The chapter discusses how most new coal-fired electricity generation plants have an
efficiency of ~38% for converting the energy from the burning of coal into electricity,
resulting in about 62% of the heat energy produced being lost to the environment. By using
cogeneration, much of that waste heat can be used for space and water heating in homes,
offices, and in industrial applications. The example of the University of Colorado, Boulder
(section 3.8, Textbook), shows that by using such cogeneration technology the University
has increased the overall efficiency of the facility to 70%. By reviewing the economics of
the plant, it can be seen that not only is the electricity produced at this plant cheaper than
that produced at the public utility, but the plant will have paid for itself in 15 years, with the
life expectancy being much longer at 40 to 50 years. This plant is fueled by natural gas,
but is so clean and quiet most cannot tell the difference between the plant and a normal
building. For the recovery and use of the waste heat, the spaces and applications that are
using the heat must be relatively close so the heat is not lost in transport; that is why it
works so well on campus.
Briefly discuss why, if so many benefits can result from this technology, are more
neighborhood scale cogeneration plants not constructed?
The power demand in the United States increased by roughly by 30% in the last decade.
According to the Public Administration, the nation needs to build 65 new power plants per
year for the next 20 years in order to meet the growing needs of the United States. The
Administration supports a mixture of conventional fossil fuel fired plants and new nuclear
technology. One major issue to consider is the effect these new plants will have on the
rivers and lakes they draw water from in order to cool their operations. The rise in the
temperature of the receiving water bodies has a major effect on the ecosystems around the
discharges. In addition to thermal pollution, hydropower dams, coal sludge spills, airborne
coal dust, and oil and methane drilling all pose threats to river ecosystems.
Research on this topic and briefly discuss how these threats can be mitigated in the
future as our power demand increases?