8.21 the Physics of Energy Fall 2009

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8.21 The Physics of Energy Fall 2009

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The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

8.21 Lecture 2

Units and the Scales of Energy Use

September 11, 2009

8.21 Lecture 2: Units and the scales of energy use 1 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation Outline

• The basics: SI units

• The principal players: ener , powergy , force, pressure

• The many forms of energy

• A tour of the energy landscape: From the macroworld to our world

• CO2 and other greenhouse gases: measurements, units, energy connection

• Perspectives on energy issues --- common sense and conversion factors

8.21 Lecture 2: Units and the scales of energy use 2 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation SI ≡ International System MKSA = M ,eter Kilogram, Second, A sUnitmpere

orcgsNot “English” units!

Electromagnetic units evDeri d itsnu ⇒ geChar ⇒ Coulombs gyEner esoulJ ⇒ Current ⇒ Amperes werPo ttsaW ⇒ Electrostatic potential ⇒ oltsV erssuePr calssaP ⇒ Resistance ⇒ Ohms ecrFo snwtoNe

tsiunlermahT More about these next... Temperature ⇒ (elvinK K)

8.21 Lecture 2: Units and the scales of energy use 3 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation Outline

• The principal players: ener , powergy , force, pressure

8.21 Lecture 2: Units and the scales of energy use 4 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation eessurPrandweroP,gyEnerce,orF

X”ofunits“Themeans]X[ physicalyanofunitsthegetcaneW ⇔ ⇔ Basics: m kilograms, l meters ordeﬁnitionausingbyquantity t ⇔ seconds and, Q ⇔ coulombs toitrelatesthatwlaphysical something ...wknoalreadywe =]speed[xample:eorF tl/ = meters/second

• wlasecondswton’Ne orceF mass= × acceleration =]eforc[ [mass][acceleration] = t/ml 2 = kilogram meter/second2 = m/skg 2 s/gm1k 2 =1 wtonNe you:onvitygraofforceThe

2 F yvitgra = mg g0k=8 × m/s9.8 wtonsNe784=

• 1 × gyenerKinetic gyEner = 2 mass velocity-squared [mass][v=]ygener[ elocity2]=ml2/t2 = kilogram meter2/second2 = kg-m2/s2 gm1k 2/s2 =1Joule eN1= wton-meter hour:permiles3atalkingwgyenerkineticourY = 1 2 1 3 miles × 1609 meters × 1 hours 2 Ekinetic 2 mv = 2 kg80 hour mile 3600 second Joules27=

8.21 Lecture 2: Units and the scales of energy use 5 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

• werPo werPo timeunitpergyener= /dtdE [ener=]werop[ gy][time−1]= ml2/t2 (1/t) = kilogram meter2/second3 = kg-m2/s3 gm1k 2/s3 =1 attW 1= Joule/second

climbingertxeyouwerPo secondpermeters0.5atstairs

ΔE = mgΔh 0=8 kg × .5 m × 9.8 m/s2 390= Joules

P bingclim =ΔE/Δt 8=7 Joules /1 second 390= attsW

• Pressure Pressure areaunitperforce= /dAdF =]epressur[ [force][area−1]= /tml 2 1/l2 = kilogram/meter second2 = mkg −1s−2 gm1k −1s−2 wton/metereN1=ascalP1= 2

ground:theonstandingou,Y orceF 784 wtonsNe 784 p yvitgra = = = =∼ 34, 000 ascalsP Area ∼ 36 in2 0.023

8.21 Lecture 2: Units and the scales of energy use 6 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation Outline

• The many forms of energy

8.21 Lecture 2: Units and the scales of energy use 7 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

gyEneroformsF

• conservgyenerrevdiscototimelongA ation. • gyEner disappears? No! Changing form... kinetic to potential to chemical to thermal to gyenerrestsEinstein’ ...

