Encyclopedia of Global Resources part 40 provides a wide variety of perspectives on both traditional and more recent views of Earth's resources. It serves as a bridge connecting the domains of resource exploitation, environmentalism, geology, and biology, and it explains their interrelationships in terms that students and other nonspecialists can understand. The articles in this set are extremely diverse, with articles covering soil, fisheries, forests, aluminum, the Industrial Revolution, the . Department of the Interior, the hydrologic cycle, glass, and placer mineral deposits. . | 360 Energy economics Global Resources smaller vehicles another crucial advantage of liquid hydrocarbons is that they can be simply and easily pumped into an engine. The complexity of feeding coal to a boiler adds to the cost of running a steam railroad locomotive and is prohibitively expensive for automobiles and trucks. When hydrocarbon fuels from petroleum eventually become very expensive because of diminishing reser ves there will undoubtedly be replacement fuels but all potential replacements currently known have expensive disadvantages. Synthetic fuels produced from coal have proved economically unfeasible except in emergencies. Production of ethyl alcohol from agricultural products involves energy losses from farming from energy used by yeasts to make alcohol and from the energy required to concentrate the alcohol. Electric automobiles involve the two-thirds waste from electrical generating plants plus the cost of buying and moving massive batteries. A revolution in batter y technology is changing those economics. Energy Resource Bell Curves and Energy Crises Geologist Marion King Hubbert noted a bell-shaped cur ve in the use of resources now commonly called the Hubbert curve and often used in estimates of resource use and reser ves. Hubbert first applied his curve to petroleum in the late 1940 s and subsequently reviewed and amended his prediction a number of times. According to the Hubbert curve a resource is used experimentally at first. Then use increases rapidly until the resource begins nearing a point of half exhaustion. At that point difficulty in obtaining the diminishing supplies begins driving up costs so demand growth begins to slow. As prices continue rising competing energy sources emerge and production of them increases. Use of the first resource declines in a mirror image of its earlier rise and it gradually fades away. Hubbert noticed this pattern in the production of onshore petroleum in the forty-eight contiguous states of the United .
