As timber for the building of ships became scarce in England, shipbuilders were forced to turn to iron for hulls; the increasing use of machinery also required iron. But the use of charcoal for the melting furnaces led to further thinning of the timber stands, resulting in erosion and, with it, resistance from, and higher prices charged by the landlords. So the iron makers turned to coke, which is made from coal. This use of coke for smelting, added to the use of coal for space heating in the growing towns, meant deepening the shafts in coal mines, and it was to pump water from the mines that the steam engine was brought into use. For a considerable time no further major use of steam was contemplated. The subsequent extension of the use of steam to the railroads made steam an integral part of the system which existed primarily for the purpose of bringing goods to shipside for trade. Steam converters took the place of men and horses in operating pumps in the mines; they slowly replaced horses for pulling cars on the railways; here and there they replaced the windmill and the water wheel in grist and textile mills. But the old general social structure long persisted--on land maintained primarily by low-energy systems, and on the sea by the sailing ships which transported surpluses for exchange.
Placing steam winches aboard to raise the sails and anchor and to load and unload cargo, made it possible to reduce the size of the crew of the sailing ship and thereby to increase the surplus energy per man to be gained from the sails. Time spent in port for loading and unloading was likewise reduced by the use of steam-powered hoists. Such engines eventually became auxiliary sources of ship propulsion and finally replaced sails.
The shift from sail to steam as the dominant source of surplus was slow and undramatic. Its significance was neither noted nor evaluated by those who were actually bringing it about; but converters using steam are not necessarily used to their best advantage in systems built under the influence of sail.
So long as the sailing ship was the only converter capable of using large amounts of energy those systems that it helped to create had a great advantage over those that still depended upon muscle to do work. The location of trading cities was greatly influenced by the advantages to be gained there.
Through surplus energy from the stream and the sailing ship, coastwise sailing ships permitted the development of ports through which the produce of the interior could be delivered by streams to the seas and oceans. These means combined to permit and reward the specialization necessary to exploit ecological differentials found among various geographic areas. But there was no converter other than muscle to tie together those areas that did not have access to stream and sail. Civilization moved toward the oceans, seas and navigable waterways. Apart from the continental system built by the Romans, most roads were built to permit access to the sea. Connections between centers located fifty or a hundred miles apart on land were much more costly to use, maintain and defend than was transportation between rivers and coastal ports hundreds of miles apart. Thus access to resources in the interior of the continents was so costly that most of those who sought wealth and power supported the system of trade reinforced by the energy of the sailing ship. I have already talked about the way this use of resources was rationalized by British economists. What I want to do now is to show how the substitution of the steam engine for muscle power made a good deal of that rationalization inapplicable to the society that was able to use the steam engine in both transportation and other forms of physical production.
The steam engine, like the organic converters, depends upon an exhaustible supply of energy. Unlike the sailing ship, whose use of the wind does not diminish the supply, the steam engine must obtain its fuel at fixed points, where it is available only in specific amounts. It must obtain this fuel at the cost of some of the energy gained. Its use thus follows the centripetal pattern exhibited by the plant. That is to say you use up energy as you move away from the fuel source. To conserve energy you must utilize it near the source. The gradient in the field is somewhat less steep than that of systems using men or animals for transportation, but the field is nevertheless limited. Moreover, the gradient of the steam-driven ship is much steeper than that of the sailing ship.
The sailing ship was most effective in the areas where the trade winds blow, but it could operate well, though with somewhat lower efficiency, elsewhere. The highways of sail and the location of the ports serving sailing ships were based upon these facts. But the efficient use of the steam engine depends in part upon the location of fuel sources, which are not found at sea. The forests near rivers and seacoasts would yield fuel for only a short time, and transporting wood from a distance would greatly reduce net surpluses. Only such fuels as coal and petroleum provided a supply of energy adequate for long-distance ocean travel. But coal is seldom found at tidewater, and those areas where agriculture support large populations engaged in sail-borne trade were frequently far from sources of coal. Thus, to be useful, coal had to be transported, at the coast of part of the surplus available at the mine, to the populations concentrated by sail and low-energy converters. The geographic distribution of population set by sail was not that which was destined to grow up around steam, though many old sites were maintained because trade patterns developed under sail were continued under steam.
Ecological and other affects
Other differences between the patterns of effective use of steam and sail are to be found in the characteristics of the converters. One of the problems of the designer of a steam engine is to transfer the maximum proportion of the heat obtained from burning coal or other fuel to the water in the boiler. This is done by exposing as large an area of the boiler as feasible to the flames. Once the steam is generated in the boiler, however, the aim is to confine all the heat possible, until it can be released usefully in driving a piston or turbine impeller. Other things being equal up to a point, the larger the steam engine, the more efficient it will be, that is, the more nearly it will satisfy these two physical requirements. It is thus desirable to make the steam unit as large as practicable and to assemble at one point tasks capable of using all of the work which the engine is capable of producing. This means the concentration of machines which use large amounts of energy and also of operators to control the machines.
The congestion in the immediate vicinity of the large engine producing great power was accentuated by the means of transmission of power available when the first steam engines were built. The cams, shafts, belts, and gears that were necessary produced a steep gradient. They quickly used up a large amount of energy through friction. The inefficiency of the early types of engines also meant that a large portion of the fuel was wasted in combustion. Centers of production near the mine mouth offered great economic advantage over those at more distant points. To lessen the losses incurred in the conveying of fuel to engines located at the distance from the mines, a means of transportation using the surplus derivable from coal was needed.
This was most quickly manifest in England, for even though coal lay at tidewater, the food and minerals required for shipbuilding and trade were often not procurable by ship. So the steam engine was substituted for them in hauling shipbuilding materials and cargo. This source of power achieved mobility in the form of the locomotive, a converter with characteristics quite unlike those of the stationary engine. The locomotive is capable of delivering great power while on the rails but is helpless and delivers no power off them. Its field is ribbon-like, as is that of the flowing stream. Unlike the stream, however, it can deliver surplus energy both in going to and in coming from the source of potential energy. It is not marked by the necessary contrast in size and weight of shipment that differentiates the downstream from the upstream journey. Thus the locomotive uses part of the energy expended in its journey away from the source to carry fuel for the return trip. Further, energy in the form of food can move in one direction, offsetting energy in the form of coal moving in the other. Populations could be relocated to make use of sites near the coal mines while remaining dependent upon the food produced in more distant areas where surpluses from food could be produced more efficiently. Thus it becomes possible through relocation of population to make the most efficient use of the new source of energy, without diminishing the surplus food available. It was still necessary for sufficient men to be available in the food-raising regions to fulfill the needs there during periods when labor was in greatest demand.
