17THMILLER/SPOOLMAN

LIVING IN THE ENVIRONMENT

Chapter 16Energy Efficiency and Renewable Energy

We Waste Huge Amounts of Energy (1)• Energy efficiency

• Advantages of reducing energy waste:• Quick and clean• Usually the cheapest to provide more energy• Reduce pollution and degradation• Slow global warming• Increase economic and national security

We Waste Huge Amounts of Energy (2)• Four widely used devices that waste energy

1. Incandescent light bulb2. Motor vehicle with internal combustion engine3. Nuclear power plant4. Coal-fired power plant

Flow of Commercial Energy through the U.S. Economy

Fig. 16-2, p. 399

Advantages of Reducing Energy Waste

Fig. 16-3, p. 399

We Can Save Energy and Money in Industry and Utilities (1)

• Cogeneration or combined heat and power (CHP)• Two forms of energy from same fuel source

• Replace energy-wasting electric motors

• Recycling materials

• Switch from low-efficiency incandescent lighting to higher-efficiency fluorescent and LED lighting

LEDs

Fig. 16-4, p. 401

We Can Save Energy and Money in Industry and Utilities (2)

• Electrical grid system: outdated and wasteful

• Utility companies switching from promote use of energy to promoting energy efficiency• Spurred by state utility commissions

Case Study: Saving Energy and Money with a Smarter Electrical Grid

• Smart grid• Ultra-high-voltage• Super-efficient transmission lines• Digitally controlled• Responds to local changes in demand and supply• Two-way flow of energy and information• Smart meters show consumers how much energy

each appliance uses

• U.S cost -- $200-$800 billion; save $100 billion/year

Proposed U.S. Smart Grid

Figure 20, Supplement 8

We Can Save Energy and Money in Transportation

• Corporate average fuel standards (CAFE) standards• Fuel economy standards lower in the U.S. countries• Fuel-efficient cars are on the market

• Hidden prices in gasoline: $12/gallon• Car manufacturers and oil companies lobby to prevent

laws to raise fuel taxes

• Should there be a feebate?

Average Fuel Economy of New Vehicles Sold in the U.S. and Other Countries

Fig. 16-5, p. 402

More Energy-Efficient Vehicles Are on the Way

• Superefficient and ultralight cars

• Gasoline-electric hybrid car

• Plug-in hybrid electric vehicle

• Energy-efficient diesel car

• Electric vehicle with a fuel cell

Solutions: A Hybrid-Gasoline-Electric Engine Car and a Plug-in Hybrid Car

Fig. 16-6, p. 403

Science Focus: The Search for Better Batteries

• Current obstacles• Storage capacity• Overheating• Flammability • Cost

• In the future• Lithium-ion battery• Viral battery• Ultracapacitor

We Can Design Buildings That Save Energy and Money

• Green architecture

• Living or green roofs

• Superinsulation

• U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED)

A Green Roof in Chicago

Fig. 16-8, p. 405

A Thermogram Shows Heat Loss

Fig. 16-9, p. 406

Individuals Matter: Ways in Which You Can Save Money Where You Live

Fig. 16-10, p. 407

Why Are We Still Wasting So Much Energy?

• Energy remains artificially cheap• Government subsidies• Tax breaks• Prices don’t include true cost

• Few large and long-lasting incentives• Tax breaks• Rebates• Low-interest loans

We Can Use Renewable Energy to Provide Heat and Electricity

• Renewable energy• Solar energy: direct or indirect• Geothermal energy

• Benefits of shifting toward renewable energy

• Renewable energy cheaper if we eliminate• Inequitable subsidies• Inaccurate prices• Artificially low pricing of nonrenewable energy

