Environmental Problems, Their Causes, and Sustainability 1

If the United States wants to save a lot of oil and money andincrease national security, there are two simple ways to do it:Stop driving Petropigs and stop living in energy sieves.AMORY B. LOVINSThis chapter evaluates the use of energy efficiencyand renewable energy as energy alternatives. It addressesthe following questions:■■■■■■■■■How can we improve energy efficiency and whatare the advantages of doing so?What are the advantages and disadvantages ofusing solar energy to heat buildings and water andproduce electricity?What are the advantages and disadvantages ofusing flowing water to produce electricity?What are the advantages and disadvantages ofusing wind to produce electricity?What are the advantages and disadvantages ofburning plant material (biomass) to heat buildingsand water, produce electricity, and propel vehicles(biofuels)?What are the advantages and disadvantages of extractingheat from the earth’s interior (geothermalenergy) and using it to heat buildings and waterand to produce electricity?What are the advantages and disadvantages ofproducing hydrogen gas and burning it to produceelectricity, heat buildings and water, and propelvehicles?What are the advantages and disadvantages ofusing smaller, decentralized micropower sourcesto heat buildings and water, produce electricity,and propel vehicles?How can we make a transition to a more sustainableenergy future?18-1 THE IMPORTANCE OFIMPROVING ENERGY EFFICIENCYWhat Is Energy Efficiency and How MuchEnergy Do We Waste? Saving Money by NotWasting EnergyUsing less energy to do useful work reduces theenvironmental impact of energy use and savesmoney.Energy efficiency is a measure of the useful energyproduced by an energy conversion device comparedto the energy that ends up being converted to lowquality,essentially useless heat. For example, the lightproduced by a light bulb is useful energy, while theheat it produces is wasted energy.If you replace an incandescent bulb that is only 5%efficient with a compact fluorescent bulb that is 20%efficient, you get the same amount of light using onefourthas much energy. This reduces pollution andcarbon dioxide emissions and saves money on yourelectric bill—a win-win solution for you and the earth.Figure 18-2 lists major economic and environmentaladvantages of reducing energy waste.Some critics like to paint proponents of conservingenergy as calling for personal sacrifice, giving up cars,freezing in winter, wearing sweaters, and burning upin the summer. This is an incorrect and misleadingview of energy conservation, which is implementedmainly by using existing technologies and developingnew ones that waste less energy.You may be surprised to learn that about 84% ofall commercial energy used in the United States iswasted (Figure 18-3). About 41% of the energy used iswasted automatically because of the degradation ofenergy quality imposed by the second law of thermodynamics.But about 43% of the energy used in theUnited States is wasted unnecessarily, mostly by usingfuel-wasting motor vehicles, furnaces, and other devicesand living and working in leaky, poorly insulated,poorly designed buildings. See the Guest Essayon this topic by Amory Lovins on the website for thischapter. The U.S. Department of Energy (DOE) estimatesthat the United States unnecessarily wastes asmuch energy as two-thirds of the world’s populationconsumes.SolutionsReducing Energy WasteProlongs fossil fuel suppliesReduces oil importsVery high net energyLow costReduces pollution andenvironmental degradationBuys time to phase in renewableenergyLess need for military protection ofMiddle East oil resourcesImproves local economy byreducing flow of money out to payfor energyCreates local jobsFigure 18-2 Solutions: advantages of reducing energy waste.Global improvements in energy efficiency could save the worldabout $1 trillion per year—an average of $114 million per hour!380 CHAPTER 18 Energy Efficiency and Renewable Energy