Chapter+17+Energy+Some+Basics.ppt

8/11/2019 Chapter+17+Energy+Some+Basics.ppt

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Energy Crisis in Ancient Greece

and Rome Greeks and Romans used wood to heat there

homes.

As local supplies ran out had to bring it in from fartheraway.

Eventually both societies learned to build housessouth facing

Allows sun to heat house in winter

Sustainable

In Rome laws pasted to protect a persons right tosolar energy.


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Energy Today and Tomorrow

Energy situation facing the US today is

similar to that faced by Greeks and Romans.

Use of wood peaked 1880s

Coal use peaked 1920

Reaching the peak of oil and gas use

The decisions we make today will affectenergy use for generations.


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Energy Basics

To understand energy it is easiest to begin

with the idea of force

We have all exerted force by pushing or pulling

The strength of force can be measured by how

much it accelerates an object

Think of pushing a car uphill


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Energy Basics

In physicists terms

Exerting force over a distance moved is work

Work is the product of a force times a distance Energy is the ability to do work

When the car id higher on the hill the potential

energy of the car has increased

Energy can be converted from one kind to another

The total energy conserved

First law of thermodynamics


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Energy Basics

To illustrate the conservation andconversion of energy think of a tire swing

At highest position all energy is stored potentialenergy

At lowest position all energy is kinetic energy

Energy of motion

With each swing friction slows the swinggenerating heat energy

Eventually all the energy converted to heat and theswing stops


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Energy Efficiency

Two fundamental types of energy

efficiencies are derived from the first and

second laws of thermodynamics:the first-law efficiency and the second-law

efficiency.

First-law efficiency deals with the amountof energy without any consideration of the

quality or availability of the energy.


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Energy Efficiency

Second-law efficiency refers to how well

matched the energy end use is with the

quality of the energy source.Low values indicate where improvements in

energy technology and planning may save

significant amounts of high-quality energy.


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Energy Efficiencies

Electricity generating plants have nearly the

same first-law and second-law efficiencies.

Generating plants are examples of heat engines.

Produces work from heat.

Most of the electricity generated in the world

today comes from heat engines Use nuclear fuel, coal, gas, or other fuels.


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Energy Source and Consumption

Industrialized countries small percentage of

the worlds population, but consume a

disproportionate share of the total energyproduced in the world.

E.g. US with only 5% of the worlds

population, uses approximately 25% of the totalenergy consumed.


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Fossil Fuels and Alternative

Energy Sources 90% of the energy consumed in the US comes

from fossil fuels

Petroleum, natural gas, and coal. They are essentially nonrenewable.

Other sources of energy

Include geothermal, nuclear, hydropower, and solar

Referred to as alternative energy sources.

Solar and wind, are not depleted by consumption and

are known as renewable energy.


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Energy Consumption in the US

Today US dependent on the three major fossil fuels

coal; natural gas; and petroleum.

From 1950 to late-1970s, energy consumptionincreased tremendously

From 30 exajoules to 80 exajoules.

Since about 1980, energy consumption has

increased by only about 20 exajoules. Suggests that policies to improve energy conservation

through efficiency improvements have been at leastpartially successful.


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Energy Consumption in the US

Today Energy losses are associated with

the production of electricity and transportation.

Most occur through the use of heat engines

Looking at the generalized energy flow of the USfor a particular year

We imported considerably more oil than we produced

Consumption distributed in three sectors:residential/commercial, industrial, and transportation.

We remain dangerously vulnerable to changingworld conditions affecting the production of oil.


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Energy Conservation, Increased

Efficiency and Cogeneration Conservation of energy

Simply getting by with less demand for energy.

Increased energy efficiency

Involves designing equipment to yield more

energy output from a given amount of input

energy (first-law efficiency)Better matches between energy source and end

use (second-law efficiency).


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Energy Conservation, Increased

Efficiency and Cogeneration Cogeneration

Processes designed to capture and use waste

heat rather than release it as a thermal pollution.Using that waste heat, can increase the overall

efficiency of a typical power plant from 33% to

as much as 75%

Could provided an estimated 10% of the power

capacity of the US


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Industrial Energy

Industrial production of goods continues to

grow significantly.

U.S. industry consumes about one-third of theenergy produced.

More industries are using co-generation and

more energy-efficient machinery.


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Automobile design

Early 1970s, the average US automobile got 14mpg.

By 1996, the average was 28 mpg for highwaydriving.

Fuel consumption rates did not improve much from1996 to 1999.

In 2004 many vehicles sold were SUVs and lighttrucks with fuel consumption of 1020 mpg.

