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17TH MILLER/SPOOLMAN

LIVING IN THE ENVIRONMENT

Chapter 16

Energy Efficiency and Renewable Energy

Core Case Study: Amory Lovins and The Rocky Mountain Institute (1)

• Amory Lovins, energy analyst

• Rocky Mountain Institute • Nonprofit and nonpartisan

• Research and consulting on energy, energy efficiency, and renewable energy

• Consults with 80 major corporations and 50 foreign countries

Core Case Study: Amory Lovins and The Rocky Mountain Institute (2)

• Location: Snowmass, CO (U.S.)

• No conventional heating system

• Heating bills: <$50/year

• How is this possible?

Sustainable Energy: Rocky Mountain Institute in Colorado, U.S.

Fig. 16-1, p. 397

16-1 Why Is Energy Efficiency an Important Energy Resource?

• Concept 16-1 Improving energy efficiency can save the world at least a third of the energy it uses, and it can save the United States up to 43% of the energy it uses.

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 bulb

2. Motor vehicle with internal combustion engine

3. Nuclear power plant

4. Coal-fired power plant

Flow of Commercial Energy through the U.S. Economy

Fig. 16-2, p. 399

Fig. 16-2, p. 399

Energy Inputs System Outputs

9%

7%

41% 85%

U. S. economy

43%

8%

4%

Nonrenewable fossil fuels Useful energy

Hydropower, geothermal, wind, solar Unnecessary energy

waste

3%

Petrochemicals

Unavoidable energy waste

Nonrenewable nuclear

Biomass

Advantages of Reducing Energy Waste

Fig. 16-3, p. 399

Fig. 16-3, p. 399

Solutions

Reducing Energy Waste

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

16-2 How Can We Cut Energy Waste?

• Concept 16-2 We have a variety of technologies for sharply increasing the energy efficiency of industrial operations, motor vehicles, and buildings.

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

Fig. 16-5a, p. 402

30

Cars

25

20 Trucks

15

Ave

rage

fu

el e

con

om

y (m

iles

pe

r ga

llon

)

10

1975 1980 1985 1990 1995 2000 2005 2010

Year

Fig. 16-5b, p. 402

50

45 Europe

40 Japan

35 China

Mile

s p

er

gallo

n (

mp

g)

(co

nve

rte

d t

o U

.S. t

est

eq

uiv

alen

ts)

30 Canada

25

20

United States

2002 2004 2006 2008

Year

Stepped Art

25 Cars

20 Cars, trucks, and SUVs

Trucks and SUVs 15

Ave

rag

e f

ue

l e

co

no

my (

mil

es

pe

r g

all

on

)

10

1975 1980 1985 1990 1995 2000 2005

Year

50

45 Europe

40 Japan

35 China

Mile

s p

er

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llo

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(co

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.S. te

st

eq

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ale

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)

30 Canada

25 United

States 20

2002 2004 2006 2008

Year

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

Fig. 16-6, p. 403

Conventional hybrid Fuel tank

Battery

Internal combustion engine

Transmission Electric motor

Fig. 16-6, p. 403

Plug-in hybrid Fuel tank

Battery

Internal combustion engine


Stepped Art

Conventional hybrid Fuel tank

Battery

Internal

combustion

engine Transmission Electric motor

Plug-in hybrid

Fuel tank

Battery

Internal

combustion

engine


Fig. 16-6, p. 403

Light-Weight Carbon Composite Concept Car

Fig. 16-7, p. 405

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

We Can Save Money and Energy in Existing Buildings (1)

• Conduct an energy survey

• Insulate and plug leaks

• Use energy-efficient windows

• Stop other heating and cooling losses

• Heat houses more efficiently

We Can Save Money and Energy in Existing Buildings (2)

• Heat water more efficiently

• Use energy-efficient appliances

• Use energy-efficient lighting

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

Fig. 16-10, p. 407

Attic Outside • Hang reflective foil near roof to reflect heat.

Plant deciduous trees to block summer sun and let in winter sunlight.

• Use house fan.

• Be sure attic insulation is at least 30 centimeters (12 inches).

