[cdn-nucl-l] Planning for Future Energy Resources

["Adam McLean" <adam.mclean@utoronto.ca>]

Posted in Science Magazine, Volume 300, Number 5619, Issue of 25 Apr 2003,
pp. 581-584. and at:
http://www.sciencemag.org/cgi/content/full/300/5619/581b?etoc
Response to a comprehensive article on energy supply that appear in Science
some time ago.

Adam

---------------------

Planning for Future Energy Resources

We agree with M. I. Hoffert et al.("Advanced technology paths to global
climate stability: energy for a greenhouse planet," Review, 1 Nov., p. 981)
that stabilizing atmospheric CO2 concentrations at 550 parts per million
(ppm) or below will require investment in energy research and development
well in excess of current levels. However, their conclusion--that known
technological options are not up to the task--suffers from two shortcomings
related to how much decarbonization is required and how soon we need it.
First, they do not consider uncertainty in future energy demand, basing
their analysis on a single reference scenario (1). In contrast, the most
recent Intergovernmental Panel on Climate Change (IPCC) report on emissions
scenarios (2) foresees a wide range of plausible development paths leading
to global primary power demand of anywhere from 20 to 50 TW by 2050.
Relative to these scenarios, as quantified by six different integrated
assessment modeling teams, stabilizing at 550 ppm may not require any
additional energy from carbon-free technologies over the next 50 years
beyond that produced by known technologies for reasons unrelated to climate
change. Or it could require that additional zero-carbon generating capacity
deliver nearly 600 TW-years of energy over that same period. Policy
responses to climate change should be robust across this wide range of
uncertainty.
Second, we doubt whether the development and implementation of the radically
new technologies such as fusion or solar power satellites advocated in the
article are feasible within the time horizon necessary for CO2
stabilization. The process from invention, to demonstration projects, to
significant market shares typically takes between five and seven decades
(3). Fundamentally new technologies that have not been demonstrated to be
feasible even on a laboratory scale today would therefore likely come much
too late to contribute to the emissions reductions necessary by 2050,
particularly for stabilization at 450 ppmv or below (4). We believe that the
appropriate mix of investments must include an initial focus on technologies
with proven feasibility if we are to embark on a path to stabilization. At
the same time, we should begin to explore new energy sources that might then
be available in the long term to finish the job.

Brian O'Neill, Arnulf Grübler, Nebojsa Nakicenovic, Michael Obersteiner,
Keywan Riahi, Leo Schrattenholzer, Ferenc Toth
International Institute for Applied Systems Analysis,
Schlossplatz 1,
A-2361 Laxenburg,
Austria.

References

W. Pepper et al., Emissions Scenarios for the IPCC (Cambridge Univ. Press,
Cambridge, 1992). 
N. Nakicenovic et al., Special Report on Emissions Scenarios (Cambridge
Univ. Press, Cambridge, 2000). 
A. Grübler, Technology and Global Change (Cambridge Univ. Press, Cambridge,
1998). 
B. C. O'Neill, M. Oppenheimer, Science 296, 1971 (2002). 

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The Review by M. I. Hoffert et al. ("Advanced technology paths to global
climate stability: energy for a greenhouse planet," 1 Nov., p. 981)
discusses a wide range of advanced technology solutions to achieving global
climate stability. Their treatment of nuclear energy, however, is completely
inadequate. Nuclear electric power and, with a small extension, nuclear
process heat are the only alternatives among those considered that have been
tested at a commercial scale. Because noncarbon alternatives to nuclear
energy are not yet proven on a commercial scale, a wide range of options for
sustainably applying nuclear technology must receive increasing attention.

In the short term, there is no fuel resource problem. Even a trebling of
capacity to meet the Kyoto accords is possible with uranium fuel at
reasonable cost for 50 years. Beyond this, W. C. Sailor et al. (1) estimated
that one-third of a postulated (high) 900 EJ/year primary energy demand in a
2050 world could be met by nuclear fission. To meet this level of demand,
either cheaper fuel must be found, an increased cost must be accepted, or
fuel must be bred from 238U or 232Th.

Breeding plutonium from 238U would extend the uranium resource base by a
factor of about 70; higher-cost uranium resources would then become
feasible, extending that resource for 1000 years.

