Energy Options & Paths toClimate Stabilization, Aspen
Global Change Institute, AspenCO, July 6-11, 2003
Predictability of TechnologicalChange
Marty HoffertPhysics DepartmentNew York University
New York, NY
Physics offers both opportunitiesand limits on new technologies;but predicting winners can be
hazardous. For example:
There has been a great deal said about a 3,000 mile highangle rocket. In my opinion such a thing is impossible for manyyears. The people who have been writing these things that annoyme, have been talking about a 3,000 mile high-angle rocket shotfrom one continent to another, carrying an atomic bomb and sodirected as to be a precise weapon which would land exactly on acertain target, such as a city. I say, technically, I don’t think anyone in the world knows howto do such a thing, and I feel confident that it will not be done fora very long period of time to come . . . I wish the American Publicwould leave that out of their thinking.
Vannevar (not George) Bush, Head of US scientific WW II effort (in 1945)
Arthur C. Clarke’s Laws ofTechnological Prophecy
• When a distinguished but elderly scientist statesthat something is possible he is almost certainlyright. When he states that something is impossible,he is very probably wrong.
• The only way of discovering the limits of thepossible is to venture a little way past them into theimpossible.
• Any sufficiently advanced technology isindistinguishable from magic.
Population)
Energy intensity)
Per capita GDP
Carbon intensity (
20001900 210020501950
IPCC IS92a“Business as
usual”scenario
assumptions
The KayaIdentity:
CO2 Emissions= N x (GDP/N) x(E/GDP) x (C/E)
= GDP x (E/GDP) x(C/E)
= GDP x (C/GDP)
YEAR
N(G
DP/
N)
(E/G
DP)
(C/E
)
Percent change in Kaya Identity termsand carbon emssions disaggregated by
region 1980-1999
Data fromhttp://sequestration.mit.edu/carbon_emissions_data/index.html
Global carbon dioxide emssions related to energy and industry from 1900 to 1990and for 40 SRES scenarios from 1990 to 2100, shown as an index (1900 = 1).Colored lines are individual SRES scenarios. The area shaded in blue is the range ofscenarios in the literature documented in the SRES database.
What does the SRES emissionuncertainty range mean ?
Glob
al c
arbo
n di
oxid
e em
issi
ons
(inde
x 19
90 =
1)
Many Worlds?A popular hypothesis of cosmology and quantum mechanics isthat universe’s continually split into infinite parallel versions,with outcomes covering every possible situation. Theirprobabilities are described by wavefunctions, much a as anelectron’s position is. If we only knew them for the 40 SRESscenarios. . .
A worldSplits . ..
. . . and herecoal-fired powerplants with CO2sequestered area dominantelectricitysource in 2050
. . . and here massive terrestrialwind and solar integrated withglobal grids plus space solarpower are a dominant electricitysource in 2050
Will civilization crashthis century?Plots are the “standard world model “run from Meadow’s (1974) “Limits toGrowth” sponsored by the Club of Romewhich assumed no major change inphysical, economic or socialrelationships that have historicallygoverned the devlopment of the worldsystem. All variables follow historicalvalues from 1900 to 1970. Food,industrial output, and population growexponentially until the rapidlydiminishing resource base forces aslowdown in industrial growth. Becauseof natural delays in the system, bothpopulation and pollution continue toincrease for some time after the peak ofindustrialization. Population growth isfinally halted by a rise in the death ratedue to decreased food and medicalservices.
That resource scarcity limits economicgrowth as embodied in this model isfundamentally opposed by theboundless growth paradigm of marketeconomics embodied in IPCC SRESscenarios.
