Harnessing the Power of the Sun (Dec, 1930)
Harnessing the Power of the Sun
Future Sources of Power, Described by WILLIAM J. HARRIS
When coal mines are exhausted, where is industry to obtain the power to keep its wheels turning? What sources of power are now lying dormant, waiting for some engineering genius to harness them? This important subject, of ever-present interest to scientist and layman, is fascinatingly discussed in this authoritative article.
DR. Georges Claude, brilliant French inventor, recently expended a million dollars and, after two unsuccessful attempts, succeeded in launching a mile long steel lube, some six feet in diameter, in the waters of the sea off Matanzas, Cuba. And most of the world is still wondering what he is trying to do.
The briefest answer is that Dr. Claude, who is best known in this country as the inventor of the neon lamp and sign, is attempting to harness the power of the sun.
Seems strange to go down under the sea to capture the power of the sun, but if he succeeds in doing on a large scale what he has already demonstrated in a small way he may soon be generating enough power to run all Cuba, with a surplus to be exported by way of an undersea cable to Florida.
The sun heats the surface ocean water in the tropics to temperatures as high as 28 degrees, Centigrade, while 400 meters down the sea is as cold as 4 degrees, Centigrade. If the two bodies at different temperatures could be brought together water could be boiled, in a partial vacuum, producing power equivalent to a 300-foot waterfall.
In demonstrations before the Havana Academy of Science last year Dr. Claude showed that with the difference in temperature between ice at melting point and water at 68 degrees Fahrenheitâ€”a difference ” of 36 degrees, sufficient vapor was released to run a small turbine at 5,000 r.p.m.
Following the launching of the tube Prof. Claude announced that 4,000 cubic meters of deep sea water was being obtained each hour, at a temperature of 13 degrees Centigrade. The actual temperature at the lower end of the tube, 650 meters below the surface, was 10-1/2 degrees, so there was a temperature rise of only one and a half degrees as the cold water was brought up through the warmer layers above.
In his power plant there is a huge tank filled with warm surface water. When the air in the tank is exhausted the water boils and provides the steam to operate the turbine driving the generator. The purpose of the cold water brought from the depths of the sea is simply to cool the exhaust steam at a rapid rate and so provide the vacuum to operate the air pump, which in turn exhausts the air from the warm water tank, and so converts the process into an endless chain.
The present plant, with a 50 kilowatt generator, is only an experimental affair, and, if successful, probably will be abandoned in favor of a much larger one located at some other spot in Cuba.
Sun motors, usually huge collections of mirrors set to capture the sun’s rays over an area of many hundred square feet and focus them on a small spot, are not new. Such motors are working in California and in the Sahara. But Dr. Claude’s plan to trap the heat of the sun indirectly is the most ambitious sun power scheme ever conceived.
The sun motor can produce, in any of its present forms, only a fairly limited amount of power because the expanse of mirrors soon becomes too unwieldy to be moved and kept in focus, and the energy that may be trapped is limited to the amount of sun heat falling on a limited area during the hours of sunshine.
But with Dr. Claude’s scheme power can be produced by night as well as by day, on cloudy days, and with no limitation on the total energy trapped. The surface water of the tropical sea does not cool enough on cloudy days or at night to make any great difference in the temperature spread between surface and the depthsâ€”even a drop of ten or fifteen degrees at the surface would still leave sufficient difference to work the thermal motor.
While a million, two hundred thousand dollars was spent on developing the plan and building the three tubes, the cost of a single tube is not particularly heavy. The one successfully launched cost $80,000 to build. If the plan works the cost of tubes would be much less than that of dams and penstocks for ordinary hydraulic power plants.
The search for new sources of power is one of the most absorbing of scientific hunts. The dream of releasing the latent energy in the atomâ€”energy sufficient to make one drop of water drive a liner across the oceanâ€”is still far in the distance, but there are other sources of power which are being tapped.
In California and Italy steam from volcanic vents, or fumeroles, is being used to run machinery. In Iceland the natives are piping the hot geyser springs to heat their homes. An adaption of the Claude plan might be used there to combine the heat of the geysers with the ice water from nearby glaciers and produce an abundance of cheap power. |
The world’s greatest reservoir of natural volcanic energy is owned by the United States, but probably never will be harnessed.