A loophole in regulations permits poorer fuelconsumption

SUVs declined in 2006.


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Automobile design

Today, some hybrid (gasoline-electric) vehicles

exceeds 90 mpg on the highway and 60 mpg in the

city. Improvement has several causes:

Increased efficiency and resulting conservation of fuel

Cars that are smaller, w/ engines constructed of lighter

materials

Combination of a fuel-burning engine with an electric

motor


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Values, Choices, and Energy

Conservation Ways of modifying behavior to conserve energy

include the following:

Ride a bike, walk, or take a bus or train to work.

Using carpools to travel to and from work orschool

Purchasing a hybrid car (gasoline-electric)

Turning off lights when leaving roomsTaking shorter showers (conserves hot water)

Putting on a sweater and turning down thethermostat


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Values, Choices, and Energy

ConservationUsing energy-efficient compact florescent lightbulbs

Purchasing energy-efficient appliances

Sealing drafts in buildings with weather strippingand caulk

Better insulating your home

Washing clothes in cold water whenever possible

Purchasing local foods to reduce energy in transport

Using powerstrips and turning them off when not in

use


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Energy Policy

U.S. energy policy during the past half-century has not moved us closer to

energy self-sufficiency. We import more oil than ever.

In the late 1990s, the US spent $2 billion

per year on R and D for energy. By comparison, $45 billion per year went to

R and D for the military.


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Energy Policy Act of 2005

Some of the provisions are as follows.

1. Promotes conventional energy sources

2. Promotes nuclear power 3. Encourages alternative energy

4. Promotes conservation measures

5. Promotes research 6. Provides for energy infrastructure


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Hard Path vs. Soft Path

Hard path involves finding greater amounts

of fossil fuels and building larger power

plants.Continuing the past emphasis on quantity of

energy used.

Requires no new thinking; no realignment ofpolitical, economic, or social conditions; and

little anticipation of coming reductions oil.


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According to hard-path proponents, we

should

1. Let the energy industry develop the availableenergy resources

2. Let industry, free from government

regulations, provide a steady supply of energy

with less total environmental damage.


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The second road of energy policy is called

the soft path.

It involves energy alternatives thatemphasize

energy quality, are renewable, are flexible, and

are environmentally more benign than those ofthe hard path.


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These alternatives have severalcharacteristics:

They rely heavily on renewable energy resources,such as sunlight, wind, and biomass.

They are diverse and are tailored for maximumeffectiveness under specific circumstances.

They are flexible, accessible, and understandableto many people.

They are matched in energy quality, geographicdistribution, and scale to end-use needs.


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Energy for Tomorrow

Future changes in population densities aswell as intensive conservation measures will

probably change existing patterns of energyuse.

To stabilize the climate in terms of globalwarming, use of energy from fossil fuels

would need to be cut by about 50%.Reductions in energy use need not be

associated w/ lower quality of life.


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Energy for Tomorrow

What is needed is increased conservation andmore efficient use of energy:

More energy-efficient land-use planning that

maximizes the accessibility of services and minimizesthe need for transportation.

Agricultural practices and personal choices thatemphasize

1. Eating more locally grown foods 2. Eating more vegetables, beans, and grains.

Industrial guidelines for factories that promote energyconservation and minimize production of waste.


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Integrated, Sustainable Energy

Management Integrated energy management recognizes

that no single energy source can provide all

the energy required.Range of options that vary from region to

region will have to be employed.

The mix of technologies and sources of energywill involve both fossil fuels and alternative,

renewable sources.


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Management A basic goal is to move toward sustainable energy

development, implemented at the local level.

Would have the following characteristics: It would provide reliable sources of energy.

It would not cause destruction or serious harm to our

global, regional, or local environments.

It would help ensure that future generations inherit aquality environment with a fair share of the Earths

resources.


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Management A good energy plan is part of an aggressive

environmental policy with the goal of

producing a quality environment for futuregenerations.

A good plan should do the following:

Provide for sustainable energy development.Provide for aggressive energy efficiency and

conservation.


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ManagementProvide for the diversity and integration of

energy sources.

Provide for a balance between economic healthand environmental quality.

Use second-law efficiencies as an energy policy

tool.


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Management The global pattern of ever-increasing

energy consumption led by the US

cannot be sustained w/o a new energyparadigm

Includes changes in human values rather

than a breakthrough in technology. Choosing to own fuel-efficient automobiles

and living in more energy-efficient homesare consistent with a sustainable energy

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Chapter+17+Energy+Some+Basics.ppt