16 Energy Efficiency and Renewable Energy - PowerPoint Presentation

Slide1

16

Energy Efficiency and Renewable EnergySlide2

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.Slide3

Fig. 16-1a, p. 402

Gearbox

Electrical generator

Power cable

Wind turbineSlide4

Fig. 16-1b, p. 402Slide5

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?Slide6

Energy efficiency A measure of how much useful work we get from each unit energy we use.

Advantages of reducing energy waste

Usually the cheapest way to provide more energyReduces pollution and degradationSlows global warming

Increases economic and national security

We Use Energy InefficientlySlide7

Four widely used devices that waste energyIncandescent light bulb

Motor vehicle with internal combustion engine

Nuclear power plantCoal-fired power plant

We Use Energy Inefficiently (cont’d.)Slide8

Fig. 16-2, p. 403

Energy Inputs

System

Outputs

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 nuclearSlide9

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 jobsSlide10

Cogeneration

Involves using combined heat and power (CHP) system

Two forms of energy from same fuel source; 75%-90% efficiency. Replace energy-wasting electric motorsRecycle materialsSwitch from low-efficiency incandescent lighting to higher-efficiency fluorescent and LED lighting

We Can Improve Energy Efficiency in Industry and UtilitiesSlide11

Current electrical grid system – outdated and wastefulSmart grid

Ultra-high-voltage

Super-efficient transmission linesDigitally controlledResponds to local changes in demand and supplyEasier to buy renewable energy

Case Study: Saving Energy and Money with a Smarter Electrical GridSlide12

Hidden prices in gasolineShould be $12/gallon

Car manufacturers and oil companies lobby to prevent laws to raise fuel taxes

Build or expand mass transit and high speed railEncourage biking

We Can Improve Energy Efficiency and Save Money in TransportationSlide13

Superefficient and ultralight carsGasoline-electric hybrid car

Plug-in hybrid electric vehicle

Energy-efficient diesel carElectric vehicle with a fuel cell

More Energy-Efficient Vehicles Are on the WaySlide14

Stepped Art

Conventional hybrid

Fuel tank

Battery

Internal combustion engine

Transmission

Electric motor

Plug-in hybrid

Fuel tank

Battery

Internal combustion engine

Transmission

Electric motor

Fig 16-6, p. 406Slide15

Green architectureLiving or green roofs

With specially designed soil and vegetation

SuperinsulationNo need for heating systemU.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED)

We Can Design Buildings That Save Energy and MoneySlide16

Fig. 16-7, p. 408Slide17

Conduct an energy audit:Insulate and plug leaks

Use energy-efficient windows

Stop other heating and cooling lossesHeat houses more efficientlyUse energy-efficient appliancesUse energy-efficient lighting

Use motion sensors to turn lights on and off

We Can Save Money and Energy in Existing BuildingsSlide18

Fig. 16-9, p. 410Slide19

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. 411Slide20

1.Energy remains artificially cheapGovernment subsidies

Tax breaks

Prices don’t include true cost2.Few large and long-lasting incentivesGovernment rebatesLow-interest loans

3.Lack of education

Why Are We Still Wasting So Much Energy and Money?Slide21

Renewable energySolar energy

Geothermal energy

Renewable energy will be cheaper if we eliminate:Inequitable subsidiesInaccurate pricesArtificially low pricing of nonrenewable energy

We Can Use Renewable Energy to Provide Heat and ElectricitySlide22

Fig. 16-11, p. 412

Available Energy Flow (

exajoules

per year)

World energy use (2010)

Direct solar

Wind

Geothermal

Biomass

Hydropower

Ocean

<1

500

600

527

>1,000

50

<250 Slide23

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

16-2 What Are the Advantages and Disadvantages of Solar Energy?Slide24

Passive solar heating systemAbsorbs and stores heat from the sun directly within a well-insulated structure

Active solar heating system

Captures energy from the sun by pumping a heat-absorbing fluid through special collectors, usually mounted on a roof or on special racks to face the sun.