• isitactfIn conserv gyenerofation singlea, number characterizing a tracedbecanthatsystem,aofparteachenveorsystem through andtime andwsﬂoitas changes, sogyeneresmakthat physics.inimportant • Units: massofunitssametheevhamustformsferentdiftheseAll × length 22 )time/ • comeotswhat’seeand8.02&8.01littleawvieRe

8.21 Lecture 2: Units and the scales of energy use 8 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

1 2 × 2 KINETIC ENERGY 2 mv mass [speed] l 2 l2 [mass] × [speed]2 = m × = m t t2

manigyEner f tioominest n

W PONDAORK TENTIAL ENERGY Fd force × distance

ml l2 [force] × [distance]= × l = m t2 t2 aneWh f arevoobjectnanoactsorce d itecistan does krwo asupwohscanthat gyenercinetki oredtsbeor as ygnerelaientpot

8.21 Lecture 2: Units and the scales of energy use 9 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

× = orcef × W PYBORK RESSURE PV pressure olumev area olumev

m l2 [pressure] × [ olumev ]= × l3 = m lt2 t2

1 ≡ 1 THERMAL ENERGY 2 TNR 2 nkBT T Thermal atfreedomofgreedepergyener temperature . iternatAl vely,

† • n • N molesofnumber— — ofnumber molecules • k 1.381 × 10−23 −1 • R constantgasthe— R =8.31447 Joules B — Boltzmann’ Constants JK Kmole • T • T — temperature elvinsKin — temperature elvinsKin Joules l2 [ TNR ]=moles × × K = m † Kmole t2 thethatNote mole departs from aisItunits:MKS gram molecular K oygereneticin af omethll lecul tisemakes s theweight, molecular aofweight appearance heatas grams.inxpressedecompound

8.21 Lecture 2: Units and the scales of energy use 10 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases

conversion The many forms of energy Common sense and computation

HERMAL NERGY TNR ≡ nkBT ) T E

enient,vCon colloquial ofunit gy:ener BTUthe

ofpound1heattogyener=BTU1 ◦ ◦ H2 60fromO 61to F )

ELECTRICAL ENERGY Q × V Q + ++++++++++++++++++++++++++++++ • Q — CHARGE V • V — ELECTR POTICAOST TENTIAL – – – – – – – – – – – – – – – – – – – – – – – – – laipotentciectrostatEl ⇒ ldeﬁciectrEl ⇒ orceF .devmoisthatgecharaonorkwdoesforcetheand measureotwHo electrostatic Units?SIinpotential

What oneevmotoevhayoudopotential ofJoule1lose)(orgettothroughgecharofCoulomb gy:ener 1 Joule 1 Joule/sec 1 attW 1 oltV = = = 1 Coulomb 1 Coulomb/sec 1 Ampere

8.21 Lecture 2: Units and the scales of energy use 11 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation T FSAEBTNOYAMTHATYGNEREFOSMROFOW AMILIAR... Q NTUMAU ENERGY E = hν h =6.626 × 10−34 Js • h constantsPlanck’is • ν light.foyfrequenctheis • ofgyEner one lightofquantum (photon). [=gy][ener h] × y][frequenc 2 1 ml =[h] × t2 t [h gy][ener=] × =[time] Js

E NTEISNI ’ YGRENETSESR : E = mc2

ers’teinsEin l ewoshityvati d itsessamatth aislf f oorm f ..actorfionrsevonctheaslightofpeedsthewithgyener . E = mc2 ml2 [E []= mc2]= t2

8.21 Lecture 2: Units and the scales of energy use 12 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation Outline

• rT anslations and scales: units and energy subcultures

8.21 Lecture 2: Units and the scales of energy use 13 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

otheronsThere’ quantity moreindescribedisthat Units of Energy and Power .gyenerthanunitsferentdif 1 electron volt (eV) 1.602 x 10-19 J 1 eV per molecule 96.49 kJ mol-1 • xajoulese , quads, teraWatt-years ALGLOB UNITS 1 erg 10-7 J 1 foot pound 1.356 J

• coaloftonnes , TNToftons , oilofbarrels , 1 calorieIT* (calIT) 4.1868 J therms, hoursattkiloW INDUSTRIAL STRENGTH UNITS 1 calorieth* (calth) 4.184 J 1 BTUIT* 1.055 kJ • BTU, kilocalories HUMAN IZEDS UNITS 1 kilocalorieIT* (kcal) 4.1868 kJ or CalorieIT* (Cal) • calories, foot-pounds, Joules CHILD SIZED UNITS 1 kilowatt-hour (kWh) 3.6 MJ 1 cubic meter natural gas 36 MJ • gser , electron-Volts ORLDWOMICR UNITS 1 therm (U.S.) 105.5 MJ 1 tonne TNT (tTNT) 4.184 GJ 1 barrel of oil equivalent 5.8x106 BTU 6.118 GJ 1 ton of coal equivalent 7 Gcal 29.3076 GJ • E RGYNE U SNIT IT 1 ton of oil equivalent 10 GcalIT 41.868 GJ 15 • P REOW U SNIT 1 quad 10 BTU 1.055 EJ 1 terawatt-year (TWy) 31.56 EJ 1 watt (W) 1 joule/sec 1 foot pound per second 1.356 W 1 horsepower (electric) 746 W 1 ton of air conditioning 3.517 kW definition * th thermochemical four significant figures * IT International Table actual value varies