We Can Heat Buildings and Water with Solar Energy

• Passive solar heating system

• Active solar heating system

Solutions: Passive and Active Solar Heating for a Home

Fig. 16-11, p. 409

Passive Solar Home in Colorado

Fig. 16-12, p. 410

Rooftop Solar Hot Water on Apartment Buildings in Kunming, China

Fig. 16-13, p. 410

Trade-Offs: Passive or Active Solar Heating

Fig. 16-14, p. 411

World Availability of Direct Solar Energy

Figure 22, Supplement 8

U.S. Availability of Direct Solar Energy

Figure 23, Supplement 8

We Can Cool Buildings Naturally

• 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 Use Sunlight to Produce High-Temperature Heat and Electricity

• Solar thermal systems• Central receiver system• Collect sunlight to boil water, generate electricity• 1% of world deserts could supply all the world’s electricity• Require large amounts of water – could limit

• Wet cooling• Dry cooling

• Low net energy yields

Solar Thermal Power in California Desert

Fig. 16-15, p. 411

Trade-Offs: Solar Energy for High Temperature Heat and Electricity

Fig. 16-16, p. 412

Solutions: Solar Cooker in India

Fig. 16-17, p. 412

We Can Use Sunlight to Produce Electricity (1)

• Photovoltaic (PV) cells (solar cells)• Convert solar energy to electric energy

• Design of solar cells• Sunlight hits cells and releases electrons into wires

• Benefits of using solar cells

• Solar-cell power plants around the world

Solutions: Solar Cells on Rooftop and for Many Purposes

Fig. 16-18, p. 413

Solar Cell Array in Niger, West Africa

Fig. 16-19, p. 413

Solar-Cell Power Plant in Arizona

Fig. 16-20, p. 414

We Can Use Sunlight to Produce Electricity (2)

• 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

• Will the cost drop with• Mass production • New designs• Government subsidies and tax breaks

We Can Use Sunlight to Produce Electricity (3)

• 2040: could solar cells produce 16%?

• Nanosolar: California (U.S.)

• Germany: huge investment in solar cell technology

• General Electric: entered the solar cell market

Global Production of Solar Electricity

Figure 11, Supplement 9

Trade-Offs: Solar Cells

Fig. 16-21, p. 414

We Can Produce Electricity from Falling and Flowing Water

• Hydropower• Uses kinetic energy of moving water• Indirect form of solar energy• World’s leading renewable energy source used to

produce electricity

• Advantages and disadvantages

• Micro-hydropower generators

Tradeoffs: Dams and Reservoirs

Fig. 13-13, p. 328

Trade-Offs: Large-Scale Hydropower, Advantages and Disadvantages

Fig. 16-22, p. 415

Tides and Waves Can Be Used to Produce Electricity

• Produce electricity from flowing water• Ocean tides and waves

• So far, power systems are limited

• Disadvantages• Few suitable sites• High costs• Equipment damaged by storms and corrosion

Using Wind to Produce Electricity Is an Important Step toward Sustainability (1)

• Wind: indirect form of solar energy• Captured by turbines• Converted into electrical energy

• Second fastest-growing source of energy

• What is the global potential for wind energy?

• Wind farms: on land and offshore

World Electricity from Wind Energy

Figure 12, Supplement 9

Solutions: Wind Turbine and Wind Farms on Land and Offshore

Fig. 16-23, p. 417

Wind Turbine

Fig. 16-24, p. 417

Using Wind to Produce Electricity Is an Important Step toward Sustainability (2)

• Countries with the highest total installed wind power capacity• Germany• United States• Spain• India• Denmark

• Installation is increasing in several other countries

Using Wind to Produce Electricity Is an Important Step toward Sustainability (3)

• Advantages of wind energy

• Drawbacks• Windy areas may be sparsely populated – need to

develop grid system to transfer electricity• Winds die down; need back-up energy• Storage of wind energy• Kills migratory birds • “Not in my backyard”

Trade-Offs: Wind Power

Fig. 16-25, p. 418

United States Wind Power Potential

Figure 24, Supplement 8

We Can Get Energy by Burning Solid Biomass

• 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

• Advantages and disadvantages

Trade-Offs: Solid Biomass

Fig. 16-26, p. 420

We Can Convert Plants and Plant Wastes to Liquid Biofuels (1)