Resources
190
0 1980
2000
2100
Food percapita
Population
Industrailouput percapita Pollution
AtmosphericCO2 Buildup
TheChalleng
e:Fossil
Fuel CO2and
PrimaryPower
Buildup:1900-2100Pr
imar
y Po
wer
(TW
)CO
2 (p
pm)
Radi
ativ
e Fo
rcin
g (w
/squ
are
met
er)
Total & Emission-Free Power toStabilize CO2Concentrations
GlobalWarm-ing
YEAR1900
2100
ExxonMobil Energy Projections
Fossil fuel electricity fromsteam turbine cycles
Fossil fuel CO2 sequestration ideasand burial rates to generate 10 TW
emission-free
Mass-produced widely distributed PVarrays and wind turbines may eventually
generate 10-30 TW emission-free
“Bucky” Fuller’s global electrical grid proposed in the1970s augmented with computerized load management and high-temperature superconducting (HTS) cables could transmit electricityfrom day to night locations and foster low-loss distribution fromremote, episodic or dangerous power sources. The resistivity ofcopper oxide HTS wires vanishes below the 77 K boiling point of liquidN2 available from air. Could HTS nanotubes do the job someday?
Capturing and controllingspace solar power
(Left) Wireless power from space could enable developingnations to avoid fossil-fuel-based industrialization. Ultralight large SPSaperture antennas and other components could be fostered bynanotechnology. (Right) Deflecting sunlight with a 2000 kmflat lens at the L1 Lagrange point or intentional aerosol injections to thestratosphere are potential “worst case” mitigators of global warming.
Solar powersatellite (SPS)
(LEFT) The conventional light water reactor (LWR)employs water as both coolant and working fluid. (RIGHT)The helium-cooled, graphite-moderated, pebble bed,modular nuclear fission reactor is theoretically immuneto loss of coolant (TMI) and criticality (Chernobyl)accidents.
FUSIONPATHS
The most successfulapproach to fusion sofar has been has beenconfining a D-T plasma(in purple) with complexmagnetic fields in a“bagel-shaped chamber(a tokamak).
“Breakeven” requires that the plasma triple product (= number density Xconfinement time X temperature) attain a critical value; as it has nearlydone in recent experiments. A fusion-fission hybrid breeder based ontokamak research may be feasible prior to a fully fusion power reactor.Experiments on advanced fusion fuel cycles and simpler designs are alsoneeded -- like the levitated dipole experiment at MIT shown above.
Energy Applications of Carbon Nanotubes
(Left) Hydrogen Storage: High H2 sorption may resultfrom polarization inside tubes enhanced by dopants
(Right) Superconductivity: So far, electron-hole dopedfullerenes superconduct at temps < 52 K
Nanotube-EnabledSpace Elevators
Climbing into space onultrastrong tethers --possibly carbon nanotubes-- a space elevator couldprovide cheap access toorbit someday. Thisvisualization appeared in anarticle by T. Ferris in the NYTimes Magazine 28 Nov.1999, where the price ofcarbon nanotubes wasestimated at ~ $1000/gm.Cost breakthroughs couldenable this technology, aswell as large aperturemicrowave antennae andsolar polar satellites evensooner.
Global Warming: Early Signs?
(Left) Coral Reefs: Marine ecosystems like the blue coral areasaround the Bahamas shown are already stressed worldwide.(Right) West Antarctic Ice Sheet: Catastrophic breakup ispossible in the long run raising sea level ~ 50 m. Satellite imageshows the Larson B ice shelf which shattered and separated 21March 2002. Much larger breakups may occur Earth warms.
Research and Demonstrations• An Apollo-like program in alternate energy is needed over a
broad spectrum of mitigation technologies. US should provideleadership. Goal is to provide options capable of transformingglobal energy system to one that can generate 10-30 TWprimary power CO2-emission-free by 2050.
• Strategic technologies need to be identified anddemonstrations conducted in user-friendly, energy-efficientrenewably-powered communities, “zero-emission” fossil-fueledplants with CO2 sequestered, “air capture’ of CO2, hydrogenstorage, global scale and “smart” electrical transmission grids,operationally safe and proliferation resistant fission reactors &breeders, wireless power transmission and space solar power,fusion power, fission-fusion & particle accelerator hybrids.
• Near-term emphasis on “leapfrog” technologies for alternateindustrialization paths (i.e., solar power satellite demonstrationcollaborative project of US/NASA, IPCC, developing nations).
• Nanotech can be major player if cost barriers fall. Aremolecular assemblers (“Engines of Creation”) real or SF?