Bathroom • Install water-saving toilets, faucets, and shower heads.

• Repair water leaks promptly. Other rooms

• Use compact fluorescent lightbulbs or LEDs and avoid using incandescent bulbs.

Kitchen • Use microwave rather than stove or oven as much as possible.

• Turn off lights, computers, TV, and other electronic devices when they are not in use.

• Run only full loads in dishwasher and use low- or no-heat drying. • Use high efficiency

windows; use insulating window covers and close them at night and on sunny, hot days.

• Clean refrigerator coils regularly.

• Set thermostat as low as you can in winter and as high as you can in summer.

Basement or utility room • Use front-loading clothes washer. If possible run only full loads with warm or cold water.

• Weather-strip and caulk doors, windows, light fixtures, and wall sockets.

• If possible, hang clothes on racks for drying.

• Run only full loads in clothes dryer and use lower heat setting. • Keep heating and cooling vents free of obstructions. • Set water heater at 140°F if dishwasher is used and 120°F or lower if

no dishwasher is used. • Keep fireplace damper closed when not in use. • Use water heater thermal blanket.

• Insulate exposed hot water pipes. • Use fans instead of, or along with, air conditioning. • Regularly clean or replace furnace filters.

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. 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

16-3 What Are the Advantages and Disadvantages of Solar Energy?

• Concept 16-3 Passive and active solar heating systems can heat water and buildings effectively, and the costs of using direct sunlight to produce high-temperature heat and electricity are coming down.

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

Fig. 16-11a, p. 409

White or light-colored roofs reduce overheating Vent allows hot

air to escape in summer Summer

sun Heavy insulation

Winter sun

Superwindow

Super- window

Stone floor and wall for heat storage

PASSIVE

Fig. 16-11b, p. 409

Solar collector White or light-colored roofs reduce overheating

Heat to house (radiators or forced air duct)

Pump

Heavy insulation Super- window

Hot water tank

Heat exchanger

ACTIVE

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

Fig. 16-14, p. 411

Trade-Offs

Passive or Active Solar Heating

Advantages Disadvantages

Net energy is moderate (active) to high (passive)

Need access to sun 60% of time during daylight

Very low emissions of CO2 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

World Availability of Direct Solar Energy


U.S. Availability of Direct Solar Energy


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

Fig. 16-16, p. 412

Solar Energy for High-Temperature Heat and Electricity

Moderate environmental impact

Low net energy and high costs


No direct emissions of CO2 and other air pollutants

Needs backup or storage system on cloudy days

Lower costs with natural gas turbine backup

High water use for cooling

Trade-Offs

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


• 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


• 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


Trade-Offs: Solar Cells

Fig. 16-21, p. 414

Fig. 16-21, p. 414

Solar Cells


Moderate net energy yield

Need access to sun

Little or no direct emissions of CO2 and other air pollutants

Need electricity storage system or backup

Easy to install, move around, and expand as needed

High costs for older systems but decreasing rapidly

Solar-cell power plants could disrupt desert ecosystems

Competitive cost for newer cells

Trade-Offs

16-4 What Are the Advantages and Disadvantages of Using Hydropower

• Concept 16-4 We can use water flowing over dams, tidal flows, and ocean waves to generate electricity, but environmental concerns and limited availability of suitable sites may limit the use of these energy resources.

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

Fig. 13-13a, p. 328

Provides irrigation water above and below dam

Flooded land destroys forests or cropland and displaces people

Large losses of water through evaporation

Provides water for drinking

Deprives downstream cropland and estuaries of nutrient-rich silt

Reservoir useful for recreation and fishing

Risk of failure and devastating downstream flooding

Can produce cheap electricity (hydropower)

Reduces down-stream flooding of cities and farms Disrupts

migration and spawning of some fish

Fig. 13-13b, p. 328

Powerlines

Reservoir

Dam

Intake Powerhouse

Turbine

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

Fig. 16-22, p. 415

Fig. 16-22, p. 415

Large-Scale Hydropower


Moderate to high net energy

Large land disturbance and displacement of people

Low-cost electricity High CH4 emissions from rapid biomass decay in shallow tropical reservoirs

Low emissions of CO2 and other air pollutants in temperate areas Disrupts downstream

aquatic ecosystems

Trade-Offs

Large untapped potential

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

16-5 What Are the Advantages and Disadvantages of Using Wind Power? • Concept 16-5 When we include the environmental

costs of using energy resources in the market prices of energy, wind power is the least expensive and least polluting way to produce electricity.