Use of the locomotive was affected by another characteristic. There is a distinct interval in space between the points at which its energy can be made useful. It will be recalled that, by the law of inertia it takes more energy to move a body at rest or to alter the velocity of a body than it does to maintain speed once gained, for once a body is in uniform unilinear motion it will continue to remain so with only the force necessary to overcome friction. This fact, while true for all converters, was accentuated in the case of the railroad.
To start or to stop a wheelbarrow or a horse-drawn wagon does not require an amount of energy that will significantly alter the cost of the operations in which they are likely to be used. It does take a lot of energy to bring a ship into port or to get it under way, but this amount is relatively small compared to the amount of energy used by the ship in a voyage. Steam engines are comparatively large and heavy for the amount of power they produce. To start, accelerate, decelerate, and stop a train requires a great deal of energy, and if variations in velocity are frequent, energy costs of operation mount swiftly. This was particularly true in the early days, when iron and steel were comparatively weak and unreliable and when designers were ignorant of how to calculate strength, stress, and strain. So the locomotives were very heavy relative to their power. Also, in those days fuel and water were used comparatively wastefully and had to be carried in large quantities. Increasing the size of the engine to improve its efficiency meant greater weight not only of the engine and its fuel and water but also of the lengthened train, it was enabled to pull. Longer trains imposed a greater strain on each car because of the increased weight of those behind it. As a result, the weight of the draft gear was increased, and this too added weight disproportionate to the carrying capacity of the car. Inertia thus became a more significant factor. If efficiency was to be secured, stops must be as infrequent as possible. The efficiency of the engine increased with the length of the intervals between the stops necessary for fuel, water, and repair, and the use of the train was most economical in the vicinity of such stops. Since intermediate stops added to the costs of operation, they were abandoned as rapidly as feasible.
The lengthening of intervals between stopping points set up a new pattern of location for regions using railroads, it differed from the pattern set up, for example, by stage coaches or, particularly, the pattern set up in old agricultural areas. There the distance between villages was determined by the efficient use of the land in terms of population density. In China, for instance, villages tended to appear wherever the services which they rendered were equal to or lower than the energy costs spent in getting to them. Fertile areas permitted increased concentration of population. This in turn permitted such services as those of the priest, medicine man, midwife, or butcher to be supported by a smaller area than was possible where the surplus energy gained from crops was less per acre and the population consequently more scattered. The location of towns in areas where population pressed less closely on the energy available might be determined by other factors, such as the requirement for protection, the common use of a cathedral, the use of common wells or water holes, etc.
With the advent of the steam railroad, transportation between towns 50 miles apart became less expensive, provided they were both on the railroad, than transportation between towns 10 miles apart of which one was not served by a railroad. Service specialists located on a railroad might draw clients from a distance of a 100 miles who could not have afforded to come 30 miles by another mode of transportation involved low-energy converters. Consequently, railroad division points, where change of engine and crew and inspection and repair were required, were convenient locations for towns, and these served a much larger population than had hitherto been possible. We shall have occasion to look more closely at these effects later.
The steam engine was perhaps more significant for the surpluses of energy it made available than for any other aspect of its operation. We must recall that apart from the sailing ship there was, before the advent of steam, no important source of mechanical energy other than those dependent upon the use of plants as a primary source of energy. The sailing ship itself was a supplier of surplus useful only for the transport of the product of surpluses generated by plants. There were definite limits on the mechanical energy available in any low-energy society, for mechanical energy was largely a direct function of population, and population was in turn a function of the effective use of agriculture.
Wood and coal as fuel
The introduction of the steam engine permitted conversion of heat energy directly into mechanical energy. It could use as fuel almost anything that would burn and therefore could convert the waste products of food raisers, or the products of land otherwise almost useless, into mechanical energy. In many cases wood was used as fuel. The average annual yield from trees in terms of mechanical energy is less than the average yield of most crops. A soft, quick-growing tree such as the Wisconsin aspen will produce about 2 tons of wood per year per acre, and Florida pine will yield about 3 tons. Such yields compare favorably with some crops, unfavorably with others. They are, for example, greater than that of tame hay, which on average in the United States yields 1½ tons per year per acre of material that when burned releases less energy per pound than does wood. On the other hand, a year’s crop of 100 bushels per acre of Iowa corn, including stalks, husks, cobs, and grain, will yield about 20 million calories as compared with 8 million calories for the complete heat product per year per acre of Wisconsin aspen. So a wood-burning locomotive such as the early ones which operated at less than 2 percent efficiency could not replace a hay and corn eating horse of 20 percent efficiency in any area where corn and hay could be raised. This is true even if we take into account only the direct operating costs of the locomotive and disregard the much fixed costs which its use entails.
Trees grow in many areas where food crops will not. Where there is rain enough they will largely replace the grass which might have served to feed livestock. In these areas the heat energy of burned trees supplies mechanical energy not otherwise available. However, in the great river valleys, where low-energy society was able to support a considerable population, the heat available from trees was also useful in cooking food and in smelting and forging metals. There, since trees were scarce and were used for other purposes, they would not be available as a fuel supply for the locomotive. Only where an abundance of such items as minerals made high-cost transportation feasible could a wood-fueled railroad be built and maintained. There the energy costs of the railroad would be low compared to the energy saved by the low costs of utilizing a rich source. Further, the locomotive might be used so infrequently that the trees along the right of way could regain from the sun the energy dissipated by the railroad. In other areas the necessary rate of fuel consumption would quickly exhaust all the economically available wood. After that happened another fuel would be required for continued operation of the railway. In most places, then, steam locomotives burned coal or oil.
It will be recalled that the steam engine came into use in coal-burning areas. It was from the surplus produced by mining coal that the steam engine gained its first advantage. Coal and the other fuels which consist of remains of ancient plant and animal life offer an entirely different set of limits from the sources of energy that make use of the recurring presence of the sun. Instead of limits determined by the annual rate of conversion of sunlight into plant life, we have limits which depend on the total supply deposited in a particular place. The availability of this deposit is dependent upon man’s ability to devise means of getting it out of the ground. The possible rate of return in the form of surplus thus is represented by a series in which part of the energy gained in []mining is immediately enlisted to reduce the number of men and animals needed in the mine. Though early mining methods were very inefficient by present-day standards, a comparison of the surpluses produced even then by mining with those obtained by use of the organic converters may be enlightening.
