© Cengage Learning 2015 LIVING IN THE ENVIRONMENT, 18e G. TYLER MILLER SCOTT E. SPOOLMAN © Cengage Learning Energy Efficiency and Renewable Energy

© Cengage Learning 2015 Wind energy – wind farms convert to electrical energy Wind power is inexhaustible Could meet electricity needs of the lower 48 states –Texas and California are top producers Core Case Study: The Astounding Potential for Wind Power in the U.S.

Fig. 16-1a, p. 402 Gearbox Electrical generator Power cable Wind turbine

© Cengage Learning 2015 Fig. 16-1b, p. 402

© Cengage Learning 2015 Improvements in energy efficiency could save at least a third of the energy used in the world and up to 43% of the energy used in the United States We have a variety of technologies for sharply increasing the energy efficiency of industrial operations, motor vehicles, appliances, and buildings 16-1 Why Is Energy Efficiency an Important Energy Resource?

© Cengage Learning 2015 Energy efficiency –How much useful work we get from each unit energy Advantages of reducing energy waste –Usually the cheapest way to provide more energy –Reduces pollution and degradation –Slows global warming –Increases economic and national security We Use Energy Inefficiently

© Cengage Learning 2015 Four widely used devices that waste energy –Incandescent light bulb –Motor vehicle with internal combustion engine –Nuclear power plant –Coal-fired power plant We Use Energy Inefficiently (cont’d.)

Fig. 16-2, p. 403 Energy InputsSystemOutputs 9% 7% 41% 85% U. S. economy 43% 8% Nonrenewable fossil fuels Useful energy Renewable (hydropower, geothermal, wind, solar, biomass) Energy waste 3% Petrochemicals Unavoidable energy loss Nonrenewable nuclear

Fig. 16-4, p. 404 Solutions Improving Energy Efficiency Prolongs fossil fuel supplies Reduces oil imports and improves energy security Very high net energy yield Low cost Reduces pollution and environmental degradation Buys time to phase in renewable energy Creates local jobs

© Cengage Learning 2015 Cogeneration –Combined heat and power (CHP) –Two forms of energy from same fuel source Replace energy-wasting electric motors Recycle materials Switch from low-efficiency incandescent lighting to higher-efficiency fluorescent and LED lighting We Can Improve Energy Efficiency in Industry and Utilities

© Cengage Learning 2015 Current electrical grid system – outdated and wasteful Smart grid –Ultra-high-voltage –Super-efficient transmission lines –Digitally controlled –Responds to local changes in demand and supply –Easier to buy renewable energy Case Study: Saving Energy and Money with a Smarter Electrical Grid

© Cengage Learning 2015 Hidden prices in gasoline –Should be $12/gallon –Car manufacturers and oil companies lobby to prevent laws to raise fuel taxes Build or expand mass transit and high speed rail Encourage biking We Can Improve Energy Efficiency and Save Money in Transportation

© Cengage Learning 2015 Superefficient and ultralight cars Gasoline-electric hybrid car Plug-in hybrid electric vehicle Energy-efficient diesel car Electric vehicle with a fuel cell More Energy-Efficient Vehicles Are on the Way

Stepped Art Conventional hybridFuel tank Battery Internal combustion engine TransmissionElectric motor Plug-in hybrid Fuel tank Battery Internal combustion engine Transmission Electric motor Fig 16-6, p. 406

© Cengage Learning 2015 Green architecture Living or green roofs –With specially designed soil and vegetation Superinsulation –No need for heating system U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) We Can Design Buildings That Save Energy and Money

© Cengage Learning 2015 Fig. 16-7, p. 408

© Cengage Learning 2015 Conduct an energy audit: –Insulate and plug leaks –Use energy-efficient windows –Stop other heating and cooling losses –Heat houses more efficiently –Use energy-efficient appliances –Use energy-efficient lighting –Use motion sensors to turn lights on and off We Can Save Money and Energy in Existing Buildings

Fig. 16-9, p. 410

Outside Plant deciduous trees to block summer sun and let in winter sunlight. Other rooms Use compact fluorescent lightbulbs or LEDs and avoid using incandescent bulbs wherever possible. Turn off lights, computers, TV, and other electronic devices when they are not in use. Use high efficiency windows; use insulating window covers and close them at night and on sunny, hot days. Set thermostat as low as you can in winter and as high as you can in summer. Weather-strip and caulk doors, windows, light fixtures, and wall sockets. Keep heating and cooling vents free of obstructions. Keep fireplace damper closed when not in use. Use fans instead of, or along with, air conditioning. Bathroom Install water-saving toilets, faucets, and shower heads. Repair water leaks promptly. Stepped Art Attic Hang reflective foil near roof to reflect heat. Use house fan. Be sure attic insulation is at least 30 centimeters (12 inches). Kitchen Use microwave rather than stove or oven as much as possible. Run only full loads in dishwasher and use low- or no-heat drying. Clean refrigerator coils regularly. Basement or utility room Use front-loading clothes washer. If possible run only full loads with warm or cold water. Hang clothes on racks for drying. Run only full loads in clothes dryer and use lower heat setting. Set water heater at 140° if dishwasher is used and 120° or lower if no dishwasher is used. Use water heater thermal blanket. Insulate exposed hot water pipes. Regularly clean or replace furnace filters. Fig , p. 411