Although Hoffert et al. state that "breeder reactors are needed for fission
to significantly displace CO2 emissions by 2050," the need for a breeder
reactor is less immediate than was perceived in the 1970s. The decrease in
the price of raw uranium presently makes breeding uncompetitive and reduces
the need for a rapid expansion, so that even more safe and economic reactor
designs with a lower breeding ratio can now be considered. Moreover,
reprocessing and recycling of spent fuel can dramatically reduce the heat
load and radiotoxicity of the long-lived actinides sent to any waste
repository. "Waste form modification," therefore, is being reconsidered for
improved repository performance independently of perceived uranium resource
issues.

Contrary to what Hoffert et al. state, breeding as well as reprocessing has
not been illegal since the Reagan administration.

Hoffert et al. raise concerns about nuclear energy but do not describe how
these concerns are being addressed. Indeed, major accidents have occurred at
the Windscale, Chernobyl, and Three-Mile Island nuclear power plants. Much
has been learned and applied from these events. Analyses of these few
serious accidents have improved operational safety, which was already high.

Nuclear fission technology is indeed deeply rooted in the bomb-making
military. Materials generated as a byproduct of commercial nuclear power
might lead to undesirable proliferation of nuclear weapons.
Proliferation-resistant commercial fuel cycles are being explored, although
no nuclear weapons proliferation has been attributable directly to a
commercial power plant or the attendant fuel cycle. Inefficiencies and
public concerns led to cost increases between 1973 and 1990; however, since
1990, the economics of nuclear power have improved significantly. Several
avenues should now be developed simultaneously: (i) further developing
low-cost uranium and (ii) improving the economic and environmental
characteristics of various breeder technologies. Fossil-coal and
fissile-uranium share one common feature--they do not have a resource
problem on the time horizon of 500 years. It is the environmental issues, in
their broadest sense, that are likely to determine the choice.

Richard D. Wilson
Department of Physics,
Harvard University,
Cambridge, MA 02138,
USA.

Robert Krakowski
Los Alamos National Laboratory,
Los Alamos, NM 87545,
USA.

Reference

W. C. Sailor, D. Bodansky, C. Braun, S. Fetter, B. van der Zwaan, Science
288, 1177 (2000). 

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We disagree with M. I. Hoffert et al.'s ("Advanced technology paths to
global climate stability: energy for a greenhouse planet," Reviews, 1 Nov.,
p. 981) characterization of the IPCC Third Assessment Report's conclusion
that "known technological options could achieve a broad range of atmospheric
stabilization levels, such as 550 ppm, 450 ppm or below over the next
hundred years or more" (1, 2, p. 8), as "a misperception of technological
readiness." First, Hoffert et al. analyze (and dismiss) individual
technologies in isolation and do not consider their full combined potential.
Absent detailed argumentation at the energy system level, background reports
(3, 4) suggest that their critique rests on pessimistic assessments of the
availability and efficiency of renewable energy. The IPCC evaluated a broad
array of demand and supply studies, not just individual supply-side
technologies (5). Most of these studies are much less pessimistic than
Hoffert et al. about biomass, solar energy, efficiency, and fossil fuel
decarbonization. Second, the authors imply that technologies not technically
feasible today (nuclear fusion and space solar power) are needed to
stabilize concentrations. But their development and diffusion may require
more than 50 years, too long for timely carbon stabilization at acceptable
levels. None of the studies assessed by the IPCC assumed penetration rates
of new technologies higher than historical experience. Third, Hoffert et al.
ignore the IPCC conclusion that no simple technological fix exists and that
a portfolio of available technologies must be evaluated "in combination with
associated socio-economic and institutional changes" (5). Fourth, they
ignore possible carbon emissions reductions unrelated to energy services,
such as options in the area of land-use changes.

We agree that carbon stabilization at low levels will be difficult and not
cost-free. We agree that enhanced R&D and investment in conventional and new
technologies is necessary. But we stand by the IPCC conclusion that today's
technically feasible technologies including energy efficiency improvements
could stabilize carbon concentrations if further developed and deployed, and
if complemented by necessary nonenergy initiatives and associated
socio-economic and institutional changes.

Rob Swart,*
National Institute of Public Health and Environment (RIVM),
Post Office Box 1,
3720 BA Bilthoven,
Netherlands.

