Environmental Problems, Their Causes, and Sustainability 1

Trade-OffsCoalxHOW WOULD YOU VOTE? Should coal use be phased outover the next 20 years? Cast your vote online at http://biology.brookscole.com/miller14.AdvantagesAmple supplies(225–900 years)High net energyyieldLow cost (withhuge subsidies)DisadvantagesVery highenvironmentalimpactSevere landdisturbance, airpollution, andwater pollutionHigh land use(including mining)What Are the Advantages and Disadvantagesof Converting Solid Coal into Gaseous andLiquid Fuels? Better for the Air, Worse forthe ClimateCoal can be converted to gaseous and liquid fuelsthat burn cleaner than coal, but costs are high, andproducing and burning them add more carbondioxide to the atmosphere than burning coal.Solid coal can be converted into synthetic natural gas(SNG) by coal gasification or into a liquid fuel such asmethanol or synthetic gasoline by coal liquefaction.Figure 17-22 lists the advantages and disadvantages ofusing these synfuels.Mining andcombustiontechnologywell-developedSevere threat tohuman healthHigh CO 2emissionswhen burnedAdvantagesT rade-OffsSynthetic FuelsDisadvantagesAir pollution canbe reduced withimprovedtechnology (butadds to cost)Releasesradioactiveparticles and toxicmercury into airLarge potentialsupplyLow to moderatenet energy yieldHigher cost thancoalFigure 17-21 Trade-offs: advantages and disadvantages ofusing coal as an energy resource. Pick the single advantageand disadvantage that you think are the most important.Vehicle fuelRequires mining50% more coalCoal is the world’s most abundant fossil fuel, but miningand burning it has a severe environmental impacton air, water, and land and accounts for over a third ofthe world’s annual CO 2 emissions. Each year in theUnited States alone, air pollutants—such as sulfurdioxide, particulates, and toxic metals such as mercury,arsenic, and lead—released when coal is burnedkill thousands of people prematurely (estimates rangefrom 65,000 to 200,000), cause at least 50,000 cases ofrespiratory disease, and result in several billion dollarsof property damage. Many people are unaware thatburning coal is also responsible for about one-fourth ofatmospheric mercury pollution in the United Statesand releases far more radioactive particles into the airthan normally operating nuclear power plants.In China, millions of people burning coal in unventedstoves for heat and cooking are exposed to dangerouslevels of particulate matter and toxic metalssuch as mercury and arsenic.Moderate cost(with largegovernmentsubsidies)Lower airpollution whenburned than coalHighenvironmentalimpactIncreased surfacemining of coalHigh water useHigher CO 2emissions thancoalFigure 17-22 Trade-offs: advantages and disadvantages ofusing synthetic natural gas (SNG) and liquid synfuels producedfrom coal. Pick the single advantage and disadvantage that youthink are the most important.http://biology.brookscole.com/miller14365