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


Solutions: Wind Turbine and Wind Farms on Land and Offshore

Fig. 16-23, p. 417

Fig. 16-23a, p. 417

Gearbox

Electrical generator

Power cable

Wind turbine

Fig. 16-23b, p. 417 Wind farm

Fig. 16-23c, p. 417 Wind farm (offshore)

Wind Turbine

Fig. 16-24, p. 417


• Countries with the highest total installed wind power capacity

• Germany

• United States

• Spain

• India

• Denmark

• Installation is increasing in several other countries


• 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

Fig. 16-25, p. 418

Trade-Offs

Wind Power


Moderate to 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 CO2 and other air pollutants

Case Study: The Astounding Potential of Wind Power in the United States

• “Saudi Arabia of wind power”

• North Dakota

• South Dakota

• Kansas

• Texas

• How much electricity is possible with wind farms in those states?

• Could create up to 500,000 jobs

United States Wind Power Potential


16-6 Advantages and Disadvantages of Using Biomass as an Energy Source

• Concept 16-6A 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, and creating biomass plantations can degrade soil biodiversity.

• Concept 16-6B We can use liquid biofuels derived from biomass in place of gasoline and diesel fuels, but creating biofuel plantations can degrade soil and biodiversity and increase food prices and greenhouse gas emissions.

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


Trade-Offs: Solid Biomass

Fig. 16-26, p. 420

Fig. 16-26, p. 420

Solid Biomass


Widely available in some areas

Moderate to high environmental impact

Increases CO2 emissions if harvested and burned unsustainably

No net CO2 increase if harvested, burned, and replanted sustainably

Moderate costs

Plantations can help restore degraded lands

Trade-Offs

Often burned in inefficient and polluting open fires and stoves

Clear cutting can cause soil erosion, water pollution, and loss of wildlife habitat

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


• Major advantages over gasoline and diesel fuel produced from oil

1. Biofuel crops can be grown almost anywhere

2. No net increase in CO2 emissions if managed properly

3. Available now


• 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


Trade-Offs: Biodiesel

Fig. 16-27, p. 421

Fig. 16-27, p. 421

Biodiesel


Reduced CO and CO2 emissions

Increased NOx emissions and smog

High net energy yield for oil palm crops

Low net energy yield for soybean crops

Competes with food for cropland

Reduced hydrocarbon emissions

Clearing natural areas for plantations reduces biodiversity and increases atmospheric CO2 levels Better mileage (up

to 40%)

Trade-Offs

Case Study: Is Ethanol the Answer? (1)

• Ethanol from plants and plant wastes

• Brazil produces ethanol from sugarcane

• Environmental consequences

• United States: ethanol from corn

• Low net energy yield

• Reduce the need for oil imports?

• Harm food supply

• Air pollution and climate change?

Case Study: Is Ethanol the Answer? (2)

• Cellulosic ethanol: alternative to corn ethanol

• Switchgrass

• Crop residues

• Municipal wastes


World Ethanol Production


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

Fig. 16-30, p. 423

Ethanol Fuel


Some reduction in CO2 emissions (sugarcane bagasse)

Low net energy yield (corn) and higher cost

Higher CO2 emissions (corn)

High net energy yield (bagasse and switchgrass)

Corn ethanol competes with food crops and may raise food prices

Potentially renewable

Trade-Offs

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 challenges

1.Need to lower costs

2.Open ponds vs. bioreactors

3.Affordable ways of extracting oil

4.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

16-7 What Are the Advantages and Disadvantages of Geothermal Energy? • Concept 16-7 Geothermal energy has great potential

for supplying many areas with heat and electricity, and it has a generally low environmental impact, but sites where it can be used economically are limited.

