33,754 research outputs found

    Power quality and electromagnetic compatibility: special report, session 2

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    The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

    Assessment of the environmental aspects of the DOE phosphoric acid fuel cell program

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    The likely facets of a nationwide phosphoric acid fuel cell (PAFC) power plant commercial system are described. The beneficial and adverse environmental impacts produced by the system are assessed. Eleven specific system activities are characterized and evaluated. Also included is a review of fuel cell technology and a description of DOE's National Fuel Cell Program. Based on current and reasonably foreseeable PAFC characteristics, no environmental or energy impact factor was identified that would significantly inhibit the commercialization of PAFC power plant technology

    Ubiquitous energy storage

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    This paper presents a vision of a future power system with "ubiquitous energy storage", where storage would be utilized at all levels of the electricity system. The growing requirement for storage is reviewed, driven by the expansion of distributed generation. The capabilities and existing applications of various storage technologies are presented, providing a useful review of the state of the art. Energy storage will have to be integrated with the power system and there are various ways in which this may be achieved. Some of these options are discussed, as are commercial and regulatory issues. In two case studies, the costs and benefits of some storage options are assessed. It is concluded that electrical storage is not cost effective but that thermal storage offers attractive opportunities

    Rethinking Electricity Restructuring

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    Electric utility restructuring was initiated in the 1990s to remedy the problem of relatively high electricity costs in the Northeast and California. While politicians hoped that reform would allow low-cost electricity to flow to highcost states and that competition would reduce prices, economists wanted reform to eliminate regulatory incentives to overbuild generating capacity and spur the introduction of real-time prices for electricity. Unfortunately, high-cost states have seen little price relief, and competition has had a negligible impact on prices. Meanwhile, the California crisis of 2000-2001 has led many states to adopt policies that would once again encourage excess capacity. Finally, real-time pricing, although the subject of experiments, has yet to emerge. Most arresting, however, is the fact that restructuring contributed to the severity of the 2000-2001 California electricity crisis and (some scholars also argue) the August 2003 blackout in the Northeast, without delivering many efficiency gains. The poor track record of restructuring stems from systemic problems inherent in the reforms themselves. We recommend total abandonment of restructuring and a more thoroughgoing embrace of markets than contemplated in current restructuring initiatives. But we recognize that such reforms are politically difficult to achieve. A second-best alternative would be for those states that have already embraced restructuring to return to an updated version of the old, vertically integrated, regulated status quo. It's likely that such an arrangement would not be that different from the arrangements that would have developed under laissez faire
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