Sources of Electricity

R. DiPippo, Geothermal Energy as a Source of Electricity, U.S. Department of Energy, Washington, D.C., 1980. 

In principle, after initiation the laser should be operatable purely by chemical reaction, without any external sources of electrical power. In practice, most chemical lasers do use a sustaining source of electrical power. 

The above has been isolated from all sources of electrical and mechanical power... 

An obvious example is the situation which can occur such that a loss of offsite power makes some power buses unavailable for RCS heat removal. In addition, this loss-of-power mitiator affects the availability of the remaining systems, because emergency power becomes the only source of electric power. 

These have the advantage that they are low-cost units to install the running costs, however, depending on the source of electricity, are generally higher than other energy sources. 

A portable source of electricity, if not a necessity, is certainly a great convenience in modem life and is dependent on compact, sealed, dry batteries. The main types are listed below and they incorporate the metals Zn, Ni, Hg and Cd as well as Mn02... 

Apart from g Pu, which is a nuclear fuel and explosive, the transuranium elements have in the past been produced mainly for research purposes. A number of specialized applications, however, have led to more widespread uses. I Pu (produced by neutron bombardment of I Np to form 93 Np which decays by jS-emission to 94Pu) is a compact heat source (0.56 Wg as it decays by a-emission) which, in conjunction with PbTe thermoelectric elements, for instance, provides a stable and totally reliable source of electricity with no moving parts. It has been... 

Ogden J., and Nitsch, J. (1993). Solar Hydrogen. In Renewable Energy Sources of Electricity and Fuels, ed. T. Johannsson, H. Kelly, A. K. N. Reddy, and R. H. Williams. Washington DC Island Press. 

Most urban rail service is electric-powered and most urban bus service is diesel-powered, although diesel rail and electric bus operations do exist, as noted above. The efficiency and environmental impacts of electricity depend gi eatly on the source of electric power. Although electric vehicles produce no tailpipe emissions, generation of electricity can produce significant emissions that can travel long distances, Eor example, coal-powered electricity plants produce particulate emissions that travel halfway across North America, Urban buses also can be powered by a variety of alternative fuels. 

Tidal energy is a renewable source of electricity that does not result m the emission of gases responsible for global warming or acid rain, which are asso-... 

Photovoltaics (photo for light, voltaic for electricity), often abbreviated as PV, is the direct conversion of sunlight to electricity. Considered by many to be the most promising of the renewable electric technologies m the long term, it is an attractive alternative to conventional sources of electricity for many reasons it is silent and non-polluting, reqnires no special... 

To design a voltaic cell using the Zn-Cu2+ reaction as a source of electrical energy, the electron transfer must occur indirectly that is, the electrons given off by zinc atoms must be made to pass through an external electric circuit before they reduce Cu2+ ions to copper atoms. One way to do this is shown in Figure 18.2. The voltaic cell consists of two half-cells—... 

This reaction, like that between Zn and Cu2+, can serve as a source of electrical energy in a voltaic cell The cell is similar to that shown in Figure 18.2 except that, in the anode compartment, a nickel electrode is surrounded by a solution of a nickel(II) salt, such as NiCl2 or NiS04. The cell notation is Ni Ni2+ Cu2+ Cu. 

Another spontaneous redox reaction that can serve as a source of electrical energy is that between zinc metal and Co3+ ions ... 

Secondary cells are galvanic cells that must be charged before they can be used this type of cell is normally rechargeable. The batteries used in portable computers and automobiles are secondary cells. In the charging process, an external source of electricity reverses the spontaneous cell reaction and creates a nonequilibrium mixture of reactants. After charging, the cell can again produce electricity. 

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