The surplus provided by coal
At first the English miner hacked the coal out with a pick and it was carried by man or animal to the mine entry. A man could mine 500 or 600 pounds a day depending upon the thickness and purity of the coal in the seam being mined and its distance from the mine entrance. The heat value of coal varies considerably from field to field and even from vein to vein, but good bituminous, which produces about 3,500 calories per pound, will serve as an illustration. A coal miner who consumes in his own body about 3,500 calories a day will, if he mines 500 pounds of coal, produce coal with a heat value 500 times the heat value of the food which he consumed while mining it. At 20 percent efficiency he expends about 1 horsepower-hour of mechanical energy to get the coal. Now, if the coal he mines is burned in a steam engine of even 1 percent efficiency it will yield about 27 horsepower-hours of mechanical energy. The surplus of mechanical energy gained would thus be 26 horsepower-hours, or the equivalent of 26 man-days per man-day. A coal miner, who consumed about 1/5 as much food as a horse, could thus deliver through the steam engine about 4 times the mechanical energy which the average horse in Watt’s day was found to deliver. Little wonder that the iron horse began to replace his organic forebear!
This was, however, only the beginning. With no change in the amount of coal delivered by the miner per day, the mechanical-energy surplus delivered could be greatly increased by raising the efficiency of the steam engine. At 2 percent the surplus would be increased to 53 man-days per man-day. Raising the efficiency to 4 percent would more than double that. And there remained the possibility of using the cheap mechanical energy made available by the steam engine to replace men and horses in the mine.
Progress in this direction in the old sites has been hampered by the character of the veins, by resistances in the social organization, by faulty taxing policies and by other factors. In the original coal mining regions the surplus is thus far below the level that is technologically possible.
More favorable conditions existed in areas such as the United States. These permitted continuous increases in the surplus delivered per miner. Sources of coal were more abundant, which made it difficult to bring coal production into a system of “monopolistic competition” such as frequently characterized the use of the ship. Many of the policies which were firmly rooted in English mining practice could not be transplanted to the American scene. Thus, technological advances could be initially installed here, whereas in the English mines they had to fight to supplant still usable, if less efficient, devices and resources. Moreover, the competition of oil and natural gas became a threat which tended to increase efficiency in the coal mines of the United States. All these factors are reflected in the present high rates of production in mines in this country.
The average production of coal per miner in the United States in 1972 was 6.76 tons a shift. If put through a modern steam electric generating plant, at 40 percent efficiency, this coal will yield about 13,408 kilowatt hours. Even if burned in an average steam locomotive, which is only 1/10 as efficient, it will yield about 1,340 kilowatt hours. Of course, this is not all surplus. Considerable energy is represented by the machines used in the mines, and such operations as cutting, loading, propping, bolting, etc., also use much energy. Even though coal mining in the United States is regarded as being technologically backward compared with other industries it produces great surpluses. Some advanced machines now in use deliver to the conveyors 100 tons per hour, and electronically controlled mining machines are now in limited use which will almost eliminate the need of miners as such. New methods of using unmined coal, such as controlled burning, promise to give rise to competition between old and new sources of coal. The use of the gas turbine permits gas from controlled-burning mines to be converted into electricity at the mine mouth without the use of large quantities of water. This will make it possible to use hitherto inaccessible or unused sources. Efficient mechanical shovels permit heavy overlay to be removed, exposing coal which would otherwise have to be mined by shaft and tunnel, which yields a smaller surplus. All things considered, the present rate of production in the United States is to be regarded as at a point rather far from the limits on surplus energy from coal which will eventually be reached. I will return to this discussion later.
British and European railroad usage
It will be recalled that in the early days of the steam engine the daily surplus of mechanical energy produced by one coal miner was about 25 horsepower-hours. It will also be recalled that the sailing ship was delivering more surplus than that in the form of transportation in the days of the Pharaohs in Egypt. The English ship was capable of delivering about 250 horsepower-hours a day for each crewman when coal came into general use. So, even when only its fuel costs were involved, the locomotive could not directly compete as a form of transportation anywhere that competition between ship and rail was possible, as in coastwise traffic. Since its track and fixed structure represented added cost, the steam railroad was relatively inefficient in comparison with the ship. Thus, railroads were built primarily to supplement the functioning of the stream in bringing goods to the ship. They fanned out from port cities to serve trade. This pattern of use of the steam engine fitted in well with British thinking and practice. However, it was often not economical in the use of energy, for coal was sometimes transported from the mine to a distant coastal city, there to drive machines which could just as well have been located nearer the mines. This use of fuel to transport fuel was not of great import in the islands and peninsulas of Western Europe, where the coal in use was relatively near water. But it would have been extremely wasteful in the interior of the continents. Here British practices were not applicable.
During the period when it was happening, the British never completely understood how British coal had come to replace British wool and other organic products as a major source of the differential advantage they had over most other areas of the world. They measured their position in terms of price alone, and price indicated merely that Britain could continue to deliver goods in distant places at prices lower than the cost of producing them locally or lower than those of others offering to sell the same product. Thus, the shift from a cost differential based on organic converters to one based on coal and water power went almost unnoticed. Once the English were militarily and politically secure within the Empire, by which time they had lost the power to coerce many of their suppliers and buyers outside it, the shift to the doctrine of free trade was made. Now the insistence was that the market alone was an adequate guide as to the efficient use of materials, and that price should reign. British physical productivity was very high compared with that of most other places on earth. Britain was also the source of most investment capital. In consequence, where free trade was adopted, there was an enlargement of those industries in Britain which could benefit from the use of coal, and a diminution of agriculture and other industries in which coal could play no part. The system built up around sail continued to increase British power throughout the nineteenth century. It seemed neither necessary nor profitable for any group to raise the question as to whether the new uses to which Germany and the United States were putting their steam power might not turn out to be a more effective way to create a viable social, economical, and political structure. “Economics” was largely based on British experience, and economics of this sort held that the American and German systems were “unsound” and bound “in the long run” to fail.
“Price” versus productive efficiency
During the nineteenth century the auxiliary steam engines on the sailing ships gradually became efficient enough to replace sail. The roundabout trade routes based upon the use of the wind came into competition with those that made increasingly effective use of steam to bring cargo to ports which could, with the aid of the railroad, tap resources previously unavailable. This altered the significance of various ports and trade routes. But fundamentally the British attitude that “trade” rather than physical productivity is the true test of efficiency for a society remained dominant.