© Cengage Learning 2015 Energy remains artificially cheap –Government subsidies –Tax breaks –Prices don’t include true cost Few large and long-lasting incentives –Government rebates –Low-interest loans Lack of education Why Are We Still Wasting So Much Energy and Money?

© Cengage Learning 2015 Renewable energy –Solar energy –Geothermal energy Renewable energy will be cheaper if we eliminate: –Inequitable subsidies –Inaccurate prices –Artificially low pricing of nonrenewable energy We Can Use Renewable Energy to Provide Heat and Electricity

Fig , p. 412 Available Energy Flow (exajoules per year) World energy use (2010) Direct solar Wind Geothermal Biomass Hydropower Ocean < >1, <250

© Cengage Learning 2015 Passive and active solar heating systems can heat water and buildings effectively The costs of using direct sunlight to produce high-temperature heat and electricity are coming down 16-3 What Are the Advantages and Disadvantages of Solar Energy?

© Cengage Learning 2015 Passive solar heating system –Absorbs and stores heat from the sun directly within a well-insulated structure Active solar heating system –Captures energy from the sun in a heat- absorbing fluid We Can Heat Buildings and Water with Solar Energy

Fig , p. 415 Trade-Offs Passive or Active Solar Heating AdvantagesDisadvantages Net energy is moderate (active) to high (passive) Need access to sun 60% of time during daylight Very low emissions of CO 2 and other air pollutants Sun can be blocked by trees and other structures High installation and maintenance costs for active systems Very low land disturbance Moderate cost (passive) Need backup system for cloudy days

© Cengage Learning 2015 Technologies available –Open windows when cooler outside –Use fans –Superinsulation and high-efficiency windows –Overhangs or awnings on windows –Light-colored roof –Geothermal pumps We Can Cool Buildings Naturally

© Cengage Learning 2015 Solar thermal systems –Collect sunlight to boil water, generate electricity –1% of world deserts could supply all the world’s electricity –Require large amounts of water Wet cooling Dry cooling Low net energy yields We Can Concentrate Sunlight to Produce High-Temperature Heat and Electricity

Fig , p. 416

Fig , p. 416 Solar Thermal Systems High potential for growth Low net energy and high costs AdvantagesDisadvantages No direct emissions of CO 2 and other air pollutants Needs backup or storage system on cloudy days Source of new jobs Can disrupt desert ecosystems Trade-Offs Lower costs with natural gas turbine backup

© Cengage Learning 2015 Photovoltaic (PV) cells – Convert solar energy to electric energy Design of solar cells –Sunlight hits cells and releases electrons into wires What are the benefits of using solar cells? We Can Use Solar Cells to Produce Electricity

© Cengage Learning 2015 Key problems –High cost of producing electricity –Need to be located in sunny desert areas –Fossil fuels used in production –Solar cells contain toxic materials Cost could drop with: –Mass production and new designs –Government subsidies and tax breaks We Can Use Solar Cells to Produce Electricity (cont’d.)

Fig , p. 418

Fig , p. 418

Fig , p. 419 Solar Cells AdvantagesDisadvantages Medium net energy yield Need access to sun Little or no direct emissions of CO 2 and other air pollutants Need electricity storage system or backup Easy to install, move around, and expand as needed Costs high for older systems but dropping rapidly Solar-cell power plants could disrupt desert ecosystems Competitive cost for newer cells Trade-Offs Some designs have low net energy yield

© Cengage Learning 2015 We can use water flowing over dams, tidal flows, and ocean waves to generate electricity –However, environmental concerns and limited availability of suitable sites may limit the use of these energy resources 16-4 What Are the Advantages and Disadvantages of Using Hydropower

© Cengage Learning 2015 Hydropower –Uses kinetic energy of moving water –Indirect form of solar energy –World’s leading renewable energy source used to produce electricity What are the advantages and disadvantages? Micro-hydropower generators: floating turbines We Can Produce Electricity from Falling and Flowing Water

