Energy Efficiency and Renewable Energy

Energy Efficiency and Renewable Energy

Chapter 16

G. Tyler Miller’sLiving in the Environment

13th Edition

Chapter 16

G. Tyler Miller’sLiving in the Environment

13th Edition

Key ConceptsKey Concepts

• Improving energy efficiencyImproving energy efficiency

• Solar energySolar energy

• Hydropower (flowing water)Hydropower (flowing water)

• WindWind

• BiomassBiomass

• Hydrogen fuelHydrogen fuel

• GeothermalGeothermal

• Decentralized power systemsDecentralized power systems

Doing more with lessDoing more with lessDoing more with lessDoing more with less

• Energy efficiencyEnergy efficiency– is the percentage of total energy is the percentage of total energy

input into an energy conversion input into an energy conversion device or system thatdevice or system that1)1) does useful work and does useful work and

2)2) is not converted to low-quality is not converted to low-quality heat.heat.

The Importance of Improving Energy EfficiencyThe Importance of Improving Energy Efficiency

• 84% of all 84% of all commercial commercial energy produced energy produced in the U.S. is in the U.S. is wastedwasted!!

Fig. 16-2 p. 381Fig. 16-2 p. 381

The Importance of Improving Energy EfficiencyThe Importance of Improving Energy Efficiency

• Lower life cycle costLower life cycle cost– Initial cost plus lifetime operating costInitial cost plus lifetime operating cost

• Net energy efficiencyNet energy efficiency– Total amount of useful energy available minus the Total amount of useful energy available minus the

amount of energyamount of energy• used (First Law of Thermodynamics)used (First Law of Thermodynamics)• automatically wasted (Second Law of Thermodynamics)automatically wasted (Second Law of Thermodynamics)• unnecessarily wasted.unnecessarily wasted.

Least Efficient• Incandescent light bulb (5%)Incandescent light bulb (5%)• Internal combustion engine (10-15%)Internal combustion engine (10-15%)• Nuclear power plants (8-14%)Nuclear power plants (8-14%)

REDUCING ENERGY WASTE AND IMPROVING ENERGY EFFICIENCYREDUCING ENERGY WASTE AND IMPROVING ENERGY EFFICIENCY

• Four widely used devices waste large amounts of energy:– Incandescent light bulb: 95% is lost as heat.– Internal combustion engine: 94% of the energy in

its fuel is wasted.– Nuclear power plant: 92% of energy is wasted

through nuclear fuel and energy needed for waste management.

– Coal-burning power plant: 66% of the energy released by burning coal is lost.

Efficiencies (fig. 16-4 p. 382)Efficiencies (fig. 16-4 p. 382)

Uranium100%

Electricity from Nuclear Power Plant

14%

Resistanceheating(100%)

90%

Wasteheat

Passive Solar

Sunlight100%

Wasteheat

14%

Transmissionof electricity

(85%)

17%

Wasteheat

Power plant(31%)

54%

Wasteheat

Uranium processingand transportation

(57%)

95%

Wasteheat

Uraniummining(95%)

Energy

Efficiency

Could we save energy by recycling energy?Could we save energy by recycling energy?

• NoNo• Second Law of ThermodynamicsSecond Law of Thermodynamics

Ways to Improve Energy EfficiencyWays to Improve Energy Efficiency

In Our HomesIn Our Homes InsulationInsulation Eliminate air leaksEliminate air leaks Air-to-air heat exchangersAir-to-air heat exchangers

IndustryIndustry CogenerationCogeneration

– Two useful sources of energy are produced from the same fuel Two useful sources of energy are produced from the same fuel sourcesource

Efficient electric motorsEfficient electric motors High efficiency lightingHigh efficiency lighting Increased fuel economyIncreased fuel economy

Saving Energy in Existing BuildingsSaving Energy in Existing Buildings

• About one-third of the heated air in typical U.S. homes and buildings escapes through closed windows and holes and cracks.

Figure 17-11Figure 17-11

WAYS TO IMPROVE ENERGY EFFICIENCYWAYS TO IMPROVE ENERGY EFFICIENCY

• Average fuel economy of new vehicles sold in the U.S. between 1975-2006.

• The government Corporate Average Fuel Economy (CAFE) has not increased after 1985.