As previously indicated, “low” price represents many things. Sometimes low price represents a geographic fact such as availability of sought-for natural resources. Sometimes it represents technological advantage. And sometimes it represents the ability of the trader to force necessitous men to cooperate in return for no more than subsistence pay. More productive men, located where there are more opportunities for employment, may refuse to cooperate for this low return. The mounting standard of living in the United States made many goods more costly to the foreign trader here than, for instance, in China, even though the physical productivity of the American worker made it possible for the goods to be produced more cheaply here. The American worker was able to claim part of his higher productivity in higher wages; accordingly, American prices were higher despite the fact that American physical costs were lower than those of the Chinese. Being guided by considerations of price, the British found themselves building up a system which, since it was incapable of differentiating between the reasons for differences in costs, sometimes made them dependent upon areas in which it would be profitable to trade only while a very low standard of living existed for the residents. They thus enlarged their investment in areas where they could trade only so long as no alternative to British rule existed for the native population. These areas were often politically less secure, militarily less defensible, and actually physically less productive than other areas, in which production might have taken place if all the consequences of the trading pattern had been examined. Some of the theory of foreign trade today is but a restatement of the axioms the use of which lost Britain her dominant world position. The theory was, however, built into British culture and helped to mold British use of the steam engine.
The pattern of railway use developed by the British was followed with modifications elsewhere. That is, the railroad was thought of as being supplementary to sea- and river-born trade. Occasionally military policy dictated that a railroad be built with a strategic objective in mind, replacing either a river or an ocean as a primary means of transportation. Thus in the middle of the nineteenth century the Germans built a railroad to their own ports from their centers of production and, by favorable rates and tariffs, cut off a good deal of the German traffic which had sustained Antwerp, almost ruining that city as a port. The Austrian Südbahn similarly diverted traffic from the foreign-held ports at the mouth of the Danube to Austrian-controlled Trieste on the Adriatic.
Use of the railroad in America
It was in the United States that steam had a chance to show the outlines of a pattern of civilization based on large surpluses from sources other than food and sail. The early coastal settlements and the plantation South, being part and parcel of the English system, developed few railroads, and such as there were served British trade. But with the westward movement a new kind of civilization began to emerge. The American “age of steel” was an outgrowth of the use of cheap transportation, furnished by steam, on the Great Lakes, the canals, and the Ohio River, plus the development of railroads. This transportation system permitted the products of the plains to be used to support an industrial population growing up around the coal of Pennsylvania and eastern Ohio. American cities grew in the interior, beyond the reach of the British cruiser and the control of London banks. The railroad subsequently provided the means by which the industrial North overcame the power of the agricultural South. Northern victory could not have been achieved without the use of steam. The railroad helped to populate the plains in spite of the resistance of the Indians. It brought together minerals which never could have been assembled in the days of sailing ships and caravans. The locations of some early American cities were determined by the same factors that produced the commercial cities of Europe in the days of sail. The pattern which they exhibit today clearly shows that influence, but cities like Columbus, Dayton, Indianapolis, and Iowa City were located during the development of steam power and in turn show its influence.
Many subsidiary settlements also show the effects of rail transportation. We have spoken of the division points that occur along all rail lines. Here trains must be stopped for service; here they are broken up when it is necessary to take cars out for repair. There are also points of interchange between railroads, where the trains are broken up and individual cars are rerouted. An industry located at one of these stations can be serviced by the railroad much more cheaply than one located at an intermediate point. This is especially true with regard to delivery of less-than-carload lots. Usually the railroads built a network of spur-line tracks beside which factories were located so that fuel and other heavy materials did not have to be transported by team-drawn wagons. Factories using less fuel and lighter materials moved into the next zone of sites away from the siding to minimize their own hauling costs, and residences were interspersed as near as possible to the factories in order to minimize the time and energy spent walking to work or the cost of horse-drawn passenger transportation. The retail and hotel district occupied a sector between the passenger station and the remoter residence districts, from which the more fortunate could come by carriage over boulevards or by horse car.
Although its great weight in proportion to its power made the energy costs of the steam-propelled train high as compared with the horse car, a trainload of people could frequently be delivered 10 or 15 miles away from a central city at a lower price-measured cost than they could travel by horse for 2 or 3 miles. The commuter type of “bedroom community” was a natural outgrowth of this fact. The influence of electricity and of the internal-combustion engine set in to modify this pattern before a complete adaptation to this steam locomotive could be manifest.
Prototype of the high-energy society
From this point on, the American rather than the British pattern must be taken as the prototype of high-energy society. The use of rail, as compared with sail or steamship, offered England few of the advantages it afforded in the United States. A social organization set up to exploit sail and trade could not be fully effective in making use of steam. Hence the new pattern has been most fully worked out in the United States, though areas in other parts of the world have also made progress along the same line.
Steam power had numerous shortcomings. The greatest of these, as has been indicated was the ratio of the weight of the engine to its power. We have seen how this drawback operated in connection with the railroad. In addition to the problems created by inertia, great weight necessitated that the railroad could be used effectively only within or between areas of relatively great population density, since only by frequent use could the great costs of fixed structure be economically recovered. But the fact that its weight precluded frequent stopping made the steam train inefficient to serve the needs of a dense population for local transport of either materials or passengers. It was the weight factor, further, that prevented the use of steam in agriculture: the steam tractor was so heavy that it packed the soil, it bogged down in many fields which could be hoed or plowed with horses. The steam tractor could not be used economically on the small diversified farms; these represented in most places the most efficient use of land when tilled by men and horses. The handicaps of steam power could be overcome only by great advances in design and in metallurgy which would permit the use of very high temperatures and pressures without the drawback of great weight. Failing that, steam engines must be complemented by another converter with lower disadvantages. Both of these developments have taken place, but not in a fixed order so that “stages” can be worked out to show how one gave rise to or replaced another. Moreover, they were accompanied by the use of new sources of surplus energy, which also had a place in determining what occurred.
Petroleum came into wide use first in the United States as a source of light. The explosive distillates which make up gasoline were a nuisance by-product until the invention of the internal-combustion engine brought them into demand and made them a chief objective of the industry.
Although natural gas has been known about as long as petroleum – its discovery today is for the most part incidental to exploration for oil
The development, refining, and transportation of gas are frequently associated with the production of oil, so that in attempting to calculate the surplus we must consider oil and gas together. Natural gas is used more widely in the United States than in any other country in the world; it is an important source of energy here, but it must be regarded as a somewhat short-lived bonanza rather than a base for long-continued development.