Fig , p. 420 Large-Scale Hydropower AdvantagesDisadvantages High net energy yield Large land disturbance and displacement of people Low-cost electricity High CH 4 emissions from rapid biomass decay in shallow tropical reservoirs Low emissions of CO 2 and other air pollutants in temperate areas Disrupts downstream aquatic ecosystems Trade-Offs Large untapped potential

© Cengage Learning 2015 Produce electricity from flowing water –Ocean tides and waves in coastal bays and estuaries Power systems are limited –Few suitable sites –High costs –Equipment damaged by storms and corrosion We Can Use Tides and Waves to Produce Electricity

© Cengage Learning 2015 When we include the environmental costs of using energy resources in their market prices, wind power is the least expensive and least polluting way to produce electricity 16-5 What Are the Advantages and Disadvantages of Using Wind Power?

© Cengage Learning 2015 Tall, long-blade turbines can extract more energy from the wind Rapidly growing power source –U.S., Europe, and China –Future is offshore wind farms Wind power has potential to produce 40 times of the world’s current electricity used Using Wind to Produce Electricity Is an Important Step toward Sustainability

© Cengage Learning 2015 Wind is abundant, widely distributed, and inexhaustible High net energy yield Drawbacks: –Largest potential areas are usually rural –Winds can die down – need backup power source Using Wind to Produce Electricity Is an Important Step (cont’d.)

Fig , p. 423 Trade-Offs Wind Power AdvantagesDisadvantages High net energy yield Needs backup or storage system when winds die down Low electricity cost Visual pollution for some people Low-level noise bothers some people Can kill birds if not properly designed and located Widely available Easy to build and expand Little or no direct emissions of CO 2 and other air pollutants

© Cengage Learning 2015 Solid biomass is a renewable resource for much of the world’s population, but burning it faster than it is replenished produces a net gain in atmospheric greenhouse gases 16-6 Advantages and Disadvantages of Using Biomass as an Energy Source

© Cengage Learning 2015 We can use liquid biofuels derived from biomass to lessen our dependence on oil- based fuels, but creating biofuel plantations can: –Degrade soil and biodiversity –Increase greenhouse gas emissions –Lead to higher food prices 16-6 Advantages and Disadvantages of Biomass as an Energy Source (cont’d.)

© Cengage Learning 2015 Biomass –Plant materials and animal waste we can burn or turn into biofuels Production of solid mass fuel –Plant fast-growing trees; biomass plantations –Collect crop residues and animal manure What are the advantages and disadvantages of biomass energy? We Can Produce Energy by Burning Solid Biomass

Fig , p. 424 Solid Biomass AdvantagesDisadvantages Widely available in some areas Contributes to deforestation Clear-cutting can cause soil erosion, water pollution, and loss of wildlife habitat No net CO 2 increase if harvested, burned, and replanted sustainably Medium net energy yield Plantations can help restore degraded lands Trade-Offs Increases CO 2 emissions if harvested and burned unsustainably Can open ecosystems to invasive species Moderate costs

© Cengage Learning 2015 Biodiesel –Produced from vegetable oil –European Union countries produce 95% of the world’s biodiesel Crops require large amounts of land Production requires fossil fuels Case Study: Is Biodiesel the Answer?

© Cengage Learning 2015 Ethanol –Can be made from sugarcane, corn, switchgrass, and various wastes –United States largest producer Made from corn; low net energy yield –Brazil second Sugarcane has medium net energy yield Cellulosic ethanol –Produced from cellulose Case Study: Is Ethanol the Answer?

© Cengage Learning 2015 Problems with cellulosic ethanol –Chemical processes still being developed –Growing enough switchgrass would require too much land Evaluating use of algae and bacteria Case Study: Is Ethanol the Answer? (cont’d.)

Fig , p. 426 Liquid Biofuels AdvantagesDisadvantages Reduced CO 2 emissions for some crops Fuel crops can compete with food crops for land and raise food prices Medium net energy yield for biodiesel from oil palms Fuel crops can be invasive species Low net energy yield for corn ethanol and for biodiesel from soybeans Medium net energy yield for ethanol from sugarcane Higher CO 2 emissions from corn ethanol Trade-Offs

© Cengage Learning 2015 Geothermal energy has great potential for supplying many areas with heat and electricity, and has a generally low environmental impact –However, the sites where it can be produced economically are limited 16-7 What Are the Advantages and Disadvantages of Geothermal Energy?

