Page 228 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

The costs of utilities are directly influenced by the cost of fuel. Specific difficulties emerge when
estimating the cost of fuel, which directly impact the price of utilities such as electricity, steam, and
thermal fluids. Figure 8.1 shows the general trends for fossil fuel costs from 1991 to 2006. The costs
presented represent average values and are not site specific. These costs do not reflect the wide
variability of cost and availability of various fuels throughout the United States.

Figure 8.1 Changes in Fuel Prices from 1991 to 2006 (Information taken from Energy Information
Administration [6])

8.3.1 Background Information on Utilities

As seen from Figure 8.1, coal represents the lowest-cost fossil fuel on an energy basis. Most coal is
consumed near the “mine mouth” in large power plants to produce electricity. The electricity is
transported by power lines to the consumer. At locations remote from mines, both the availability and cost
of transportation reduce and/or eliminate much of the cost advantage of coal. Coal suffers further from its
negative environmental impact—for example, relatively high sulfur content and relatively high ratio of

CO produced per unit of energy.
2

After no. 6 fuel oil (a heavy oil with a relatively high sulfur content), the next lowest cost fuel source
shown in Figure 8.1 is natural gas. Natural gas fuel is the least damaging fossil fuel energy supply with
respect to the environment. It is transported by pipelines throughout much of the country. The cost is more
uniform than coal throughout different regions of the country. There remain, however, regions in the
country that are not yet serviced by the natural gas distribution system. In these regions, the use of natural
gas is not an option that can be considered. Although natural gas is a mixture of several light
hydrocarbons, it consists predominantly of methane. For the calculations used in this text, it is assumed
that methane and natural gas are equivalent.