8.21 Lecture 2: Units and the scales of energy use 14 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation E RGYNE U SNIT †, G LABLO U SNIT † I IALRNDUST S HTGENTR U SNIT UNIT SI UIVEQ ALENT H2005 UMAN CONSUMPTION UNIT SI UIVEQ ALENT A ETIMAXOPPR PHYSICAL EXAJOULE (EJ) ≡ 1018 J EJ488 SIGNIFICANCE 1 KWH ≡ 3.6 × 106 J Q AU DRILLION (BTU DAQU ) ≈ 1.055 × 1018 J quads463 ≈ 1 055 × 108 5 18 THERM . J 10 BTU TRILLION K TTAWILO -HOURS ≡ 3.6 × 10 J TkWh136 ◦ oflb1000Raise H2O 100 F ≡ 31 54 × 1018 T TTAWERA -YEARS (TWYR) . J yrTW14.5 MILLION BTU ≈ 1.055 × 109 J ≡ 4 184 × 109 gyEnerotalTorldW consumption (2005) EJ488 TON TNT . J Definition. Approx chemical OilorldW consumption (2006) 31.0×109 barrels EJ190 TNToflb2000ingyener NetorldW Electricity consumption (2005) TkWh15.7 EJ56.5 BARREL OILOF ∼ 6.12 × 109 J Definition: 5.8×106 BTU gyEnerotalTS.U. consumption (2005) quads101 EJ106 ofgyener ∼ oilofliters159 OilS.U. consumption (2006) 6.9×109 barrels EJ42 otalTS.U. Electricity consumption (2005) TkWh2.8 EJ10.1 LAOFCEONNOT ∼ 2.9 × 1010 J Definition: GCal7 TS.U. ransportation gyener consumption quads28.4 EJ30.0 coalofkg1000ingyEner

† ≡ definitionasit’means ≈ significant4toenvigsit’means figures ∼ aries,valuevActualalue.v“nominal”asit’means .usedoftenisaluevquoted 9 10tocloseareunitsymanwhoNotice accidentannot—J siteebWnistratioinmdAnatiomrofnIygerEnDOES.U.moFr later!)(seeorkwofyearhumanonetoclose—

† HUMAN DESIZ AND C ZEDISLDIH SUNIT M DRLOWOICR U SNIT

UNIT SI TLENAVIUEQ PHYSICAL CANCEISIGNIF −7 2 UNIT SI TLENAVIUEQ A PETIMAXOPPR HYSICAL GER ≡ 10 J tunicgs ≡ ecm-cm/sg1 ≡ dyne-cm1 − CANCEISIGNIF EV ≈ 1.602 × 10 19 J tlovonehroughtronecteloneevMo 1 RIEOCAL ≡ 4.1868 J heattoneededgyEner ◦ gerandoltvelectrontheonMore Hmar1g 2O1 C • =1.602176462(63) × 10−19 1 FT-LB ≈ 1.356 J ootf1poundoneftLi electron1ofgeChar Coulombs ityvgrasearth’tagains (electron1 ge)char × 1=oltV1 “electron-volt V”=1e 3 =1602176462(63) × 10−19 UT1B ≈ 1.055 × 10 J bH1ltaeH 2 morOf V1e . Joules ◦ ◦ 60 16to atmoneat • singleaofgyEner (quantum E = hν eV2.5islightgreenfo) 3 1C ORIEAL ≡ 4.1868 × 10 J • Present record siyﬁciencefcomputer ∼ 36 gﬂop/er † OR K OCALIL ORIE 2.78iswhich kJ/TFlop

† itewebs500”Green“The http://www.baselinemag.com/c/b/P lue-Gene-Batslis/tmengeaMan-rojects L supercomput fetosmehtas,BGab,LurybresaDater ﬁ 2007nieromputcentci

