full abstract»

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  • Mod-2 wind-turbine field-operations experience

    Page(s): 450 - 454
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    The Mod-2 wind-turbine project is a development and research test operations programme sponsored by the US Department of Energy (Office of Solar Electric Technologies), managed by the NASA Lewis Research Center. The development of the turbine was initiated in 1977 under a contract which NASA awarded to the Boeing Engineering Company (now Boeing Aerospace Co.). The three-machine, 7.5 MW Goodnoe Hills cluster, located near Goldendale, Washington, is now in a research/experimental operations phase that offers a unique opportunity to study the effects of single and multiple wind turbines interacting with each other, the power grid and the environment. Following a brief description of the turbine and project history, the paper addresses major problem areas and research and development test results. Field operations, both routine and nonroutine, are discussed. Routine operation to date has produced over 13 379 000 kWh of electrical energy during 11 064 h of rotation. Nonroutine operation includes suspended activities caused by a crack in the low-speed shaft that necessitated a redesign and reinstallation of this assembly on all three turbines. With the world's largest cluster back in full operation, two of the turbines will be operated over the next several years to determine their value as energy producers. The third unit will be used primarily for conducting research tests requiring configuration changes to better understand the wind-turbine technology. Technical areas summarised in the paper pertain to system performance and enhancements. Specific research tests relating to acoustics, TV interference and wake effects conclude the paper. View full abstract»

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  • Book review: Wind Power for the UK

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    Freely Available from IEEE
  • Solar photovoltaic and wind power in Greece

    Page(s): 457 - 463
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    The high energy cost for power supply to the Greek islands, as well as the favourable solar and wind conditions, led to the utilisation of these local energy sources for power generation. On the island of Kythnos, the first wind park of a capacity of 100 kW was installed as well as a 100 kWp solar photovoltaic plant with storage facility. Both plants are grid-connected for parallel operation with the existing diesel power station. Also, a stand-alone 50 kWp solar photovoltaic plant was installed in Aghia Roumeli, Crete, to supply the community. The experience gained from the design, installation and operation of the above projects led to the implementation of some demonstration projects, and to a five-year programme in solar and wind energy for power generation. Existing data and results from the islands favour a large-scale wind usage for oil saving. Small stand-alone PV plants for small systems are cost-effective. Hybrid solar and wind power systems for small islands are realisable. View full abstract»

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