For it is situated in the Valley of Ten Thousand Smokes, far out in the Aleutian islands, off Alaska, where literally thousands of fumeroles give off hot gases and boiling water the year around.
The earth offers an inexhaustible supply of power, if it can be tapped. A shaft a few miles deep would penetrate a region where temperatures are so high that water poured down the hole would come back as superheated steam. Even in mines a mile deep the temperatures become almost unbearably high. Gold workings on the Rand in Africa are so hot that even natives break down after a few months, and inner world heat has been a source of trouble in the Montana copper mines.
Owen D. Young, the chairman of the board of the General Electric company, and author of the Young plan for the settlement of Germany’s war debts, has suggested that it would pay capital to sink a ten mile shaft into the earth merely to find out what may be there. Power probably would be the only product, for even if minerals were found no miners could stand the heat and work the veins.
The idea of a ten mile deep shaft is not as fantastic as it might seem. In California oil well drillers are flirting with the two-mile mark, and as drilling tools improve and experience in their operation at such great depths increases it is probable that much deeper shafts may be sunk.
Wave motors, always an intriguing subject with inventors, continue to be built, though no one has yet succeeded in capturing a steady and reliable source of power from the waves of the sea. Untold millions of horsepower are available on any coast for the inventor who solves the problem of harnessing them.
Indirectly, the power of the waves and tides may be trapped, and Maine has under consideration an ambitious scheme to do just that. Twice a day the tides rush up a long arm of the sea that steadily narrows toward the land end, with the result that the tremendous bulk of water crowding in the wide mouth is piled up into tides that at some periods of the year reach forty feet or more in depth. It is planned to build a dam across the bay, connecting various islands with the shore. At each incoming tide the gates would be opened to admit the water, and then closed to hold it while the tide recedes, giving millions of acre feet of stored water, with a fairly large head, to be carried down to the power house turbines.
The scheme has had one stumbling block, a state law against the export of Maine generated water power to other states, and as long as that law exists the state does not offer a sufficient market for the enormous power which could be generated from the sea. On the Maine-New Brunswick border the Bay of Fundy offers even greater tidal bores, while south of the Imperial Valley on the California-Mexico border, there is a similar great tidal bore at the mouth of the Colorado river, where the incoming tides sweep up the Gulf of California and spill out over the marsh lands.
With all the schemes for power from new sources, much remains to be done in utilizing the already known fields. Improvement in electrical transmission and extension of super-power networks to form inter-connection between power plants throughout the country may some day soon lead to burning coal at the mines, instead of hauling it hundreds of miles to market.
Leaders in the electrical power industry I confidently expect that some day the coal will not even be hauled to the surface, but will be burned in power houses situated on the lower levels of the mines, where the coal can be fed direct to the boilers by gravity. The Pennsylvania anthracite fields may some day export their power over wires to New York and New England; the West Virginia mines may be wired to the Pittsburgh steel mills, and the soft coal veins of Southern Illinois and southwestern Indiana may house superpower plants to run Chicago, already the largest per capita consumer of electrical energy in the world.
The only problem in burning the fuel at the mines is one of obtaining boiler water in sufficient quantities. For every ton of coal burned an enormous quantity, of water is turned into steam, and water supplies rather than fuel always dictate the location of a steam power plant.
For several years the problem of transmitting electrical energy by radio instead of by wire has intrigued inventors as well as the public. That it will ever be realized on a commercial scale is hardly possible, but C. Francis Jenkins, the famous motion picture, radio and television inventor had a tiny radio motor running as long ago as 1926. The motor was almost microscopic in size, but it did pick up the carrier wave of a local broadcasting station and turn at a merry rate.
Aside from sun, wave and thermal power, and the latent heat stored in the interior of the earth, there are new fuels to be utilized. Corn stalks and other farm waste may be turned into fuel, and fuel alcohol extracted on a large scale from wood waste, potatoes, and other crops. If the gasoline supply ever does fail, as has been so many times predicted, it is a fairly safe bet that science will be ready to step into the breach with an efficient substitute. And, if science fails, there’s always electricity to fall back on. Some day we may all be driving electrical cars charged from the successors of Dr. Claude’s thermal power plant.