8.21 Lecture 2: Units and the scales of energy use 15 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation E RGYNE U SNIT †, G LABLO U SNIT UNIT SI UIVEQ ALENT H2005 UMAN CONSUMPTION EXAJOULE (EJ) ≡ 1018 J EJ488 Q AU DRILLION (BTU DAQU ) ≈ 1.055 × 1018 J quads463 TRILLION K TTAWILO -HOURS ≡ 3.6 × 1018 J TkWh136 T TTAWERA -YEARS (TWYR) ≡ 31.54 × 1018 J yrTW14.5

gyEnerotalTorldW consumption (2005) EJ488 OilorldW consumption (2006) 31.0×109 barrels EJ190 NetorldW Electricity consumption (2005) TkWh15.7 EJ56.5 gyEnerotalTS.U. consumption (2005) quads101 EJ106 OilS.U. consumption (2006) 6.9×109 barrels EJ42 otalTS.U. Electricity consumption (2005) TkWh2.8 EJ10.1 TS.U. ransportation gyener consumption quads28.4 EJ30.0

† ≡ definitionasit’means ≈ significant4toenvigsit’means figures ∼ aries,valuevActualalue.v“nominal”asit’means .usedoftenisaluevquoted siteebWnistratioinmdAnatiomrofnIygerEnDOES.U.mFro

8.21 Lecture 2: Units and the scales of energy use 16 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation † I IALRNDUST S HTGENTR U SNIT

UNIT SI UIVEQ ALENT A ETIMAXOPPR PHYSICAL SIGNIFICANCE 1 KWH ≡ 3.6 × 106 J THERM ≈ 1.055 × 108 J 105 BTU ◦ oflb1000Raise H2O 100 F MILLION BTU ≈ 1.055 × 109 J TON TNT ≡ 4.184 × 109 J Definition. Approx chemical TNToflb2000ingyener BARREL OILOF ∼ 6.12 × 109 J Definition: 5.8×106 BTU ofgyener ∼ oilofliters159 LAOFCEONNOT ∼ 2.9 × 1010 J Definition: GCal7 coalofkg1000ingyEner

10tocloseareunitsymanwhoNotice 9 accidentannot—J later!)(seeorkwofyearhumanonetoclose—

8.21 Lecture 2: Units and the scales of energy use 17 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

† HUMAN DESIZ AND C ZEDISLDIH SUNIT

UNIT SI EQUIVALENT APPROXIMATE PHYSICAL SIGNIFICANCE 1 CALORIE ≡ 4.1868 J Energy needed to heat ◦ 1gramH2O1 C 1 FT-LB ≈ 1.356 J Lift one pound 1 foot against earth’s gravity 3 1BTU ≈ 1.055 × 10 J Heat1lbH2O from 60◦ to 61◦ at one atm 1CALORIE ≡ 4.1868 × 103 J OR KILOCALORIE

8.21 Lecture 2: Units and the scales of energy use 18 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation M DRLOWOICR U SNIT

UNIT SI TLENAVIUEQ PHYSICAL CANCEISIGNIF − GER ≡ 10 7 J tunicgs ≡ ecm-cm/sg1 2 ≡ dyne-cm1 − EV ≈ 1.602 × 10 19 J tlovonehroughtronecteloneevMo

gerandoltvelectrontheonMore • electron1ofgeChar =1.602176462(63) × 10−19 Coulombs (electron1 ge)char × 1=oltV1 “electron-volt V”=1e

V1e =1.602176462(63) × 10−19 Joules • singleaofgyEner (quantum E = hν eV2.5islightgreenfo) • Present record siyﬁciencefcomputer ∼ 36 gﬂop/er † 2.78iswhich kJ/TFlop

† itewebs500”Green“The http://www.baselinemag.com/c/b/P lue-Gene-Batslis/tmengeaMan-rojects L supercomput fetosmehtas,BGab,LurybresaDater ﬁ 2007nieromputcentci 8.21 Lecture 2: Units and the scales of energy use 19 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation P WERO UNITS

UNIT SI TLENAVIUEQ PHYSICAL CANCEISIGNIF W TAT ≡ 1 it)UnSI(cJ/se mhOonehrutmpereAenO )example(forancetsires

TFOO -LB/ CSE ≈ W1.356 !sysaittawhstJu

RWEPOSEHOR ≡ W746 !sysaittawhstJu

gy:enertoackbwerPo dnatt-secoW1 = moreore,oulJ1 ycommonl hour-ttawolki1 = hW1k = 103 × 3=3600 .6 × 106 MJ.63=esoulJ J1M = e”oulgaJMe“1 ≈ ngorkihard-w5-10 houranorfgnrkiowngsbeihuman

