Agriculture’s Role in Energy Production: Curent Levels and Future Prospects.” Paper presented at a conference Energy from Agriculture

There have been many changes over time in the predominant source of energy consumed by the American economy (Figure 1). Wood was the predominant source of energy through 1880. Coal surpassed wood about that time and was dominant until the late 1940s. Petroleum use increased rapidly during the first half of the 20th century and overtook coal about 1950. The use of natural gas developed somewhat later than petroleum, and also surpassed coal about 1958. Coal use declined somewhat during the middle of the 20th Century, but its use has increased in parallel with natural gas during the past 20 years (DOE, 2005a). There is a great deal of interest in the role renewable energy sources are playing and will play in supplying the nation’s energy needs. Figure 2 highlights the contribution of renewables to total supplies more clearly. Hydro electric power is about equal to all of the other renewables combined. Figure 2 also shows the Department of Energy’s projected use by source to 2025. U.S. energy consumption is projected to grow over the next two decades with continued reliance on the major fossil fuels, petroleum, natural gas, and coal. The projections for nuclear electric power are relatively flat and onl