Figure 17-5Figure 17-5

Increased Fuel EconomyIncreased Fuel EconomyIncreased Fuel EconomyIncreased Fuel Economy

Rechargeable battery systems Rechargeable battery systems Hybrid electric-internal combustion engine Hybrid electric-internal combustion engine Fuel cells Fuel cells

ElectricityFuel

Combustion engineCombustion engineAA

Fuel tankFuel tankBB

Electric motorElectric motorCC

Battery bankBattery bankDD

RegulatorRegulatorEE

TransmissionTransmissionFF

A

B

C

D

EF

Hybrid Car Hybrid Car (Electric – Internal (Electric – Internal

Combustion Engine)Combustion Engine)

A

C

E

D

B

ElectricityFuel

AA Fuel cell stackFuel cell stack

BB Fuel tankFuel tank

CC Turbo compressorTurbo compressor

DD Traction inverterTraction inverter

EE Electric motor /Electric motor /transaxletransaxle

Fuel Cell CarsFuel Cell Cars

1

2

3

4

1

2

3

4

H2

O2

H2O

Hydrogen gasHydrogen gas

Emits water Emits water (H(H22O) vapor.O) vapor.

Produce electrical Produce electrical energy (flow of energy (flow of electrons) to power car.electrons) to power car.

React with oxygen (OReact with oxygen (O22).).

Cell splits HCell splits H22 into protons into protons

and electrons. Protons flowand electrons. Protons flowacross catalyst membrane.across catalyst membrane.

The Solar-Hydrogen RevolutionThe Solar-Hydrogen Revolution

Extracting hydrogen efficientlyExtracting hydrogen efficientlyStoring hydrogenStoring hydrogenFuel cellsFuel cells

Fuel CellsFuel CellsFuel CellsFuel Cells

AdvantagesAdvantages• Energy efficiencies of 65-90%Energy efficiencies of 65-90%• No moving partsNo moving parts• QuietQuiet• Emit only water and heatEmit only water and heat• More reliableMore reliable

DisadvantageDisadvantage• CostCost

Using Solar Energy to Provide Heat and ElectricityUsing Solar Energy to Provide Heat and Electricity

Passive solar heating

Passive solar heating

Active solar heating

Active solar heating

Using Solar Energy to Provide High-Temperature Heat and Electricity

Using Solar Energy to Provide High-Temperature Heat and Electricity

Solar thermal systemsSolar thermal systems

Using Solar Energy to Provide High-Temperature Heat and Electricity

Using Solar Energy to Provide High-Temperature Heat and Electricity

Photovoltaic (PV) cellsPhotovoltaic (PV) cells

Using Solar Energy to Provide High-Temperature Heat and Electricity

Using Solar Energy to Provide High-Temperature Heat and Electricity

Producing Electricity from Moving WaterProducing Electricity from Moving Water

Large-scale hydropower

Small-scale hydropower

Pumped-storage hydropower

Large-scale hydropower

Small-scale hydropower

Pumped-storage hydropower

Producing Electricity from Moving WaterProducing Electricity from Moving Water

Tidal power plant

Wave power

Tidal power plant

Wave power

Producing Electricity from Heat Stored in WaterProducing Electricity from Heat Stored in Water

Ocean thermal energy conversion (OTEC) Ocean thermal energy conversion (OTEC)

Saline solar ponds Saline solar ponds

Freshwater solar ponds Freshwater solar ponds

Producing Electricity from WindProducing Electricity from WindFig. 16-28 p. 402Fig. 16-28 p. 402 Fig. 16-29 p. 402Fig. 16-29 p. 402

Producing Energy from BiomassProducing Energy from Biomass

BiofuelsBiomass plantationsCrop residuesAnimal manureBiogasEthanolMethanol

BiofuelsBiomass plantationsCrop residuesAnimal manureBiogasEthanolMethanol

Geothermal EnergyGeothermal Energy

Geothermal reservoirsGeothermal reservoirs

Dry steamDry steam

Wet steamWet steam

Hot waterHot water

Molten rockMolten rock

Hot dry-rock zonesHot dry-rock zones

Fig. 16-36p. 409

Fig. 16-36p. 409

Geothermal ReservoirsGeothermal Reservoirs

Fig. 16-37 p. 410

Entering the Age of Decentralized MicropowerEntering the Age of Decentralized Micropower

Current Centralized power systems Current Centralized power systems

Future Decentralized power systems Future Decentralized power systems

Micropower systems Micropower systems

Fig. 16-39p. 411

Fig. 16-40 p. 411Fig. 16-40 p. 411

Solutions:A Sustainable Energy StrategySolutions:A Sustainable Energy Strategy