We Can Heat Buildings and Water with Solar EnergySlide25

Fig. 16-14, p. 415

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 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 daysSlide26

Technologies availableOpen windows when cooler outside

Use fans

Superinsulation and high-efficiency windowsOverhangs or awnings on windowsLight-colored roofGeothermal pumps

We Can Cool Buildings NaturallySlide27

Solar thermal systems (CSP)Collect sunlight to boil water and produce steam to generate electricity

1% of world deserts could supply all the world’s electricity

Require large amounts of waterWet coolingDry cooling

Low net energy yields

We Can Concentrate Sunlight to Produce High-Temperature Heat and ElectricitySlide28

Fig. 16-15, p. 416Slide29

Fig. 16-16, p. 416

Solar Thermal Systems

High potential for growth

Low net energy and high costs

Advantages

Disadvantages

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 Slide30

Photovoltaic (PV) cells, aka solar cells Convert solar energy to electric energy

Design of solar cells

Thin wafers of purified silicon (Si) or polycrystalline silicon with trace amounts of metals that allow them to conduct electricity.Sunlight hits cells and releases electrons into wires, producing electrical power

We Can Use Solar Cells to Produce ElectricitySlide31

Key problemsHigh cost of producing electricity

Need to be located in sunny desert areas

Fossil fuels used in productionSolar cells contain toxic materialsCost could drop with:Mass production and new designs

Government subsidies and tax breaks

We Can Use Solar Cells to Produce Electricity (cont’d.)Slide32

Fig. 16-18, p. 418Slide33

Fig. 16-19, p. 418Slide34

Fig. 16-21, p. 419

Solar Cells

Advantages

Disadvantages

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 Slide35

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 Slide36

Hydropower

Uses kinetic energy of moving

water to produce electricity.Indirect form of solar energy; depends on heat from the sun evaporating water, which is deposited as rain or snow at higher elevations where it can flow to lower elevations in rivers

World’s leading renewable energy source used to produce

electricity

We Can Produce Electricity from Falling and Flowing Water Slide37

Fig. 16-22, p. 420

Large-Scale Hydropower

Advantages

Disadvantages

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 potentialSlide38

Produce electricity from flowing waterOcean tides and waves in coastal bays and estuaries

Power systems are limited

Few suitable sitesCitizen opposition High costs

Equipment damaged by storms and

saltwater corrosion

We Can Use Tides and Waves to Produce ElectricitySlide39

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?Slide40

Tall, long-blade turbines can extract more energy from the wind with less ecological footprint.

Rapidly growing power source

U.S., Europe, and ChinaFuture is offshore wind farmsWind power has potential to produce 40 times of the world’s current electricity used

Using Wind to Produce Electricity Is an Important Step toward SustainabilitySlide41

Wind is abundant, widely distributed, and inexhaustibleHigh net energy yield

Drawbacks:

Largest potential areas are usually ruralWinds can die down – need backup power source

Using Wind to Produce Electricity Is an Important Step (cont’d.)Slide42

Fig. 16-25, p. 423

Trade-Offs

Wind Power

Advantages

Disadvantages

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 pollutantsSlide43

Biomass

Consists of p

lant materials and animal waste we can burn or turn into biofuelsWood, wood wastes, charcoal made from wood, are burned mostly for heating and cooking

Production of solid mass fuel

Plant fast-growing

trees in biomass plantations

Collect crop residues and animal manureWe Can Produce Energy by Burning Solid BiomassSlide44

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

Biomass

as an Energy SourceSlide45

Fig. 16-26, p. 424

Solid Biomass

Advantages

Disadvantages

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 costsSlide46

We can use liquid biofuels, ethanol and biodiesel,

derived from biomass to lessen our dependence on oil-based fuels, but creating biofuel plantations can:Degrade soil and biodiversityIncrease greenhouse gas emissions