8.21 Lecture 2: Units and the scales of energy use 20 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation Outline

• A tour of the energy landscape: From the macroworld to our world

8.21 Lecture 2: Units and the scales of energy use 21 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation A guide for our tour: The workingman (or woman). Although we use Joules for units (as consistently as possible), it will be helpful to relate to a human scale. 100 W atts is an average value for power production by a manual laborer...

fosattW010 r8hoursa day020,yda sayear THE HUMAN YEAR = HYR

Joules hours seconds days One 100= × 8 × 3600 × 200 580= gaJouleseM second day hour year

• ursbygamma-raltypicaA t— thesperhap oecollaps fa holekblacamforotrstanneutro

10 44 Joules 1.7 × 10 53 hyr

• itoutpuygrenerSola nayear 3.8 × 10 62 attsW × 3.16 × 107 seconds/yea =r 12 × 10 43 Joules (12 × 10 43 J/year)/ MJ/hyr)0(58 2.1 × 10 62 hyr/year

8.21 Lecture 2: Units and the scales of energy use 22 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

• annualorldW gyenerhuman consumption 2005in Efforts of > 100 times populationsthe earth’ populationsthe 9 =EJ490 884 × 10 hyr for a year

• (2005)S.U.inlossesgyenerAnnual Efforts of ~ 15 times populationsthe earth’ populationsthe × quads56 1.055 JE95=EJ/quad for a year =EJ59 102 ×109 hyr • personaofgyenerRest Efforts of 2 times populationsthe earth’ populationsthe (3kg80 ×× 108 m/sec)2 EJ7.2= for a year 7.2 ×1018 J=12.4 × 109 hyr

• Solar radiation searth’theoftoptheatvingarri Efforts of ~ U. S. atmosphere secondper population for a year 1.7 × 1017 J=2.93 × 108 hyr

• Annual typicalofoutput plantwerponuclear Efforts of 2 times California’s population W1G ×3.6 × 107 3.6=sec/year ×1016 J for a year =EJ.036 6.2 ×107 hyr

8.21 Lecture 2: Units and the scales of energy use 23 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

• capitaperS.U. gyeneryearly consumption 2005in

300/EJ106 ×106 350=people GJ/person 350 =GJ/person 600 hyr/person orld:wtoCompare 130 /person

day?Per 1 GJ/(person-day) ≈ h2 yr/(person-day)

• yearlyeragevA Northeast S.U. household gyener consumption

×106 BTU × 1.06 × 103 Joule 180 year BTU GJ/year191= =GJ/year191 329 hyr/household

http://en.wikipedia.org/wiki/ Energy_use_in_the_United_States

8.21 Lecture 2: Units and the scales of energy use 24 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

• personperrequiredgyEner BOS-LAX 747Boeingvia 0.01 gallon/mile × allonsg62=miles2600 142 MJ/gallon Jetfuelof ×26 GJ3.692=gallons GJ3.692 ⇒ hyr6.36 stuffwwl.hoevhttp://tra orks.com/question192.htm

• gasolineoftankOne http://en.wikipedia.org/wiki/Gasoline#Energy_content

gallons15 × 3.79 liters/gallon liters56.9= l56.9 × =GJ1.98=MJ/l34.8 hyr3.4

8.21 Lecture 2: Units and the scales of energy use 25 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

• Recommended eintakgyenerdietaryS.U. 2,500–2,000 kCal/person-day 2000 kCal/day × 4.187 ×103 J/kCal × 365 GJ/3.1=days/year (person-year) pereintakgyenersyear’OneResult: Or ≈ 10 MJ/(person-day) GJ3.9–3.1person, ⇒ personperinputgyenerearlyY toamounts hyr6.7–5.3 • eragevaproducetoinputgyEner Swedish dietsdata)ﬁndcouldI(where deﬁnitionsxComple systemof boundaries Include: crop production, processing, storage, transportation, storage, preparation, cooking... bounmetyssThe d utshetniaries d cnyi edul df roparm d orpithwntiocu d ontiocu ffarm osalyThe.reliarethetotpunoitaportansrtndaoragetsng,isrocesp,cropsofngdryi,snputi ngcookindanoireparatprage,otsudedclni emtsysheT.dseholhousni udedclxeesboundari Exclude: ofcostCapital equipment, etsaw,laeriatmgnackagip,ngsidliubndaerynmachiaschusgoodslatcapifonoiproduct Theng.hiashwsidandumerconshetotreliarethetfromnoitaportranst,mentreatt packaging, humanaste,w ...labor andsroductpfoeulavceconomi esuygnerefonoicatolalforsibashetsawsby-product ygrenecessropsalatedcalcusawseuygreneeThs.tuptuoleltipumithwcessesorpginrud 21.0—6.9Result: GJ/person-year ⇒ .sessolonissmiansrtndanoirsevonc,gyenerryevidelndanoiroductpfonoiusclninohtiw fuel,ytciriectlefromedveridsnputi.g.,eered,dionscerewsnputiygnerelacommerciylnO yr/personh36–12 notreewbouralhumanfromronushetfromsnputigyEnere.nilogasorcoal,loi ideredcons