Jose Roberto Moreira,
Biomass Users Network (BUN),
Rua Francisco Dias Velho 814,
04581-001 CEP, Sao Paulo,
Brazil.

Tsuneyuki Morita,
National Institute for Environmental Studies,
16-2 Onogawa,
Tsukuba, Ibaraki 305-8506,
Japan.

Nebojsa Nakicenovic,
Transitions to New Technologies Project,
IIASA,
Schlossplatz 1,
Laxenburg A-2361,
Austria.

Hugh Pitcher,
Joint Global Change Research Institute,
Pacific Northwest,
National Laboratory,
8400 Baltimore Avenue,
College Park, MD 20740,
USA.

Hans-Holger Rogner
Department of Nuclear Energy,
International Atomic Energy Agency (IAEA),
Post Office Box 100,
A-1400, Vienna,
Austria.

*To whom correspondence should be addressed.
E-mail: rob.swart@rivm.nl

References and Notes


"Known" refers to "technologies that exist in operation or pilot plant stage
today. It does not include any new technologies that will require drastic
technological breakthroughs" (2, p. 8). 
B. Metz, O. Davidson, R. Swart, J. Pan, Eds., Climate Change 2001 (Cambridge
Univ. Press, Cambridge, 2001). 
H. D. Lightfoot, C. Green, Report No. 2002-5 (McGill University, Montreal,
Canada, 2002). 
H. D. Lightfoot, C. Green, Report No. 2002-9 (McGill University, Montreal,
Canada, 2002). 
T. Morita et al., in Climate Change 2001, B. Metz, O. Davidson, R. Swart, J.
Pan, Eds. (Cambridge Univ. Press, Cambridge, 2001). 

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Response
Existing technologies can contribute to global warming mitigation. However,
projected levels of emission-free power needed later this century to
stabilize climate change appear to be so unprecedented (1, 2) that it would
be foolhardy not to assess a broad spectrum of advanced energy sources,
converters, and enabling technologies.

The IPCC Special Report on Emission Scenarios (SRES) projects 40 energy
scenarios (3). Unfortunately, no reliable theory exists to assess their
probabilities. Our 33 TW primary power in 2050 is close to the midcentury
mean of the SRES range. Unlike SRES, we specify a range of concentration
targets and compute CO2 emission-free power required as a function of time.
We recently extended our analysis to global warming targets, including
climate sensitivity uncertainty effects (4). For example, a 2ºC warming
target (which can still produce adverse climate impacts) requires
non-CO2-emitting primary power in the 10 to 30 TW range by 2050.

The crux of our disagreement with the IPCC Mitigation Panel is whether
"known technologies"--which they define as already existing "in operation or
as pilot plants"--can generate such massive emission-free power. Remarkably,
their definition excludes fossil-fueled zero emission plants (ZEPs), with
CO2 sequestered. DOE just announced plans to build the first ZEP pilot plant
by 2010-15 (5).

O'Neill et al. say that fusion and solar power satellites are not feasible
because the process "from invention, to demonstration projects, to
significant market shares typically takes between five and seven decades."
Fusion power reactors may be unlikely before the latter half of the 21st
century, but a fission path employing fusion-fission hybrid breeders based
on paid-for tokamak technology (advocated by Andrei Sakharov) could come
online earlier (2, 6). Contrary to O'Neill et al. and Swart et al., both the
NASA "Fresh Look Study" and recent U.S. National Research Council
assessments find space solar power feasible on decadal time scales (7).
Leisurely market penetration times may apply to classic fuel substitutions,
but not, historically, to technologies accelerated by government research:
Gas turbines, commercial aircraft, spaceflight, radar, lasers, integrated
circuits, satellite telecommunications, personal computers, fiber optics,
cell phones, and the Internet all developed faster (8).

What about demand? Our 10 to 30 TW emission-free requirement by 2050 assumes
~2%/year growth in primary power demand: ~3%/year GDP growth (for some
measure of equity for developing nations) less ~1%/year from declining E/GDP
(energy per unit of GDP). The latter is where efficiency improvements come
in (9, 10). We realize there are many efficiency improvements possible. The
question is whether they add up to >1%/year (11).