Lead to higher food prices

Biomass

as an Energy Source (cont’d.)Slide47

Ethanol

Can be made from sugarcane, corn, switchgrass, and various wastes

United States largest producerMade from corn; low net energy yieldBrazil secondSugarcane has medium net energy yield

Cellulosic

ethanol

Possible alternative to corn-based ethanolProduced from

cellulose needs more research!Case Study: Is Ethanol the Answer?Slide48

Problems with cellulosic ethanolChemical processes still being developed

Growing enough switchgrass would require too much land

Evaluating use of algae and bacteriaCase Study: Is Ethanol the Answer? (cont’d.)Slide49

BiodieselProduced from vegetable oil

European Union countries produce 95% of the world’s biodiesel

Crops require large amounts of landProduction requires fossil fuels

Case Study: Is Biodiesel the Answer?Slide50

Fig. 16-28, p. 426

Liquid Biofuels

Advantages

Disadvantages

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-OffsSlide51

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?Slide52

With geothermal energy, heat is stored in:Soil

Underground rocks

Fluids in the earth’s mantleGeothermal heat pump systemEnergy efficient and reliableEnvironmentally clean

Cost effective to heat or cool a space

We Can Get Energy by Tapping the Earth’s

Internal HeatSlide53

Hydrothermal reservoirs Drill wells and extract various

steams and water

U.S. is the world’s largest producerGeothermal energy problemsHigh cost of tapping hydrothermal reservoirsDry- or wet-steam geothermal reservoirs could be depleted

Could create earthquakes

We Can Get Energy by Tapping the Earth’s

Internal Heat (cont’d.)Slide54

Fig. 16-30a, 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 Slide55

Fig. 16-30b, p. 428Slide56

Fig. 16-31, p. 430

Geothermal Energy

Advantages

Disadvantages

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-OffsSlide57

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 SourceSlide58

Hydrogen as a fuelEliminates most of the air pollution problems

Reduces threats of global

warmingH2 is said to be a fuel of the future and Fuel cells that combine H

2

and O

2 to produce electricity and water vapor

Will Hydrogen Save Us?Slide59

Some challenges1. Chemically

locked in water and organic compounds –

has a net negative energy yield2. Expensive fuel cells are the best way to use hydrogen

3. CO

2

levels dependent on method of hydrogen production

Will Hydrogen Save Us?Slide60

Fig. 16-32, p. 430

Electrons

Hydrogen gas (H

2

) in

Polymer electrolyte membrane

Anode

Cathode

Protons

Water

vapor (H

2

O) out

Air (O

2

) inSlide61

Fig. 16-33, p. 432

Trade-Offs

Hydrogen

Advantages

Disadvantages

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 systemSlide62

We can make the transition to a more sustainable energy future by:

Greatly improving energy efficiency

Using a mix of renewable energy resourcesIncluding the environmental and health costs of energy resources in their market prices

16-8

How Can We Make the Transition to a More Sustainable Energy Future?Slide63

General conclusions:1. We will gradually

shift to smaller, decentralized

micropower systems.2. Combination of increased energy efficiency and regulated use of natural gas will be the best way to transition to renewable

energy.

3. Because

fossil fuels are abundant and artificially

cheap we will continue to use them in large quantities. Choosing Energy PathsSlide64

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-

34,

p.

433

© Cengage Learning 2015Slide65

Government strategies:1. Keep

the prices of selected energy resources artificially low

via subsidies to encourage their use1. Keep energy prices artificially high for selected resources

by removing subsidies to

discourage their use

3. Consumer education

Economics, Politics, Education, and Sustainable Energy ResourcesSlide66

Fig. 16-35, p. 434Slide67

We should evaluate energy resources on the basis of:Their potential supplies

Their net energy yields

Environmental and health impacts of using themThree Big IdeasSlide68

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.)Slide69

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.)Slide70

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