8.21 Lecture 2: Units and the scales of energy use 26 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation Outline

• CO2 and other greenhouse gases: measurements, units, energy connection

8.21 Lecture 2: Units and the scales of energy use 27 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

Measurement of CO2 (and other greenhouse gases)

lnI ater l wiweectures ll gboutayasotmuchevha loba lcl sinigroits,egnahcateim OCotandesuygnereotelationrand 2 ere...H.

• OCfoseiopertrP 2.

• OCofuresmeasntaImport 2. • .esasgereenhousghertO

oseiopertrP f CO2 • ghtiewcomitA 12+16+16=44. raiotedmparoC ≈ N78% 2 O21%and 2 ghteiwcmiotA. oS6.28. CO2 541.=628.44/ytensidhas × .raiofytdensi • 0-7tas)agtolidosmfrotlycire(dslimebSu ◦ re.ressupricehpstmoataC ◦ • OCsressureprehightAtm.a5wolebsressuerptatetasdiuliqNo 2 7-5taltsme C.

8.21 Lecture 2: Units and the scales of energy use 28 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

mportantI COofmeasures 2 • theIn atmosphere millionperpartsin— (ppm) • andransferT production through —ycleccarbonsearth’inandvityactihuman metricofmillionsinusually tonnes (MMT)

• Emissions gyenerin processes: kilograms CO2 producedgyenerofJouleper (kg/J). (Usually notsource,theatproducedgyener including otherandlosses inefﬁciencies.†)

CO 2 retmospheathein on:iratoncentclairtndusre-iP 280 ± 10 ppm. centPres oncentration: ≈ 383 ppm. ityvactihumantodueeIncreas

† xample:eorF COquotedFind 2 emission coalofkWhper produced (plantwerpoofyﬁciencefincludenotDoes.electricity ∼ 35% r)o transmission ersionvconorlosses, inlosses application.

8.21 Lecture 2: Units and the scales of energy use 29 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation S.U.emSo data CO2 vityactihumanbyproduced metricof(millions tonnes!)

• COotalT 2 thein atmosphere: 2,996,000 MMT

• COorldW 2 emissions (2007):fuelfossilfrom 28,190 MMT • Emissions total:offractionaas 0.94% • Leading emitters (2007):fuelfossilfrom

Region CO2 (MMT) United States 5,957 China 5,322 Europe 4,675

• CO2 sectorbyS.U.inemission (2006):

Sector CO2 (MMT) Residential 1,204 Commercial 1,045 Industrial 1,650 Transportation 1,990 Electric Power 2,344

• CO2 emissions year:perS.U.inpersonper

6 × 109 tonnes ∼ 0=2 , 000 kg/person 3 × 108 persons Staggering! http://www.eia.doe.gov/oiaf/1605/ggrpt/carbon.html 8.21 Lecture 2: Units and the scales of energy use 30 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

CO2 sesprocesgyenerinonisemis

.nteontcygnereandboncarenterffdievhasuelflossifenterffiD foamsogrlikfotunidndaratsninevgiylcalypitataD carbon foTUBnilliomrep foamsogrlkiottrevoncll’eWce.oursehtatoducedprgyener CO2 ygrenfeoJrGep .

leFu CO2 oractfonssiemi BTU)(nillioC)/M(gk OCkg( 2)/GJ alCo ∼ 26 90 eniasolgsene,oerk,uelfJet ∼ 19 66 quiiL ﬁ asgeumolrpeted ∼ 17 59 asgralNatu ∼ 514. 50

