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8.21 The Physics of Energy Fall 2009

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The Energy Problem Course Mechanics Physics of Energy

8.21 Lecture 1

The Physics of Energy:

Introduction to Course

September 9, 2009

8.21 Lecture 1: Course Introduction 1 / 11

1. The Energy Problem

The Energy Problem Course Mechanics Physics of Energy

Energy issues seem to be everywhere

Economics Volatile oil prices Corn-based ethanol & rising food prices Cape wind & property values

Politics Iraq and Middle East politics Russian Gazprom cuts natural gas to Ukraine Offshore drilling

Environment

Global warming from CO2 →Pressure on many ecosystems, species →Sea level rise →Floods, hurricanes, drought

Mercury from coal plants

8.21 Lecture 1: Course Introduction 2 / 11

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1965 1970 1975 1980 1985 1990 1995 2000 2005

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The Energy Problem Course Mechanics Physics of Energy

We use more and more energy

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1965 1970 1975 1980 1985 1990 1995 2000 2005

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1965 1970 1975 1980 1985 1990 1995 2000 2005

Wor

ld e

nerg

y us

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Global energy use [data from BP]

But resources are limited World Population

[Data from U.S. Census bureau]

8.21 Lecture 1: Course Introduction 3 / 11

The Energy Problem Course Mechanics Physics of Energy

[image: EIA]

Energy flow from sources to uses is COMPLEX

8.21 Lecture 1: Course Introduction 4 / 11

The Energy Problem Course Mechanics Physics of Energy

In this class, we’ll use physics to understand Energy:

∼28% transport (mechanics)

∼40% heating/AC (thermodynamics) ∼3% lighting (EM)

Transport28 EJ (27.28%)Residential

21 EJ (20.87%)

Commercial18 EJ (17.79%)

Industry35 EJ (34.06%)

2001 U.S. Energy Use By SectorTotal 102 EJ

[data: EIA]

U.S. energy use

Physical requirements: ?How much energy do we need to use?

Physical limitations: ?How much energy is available for use?

?How efficiently can we use energy?

Physical consequences: ?Can we limit side effects?

8.21 Lecture 1: Course Introduction 5 / 11

The Energy ProblemCourse MechanicsPhysics of Energy

Energy Sources

Currently about 85% of U.S. energy from fossil fuels

Coal (23%) Petroleum (40%)

Many issues:

Political: Foreign sourcesEconomic: Increased global demand, limited resourceEnvironmental: CO2� warming, NOx � smog

11/6noitcudortnIesruoC:1erutceL12.8

Photo courtesy of Rennett Stowe on Flickr. Photo courtesy of craig1black on Flickr.

The Energy Problem Course Mechanics Physics of Energy

Alternative Energy Sources

Solar solar thermal

[thermo]

PV [quantum]

Ultimate source of most E Vast potential Issues: efficiency, scaling, distribution

Nuclear fission, fusion

[quantum]

Vast potential Issues: safety, waste, security, technology

Other renewables

wind, waves, hydro, tides, [fluid mech]

ocean, geothermal [thermo]

Clean energy sources Substantial potential in wind, geothermal; others more limited Study physics of each

8.21 Lecture 1: Course Introduction 7 / 11

The Energy Problem Course Mechanics Physics of Energy

Some course objectives

Overview of natural and human earth energy systems

–Underlying physical processes –Order of magnitude quantities + efficiencies –Example: energy flow from sun → this slide → space

New physics relevant for energy

–Thermodynamics –Quantum mechanics –Fluid mechanics

Abstract theoretical principles → concrete energy applications

–Principles → order of magnitude estimates –Learn to estimate or look up details

8.21 Lecture 1: Course Introduction 9 / 11

The Energy Problem Course Mechanics Physics of Energy

8.21: Not just a class It’s an Adventure!

We are teachingthis course

for the second time,learning as we go

You are invited toparticipate

in optimizing the course.We want your Feedback!

Ask questions!

We will cover more material

than you can absorb Focus on core, rest is optional.

Give us comments!What works,what doesn’t?

Find errors in notes, andother material

–There will be prizes!–

8.21 Lecture 1: Course Introduction 10 / 11

3. Physics of Energy

The Energy Problem Course Mechanics Physics of Energy

Now over to BOB

8.21 Lecture 1: Course Introduction 11 / 11

8.21 Lecture 1: Course Introduction

The Energy Problem Course Mechanics

The Physics of Energy

The Big Picture •� Uses � � � � (12 lectures)

•� Sources � � � � (19 lectures)

•� Environmental physics and systems (7 lectures)

Review of GIR level physics

Novel: stat. mech, quantum, fluid dynamics

Physics/energy systems

8.21 Lecture 1: Course Introduction

The Energy Problem Course Mechanics

The Physics of Energy

What’s the physics? •� Mechanics •� Electricity and magnetism •� Heat •� Energy in chemical processes

•� Statistical physics � Thermodynamics, entropy, efficiency, cycles, phase

changes, thermal radiation

•� Quantum physics � States, probabilities, wave functions, eigenenergies

and eigenstates, tunneling, radiation

•� Fundamental physics � Particles and forces, the Standard Model, origins

and flow of energy in the Universe

8.21 Lecture 1: Course Introduction

The Energy Problem Course Mechanics

The Physics of Energy

•� Nuclear fission reactor design, dynamics, stability, and safety •� Solar voltaic energy flow, thermodynamics, and efficiency •� Wind power potential, aerodynamics, design •� Atmospheric energy flow and climate change •� Environmental radiation •� Energy storage •� Conservation

Ambitious!!

