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Heat Engines Electricity Efficiency The chapter discusses how most new coal-fired electricity generation plants have an the 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 them heat must be relatively close to the heat is not lost in transport; that is why it works so well on campus. 1. Briefly discuss why, if so many benefits can result from this technology, are more neighborhood scale cogeneration plants not constructed? 

Power Demand 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 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. 2.Research on this topic and briefly discuss how these threats can be mitigated in the future as our power demand increases?