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

Issue 5 • Date June 1980

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Displaying Results 1 - 11 of 11
  • Future energy concepts

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    Freely Available from IEEE
  • Energy analysis of wave and tidal power

    Page(s): 274 - 278
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    Energy requirements for building wave and tidal-power systems have been estimated. For wave-power systems, the relationship between energy requirements and extraction efficiency is examined. It is found that a point of maximum net output is reached, beyond which further increases in extraction efficiency result in decreased net energy. Energy analysis thus identifies a limit on the energy which could, in principle, be extracted by a wave-energy system. Although similar limits could be identified for other types of energy source, the tidal-power analysis is confined to a brief comparison of energy inputs and outputs. View full abstract»

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  • Economic assessment of the renewable energy sources

    Page(s): 279 - 288
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    The paper considers possible approaches to the economic assessment of the renewable energy sources in electricity supply. The major ways in which renewables may contribute to the UK electricity supply system are stated and quantified, and the major differences and similarities between renewables and conventional electricity generating plant types are discussed. An introduction to a method of economic assessment used for conventional plant types is given. This method is not directly suited to the economic assessment of renewables and the paper proceeds to a critique of variants which have been developed. These are shown to be inadequate, and a new approach is proposed. Some illustrative results are presented in terms of `breakeven capital costs¿¿ for a hypothetical renewable and the sensitivity of the results to some of the major assumptions is shown. View full abstract»

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  • Economic and operational implications of a complex of wind-driven generators on a power system

    Page(s): 289 - 295
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    An assessment is presented of the technical and economic implications of integrating a sizeable complex of aerogenerators into a power system. An important economic and operational factor is the variable and uncertain nature of the wind. However, it is shown that the effects of the more rapid fluctuations are largely mitigated by the incoherency of different machine outputs; a diversity factor is defined in terms of the spacing of an array of machines and the turbulence length scale. In contrast, the slower variations are shown to require a significant enhancement of the operational reserve capacity but not to necessitate the addition of dedicated storage, to accommodate wind-power penetration up to about 20% of maximum demand. The increased uncertainty of the residual generation, over the scheduling period, significantly affects the economics of utilisation of pumped-storage and gas-turbines as standby plant. The results of an analysis of a year's data, pertaining to demand and wind speed at 4 well separated sites, are presented. Finally, those principal system aspects, that require detailed evaluation, are identified and discussed. View full abstract»

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  • System-reliability studies for wave-energy generation

    Page(s): 296 - 300
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    A study is being undertaken in the United Kingdom of means of developing the potential of the large wave-energy resource around the coast, in particular, that to the west facing the Atlantic. Derivation of the mean annual energy to be expected involved knowledge, not only of the wave climates, conversion efficiency characteristics of the proposed devices and of the power transmission system, but also of factors reflecting the availability overall. The paper sets out a first simplified approach to the quantifying of reliability for each stage of the process, and, after establishing an appropriate method of analysis, gives a summary of the preliminary results obtained. View full abstract»

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  • Wave energy

    Page(s): 301 - 307
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    Wave-energy studies to date have aimed at producing outline system designs and realistic estimates of their performance and costs. The original devices, which included simple inshore systems, bulky floating `oscillating-water-column/air turbine¿¿ systems and technically complex devices like the duck, have resulted in net generating cost estimates of 10¿¿30p/kWhe, the main differences being in productivity (efficiency) estimates. `Second-generation¿¿ devices are claimed capable of around 6p/kWhe. Generic work has shown that the resource size is less than originally believed. Wave-directional effects, equipment reliability and basic device/converter efficiency lead to a maximum productivity of ~ 25%, say 60¿¿70 TWhe/yr or 10% of UK energy needs. The research does point to ways of improving wave-energy economics. Device efficiency is not an issue, since theoretical considerations have proved that all concepts have equal efficiency potential. Maintenance assessments have shown the importance of using simple systems, like the air turbine. Performance and cost of structures, moorings and power-conversion equipment, benefit from long (spine) structures and are further enhanced by advanced control methods. Improved systems capable of 5¿¿10p/KWh should be possible, but wave energy is unlikely to compete economically with nuclear power. View full abstract»

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  • Recent progress on ducks

    Page(s): 308 - 319
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    Until the end of 1978, the team at Edinburgh put most of its effort into small-scale laboratory tests with increasing levels of hydrodynamic realism. Some test results show that the requirement for rigidity of the duck backbone is much lower than was predicted, and that in waves with lengths of twenty diameters and more, there are considerable benefits to be derived from controlled backbone movements. Since the beginning of 1979, we have been working on the problems of full-scale design. The CEGB-preferred schemes use low-pressure air turbines, asynchronous generation, d.c. transmission, serial connections and simple designs with reliability achieved by easy access and maintenance. We prefer high-pressure oil hydraulics, synchronous generation, a.c. transmission and parallel connections. We exploit the techniques of modern electronics and plan to achieve reliability by total hermetic sealing of the power conversion mechanism which will exclude all organisms, both marine and human. I shall attempt to justify our approach. View full abstract»

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  • Heat-pump applications to single-family dwellings-an analysis by computer model

    Page(s): 320 - 325
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    When introducing new kinds of advanced heating systems and energy conservation measures in buildings it is important to have an appropriate model to compute the impact both on the energy demand of the house and on the electric energy system. A heating system and its interaction with the heated house and the indoor and outdoor climate is extremely complex. This is especially so when the heating energy is taken from insolation, the outside air or the soil, as is the case with heat-pump applications. View full abstract»

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  • Fossil-fuel heat pumps for domestic, commercial and industrial space heating

    Page(s): 326 - 329
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    The advantages of using a fossil-fuel heat pump (f.f.h.p.) compared with an electric heat pump are explained, and performance discussed. Full application of f.f.h.p.s to space heating could reduce the UK primary energy demand by up to 20%. Various types of f.f.h.p. are described and their performance is estimated. The OUERG/Lucas Aerospace gas-fired heat pump is described in detail, and preliminary results given. View full abstract»

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  • Advantage of incorporating geothermal energy into power-station cycles

    Page(s): 330 - 335
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    The generation of electricity from low-temperature geothermal sources has been hampered by the low conversion efficiencies of Rankine cycle operating below 150¿¿C. In the paper, the author shows how the electrical output derived from a geothermal borehole may be substantially improved on that expected from these cycles by incorporating the geothermal heat into a conventional steam-cycle power station to provide feedwater heating. This technique can yield thermal conversion efficiencies of 11% which, for a well-head temperature of 100¿¿C, is 50% greater than the output expected from a Rankine cycle. Coupled with the smaller capital costs involved, feedwater heating is thus a more attractive technique of converting heat into electricity. Although power stations above suitable geothermal resources would, ideally, have the geothermal heat incorporated from the design stage, experiments at Marchwood Power Station have shown that small existing sets can be modified to accept geothermal feedwater heating. View full abstract»

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  • Implications for the UK of solar-power satellites(s.p.s) as an energy source

    Page(s): 336 - 343
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    Rapid depletion of fossil-fuel resources is leading to increased interest in alternative energy sources. The sun's radiation in space is a continuously available, virtually nondepletable and environmentally benign source of energy which could be made available on earth by the s.p.s. concept. This paper describes the concept currently under evaluation in the USA, and also in Europe (particularly in UK), though to a lesser extent. The advantages and problems associated with its adoption by the UK as a major source of electrical energy are discussed. View full abstract»

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