•� Nuclear physics � Nuclear structure, nuclear binding, stability and decays,

radiation

•� Condensed matter physics � Electrons in matter, bands and gaps, semiconductors,

radiation absorption

•� Fluid dynamics � Fluid flow, pressure, viscosity, Bernoulli’s law, drag, lift

8.21 Lecture 1: Course Introduction

The Energy ProblemCourse Mechanics

The Physics of Energy

Fissionableisotopes

Nuclearfission power

Fusionfuels

Fusionpower

Radioactiveisotopes

Nucleosynthesis

Matter collapsingunder gravity

Nuclear fusionin stars

GRAVITYE LECTROMAGNETISMSTRONG I NTERACTIONSWEAK I NTERACTIONS

SOLAR FUSION CYCLENUCLEAR STABILITYNUCLEAR DECAYSQUANTUM TUNNELING

Fossilfuels Solar thermal

energy

Solar voltaicenergy

Hydropower Wind

Sunlight

SEMICONDUCTORPHYSICS

FLUIDDYNAMICS

Geothermalenergy

Tidalenergy

Fissionableisotopes

Nuclearfission power

Fusionfuels

Fusionpower

Radioactiveisotopes

Nucleosynthesis

Fossilfuels Solar thermal

energy

Solar voltaicenergy

Hydropower Wind

SunlightTHERMALRADIATION

8.21 Lecture 1: Course Introduction

The Energy Problem Course Mechanics

The Physics of Energy

• Why is coastal Massachusetts prime wind power real estate.

Wind power class 6 near population centers is a winning combination.

http://rredc.nrel.gov/wind/pubs/atlas/

0.5 1.0 1.5 2.0

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1.4 k = 1.3, λ = 1

k = 1.9, λ = 1

k = 2.5, λ = 1

k = 3.1, λ = 1

k = 3.7, λ = 1

v

f(v, k, λ)

2 4 6 8 10

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k = 1.8, λ = 1

k = 1.8, λ = 2

k = 1.8, λ = 3

k = 1.8, λ = 4

k = 1.8, λ = 5

v

f(v, k, λ)

To whet your appetite

• Why a rare isotope of lithium is a key player in the future of nuclear fusion power.

It’s the fundamental fuel because tritium is made from it.

d + t → 4He + n n + 6Li → 4He + t

And tritium is the fuel for fusion energy for the foreseeable future.

8.21 Lecture 1: Course Introduction

The Energy Problem Course Mechanics

The Physics of Energy

To whet your appetite (II)

• Why is geothermal energy a form of nuclear energy? What does it have to do with refrigeration?

• Is the role of hydrogen more similar to ??

• methane?

• a flywheel?

• Answer: a flywheel! Methane (Natural gas) is a naturally occurring energy source that can be used as a fuel. Hydrogen would also be fuel if it occurred as molecular hydrogen (H2) in nature. Instead it is always found tightly bound to other elements. It always takes more energy to liberate they hydrogen than it will generate when it is used (2nd law of thermodynamics), so hydrogen is an energy storage device like a flywheel (and not, at present, a very efficient one).

• Because the ultimate heat source is radioactive decay of potassium, thorium and uranium in the earth’s interior.

• Perhaps the most promising exploitation of geothermal energy is through the use of heat pumps, which are basically refrigerators run backwards.

8.21 Lecture 1: Course Introduction

The Energy Problem Course Mechanics

The Physics of Energy

To whet your appetite (III)

• What is a fission poison and why is it important for power grid operation?

• What is the difference between solar thermal energy and solar voltaic energy, and what are the roles of each in our energy future?

• It is a fission product that continues to be created after a reactor is turned off. A fission poison absorbs neutrons and prevents the reactor being restarted for several days.

• The differences are huge:

– Solar Thermal: thermal fluid power technology resembling fossil fuel and nuclear plants, relatively mature technology, few exotic materials, promising storage options, significant economies of scale suggest commodity applications.

– Solar Voltaic: solid state electrodynamics unlike other energy sources, rapidly developing technology, rare and exotic materials, storage issues, relatively efficient at small scales suggesting end user implementation.

I wish I knew!

8.21 Lecture 1: Course Introduction

The Energy Problem Course Mechanics

The Physics of Energy

What we do not cover in 8.21

• A lot!

• All of the crucial economic, political, and policy issues.

• Chemistry and biology of energy

– Coal! Carbon capture and sequestration, coal gasification.

– Biofuels. . . cellulosic ethanol, advanced biofuels

– “Artificial” photosynthesis

– Fuel cells

• And, of course, everything at an advanced level!