Showing papers on "Stand-alone power system published in 1982"

Power supply system for heat and electricity

Abstract: A power supply system for generating at least one of heat and electricity which includes a number of statically and functionally independent units adapted to generate at least one of heat and electricity which enable a maximum utilization of primary energy. For decentralized power supply over short and low loss supply lines the individual units are constructed as stackable modules. By exchanging or adding one or more modules, it is possible to adapt the flexibility of the power supply system to changes in demand for the energy thereby providing a practical approach to the utilization of waste heat for energy conservation purposes.

Greatly prolonged period non-interruptible power supply system

Abstract: This invention relates to a power supply system having the capability of furnishing to a load sensitive to electrical faults and interruptions, electrical power for prolonged periods of time after a utility or other external power supply source thereto is interrupted. The system comprises a main A.C. generator furnishing A.C. potential at a selected frequency and a selected voltage to the sensitive load, an auxiliary A.C. generator connected operatively thereto and a driving means for the generators energized with electricity from the external power supply source which is subject to outages and faults. The auxiliary generator generates A.C. potential at a much higher frequency than from the main A.C. generator and this higher frequency A.C. is supplied to a high speed A.C. induction motor and a flywheel unit in a sealed chamber, which unit can store large amounts of kinetic energy at full speed. Upon interruption of electricity from the utility or other external power source, the high speed A.C. induction motor in the sealed casing will function as a generator and feed back A.C. potential to the auxiliary generator which begins to operate as a motor and drives the main A.C. generator. A relatively small A.C. motor and flywheel unit can store and supply power to keep the main A.C. generator operating for from 1 to 20 minutes so as to ride out practically all reasonably expected power line outages. Particularly good results are obtained if the main A.C. generator is the Roesel generator of U.S. Pat. No. 4,168,459.

Method for utilizing wind energy for autonomous electricity production

Abstract: A method for utilizing wind energy for electricity production based on a wind motor and an auxiliary direct current electric motor coupled by an angular speed summation mechanism to an alternating current electric generator maintained at constant speed. The generator can be connected to a power grid or can supply local user appliances by means of a circuit to which other constant frequency generators are either connected or not. If connected to the power grid or to other generators, electricity can be produced at constant frequency by the wind with high efficiency by modulating the power supplied by the auxiliary electric motor. In the case of isolated operation, a low priority user appliance which can be modulated over a certain range has also to be provided in order to produce wind electricity under optimum conditions.

Solar Thermal Electricity Generation EURELIOS, the 1 MW(el) Helioelectric Power Plant of the European Communities

Abstract: The different technologies of solar thermal power electricity conversion are discussed and the main power plants under construction or already in operation are listed. EURELIOS, the world's first experimental solar power plant in the megawatt range, the construction of which was completed by the end of 1980 and which feeds electricity into the grid of ENEL, the Italian National Electricity Board, is described in detail. First operational results are presented. The costs of solar electricity, as well as means to achieve cost reductions are considered. With future total conversion efficiencies of 35% for gas/steam hybrid systems, e.g., and indicated heliostat costs of US $ 100/m 2 there is room for hope that solar thermal systems will remain competitive with photovoltaics, especially if process heat is used as a by-product.

A Low Distortion PWM DC-AC Inverter, with Active Current and Voltage Control, Allowing Line-Interfaced and Stand-Alone Photovoltaic Applications

Abstract: The energy transfer between a photovoltaic solar panel and the grid can be realized by means of a DC-AC inverter, which is described in this paper. A reliability study of the entire system (i.e. the solar panels and the inverter) shows that the voltage generated by the solar panel matrix has to be low (≪ 100 V). The stability conditions of the energy transfer dictate a current source behaviour of the inverter. This is realized by means of an appropriate feedback system. In this way a voltage inverter type can be used instead of the current inverters which are usually proposed, so the relatively heavy and expensive inductors can be omitted. This also allows the inverter to be used as an AC voltage power supply, in the absence of the power grid.

Design of a stand alone Photovoltaic Power System

Abstract: The overall objective of the project reported in this paper was to develop a low power (about 50 watts) Stand Alone Photovoltaic Power System with battery storage using Canadian manufactured photovoltaic modules and a storage battery. The specific objectives were: a simple design; reliability with low maintenance and costs; stimulation photovoltaic power system technology and storage battery capabilities in Canada; a methodology with multiple applications; and the transfer of the design of the working system to the private sector.

Promoting energy efficiency through improved electricity pricing: A mid-project report

Abstract: Five related areas of electricity demand analysis under alternative rate forms were studied. Adjustments by large commercial and industrial customers are examined. Residential demand under time of day (TOD) pricing is examined. A methodology for evaluating alternative rate structures is developed and applied.

Wind/Diesel Integration for Electricity Supply to Isolated Communities

Abstract: Wind energy now appears to be economically viable, especially for some isolated communities where the cost of electricity generated using conventional fuels is high. This paper discusses the problems encountered when trying to integrate a highly variable power supply, such as wind, into a small electricity supply system, and describes various possible integration strategies.

Advanced System Design for Solar Power Plants

Abstract: This report gives an overvieu on applied technology of Photovoltaic Systems as well as a vieu into the advanced subcomponent technology. It turns out more and more as a reliable source in the field of alternative energy. The now achieved standard of technology for complete systems as uell as for subcomponents is already approved in various applications. In order to have the opportunity to build up pouer plants in the Megauatt range a continuous reduction of costs by intensive development uork is necessary. In addition an approved uind generator technology would be a reasonable supplement for many applications and uould decrease the storage part, uhich means a reduction of system costs.

The potential of electrochemical batteries for bulk energy storage in an electricity supply system

Abstract: Possible applications of large-scale energy storage in an electricity supply system are examined with particular reference to rechargeable batteries. The economic considerations for each application are described and the various electrochemical storage schemes now under development are assessed in terms of their potential for meeting a storage application economically.

Direct Generation of Electricity from Solar Energy

Abstract: Publisher Summary The two most widely used methods to convert solar radiation into electricity are the thermodynamic one and the photovoltaic, one. In the thermodynamic method, an array of sun-tracking mirrors focus solar radiation into a centrally located receiver, usually at the top of a tower. The heat transmitted to the receiver is transferred to a fluid which through a heat exchanger, produces steam to run a conventional steam engine, producing electricity. Photovoltaic conversion is the direct generation of electricity from solar radiation. This method is based on the use of solar cells. Photovoltaic conversion can play a major role in providing electricity in developing countries. The modular nature allows a gradual expansion of the installation. The decentralized power generation is ideal for rural sites. Once stabilized the photovoltaic technology can also be transferred to developing countries. A few decades from now, photovoltaic generation w d also give an important contribution to electricity generation in industrialized countries. Use in residential applications will start less than ten years from now.