Solar power

“ I have addressed hundreds of audiences in Great Britain and America on the subject of recent solar discoveries, and I have conversed with many hundreds of persons of various capacity and education, from men almost uncultured to men of the highest intellectual power; and my invariable experience has been that solar research derives its chief interest when viewed in relation to the sun's position as the mighty ruler, the steadfast sustainer, the beneficent almoner of the system of worlds to which our earth belongs. ”

“ Many attempts have been made to produce power directly from the sun through solar engines, or by concentrating it in furnaces. At the St. Louis Exposition a few years ago, a Portuguese priest exhibited a solar engine called a heliophore, in which, by means of the sun's rays, the temperature was raised to 6000 degrees F., and a cube of iron placed in it melted like a snowball. The sun helps to raise the tides and some day they may be used to produce power. ”

“ Solar energy powers the systems which gather nonterrestrial materials for conversion into refined materials products. These "products" can be additional power systems, materials gathering/processing/ manufacturing systems, or simply support for other human and machine systems in space. ”

“ It is now an admitted fact of science that the earth is dependent upon the sun for the chief portion of the energy by which terrestrial effects are produced. With the exception of the ebb and flow of the tides, all the forms of earthly power are recognized as having, directly or indirectly, a solar origin. Wind-power, water-power, steam-power, the activities of organic growth, all animal energy, and the great phenomena of changes in the crust of the globe, due to the circulation of waters through atmospheric agency, are caused by the forces of solar radiation. ”

“ What is the longest mission where the total weight of the fuel cell will be less than the weight of the nuclear power plant?
26 SOLAR CELLS Photons as Energy Carriers
All our fossil fuels, such as coal and oil, owe their existence to the solar energy stream that has engulfed the earth for billions of years. The power in this stream amounts to about 1400 watts per square meter at the earth, nearly enough to supply an average home if all the energy were converted to electricity. The problem is to get the sun’s rays to yield up their energy with high efficiency. ”

“ The coal-beds and the forests are to the sun what the fly-wheel is to the engine: all their power comes from him; they retain a little of it in store, but very little by comparison with the original; and were the change we have already spoken of to come over the sun’s circulation,—were the solar engine disconnected from us,—we could go on perhaps a short time at the cost of this store, but when this was over it would be over with us, and all would be still here too. ”

“ When we talk about transforming our energy system and moving away from fossil fuel and making our homes more energy efficient and building solar panels, moving toward solar thermal power, in the Southwest of this country—New Mexico, Arizona, Nevada—we have some of the best solar exposure in the entire world. ”

“ Heat and light are derived from the sun, and we have attempted to show, not only that the phenomena of these two principles are different, but that they can scarcely, in the present condition of our knowledge, be regarded as modified manifestations of one superior power. Associated with these two remarkable elements, others may exist in the solar rays. Electrical phenomena are certainly developed by both heat and light, and peculiar electric changes are produced by exposure to sunshine. Electricity may be merely excited by the solar rays, or it may flow like light from the sun. ”

“ Once completed, this plant will be the first large-scale solar plant in the U.S. to actually store the energy it generates for later use – even at night. And it will generate enough clean, renewable energy to power 70,000 homes. ”

“ But as yet none of us are able to prophesy the weather for even the coming week from our knowledge of the sun. A more promising field of utility is opened in the construction of solar engines. These may be made at some future day to employ the sun's heat to better advantage than we now use steam, power. ”

“ It must be evident, however, that if we derive, as it is asserted we do, almost all our mechanical power from this solar heat,—if our water-wheel is driven by rivers which the sun feeds by the rain he sucks up for them into the clouds, if the coal is stored sun-power, and if, as Stevenson said, it really is the sun which drives our engines, though at second hand,—there is an immense fund of possible mechanical power still coming to us from him which might be economically utilized. ”

“ While they aim to account for the sun’s light and heat, they all fail to consider the active medium of the solar light and heat in the sun itself. It is not simply a highly-heated central mass glowing in space. It is a vast orb surrounded by different envelopes of incandescent vapors or gases, and by far the most vast in volume, as well as in light and heat-radiating power, are the photosphere and its superincumbent chromosphere, composed almost entirely of free hydrogen gas in a state of intense incandescence. ”

“ These photoelectric devices convert sunlight into 200 watts of electricity for powering spacecraft equipment. Auxiliary power is furnished by two silver zinc storage batteries which are used when the solar panels are not functioning, particularly during launch when they are still folded and during mid- course correction. During its flight, Ranger must be positioned so that its solar panels face the sun for power and its high-gain antenna points to earth. A complex system of sun and earth sensors, gyroscopes, and nitrogen gas jets keep the craft oriented. ”

“ Ericsson estimated that the mechanical power that would result from utilizing the solar heat on a strip of land a single mile wide and eight thousand miles long would suffice to keep twenty-two million solar-engines, of one hundred192 horse-power each, going nine hours a day. ”

“ Yet this appearance, which superstition declared to be miraculous, was only electrical; for, while the solar heat is converting into vapour the water and moisture of the earth, electricity is freely disengaged. “The clouds which this power forms are in different electrical conditions, though the electricity of the atmosphere, when serene, is invariably the same. Hence the descent of clouds towards the earth, their mutual approach, the force of atmospherical currents, and the ever-varying agencies of heat and cold convert the aërial envelope of the globe into a complete electrical apparatus ”