We agree with Krakowski and Wilson that fission can contribute fundamentally
to global climate stability. Today, anxieties over waste disposal and
diversion to weapons are evident in Nevada's opposition to a spent nuclear
fuel repository in Yucca Mountain and the Pentagon's deployment of
long-range bombers capable of destroying North Korea's Yongbyon reactor
complex. These issues may indeed be amenable to technical solutions (12).
But, as indicated above, holding global warming to <2ºC requires 10 to 30 TW
emission-free power in 50 years for plausible economic growth, regardless of
power sources. W. C. Sailor and colleagues independently recognized this by
putting ~10 TW from fission by 2050 in their nuclear scenario (13).

Although it is no longer technically illegal in the United States,
commercial breeding of fissile fuels is not being done anywhere today to our
knowledge (the United States, France, Japan, and Germany have suspended
their commercial breeder reactor programs). Continued 235U burning at 10 TW
rates will require finding major new high-grade uranium deposits to prevent
rapid exhaustion (2). Low-grade ores face serious environmental and cost
issues. Our finding of massive flow rates needed for seawater extraction of
235U surprised us. And we are nowhere near able to breed on the scale needed
to realize theoretical factors of 60 (238U  plutonium) or 180 (Th  233U)
increase in fissionable fuels. The issue for global warming is not breeding,
as such, but our ability to breed fast enough. This will require drastic
shifts in technology and substantial research and development.

We are astonished at continued confident forecasts by Swart et al. that
"existing" technology can accomplish the mitigation job ahead, while they
discount or ignore technologies they deem too advanced. Expert predictions
of technological readiness are notoriously unreliable (14). The near-term
maturity of highly desired technologies is commonly overestimated (ballistic
missile defense, cancer cures, controlled fusion), even as promising
innovations perceived as too futuristic are often underestimated (8, 15-17).

Market penetration rates of new technologies are not physical constants.
They can be strongly impacted by targeted research and development, by
ideology, and by economic incentives. Apollo 11 landed on the Moon less than
a decade after the program started. We are confident that the world's
engineers and scientists can rise to the even greater challenge of
stabilizing global warming. But it does not advance the mitigation cause to
gloss over technical hurdles or to say that the technology problem is
already solved.

Martin I. Hoffert,*
Department of Physics,
New York University,
New York, NY 10003,
USA.

Ken Caldeira,
Lawrence Livermore National Laboratory,
Livermore, CA 94550,
USA.

Gregory Benford,
Department of Physics and Astronomy,
University of California,
Irvine, CA 92697,
USA.

Tyler Volk,
Lawrence Livermore National Laboratory,
Livermore, CA 94550,
USA. 

Department of Biology,
New York University,
New York, NY 10003,
USA.

David R. Criswell,
Institute of Space Systems Operations,
University of Houston,
Houston, TX 77204,
USA.

Christopher Green,
Department of Economics,
McGill University,
Montreal, Quebec H3A 2T7,
Canada.

Howard Herzog,
MIT Laboratory for Energy and the Environment,
Cambridge, MA 02139,
USA.

Atul K. Jain,
Department of Atmospheric Sciences,
University of Illinois at Urbana-Champaign,
Urbana, IL 61801,
USA.

Haroon S. Kheshgi,
Exxon-Mobil Research and Engineering Company,
Annandale, NJ 08801,
USA.

Klaus S. Lackner,
Department of Earth and Environmental Engineering,
Columbia University,
New York, NY 10027,
USA.

John S. Lewis,
Lunar and Planetary Laboratory,
University of Arizona,
Tucson, AZ 85721,
USA.

H. Douglas Lightfoot,
Centre for Climate and Global Change Research,
McGill University,
Montreal, Quebec H3A 2K6,
Canada.

Wallace Manheimer,
Plasma Physics Division,
Naval Research Laboratory,
Washington, DC 20375,
USA.

John C. Mankins,
NASA Headquarters,
Washington, DC 20375,
USA.

Michael E. Mauel,
Department of Applied Physics and Applied Mathematics,
Columbia University,
New York, NY 10027,
USA.

L. John Perkins,
Lawrence Livermore National Laboratory,
Livermore, CA 94550,
USA.

Michael E. Schlesinger,
Department of Atmospheric Sciences,
University of Illinois at Urbana-Champaign,
Urbana, IL 61801,
USA.