In case of petroleum and gas mining the calculation of the surplus energy derived is more difficult than in the case of coal. Coal companies usually sell the raw coal at the tipple, and in available statistics coal-mine employees are not usually grouped with coal refiners or processors. But since oil is generally sold by the oil companies in some stage of refinement, oil and gas employees are as likely to be engaged in processing or refining as in well drilling or pumping, and so, in reports, workers in all the processes are lumped together. Moreover, since coal reserves are already well explored, there is considerably greater outlay for exploration and discovery before workable sources of oil are located than is the case with coal. Drilling is expensive, and the holes that are drilled are more likely to turn out to be dry than productive. Then there is more cost entailed in processing oil than in putting coal into usable form for delivery to the consumer.
It is thus difficult to make an over-all calculation of the costs which should be included in making an accurate estimate of the surplus energy available from petroleum. To make an extremely rough comparison the ratio of heat energy produced per man employed in gas and oil to that produced per coal miner appears to be about 4 to 1. Put in another way: for every kilowatt-hour of heat produced by the coal miner in a day an oil or gas worker produced 4 kilowatt-hours. So it is evident that the surplus energy produced by each worker in the petroleum industry in the United States today is much greater than that produced by the coal miner. Since the surplus of the coal miner is very large, and that of the oil and gas worker is even larger, it is clear that the energy costs of producing energy in the form of coal, gas, and oil in the United States have become so low that even cutting them in half would not greatly alter the surplus available.
Social effects of oil
At first glance it would appear inevitable that, with its much greater surplus, oil would replace coal and would act as a magnet drawing off population and industry from the old energy-producing areas. This has been to a degree the case, and certain specialized industries, such as those producing petrochemicals, have been built up in the regions where oil and gas are abundant. However, a number of factors mitigate against any wholesale reorientation of industry away from coal and toward petroleum and gas. The first is that the reserves of petroleum in any specific area known to be relatively small as compared with the known reserves of coal in the major coal-producing areas of the world. In a number of cases, oil fields have been pumped out and abandoned even before the short-lived structures built up to serve oil-well employees had outlived their usefulness. Much of the effort of the petroleum producers has been directed toward making it possible for oil fields to be exploited rapidly so as to reduce taxes and other overhead costs which are fairly independent of the volume of oil produced. This has, of course, been controlled in some areas by proration of other legal device. But there are some very large fields which are being exploited as rapidly as possible. Such instances would seem to indicate that oil is a short-term energy source when considered as a base on which to erect the structure of a civilization.
Second, and very important, while petroleum is at the moment a cheaper fuel (energy wise) than coal, it cannot be used as efficiently as coal in smelting iron. While coke can be made from petroleum, it does not have the structure necessary for blast-furnace use; and, being a residue from the production of the distillates and lubricating oils, it is not produced in the quantities which would be necessary if it was to be used in smelting. Thus steel-producing centers will probably continue to be located on the basis of the energy costs of bringing coal and iron together and transporting their product to market.
Steel centers, in turn, give rise to a host of associated industries. Being located near steel mills is very advantageous for many industries, particularly those which produce large quantities of steel scrap, since this proximity reduces to a minimum the cost of transportation of the scrap.
In a sense the influence of oil regions in forming a basis for the growth of population and the relocation of industry is negated by the fact that oil can be so cheaply transported. This fact and the fact that oil is so widely used as a fuel for internal-combustion engines, which are widely used in automotive equipment, have resulted in a pattern of very scattered and widely dispersed use. Petroleum products are much more likely to be shipped far from their source than is coal.
To sum up, in consequence of these three factors – difficulty of substituting other fuels for coal in steelmaking, relatively small deposits of oil in any one region as compared with coal, and low cost of transportation of oil-petroleum is less likely to affect the distribution of population (that is, to cause the kind of relocation that resulted from the adoption of sail or coal) than the great surpluses it produces would at first seem to indicate.
It appears, then, that petroleum, a relatively great but short-lived source of surplus energy, contributes to the emergence of new techniques and alters some of the patterns developed by other converters but does not lead to a permanent shift in the location of power, speaking either spatially or in terms of the power position of a class or nation.
What we have said about oil is even more applicable to gas. At the moment it is so cheap and so easily transported that it is being used in large quantities at the very mouth of coal mines. But the reserves are rapidly being exhausted.
The prospect of reducing the energy costs of producing coal is, as noted above, very favorable. Machines and processes have already been developed which can greatly increase the per capita output of coal in many mines. In the last half century new sources of petroleum, and new techniques of drilling for it, made it extremely abundant relative to the demand for it, and the price was accordingly set very low relative to that of coal. As time passed and it became necessary to explore less attractive sites the energy costs of producing, refining and delivering it went up. But the surplus was still so great that there was enormous profit even after very high costs and taxes were added. Since the advent of the cartel governing prices by those who control the land under which oil is to be found, the price has had no relation to the price-measured cost of production nor the size of the energy surplus gained from the oil. The precipitous rise in the price of petroleum, and the imminent scarcity of gas at any price has created a new economic environment for coal. It will now be possible to pay much higher wages, install safer and more productive equipment, and still deliver coal at a price competitive with petroleum for fuel.
Coal is more abundant than petroleum in most of the industrialized states, so its strategic value becomes high as nationalization spreads in those under-developed areas in which oil is to be found.
Both for strategic and economic reasons coal is likely to replace petroleum as a base for synthetic fiber, plastics, and pharmaceuticals. Countries like France, and Germany, which are apparently deficient in petroleum, will seek and find a source of these materials in their coal. So the centripetal pull of the great coal beds of the world will probably continue to exert a major influence, and the character of fields generated by coal-burning converters – though somewhat distorted by the use of other fuels – will probably remain basic in the shaping of society for some time to come.
This statement may be challenged by the proponents of nuclear energy for peacetime use. The size of the surplus to be gained from nuclear fuel for such use is at the moment indeterminable. It seems probable that many times as much energy was expended in building the equipment and assembling and processing the materials necessary to produce the first atom bomb than has been made available from the fissionable materials out of which it was made. The present annual expenditure of power in refining ores containing fissionable elements is also enormous, and while it is true that a pound of uranium will under ideal circumstances yield the equivalent of 1,500 tons of coal, figures are not yet available to show that it does not require more energy to make the product of a pound of uranium available for peacetime use than it does to make available its energy equivalent in the form of coal, gas, or oil.