© Cengage Learning 2015 With geothermal energy, heat is stored in: –Soil –Underground rocks –Fluids in the earth’s mantle Geothermal heat pump system –Energy efficient and reliable –Environmentally clean –Cost effective to heat or cool a space We Can Get Energy by Tapping the Earth’s Internal Heat

© Cengage Learning 2015 Hydrothermal reservoirs –Drill wells and extract various steams, water –U.S. is the world’s largest producer Geothermal energy problems –High cost of tapping hydrothermal reservoirs –Dry- or wet-steam geothermal reservoirs could be depleted –Could create earthquakes We Can Get Energy by Tapping the Earth’s Internal Heat (cont’d.)

© Cengage Learning 2015 Fig a, p. 428 Production well Geothermal reservoir Injection well Heat exchanger Steam turbine Generator 2. Heat from underground spins a turbine to power a generator and produce electricity 1. Hot water or steam is pumped under pressure to the surface from underground 3. Steam from turbine condenses to water and is pumped back down to geothermal reservoir

© Cengage Learning 2015 Fig b, p. 428

Fig , p. 430 Geothermal Energy AdvantagesDisadvantages Medium net energy yield and high efficiency at accessible sites High cost except at concentrated and accessible sites Lower CO 2 emissions than fossil fuels Scarcity of suitable sites Low cost at favorable sites Noise and some CO 2 emissions Trade-Offs

© Cengage Learning 2015 Hydrogen is a clean energy source as long as it is not produced with the use of fossil fuels –However, it has a negative net energy yield 16-8 The Advantages and Disadvantages of Using Hydrogen as an Energy Source

© Cengage Learning 2015 Hydrogen as a fuel –Eliminates most of the air pollution problems –Reduces threats of global warming Will Hydrogen Save Us?

© Cengage Learning 2015 Some challenges –Chemically locked in water and organic compounds – net negative energy yield –Expensive fuel cells are the best way to use hydrogen –CO 2 levels dependent on method of hydrogen production Will Hydrogen Save Us?

Fig , p. 430 Electrons Hydrogen gas (H 2 ) in Polymer electrolyte membrane Anode Cathode Protons Water vapor (H 2 O) out Air (O 2 ) in

© Cengage Learning 2015 Production and storage of H 2 –Must be produced using other sources of energy Hydrogen-powered vehicles – prototypes available Can we produce hydrogen on demand? Larger fuel cells – fuel-cell stacks Will Hydrogen Save Us? (cont’d.)

Fig , p. 432 Trade-Offs Hydrogen AdvantagesDisadvantages Can be produced from plentiful water at some sites Fuel cell Negative net energy yield CO 2 emissions if produced from carbon-containing compounds No CO 2 emissions if produced with use of renewables Good substitute for oil High costs create need for subsidies High efficiency in fuel cells Needs H 2 storage and distribution system

© Cengage Learning 2015 We can make the transition to a more sustainable energy future by: –Greatly improving energy efficiency –Using a mix of renewable energy resources –Including the environmental and health costs of energy resources in their market prices 16-9 How Can We Make the Transition to a More Sustainable Energy Future?

© Cengage Learning 2015 General conclusions: –Gradual shift to smaller, decentralized micropower systems –Combination of increased energy efficiency and regulated use of natural gas will be the best way to transition to renewable energy –Because fossil fuels are cheap we will continue to use them Choosing Energy Paths

Bioenergy power plants Smart electrical and distribution system Small solar-cell power plants Solar-cell rooftop systems Commercial Fuel cells Rooftop solar- cell arrays Residential Small wind turbine Stepped Art Industrial Microturbines Wind farm Fig , p. 433 © Cengage Learning 2015

Government strategies: –Keep the prices of selected energy resources artificially low to encourage their use –Keep energy prices artificially high for selected resources to discourage their use –Consumer education Economics, Politics, Education, and Sustainable Energy Resources

© Cengage Learning 2015 Fig , p. 434

© Cengage Learning 2015 We should evaluate energy resources on the basis of: –Their potential supplies –Their net energy yields –Environmental and health impacts of using them Three Big Ideas

© Cengage Learning 2015 By using a mix of renewable energy sources we could drastically reduce pollution, greenhouse gas emissions, and biodiversity losses –Solar, wind, flowing water, sustainable biofuels, and geothermal energy Three Big Ideas (cont’d.)

© Cengage Learning 2015 Making the transition to a more sustainable energy future will require: –Sharply increasing energy efficiency –Using a mix of environmentally friendly renewable energy resources –Including the harmful environmental and health costs of energy resources in their market prices Three Big Ideas (cont’d.)

© Cengage Learning 2015 Relying on a diversity of direct and indirect forms of solar energy: –Would implement three principles of sustainability –Recycle and reuse materials to reduce consumption of energy –Mimic nature’s reliance on biodiversity by diversifying energy sources Tying It All Together: Wind Power and Sustainability