Tom M. L. Wigley
National Center for Atmospheric Research,
Boulder, CO 80307,
USA.

*To whom correspondence should be addressed.
E-mail: marty.hoffert@nyu.edu

References and Notes


M. I. Hoffert et al., Nature 395, 881 (1998). 
M. I. Hoffert et al., Science 298, 981 (2002). 
N. Nakicenovic et al., Eds., Special Report on Emissions Scenarios
(Cambridge Univ. Press, New York, 2000). 
K. Caldeira, A. K. Jain, M. I. Hoffert, Science 299, 2052 (2003). 
Department of Energy, Vision 21: Power Plant of the Future (available at
www.fe.doe.gov/coal_power/vision21/index.shtml ). 
T. K. Fowler, The Fusion Quest (Johns Hopkins, Baltimore, MD, 1997), p. 195.

Committee for the Assessment of NASA's Space Solar Power Investment
Strategy, Aeronautics and Space Engineering Board, National Research
Council, Laying the Foundation for Space Solar Power: An Assessment of
NASA's Space Solar Power Investment Strategy (National Academy Press,
Washington, DC, 2001). 
M. I. Hoffert, S. D. Potter, in R. G. Watts, Ed., Engineering Response to
Global Climate Change, (Lewis Publishers, Boca Raton, FL, 1997), pp.
205-259. 
A. B. Lovins et al., Least-Cost Energy: Solving the CO2 Problem (Rocky
Mountain Institute, Snowmass, CO, 1989). 
H. D. Lightfoot, C. Green, Energy Intensity Decline Implications for
Stabilization of Atmospheric CO2 Content (Report 2001-7, McGill Centre for
Climate and Global Change Research, Montreal, Canada, 2001). 
Large carbon emission reductions over the 21st century from "efficiency"
improvements reflected in E/GDP declines as high as 2%/year (a factor of 7.2
by 2100) have been proposed (3, 9). However, the average global energy
intensity decline over the 20th century was <1%/year, and some analyses of
the combined potential from sectoral change and engineering efficiency
improvements suggest that 1%/year may be an upper limit (2, 10). 
R. Krakowski, R. Wilson, in Innovative Energy Strategies for CO2
Stabilization, R. G. Watts, Ed. (Cambridge Univ. Press, Cambridge, 2002),
pp. 211-323. 
W. C. Sailor, D. Bodansky, C. Braun, S. Fetter, B. van der Zwaan, Science
288, 1177 (2000). 
A. C. Clarke, Profiles of the Future: An Inquiry Into the Limits of the
Possible (Holt, Rinehart & Winston, New York, 1982). 
D. Walter, Today Then: America's Best Minds Look 100 Years into the Future
on the Occasion of the 1893 World's Columbian Exposition (America & World
Geographic Pub., St. Helena, MT, 1992). 
J. Verne, Paris in the Twentieth Century, translated by R. Howard (Random
House, New York,1996). 
This "lost novel" by Jules Verne (16) written in the 1860s was rejected for
publication in its time because it pictured a future too strange to be
credible. In this work, Verne imagined a future in the 1960s where people
traveled by subway and in gas-driven cars, where they communicated by fax
and telephone, where they used computers, and where "electric concerts"
provided entertainment. In this world, everyone could read, but no one read
books. It was a society dominated by money where destitute homeless people
roamed the streets. Strange indeed. 

Related articles in Science:

Advanced Technology Paths to Global Climate Stability: Energy for a
Greenhouse Planet

Martin I. Hoffert, Ken Caldeira, Gregory Benford, David R. Criswell,
Christopher Green, Howard Herzog, Atul K. Jain, Haroon S. Kheshgi, Klaus S.
Lackner, John S. Lewis, H. Douglas Lightfoot, Wallace Manheimer, John C.
Mankins, Michael E. Mauel, L. John Perkins, Michael E. Schlesinger, Tyler
Volk, and Tom M. L. Wigley 
Science 2002 298: 981-987. (in Review) [Abstract] [Full Text]   


Volume 300, Number 5619, Issue of 25 Apr 2003, pp. 581-584. 
Copyright © 2003 by The American Association for the Advancement of Science.
All rights reserved.