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

Fig. 16-31a, p. 425

Basement pump

Geothermal heating

Fig. 16-31b, p. 425

Geothermal cooling

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


Geothermal Sites Worldwide


Geothermal Power Plant in Iceland

Fig. 16-32, p. 425

Trade Offs: Geothermal Energy

Fig. 16-33, p. 426

Fig. 16-33, p. 426

Geothermal Energy


Moderate net energy and high efficiency at accessible sites

High cost and low efficiency except at concentrated and accessible sites

Lower CO2 emissions than fossil fuels Scarcity of suitable

sites

Low cost at favorable sites

Noise and some CO2 emissions

Trade-Offs

16-8 The Advantages and Disadvantages of Using Hydrogen as an Energy Source

• Concept 16-8 Hydrogen fuel holds great promise for powering cars and generating electricity, but for it to be environmentally beneficial, we would have to produce it without the use of fossil fuels.

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

Fig. 16-34a, p. 427

Electrons

Hydrogen gas (H2) in Polymer electrolyte

membrane

Anode

Cathode

Protons

Water vapor (H2O) out Air (O2) in

Trade-Offs: Hydrogen, Advantages and Disadvantages

Fig. 16-35, p. 428

Fig. 16-35, p. 428

Trade-Offs

Hydrogen


Can be produced from plentiful water at some sites

Fuel cell Negative net energy yield

CO2 emissions if produced from carbon-containing compounds

No direct CO2 emissions if produced from water

Good substitute for oil

High costs require subsidies

High efficiency (45–65%) in fuel cells

Needs H2 storage and distribution system

Science Focus: The Quest to Make Hydrogen Workable

• Bacteria and algae can produce hydrogen through biodegrading organic material

• Use electricity from renewable energy sources to produce hydrogen

• Storage options for hydrogen

16-9 How Can We Make the Transition to a More Sustainable Energy Future?

• Concept 16-9 We can make the transition to a more sustainable energy future if we greatly improve energy efficiency, use a mix of renewable energy resources, and include environmental costs in the market prices of all energy resources.

Choosing Energy Paths (1)

• How will energy policies be created?

• Hard energy path

• Soft energy path

Choosing Energy Paths (2)

• General conclusions • Gradual shift to smaller, decentralized micropower

systems

• Transition to a diverse mix of locally available renewable energy resources

• Improved energy efficiency

• Fossil fuels will still be used in large amounts • Natural gas is the best choice

Solutions: Decentralized Power System

Fig. 16-36, p. 430

Fig. 16-36, p. 430

Small solar-cell power plants Bioenergy power plants Wind farm

Fuel cells

Rooftop solar- cell arrays

Solar-cell rooftop systems

Smart electrical and distribution system

Commercial

Small wind turbine Residential

Industrial Microturbines

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. 16-36, p. 430

Solutions: Making the Transition to a More Sustainable Energy Future

Fig. 16-37, p. 431

Fig. 16-37, p. 431

Solutions

Making the Transition to a More Sustainable Energy Future

Improve Energy Efficiency More Renewable Energy Increase fuel-efficiency standards for vehicles, buildings, and appliances

Greatly increase use of renewable energy

Provide large subsidies and tax credits for use of renewable energy

Provide large tax credits or feebates for buying efficient cars, houses, and appliances

Greatly increase renewable energy research and development

Reduce Pollution and Health Risk

Reward utilities for reducing demand for electricity

Phase out coal subsidies and tax breaks

Levy taxes on coal and oil use Greatly increase energy efficiency research and development Phase out nuclear power subsidies, tax breaks,

and loan guarantees

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

Three Big Ideas

1. We should evaluate energy resources on the basis of their potential supplies, how much net useful energy they provide, and the environmental impacts of using them.

2. Using a mix of renewable energy sources—especially solar, wind, flowing water, sustainable biofuels, and geothermal energy—can drastically reduce pollution, greenhouse gas emissions, and biodiversity losses.

Three Big Ideas

3. Making the transition to a more sustainable energy future will require sharply reducing energy waste, using a mix of environmentally friendly renewable energy resources, and including the harmful environmental costs of energy resources in their market prices.

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