O ne human activity that contributes to global warming is the dumping of organic material into landfills. This material decomposes over time, producing a significant amount of landfill gas (LFG). About 50% of LFG is methane, which traps heat in the atmosphere with an effect that is twenty times greater than carbon dioxide. Landfills that do not control the escape of landfill gas are the largest single human source of methane emissions in the United States, as well as a source of air pollution and odors. But humans must produce waste to live-it is one of the basic laws of thermodynamics. That is bad news all around-except that using engineering principles, bringing together various "constituencies," and evaluating alternatives with engineering economy can bring benefits out of almost every one of these issues. Landfill gas (LFG) can be an asset if it is extracted and properly utilized. LFG has about half of the heating value of natural gas. As a result, more and more owners of municipal solid waste landfills extract this gas and use it to generate electricity. Such electricity is used directly for their power needs or is sold to the general power grid. Extracting and using a landfill to generate electricity is a "6 win" situation. 1. It benefits the environment by reducing unwanted gas emission; 2. It adds electrical power to the grid: 3. It produces cash flow for the landfill owner; 4. It lowers the use of non-renewable fossil fuels; 5. It reduces financial costs to the local population; and 6. It reduces the hazardous, noxious, and odorous gases for those nearby and down- wind. QUESTIONS TO CONSIDER 1. How can this topic best be summarized for a non-technical public audience? This is an important "skill" of an engineer-conveying sometimes complex and confusing scientific issues to a less informed, less scientific, and less interested audience with a short attention span. 2. What engineering economic principles would you apply in analyzing this appli- cation? Which measures would be most effective for the public audience? The important measures, and the metrics used to describe them, may be considered "key performance indicators." 3. This waste to power application cannot be answered with a simple equation with a closed-ended answer that is either "correct" or "wrong." This problem requires the cooperation of several (at least) agencies and communities of interest. Name some of these stakeholders and identify how their objectives are aligned or in conflict. 4. The Enron example which is a "poster child" of what can go wrong in business- like this vignette is related to electric power generation. Discuss ways in which some of the stakeholders may be "shady" in such situations. Discuss how you-as an engineer-could not only affect factual answers but could project perhaps an image that may not be real. As an engineer, you can be honored for (or guilty of your representations. After Completing This Chapter... The student should be able to: Distinguish the unique objective and viewpoint of public decisions. Explain methods for determining the interest rates for evaluating public projects. . Use the benefit-cost ratio to analysis projects. . Distinguish between the conventional and modified versions of the benefit-cost ratio. Use an incremental benefit-cost ratio to evaluate a set of mutually exclusive projects. Discuss the impact of financing, duration, quantifying and valuing consequences. and politics in public investment analysis.