We have no idea what is the energy cost of producing energy from uranium or thorium ores that were mined and refined and converted to electricity by nuclear energy instead of being produced using fossil fuels for all the processes involved. There are other handicaps involved in its production that greatly influence its price, about which we will talk later. Here we are just comparing energy costs and yields. In any event, as we have already indicated, the energy costs of producing energy from present fuels are now very low, and a new low-cost source would be most significant in serving specialized purposes which the other more abundant and easily available sources of energy are less well able to serve. Early studies indicated that atomic power would be most likely to compete successfully in industries using large quantities of heat as such rather than in those primarily using electricity or [mechanical power]]. It might also serve areas requiring large amounts of power which lie far from coal, oil, gas, or hydro power and are poorly served by railroads or navigable waterways. The main result of experience with it to date is to indicate that it is not likely to work a major revolution in areas now well supplied with other power sources. It will come into general use only as the surpluses from petroleum and gas are reduced to the point that they become more expensive. Continued research is costly and the supply of trained technicians, uniform designs, metallurgical alloys and other things necessary is short. Only already industrialized areas are at present equipped to make much use of atomic power, even though some token “investments” have been made for political and diplomatic reasons.
Electricity is a form of energy in increasingly widespread use. In most cases, however, it is derived from the sources of energy already discussed. Very small amounts of electricity are secured from the use of batteries. It has been known for over a century that certain chemical reactions are accompanied by energy changes that can be measured by the same instruments that gauge electrical potential and current from generators. These chemical changes would represent a significant new source of energy for man’s direct use if they could be converted cheaply in great quantities. So far this has not seemed feasible; moreover, the potential of such conversion is apparently small as compared with the energy regularly coming from the sun or that to be found in such cheap sources as coal. The direct conversion of the energy of the sun into electrical current, in amounts and with characteristics that permit its cheap and ready use, is another alternative which has been the subject of speculation and research. It is possible that such a development will make even more efficient use of the sun than does photosynthesis by plants.
We will later discuss Solar energy as an alternative. But for the present at least, the overwhelming proportion of usable electricity is created by a generator attached to a source of mechanical energy. This energy may be derived from any of the fuels or any of the converters of mechanical energy which we have mentioned. Electricity usually represents not a new source of mechanical power but mechanical power converted into another form.
Characteristics of electricity
The mechanical power delivered by a motor never equals the mechanical power that went into the generator supplying the current to drive it. Since conversion thus involves some loss, the use of electricity reduces, rather than increases, available mechanical energy. Why then make the conversion into electricity? The answer is to be found in the characteristics of electricity. In the first place, it can be divided or combined with little loss. Also, it can be converted into heat, light, and sound, into X ray, infrared, ultraviolet, radio, radar, and television, and waves of various other frequencies and amplitudes, and into mechanical power. This is a convenience where many forms of energy conversion are likely to be used at the same site. Furthermore, it can be transported easily, quickly, silently, and comparatively cheaply. The gradient in the field is extremely gentle and the limits of the field are very wide as contrasted with mechanical transmission. Therefore, while the conversion from mechanical to electrical form actually lessens the surplus available, the energy losses are in most cases more than offset by other gains. The chief exception is in the use of electricity for space heating; for this use the advantages of electric heating over heating by gas or oil are not sufficient to offset the loss in conversion from heat through mechanical energy to electricity and back again into heat.
It is difficult to discover exactly what portion of the mechanical energy which would otherwise be available is lost through conversion into electricity. The steam engines which are used to drive generators were developed for just that purpose. They might have altogether different characteristics, and perhaps be much less efficient, if they had been designed for use with mechanical transmission rather than for being attached to generators. For example, the best of the reciprocating steam locomotives never delivered in the form of tractive effort at the draw-bar as much as 10 percent of the heat energy that was contained in the coal and placed in the firebox. On the other hand, the average efficiency of the steam electric plants in the United States in 1970 approached 46 percent, and the most efficient delivered almost 50 percent. In the case of the steam engine the characteristics developed for conversion of its energy into electricity, by increasing the surplus to be derived over that obtainable from engines not using electrical transmission, actually offset to some degree the losses incurred in conversion.
Electrification of transport
Electrification of railroads was in fact embarked upon to take advantage of the facts of which we have just spoken. Making the boilers and the steam engine stationary and paring down the driving mechanism carried on the tracks to a simple motor greatly reduced the weight-to-power ratio which handicapped the steam locomotive, and made it possible to exploit the efficiency of the turbine. This permitted lighter equipment and lighter track, and the accompanying decrease in inertia made frequent stops less costly. By the use of electricity the steam engine could be made large enough to be efficient, and the power it produced could be distributed among a number of motors. In place of one long train a number of shorter ones could be run, with no accompanying decrease in efficiency of the steam engine in use.
The trolley car, which similarly made use of electricity, replaced the horse car and filled in some of the interstices left between the infrequent stops required by the use of the steam train. The development of the interurban train (heavier than the trolley, but much lighter than the steam train) to serve outlying regions permitted the specialization of services which none of the small areas served could support alone. However, this kind of transportation was feasible only for passenger traffic, which, since passengers can in most cases get on and off by themselves, operates with short stops. To handle any considerable amount of freight, stops must be made longer, and this interferes with the frequency of service demanded of passenger vehicles. In addition, carrying any considerable amount of freight necessitates an increase in the size of the crew. In the heyday of the trolley car, car tracks were used for freight in only low-demand hours to deliver only small amounts of freight, particularly the supplies needed to operate the street railway.
Peculiarly enough, a situation thus arose in which it was possible to handle the transportation of humans more cheaply than that of materials. The consequences were that while it was still necessary for the factory to be near rail facilities, where the cost of team haulage could be kept at a minimum or dispensed with, with trolley cars workers could move away from the areas around the factories and avoid such penalties of congestion as overcrowding, insufficient light and contaminated air, lack of play space, etc.
Residence areas began to expand outward along the trolley and interurban lines. The trolley car could be stopped at very short intervals, so that waking from a stop to any point between stops became a trifling matter. Compact rows of residences formed a continuous line along the rails and back from them for short distances. Either by running parallel lines in a checkerboard fashion or by zigzagging along diagonals drawn outward from the retail centers, it was possible to fill in cheaply all the space between the periphery and the center of the city.
Interurban trains on the other hand produced a distribution of population which exhibited a pattern like a number of strings of beads radiating from a central point, the rails serving as the thread and the communities centered around the suburban railway station being the “beads.” This is a pattern still discernible around cities like Indianapolis whose early growth was largely based on steam.