• Liquid biofuels• Biodiesel• Ethanol

• Biggest producers of biofuel• The United States• Brazil• The European Union • China

We Can Convert Plants and Plant Wastes to Liquid Biofuels (2)

• Major advantages over gasoline and diesel fuel produced from oil1. Biofuel crops can be grown almost anywhere2. No net increase in CO2 emissions if managed

properly3. Available now

We Can Convert Plants and Plant Wastes to Liquid Biofuels (3)

• Studies warn of problems:• Decrease biodiversity• Increase soil degrading, erosion, and nutrient leaching• Push farmers off their land• Raise food prices• Reduce water supplies, especially for corn and soy

Case Study: Is Biodiesel the Answer?

• Biodiesel production from vegetable oil from various sources

• 95% produced by the European Union

• Subsidies promote rapid growth in United States

• Advantages and disadvantages

Trade-Offs: Biodiesel

Fig. 16-27, p. 421

World Ethanol Production

Figure 13, Supplement 9

Bagasse is Sugarcane Residue

Fig. 16-28, p. 421

Natural Capital: Rapidly Growing Switchgrass

Fig. 16-29, p. 423

Trade-Offs: Ethanol Fuel

Fig. 16-30, p. 423

Case Study: Getting Gasoline and Diesel Fuel from Algae and Bacteria (1)

• Algae remove CO2 and convert it to oil• Not compete for cropland = not affect food prices• Wastewater/sewage treatment plants• Could transfer CO2 from power plants

• Algae challenges1.Need to lower costs2.Open ponds vs. bioreactors3.Affordable ways of extracting oil4.Scaling to large production

Case Study: Getting Gasoline and Diesel Fuel from Algae and Bacteria (2)

• Bacteria: synthetic biology• Convert sugarcane juice to biodiesel• Need large regions growing sugarcane

• Producing fuels from algae and bacteria can be done almost anywhere

Getting Energy from the Earth’s Internal Heat (1)

• Geothermal energy: heat 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

Natural Capital: A Geothermal Heat Pump System Can Heat or Cool a House

Fig. 16-31, p. 425

Getting Energy from the Earth’s Internal Heat (2)

• Hydrothermal reservoirs • U.S. is the world’s largest producer

• Hot, dry rock

• Geothermal energy problems• High cost of tapping hydrothermal reservoirs• Dry- or wet-steam geothermal reservoirs could be

depleted• Could create earthquakes

Geothermal Sites in the United States

Figure 26, Supplement 8

Geothermal Sites Worldwide

Figure 25, Supplement 8

Geothermal Power Plant in Iceland

Fig. 16-32, p. 425

Trade Offs: Geothermal Energy

Fig. 16-33, p. 426

Will Hydrogen Save Us? (1)

• Hydrogen as a fuel• Eliminate most of the air pollution problems• Reduce threats of global warming

• Some challenges• Chemically locked in water and organic compounds = net

negative energy yield• Expensive fuel cells are the best way to use hydrogen• CO2 levels dependent on method of hydrogen production

Will Hydrogen Save Us? (2)

• Net negative energy yield

• Production and storage of H2

• Hydrogen-powered vehicles: prototypes available

• Can we produce hydrogen on demand?

• Larger fuel cells – fuel-cell stacks

A Fuel Cell Separates the Hydrogen Atoms’ Electrons from Their Protons

Fig. 16-34, p. 427

Trade-Offs: Hydrogen, Advantages and Disadvantages

Fig. 16-35, p. 428

Solutions: Decentralized Power System

Fig. 16-36, p. 430

Solutions: Making the Transition to a More Sustainable Energy Future

Fig. 16-37, p. 431

Economics, Politics, Education, and Sustainable Energy Resources

• 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

What Can you Do? Shifting to More Sustainable Energy Use

Fig. 16-38, p. 432