IMPORTANCE OF NEW ENERGIES

It has been estimated that our presently known reserves of fossil fuels may be depleted within 70 to 250 years to the point where their low-cost extraction is no longer possible (17). Our estimated reserve of low-cost nuclear fuels (not more than double the 1950 cost per British thermal units of coal, measured in 1950 dollars) is about 575Q (1 Q equals 1018 B.t.u. or about 38 billion tons of coal). This compares with our reserve of about 27Q in fossil fuels (24). Although nuclear fuel reserves are about 20 times as great as fossil fuel reserves, it is unlikely that more than one-fifth of the total energy load will ever be supplied by nuclear fuels (23). Furthermore, many relatively undeveloped areas of the world cannot get either fossil fuels or nuclear fuels at a cost low enough for extensive use.

THERMAL SOLAR COLLECTORS

U.S. agriculture is the major user of heat energy. In addition to using 27 billion kilowatt-hours of electric energy annually, agriculture is industry's largest user of petroleum.

The daily efficiency of collection of solar heat depends on the number of transparent covers in a collector and the average temperature difference between the absorber plate and the outside air. The efficiency of a collector decreases rapidly as this temperature difference is increased because of accelerated heat loss. If solar energy is to be used in winter for house heating, this temperature difference can be maintained at a minimum value when an adequate volume of air to be heated is passed over the collector, even when the outside air is very cold.

Possible applications of solar energy as a substitute for heat on the farm are many. The experimental use of plastic materials for solar collectors has shown wide potential for many applications. Additional research should perfect existing know-how and develop new applications.

It is estimated that thousands of tons of grain are harvested with excessively high moisture content each year and thus require drying or some kind of preservation. The development of inexpensive plastic solar grain dryers would save much of this grain with little

waste or expense.

Past efforts

NEW IMPETUS ON USE OF SOLAR ENERGY

Scientists have long been intrigued by the possibility of converting solar radiation directly into usable heat and power. Past attempts to harness this energy, however, have not been well coordinated and relatively little money has been spent for research on solar energy applications. Since 1945, however, interest in this field has increased considerably. In 1955, the chairman of the executive committee of the Association of Applied Solar Energy Research stated that the problem of harnessing this energy presents scientific, technological, and economic challenges worthy of extraordinary effort and unusual initiative, before world energy supply becomes a critical problem.

The President's Materials Policy Commission (23) predicted that, by 1975, some 13 million dwelling units might be heated with solar

energy if sufficient research and development is devoted to the problem.

Recent developments

Recent developments include the building of experimental houses heated wholly or in part by solar energy (16, 21, 26); a solar cookstove which can be sold for about $5 (7); a Russian solar refrigerating plant producing 250 kilograms of ice per day (7); the installation of a solar battery for powering telephone circuits at Americus, Ga.; the discovery of a method of artificial photosynthesis at the University of California (7); and the initiation of a research project at Manhattan, Kans., to study the combination of solar heat collectors and heat pumps for farm use (9).

NEW SOURCES OF ELECTRIC ENERGY REQUIRED

The generation of electricity for small loads in remote locations has long been a problem. Improved solar thermoelectric generators are needed.

Direct generation of electric power from new sources of fuel is of great concern to the Nation. Some basic research has shown that this is possible for limited applications.

Generation of electric power from new materials that are now useless or from waste material would save our fast depleting supply of fossil fuel-for example, a biochemical cell that would use waste wood, sewage, and so forth.

More than 40 million tons of chemicals are used annually in agriculture. The bulk of these chemicals not used for fertilizer are applied for insect and weed control. When not carefully used these chemicals not only are injurious to man, but they can kill bees and other beneficial insects.

A universal light trap capable of attracting and killing economic insects is needed. In addition, light traps capable of attracting certain specific insects for detection purposes are also needed. These insect traps require a source of electric energy. In many instances, conventional electric service is not available or is not practical to use.

A small inexpensive portable power supply is needed to operate these insect attractant traps. Some of the potential sources of such a power supply are:

Fuel cell.

Thermoelectric generator-solar operated.
Thermoelectric generator-fuel operated.
Biochemical cell.

Hundreds of traps are presently being used by the Federal Government in surveys of insect infestations to determine control measures. Some are used at ports of entry to monitor foreign infestations.

Other traps are used to check insect migration from county to county and from State to State. A new portable power source is needed for these traps.

ELECTRORECLAMATION FOR ALKALI SOILS

The term "electroreclamation" refers to electric treatment of alkali soils to reduce the sodium content and improve drainage. Some work has indicated intriguing success in using electric treatment of alkali soil while other work has indicated it to be of little value. On an energy basis, the successful use of electric treatment is as yet unexplained.

Irrigation agriculture has been and will continue to be one of the primary factors sustaining the growth of the semiarid and western portions of the United States. But irrigation agriculture has yet to free itself of the serious problem of controlling the salt or alkali conditions which inevitably are present in many irrigated areas.

Land which is, or can be made, productive for agricultural purposes constitutes one of our most valuable natural resources. About 600,000 acres of land in the Western States could probably achieve greater crop production through improved drainage and removal of excess soluble salts and exchangeable sodium. It is not unreasonable to assume that another 400,000 acres of land within, or adjacent to, these reclamation developments have not been brought under irrigation because economic means of reclaiming the soils are not available. On privately developed irrigated land in the Western States about 900,000 additional acres could achieve increased production by removal of excess ions or exchangeable sodium.

A recent survey shows that approximately 28 percent of the irrigated acreage in the Western United States and Hawaii has been damaged by excess salts. In addition to this, thousands of acres of our present irrigation projects could be saved from a complete loss or marginal production caused by increased alkali soil condition.

A research program involving soil and electroagricultural engineering scientists is needed to establish the basic factors involved and to provide authentic information for farmers on the economy of such treatment under varying soil conditions.