380 18.Economic and Environmental Considerations 70 (sKep/slaueq % World total 50 是 40 30 Western Europe 20 USA 10 Eastern Europe former USSR Japan L1 Canada-P+--F土 80 8284868890929496 9820002002 Year FiGURE 18.4.Daily world petroleum (crude oil)consumption in selected countries during 1980 through 2002.(Source:"International Energy Annual 2003,"U.S.Department of Energy.) nancial value.Thus,any exploration efforts to find reserves beyond 20 years are generally not performed for economic reasons.On the other hand,the present coal deposits seem to last for a much longer time period.However,mining will become increasingly expensive and dangerous once greater depths must be confronted. 35 30- 25 20 15- 10- 5 0 19821984198619881990199219941996199820002002 Year FIGURE 18.5.Crude oil posted prices from 1981-2003.(Kern River oil field, 13 API gravity).Source:Chevron USA Inc.,crude oil price bulletins.nancial value. Thus, any exploration efforts to find reserves beyond 20 years are generally not performed for economic reasons. On the other hand, the present coal deposits seem to last for a much longer time period. However, mining will become increasingly expensive and dangerous once greater depths must be confronted. 380 18 • Economic and Environmental Considerations 70 60 50 40 30 20 10 0 80 82 84 World total Western Europe Eastern Europe & former USSR USA Japan 86 88 90 92 94 96 98 2000 2002 Year Consumption (103 barrels/days) Canada FIGURE 18.4. Daily world petroleum (crude oil) consumption in selected countries during 1980 through 2002. (Source: “International Energy Annual 2003,” U.S. Department of Energy.) FIGURE 18.5. Crude oil posted prices from 1981–2003. (Kern River oil field, 13° API gravity). Source: Chevron USA Inc., crude oil price bulletins. 1982 1984 1988 Dollars Per Barrel 1986 1992 1990 1994 1996 1998 Year 2000 2002 25 20 5 10 15 0 35 30