8.21 Lecture 2: Units and the scales of energy use 31 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

Other greenhouse gases:†

• Methane (CH4 nitrous), (Noxide 2 andchloro-ofarietyvaandO), ﬂuorocarbons elyv(collecti halocarbons utecontrib) signiﬁcantly theto greenhouse fect.ef

Current Atmospheric Increased Gas concentration GWP lifetime (years) radiative forcing (W/m 2) Carbon dioxide 383 ppm 1 Variable (5 – 200)†† 1.66 Methane ∼ 1800 ppb 23 ∼ 12 0.5 Nitrous oxide 319 ppb 296 114 0.16 Halocarbons ∼ 1 ppb 140 — 10,000 5 – 250 0.34

• armingw“globalofmeasureaisGWP potential” COwithmass)unit(per 2 1.asdeﬁned • “Increased theatailablevamadeisgyenerthatratetheinincreasetheisforcing”evradiati thistodueacesurfsearth’ greenhouse gas, W/minmeasured 2 becanand compared thewith input.gyenersolar • Source: Carbon Dioxide Information Analysis Center, [email protected] .v † anwhile,aterW important greenhouse omittedisgas, table.thefrom †† Atmospheric COoflifetime 2 estimatetohardis ferentdifymansobecause it.fectafprocesses

8.21 Lecture 2: Units and the scales of energy use 32 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation Outline

• Perspectives on energy issues --- common sense and conversion factors

8.21 Lecture 2: Units and the scales of energy use 33 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

enormousismatterofcontentgyenerThe1. annualofalentvequiMatter udget:bgyenerhuman

4.9 × 1020 J = Mc2 c =3.0 × 108 m/sec M =4.9 × 1020/9.0 × 1016 =5.4 × 103 kg

lifting!vyheaenvenot

uy?bgramonedoesWhat

10−3 kg × (3 × 108 m/sec)2 =9× 1013 J

aruntoenough 2.86 .yearaforwerplantpoattwgame

8.21 Lecture 2: Units and the scales of energy use 34 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

enormousisearththeonincidentgyenersolarThe2. searth’theoftoptheatincidentgyenersSun’ atmosphere ariesv between 1321 atts/mw1412and 2 throughout atts/mw1366oferagevA.yearthe 2 Solar. earththeonincidentwerpo

2 2 17 1366 W/m × πR⊕ ≈ 1.74 × 10 W =0.174 EJ/sec

inso 488/(.174) byusedgyenertheallersvdelisuntheminutes47=seconds .yearainhumanity

8.21 Lecture 2: Units and the scales of energy use 35 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation Estimate3. solarofareawhat annualS.U.videproouldw 100%atudgetbgyener y?ﬁciencef • data:Find National ablewRene gyEner Laboratory solarhas radiation atlas. (www.nrel.gov/gis/solar.html) • areUnitsunits:SItoertvCon “kWh/m2 hours,24=day1/day”,

1 kWh/day =1kWh÷ 24h/day ≈ 42 W ERWOPGEERAVA

So W/m42isinsolation 2 ,actorfthetimes I table.thein, Compute area forneeded E =1.05 × 1020 J/year • ekTa I =6.5 (looks fortypical American southwest),

1.05 × 1020J/year ÷ (3.15 × 107 sec/year) ÷ (6.5 × 42 W/m2)

=1. × 102 4 km2

8.21 Lecture 2: Units and the scales of energy use 36 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

Collector area =1.2 × 104 km2

Looks pretty promising. thesIt’ genersolarevbeliewewhyreason y besttheis long-term source.gyener arning,W big multiplication actorf ineffrom ﬁciencies tuned).(stay

8.21 Lecture 2: Units and the scales of energy use 37 The Basics: SI Units A tour of the energy landscape Units and Energy, power, force, pressure CO2 and other greenhouse gases conversion The many forms of energy Common sense and computation

typicalofratiothesWhat’4. carbon typicaltosourcegyenerbased source?gyenernuclear • gyener—eVarescalesgyenerAtomic ionizetonecessary eV13.6ishydrogen . • Nuclear gyener—MeVarescalesgyener afromprotonaevremotonecessary typical isnucleus ∼ .MeV8 • + 1 → ∼ 3 forreactionofgyEner H2 2 O2 H2O is eV/reaction. • isuraniumofﬁssionforreactionofgyEner ∼ 200 MeV/reaction. Nuclear million1roughlyevhafuels carbonofdensitygyenerthetimes fuels.

8.21 Lecture 2: Units and the scales of energy use 38