“ The solar engine, if generally introduced, would be found more intermittent in its action than the windmill—excepting perhaps in a very few localities where there is a cloudless sky throughout the year. The windmill gathers up the power generated by the expansion of the air in passing over long stretches of heated ground, while a solar engine cannot command more of the sun's heat than that which falls upon the reflector or condenser of the engine itself. ”

“ If the amount of solar light is enormous as compared with terrestrial standards, the same thing is still more true of the solar heat, which admits of somewhat more accurate measurement, since we are no longer dependent on a so unsatisfactory unit as the "candle-power," and can substitute thermometers and balances for the human eye. ”

“ Notes ↑ Note that an average efficiency across a range of technologies was used here as the range of module efficiencies has a much smaller effect on the overall result than other factors, e.g. availability.↑ The ground coverage factor was derived from typical power densities of solar farms (25–50 MW/km2) in comparison with the raw module power density of a typical solar cell of 125–150 MW/km2.↑ The total potential on land was calculated by summing the potential of the best technology on those available areas where more than one technology was suitable. ”

“ The heat motion then disappears as heat by its conversion into work, just as the motion of a belt in a mill disappears in the work of the machine which it drives. One two-hundred-and-thirty-two-millionth part of the radiant solar energy, we know, is caught by the flying planets of our system in the forms of heat and light, adapted to sustain life and its continued [140] potentiality, and we know that this solar energy is the sole source of all the development and maintenance of the planets as the possible abodes of organic life, past, present or future. ”

“ Solar electricity production The potential per area for solar electricity production can be calculated from the solar energy incident upon the surface per year and the conversion efficiency of the harvesting technology, as shown in Eq. (4) .
where P/A = potential per area in EJ/km2 per study period and technology (PV vs CSP) ; p = the study period (2010, 2030, 2070) ; t = the technology (PV or CSP) ; I = resource intensity in J/m2 for solar irradiation; E = conversion efficiency in % by technology. ”

“ The sun is thus, in effect, a self-compensating machine, and its passage through a region of increased electrical generation would first manifest itself in a vast increase of brilliancy, due to higher incandescence of its hydrogen envelope; this, in turn, would be communicated to the deeper structures of the sun, producing increased volatilization [196] and dark absorption bands, and finally to the whole solar mass, expanding its volume in proportion to the heat absorbed. ”

“ The great difficulty, that of the perpetual renewal of the solar fuel, still remains unsolved; the fact that during the millions of years of geological history we find no indications of any declining average of solar energy is so far still unexplained by this, as by every other, attempt to account for the origin of solar and stellar light and heat. ”

“ Harnessing the Sun’s Energy
Historically, the sun’s energy has most often been used by concentrating it with a lens or mirror and then converting it to heat. We could do this and run a heat engine, but a more direct avenue is open.
About a decade ago it was found that the junction between p and n semiconductors would generate electricity if illuminated. This discovery led to the development of the solar cell, a thin, lopsided sandwich of silicon semiconductors. As shown in Figure 12, the top semiconductor layer exposed to the sun is extremely thin, only 2.5 microns. ”

“ If, however, we consider, as is generally believed to be the case, the sun itself to be the sole prime source of its visible energy, nothing but difficulty and vague speculation can be looked for on every hand; but by relegating the solar orb to its proper place, and taking as the starting-point the true source of all energy,—to wit, the hidden forces embodied in the vapors or gases of interstellar space,—the whole process and mode of action will logically follow, and obscurity and difficulty together disappear. ”

“ By the nebular hypothesis the whole course of development, of necessity, is rigidly forward to its culmination; but by employing the analogies presented to us in other operations of nature, we can readily account for variations, haltings, ineffectual efforts, uncompleted processes, and even reversals and redistributions into other secondary sources of energy. They equally comprise the agencies for the production of a single solar system or of a myriad, just as we see the vortical water-spouts or sand-storms either single, double, or multiple ”

“ The condensation of volume of the planets will give rise to great elevation of temperature, while their currents of electricity, poured into the sun, will, by their passage through its enormously compressed hydrogen atmosphere, produce intense heat, and this, rapidly communicated to the solar core within, will raise its temperature to that of the sun as we now see it, and permanently maintain it in that state of incandescence. ”

“ We must also bear in mind that sun-spots do not diminish the solar heat, as they are the result of increased and not of diminished energy. Electric currents of high potential pass directly, as we know, along the lines of least resistance to their opposite center of polarity, so that two planets nearly in conjunction with each other transmit their currents almost directly towards the sun’s center, and upon the same point of solar latitude, while, if at right angles with the sun, they must deliver their electricity along converging lines and thus strike the solar surface at different points. ”

“ But while the sun’s energy is—as it must be in this case—the outcome of that of the planets, it is equally obvious that the planets themselves can have no permanent, inherent energy of their own to generate or modify such energy of the sun, since they are in fact supplied by the solar energy, and their motions are controlled and regulated by the sun itself. ”

“ The sun is only a little more than a hundred times its own diameter away from the earth. Why, then, with the subtle connection between them afforded by the ether which conveys to us the blinding solar light and the life-sustaining solar heat, should it be so difficult to believe that the sun’s enormous electric energies find a way to us also? No doubt the impulse coming from the sun acts upon the earth after the manner of a touch upon a trigger, releasing energies which are already stored up in our planet. ”

“ A wondrous change will occur, and instead of a current which could scarcely flash across a few inches of space, we will now have so great an increase of energy that its tension will even cause the spark to perforate and destroy the glass walls of the heavy Leyden jars in which it is condensed. The vast realms of space, with their attenuated vapors, are the field in which the planetary electric generators operate, and into which, likewise, myriads of suns constantly pour their light and heat. ”