The use of electricity for other purposes than transportation developed a little more slowly. The structure of the city, as well as traditional business practices and architectural design, were based on the pattern in which congestion due to the use of the old type of converters had been capitalized upon.
The electric generators in use at first did not offer any great incentive for the adoption of another pattern. Electricity is commonly produced by revolving a specially wound coil of wire in a magnetic field, or the reverse. The electricity generated by the spinning armature has to be delivered to a fixed conductor through which it can be delivered to the user. Some device for efficiently transferring current from a rotating to a fixed point is necessary, and a system of commutators and brushes at the generator accomplishes this purpose. Now, if voltages are very high, the resistance at the point where the commutators and the brushes are in contact will create arcs which waste current and are also likely to destroy the commutator. Thus current must be initially produced at relatively low voltages. But the cost of transmission is much higher at low voltages than at high current, which cannot easily be transformed into high voltages. This is not particularly significant if the current is to be delivered over a short distance, but, since the weight of the conductor varies directly as the square of the distance current is transmitted, it becomes immensely significant if any great distance is involved. Consequently, as current is conducted away from the generator the energy costs of building lines, and the losses suffered through conduction, eat into the surpluses until it becomes cheaper to build another generating plant at some point nearer to that at which the current is to be used than to transmit the power to that point.
Generators, other than those used for trolley and interurban lines, were first used to supply illumination. The quantity of current used for this purpose by any one customer was small. Hence, in order to recover transmission costs, the number of customers in the area of service had to be high, even to use a small plant. Frequently a user of power such as a factory, hotel, or hospital could buy or make all its current from a central station. Therefore, while the gradient in the field of the direct-current low-voltage generator was much less steep than that of mechanical transmission, it was still too steep to permit a power plant to serve any large area efficiently. Thus no great demand for power could be concentrated at any one point. The direct-current generator, which limited the demand on the steam engine, kept it small and thus, since up to a point the efficiency of the steam engine increases with its size, often constricted its efficiency far more than did the actual limitations inherent in the then known materials and designs. The introduction of the alternating-current generator changed this situation and made the generation of electricity much more effective.
Alternating current can be transformed from low to very high voltages, and vice versa, without much energy loss. Hence it is possible to generate current at a low voltage, “step it up” to a high voltage for transmission, and “step it down” at the point needed. The reason this is desirable is that the required weight of the conductor varies inversely as the square of the voltage. Consequently, with high voltage, current can be conducted on a small line which would be burned up if the same amount of power was put through it at a lower voltage. The problems of handling and transmitting high-voltage current were solved in quick succession. As a result there has been a rather rapid increase in the voltage at which current is transmitted. At present the maximum is around 750,000 volts. The entire power surplus of Hoover Dam, for example, is conducted to Los Angeles by cables not much thicker than a man’s thumb. While such very high voltages were not immediately obtainable, even the first alternating–current stations could be built much larger than their forebears. The limit on the size of the steam turbines used to generate current was lifted, and engineers began to investigate the possibilities of new designs, new materials, and new methods to take advantage of large size, higher steam temperatures, and higher pressures. The result was a rapid decrease in the slope of the gradient in the field, with a great consequent widening of the limits to the area served by a plant.
Thus as the length of the line which could efficiently carry a given amount of power increased, the area to be served by one generator increased even more rapidly. This is of course due to the fact that lines can be strung in all directions from the power plant, the potential field being a circle, which increases in area as the square of the radius. There was a corresponding increase in the ability to serve less congested areas, or to reduce the advantages to be gained by congestion. It is now a matter of relative indifference in terms of energy costs whether a motor is located 50 yards from a boiler or 5 miles. The difference in cost of lighting for two houses, both on a high-tension line and, respectively, 1 and 3 miles from the generator, is frequently not as great as the difference in cost for two houses 500 yards apart but connected by low-voltage current. Difference in power costs between plants nearer to and farther from power stations were greatly reduced, and in many cases the costs of transmitting power to a new plant at some distance from the power station were less than the costs arising from congestion in the old location.
It is still true that the cost of generating current and delivering it at a great distance is higher than the cost of delivering a comparable quantity of energy in the form of oil and gas by pipeline or of oil and coal by rail or barge. A point is reached at which it is cheaper to locate additional steam-electric plants where they will have to be connected to their fuel sources by rail, pipeline, or barge than it is to generate more current from a central station and deliver it. Within the radius so determined the exact location of large consumers of power is frequently in energy terms a matter almost of indifference. In the case of small users, however, the cost of stringing and servicing lines represents a rather large part of the continuing cost of delivering current, and such users are most economically located near the lines connecting the generating plants with each other or with large users of power.
Connecting several power plants in a grid makes it possible to deliver power equally cheaply to consumers of equal amounts of energy in areas of equally great demand. Just as the streetcar, by charging a fixed fare in an entire zone, made it almost a matter of indifference whether one rode 5 blocks or 15, and hence tended to equalize residence rentals within each fare zone, so the effect of the grid has been to make differences in energy costs negligible within large areas and thus to equalize the land charges related to power costs within these areas. The areas of equalized costs produce a pattern altogether different from those previously existing, and their effect has only recently begun to be felt. But they have not affected costs related to the handling of freight other than fuel, so long as that freight has had to be brought by team from congested sites where industries handling heavy masses had to be located. Selective migration of industry occurred as the light industries moved to sites which were less congested, nearer their markets, or nearer the residences of their labor forces.
The effect of the invention of the alternating-current generator on the use of water power was analogous to its effect on the use of the steam engine. As we have pointed out, power generated by water suffered from exactly the same limitations as characterized the use of other devices based upon mechanical transmission. But in addition it suffered from the fact that the areas in which there is sufficient fall to make it possible to handle the volume of water necessary to generate much current are the very areas which are unable to support a dense population based on agriculture or trade. Consequently, the introduction of a means of cheaply transmitting water-generated electric power a great distance frequently made the energy of rivers available at points where the river would otherwise have had no economic value. The modern hydroelectric turbine has exceeded 90 percent efficiency in converting the potential energy of the water at the top of the dam into electricity. Since the energy of falling water is cost-free, hydroelectric power delivers great surpluses. However, the surplus can often be secured only by building very expensive dams, flumes, penstocks, and other works in addition to turbines and generators. The life of these works is limited by the fact that areas in which there is rapid fall of water are also likely to be areas of great erosion; the filling up of the dams with silt makes them useless for water-storage purposes. Hence investment in them has to be quickly amortized. When these costs are added, the hydroelectric plant is sometimes no more efficient in delivering surplus than the steam electric plant. Thus hydroelectricity can be considered one more source of surplus, an alternative to the power from coal, oil, or gas, with the same general implications. In special circumstances it may pay to take materials for processing to the hydro plant, rather than to deliver the power to areas more convenient for other purposes. The building of aluminum plants in Alaska is an example. For one region hydro power may be by far the best source of surplus, for another it may be a very poor source.
