Environmental Problems, Their Causes, and Sustainability 1

Figure 17-5 shows energy consumption by fuel inthe United States from 1970 to 2003, with projections to2020. Note that the main projected trends between2003 and 2020 are increased use of oil and natural gasand a leveling off of coal use.An important environmental, economic, and politicalissue is what energy resources the United Statesmight be using by 2050 and 2100. Figure 17-6 showsshifts in use of various commercial sources of energyin the United States since 1800 and one scenario projectingchanges to a solar–hydrogen energy age by2100. According to the U.S. Department of Energy andthe Environmental Protection Agency, burning fossilfuels causes more than 80% of U.S. air pollution and80% of U.S. carbon dioxide emissions. For many energyexperts the need to use cleaner and less climatedisrupting(noncarbon) energy resources—not thedepletion of fossil fuels—is the driving force behindthe projected transition to a solar–hydrogen energyage in the United States and in other parts of the worldbefore the end of this century.Whether the shift shown in Figure 17-6, or someother scenario, occurs depends primarily on energy resourcesthe U.S. government decides to promote by useof subsidies and tax breaks. If we want energy alternativessuch as solar energy and hydrogen to becomemain dishes instead of side orders on our energymenu, they must be nurtured by subsidies and taxbreaks.A political problem is that the fossil fuel andnuclear power industries that have been receivinggovernment subsidies for over 50 years understandablydo not want to give them up. And they use theirconsiderable political power to keep them, eventhough they are mature industries that do not needsuch nurturing.Thus the energy path of the United States (or anycountry) is primarily a political decision made by governmentofficials with pressure from officials of energycompanies and from citizens. As a citizen, you canEnergy consumption (quadrillion Btus)60504030201019701980History1990YearProjectionsOilNatural gasCoalNuclearNonhydrorenewableRenewable hydro200320102020Figure 17-5 Energy consumption by fuel in the United States,1970–2003, with projections to 2020. (U.S. Department of Energy,Annual Energy Review, 2003 and 2004)Contribution to total energyconsumption (percent)1008060402001800Wood1875Coalplay an important role in helping decide the energyfuture for yourself and future generations. Indeed, it isone of the most important political acts you can undertake.This explains why you should have an understandingof the advantages and disadvantages of ourmajor energy options, as discussed in this chapter andthe one that follows.How Can We Decide Which EnergyResources to Use? Evaluating AlternativeResourcesWe need to answer several questions in decidingwhich energy resources to promote.Energy policies must be developed with the future inmind because experience shows that it usually takes atleast 50 years and huge investments to phase in newenergy alternatives to the point where they provide10–20% of total energy use. Making projections such asthose in Figure 17-6 and converting them into energypolicy involves answering the following questions foreach alternative:■ How much of the energy resource is likely to beavailable in the near future (the next 15–25 years) andthe long term (the next 25–50 years)?■ What is the net energy yield for the resource?■ How much will it cost to develop, phase in, anduse the resource?■ What government research and development subsidiesand tax breaks will be used to help develop theresource?■ How will dependence on the resource affectnational and global economic and military security?■ How vulnerable is the resource to terrorism?OilNuclearNatural gas?HydrogenSolar1950 2025 2100YearFigure 17-6 Shifts in the use of commercial energy resourcesin the United States since 1800, with projected changes to2100. Shifts from wood to coal and then from coal to oil andnatural gas have each taken about 50 years. The projectedshift to 2100 is only one of many possible scenarios that dependon a variety of assumptions. (U.S. Department ofEnergy)http://biology.brookscole.com/miller14353