Electricity helped to remove some of the limitations of the steam engine. It made power delivered to fixed sites relatively cheap. It changed the potential of the railroad, modifying the limits imposed by the nature of steam locomotives. But the means of power it provided, though mobile, was fixed either to a railroad track or to a central power plant through the medium of transmission lines.
Steam and electricity hardly changed the character of most of the problems of the food raiser, though they did permit the creation of agricultural specialists by providing a cheap means of transportation of the product. Most of the early increase in production per man in United States agriculture resulted from the use of the horse. With land abundant and population limited, horses, which could deliver energy at a very high rate in the short planting or harvesting seasons, came into their most effective use. But compared to the potential which might be secured by utilizing coal or oil as fuel they were extremely inefficient. Thus, experiments directed toward producing a replacement for the horse, both in the fields and in the cities, were stimulated by the prospect of very high returns.
The internal combustion engine
Such a replacement must be efficient in fairly small sizes, weigh relatively little per unit of power produced, and be flexible. What was called for was the invention of an engine that would change the nature of the application of heat. As we have seen, the problem of the steam engineer was to preserve the heat generated in the form of steam in every way possible. But the internal-combustion engine generates heat within the cylinder in which motion is produced by the explosion which drives the piston. Unless the temperature of the heat generated is immediately reduced, the next charge of gas entering the cylinder will be prematurely exploded. Consequently, the larger the area available to dissipate the heat in proportion to the volume of gas to be exploded, the higher the initial temperature of that explosion can be. The engineers accomplished this increase in area-to-volume ration by decreasing the size of the cylinders. To get more power they multiplied the number of cylinders. The problem now became one of getting rid of the heat being conducted through the cylinder walls. In a large internal combustion engine much of the energy produced is spent cooling the engine; a small engine, which can directly radiate heat to the atmosphere, does not suffer from this disadvantage. In a small engine, then, a greater proportion of the energy released by the explosion can be used to create mechanical energy than in a larger one. The small internal-combustion engine satisfies many of the needs for mobile power which the steam engine was unable to fulfill. Moreover, the internal-combustion engine burns gasoline, which pound for pound is about 1½ times as powerful as coal. Since gasoline is burned in a more efficient engine, the margin of its superiority to coal as a source of energy becomes even greater. For the same reason the amount of fuel carried can be reduced. Water is used only for cooling, if at all, and much smaller amounts of water need be carried than with steam.
As the gasoline engine was being developed, engineers were also experimenting in an effort to produce an engine which would burn powdered coal, and the first diesels were designed with this in view. In diesels, fuel is injected into the cylinder at the top of the piston’s stroke. The fuel is there ignited by the compression-heated air and the heat remaining from previous explosions. Since the fuel is not injected until the moment of explosion, the diesel can be operated at much higher temperatures than the spark-ignited engine. This makes it a more efficient converter.
The ash produced by burning coal quickly ground away the metal of the cylinders and piston of the early diesel. As a result, coal-burning diesels were not perfected. However, the fractions of petroleum left after gasoline had been distilled off provided a cheap fuel without ash. Since these oils were by-products of gasoline they could be sold cheaply. Further, in many countries fuel used on the highways is in a different tax category from other fuels, and diesel fuel, being untaxed, was cheaper to use than gasoline. The combined effect of high efficiency and low-cost fuel led to the introduction of the diesel where great weight, necessitated by the high temperature and pressures at which it works, was not a handicap. In the locomotive, for example, a certain amount of weight is necessary to give the engine traction with which to start the train and to increase the friction between wheels and rail when the brakes are applied to stop it. The diesel operates at rates up to about 35 percent efficiency; this rate is higher than that of any but the most modern steam plants and is far in excess of the 7 percent efficiency characteristic of the best reciprocating steam locomotives. The average efficiency of the diesels in use on American railroads in 1950 was about 23 percent, while that of the average steam locomotive was about 4 percent. The diesel has taken over many of the jobs previously performed by electricity, steam, and spark-ignition engines.
With the diesel and the spark-ignition engine, small mobile power units can be used to bring power to places far removed from fixed power sources. They can be taken into field and forest, into mines, and on board small boats. The advantages once gained from concentration of power users are thus greatly reduced. Moreover, the energy costs of the congestion that arises from using automobiles and trucks in the cities built around streams, railroads, and trolley cars mount much more rapidly than any energy gains that might come from so using automotive units there. With a network of roads and highways and a grid of power lines, industry can be taken away from centers of congestion. It is now much cheaper to bring power and materials to residence areas, or to empty spaces in which such residence areas with their associated services can be built up, than to redesign and rebuild the central city in order to make it an efficient means to use modern converters. The story of the movement from the central city is well documented. The pattern that emerges shows the influence of the automobile, the pipeline, and the power grid in modifying the size and the shape of the zones of equalized cost that radiate from highways, industry, and trade within them. Again the influence of fixed physical structures and, perhaps even more powerful, that of social structure, which gives certain groups far more weight than others in determining the location and nature of trade and industry, has the effect of distorting or delaying the appearance of a system designed to take full advantage of the new sources and new converters. But where new cities are growing up and new industries are choosing sites, the pattern is more clear and the influence of the new sources of energy is apparent.
Just as the social and economic structure reflecting the efficient use of sail proved to be a poor environment for the exploitation of steam, so that produced by steam and its forerunners is demonstrated to be poorly adapted for the exploitation of the power grid, diesel, automobile, tractor, and truck. The manner in which all these new energy sources have affected and more likely to affect the shape of things to come will be our concern in the rest of this book.
However, the increasing cost of liquid fuels, the pollution produced by the internal combustion engine, the development of air conditioning, elevators and escalators have greatly reduced the advantage of the dispersion to which the automotive vehicles contributed, and enhanced the probability that earlier patterns of urban settlement will re-emerge.
This is a chapter from Energy and Society: The Relationship Between Energy, Social Change, and Economic Development (e-book).
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