In 1968 Jerry
Olson, an ORNL ecologist, began studying how trees take carbon from
the atmosphere, incorporate it into their leaves and wood, and return
it as carbon dioxide after they die. Ever since, studies of the global
carbon cycle have been under way at ORNL.
In 1975, a former
ORNL director and nuclear power enthusiast, Alvin Weinberg, met with
a number of government officials. He reiterated the scientific concern
expressed by Roger Revelle of Harvard University in 1965. Weinberg told
them that the carbon dioxide buildup in the atmosphere as a result of
increased fossil fuel combustion for power production could lead to
climate change. He reminded them that nuclear power plants do not produce
carbon dioxide, a greenhouse gas that traps excess heat from the sun,
warming the earth's surface. As a result, the effect of human activities
on atmospheric carbon dioxide levels began to receive government attention;
a carbon dioxide effects office was established in the Energy Research
and Development Administration, the predecessor of the Department of
Energy.
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Jeff
Christian, director of DOE's Buildings Technology Center User
Facility, shows a sample of polystyrene wall insulation that cuts
energy use in a new Habitat for Humanity home.
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Also in 1975,
a program of carbon dioxide research was started at the Laboratory,
which for years had focused on the development of nuclear reactors as
power sources. During the same decade, because of the rising price of
imported oil and concerns about nuclear reactor safety, ORNL researchers
received funding to develop ways to use energy more efficiently and
explore alternative, non-nuclear energy sources such as solar power,
hydrogen, and fuels from biomass. As a result, ORNL researchers have
developed insulation standards and more efficient refrigerators and
heat pumps (for cooling homes and heating water) and have led a program
that could bring large-scale production of biofuels from hybrid poplar
trees and switchgrass.
From 1976 to 1984,
Weinberg's Institute for Energy Analysis (IEA) in Oak Ridge was the
nation's center for issues related to carbon dioxide. Then emerging
studies of carbon dioxide and global climate at ORNL and other labs
began receiving increased support from DOE, and IEA researchers such
as Gregg Marland and David Reister came to ORNL. In 1989 ORNL Director
Alvin Trivelpiece established the Center for Global Environmental Studies
at the Laboratory.
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Marilyn
Brown has studied ways to control the greenhouse effect.
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In 1997 a group
co-led by Marilyn Brown, deputy director of the Energy Efficiency and
Renewable Energy Program at ORNL, completed a report entitled Scenarios
of U.S. Carbon Reductions, which involved contributions from five
Department of Energy national laboratories. This report identified a
portfolio of energy-efficient and low-carbon technologies that could
provide a low-cost path for reducing carbon emissions in the United
States to their 1990 levels by the year 2010. In 1999 the same five
labs were asked to extend their analysis to 2020 and to identify specific
policies and programs that could produce the technological advances
and market penetration levels needed to address a range of energy and
environmental challenges facing the nation. This follow-on study, Scenarios
for a Clean Energy Future, is expected to be published later this
year.
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Covers
of Technology Opportunities to Reduce U.S. Greenhouse Gas Emissions
and Carbon Sequestration Research and Development, two
DOE reports that ORNL played a major role in writing, editing,
and publishing.
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On Earth Day,
April 24, 1998, DOE released a two-volume report entitled Technology
Opportunities to Reduce U.S. Greenhouse Gas Emissions. ORNL's David
Reichle, Marilyn Brown, John Sheffield, and Mike Farrell were the technical
co-leaders for the planning and drafting of the DOE report. The same
year DOE organized a workshop to devise a roadmap for doing research
on carbon sequestration, methods for capturing and securely storing
carbon dioxide from fossil fuel plants. In December 1999 another DOE
report, Carbon Sequestration Research and Development, was released;
its technical co-leaders included ORNL's Reichle, Rod Judkins, and Gary
Jacobs.
ORNL Emerging
as Leader
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Mike
Farrell examines a carbon management flow chart on the computer
screen.
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"For 25 years
ORNL has been conducting research that positions us well to be a leader
among DOE labs in carbon management," says Mike Farrell, director
of ORNL's Global Environmental Studies Program and leader of the Laboratory's
carbon management programs. "We have explored energy efficiency,
clean energy, carbon sources and sinks, the global carbon cycle, biomass,
and climate modeling.
"Because
of our historically broad background in these areas, we were asked to
co-lead the development of the greenhouse gas emission reduction and
carbon sequestration reports. Doing this suite of reports allowed us
to look at our own skills, other labs' capabilities, and available technologies
related to carbon management."
Farrell defines
carbon management as "the full range of science and technology
opportunities (including policy options) to stabilize atmospheric CO2
concentrations by decreasing the carbon-production potential of the
energy system and by reducing CO2 emissions, including the
capture and sequestration of atmospheric CO2 and modification
of the carbon biogeochemical cycle." The term "carbon management"
has been adopted by the business community (e.g., electric utilities,
coal mining firms, etc.) as preferable to "development of climate change
technologies."
The carbon- and
energy-related research being conducted at ORNL today is certainly no
carbon copy of the type of research performed here in the past two-and-a-half
decades. "What is new," says Farrell, "is research on
carbon capture, emission reduction technologies, and sequestration."
One way to manage carbon is to use energy more efficiently
to reduce our need for a major energy and carbon source—fossil
fuel combustion. Another way is to increase our use of low-carbon fuels
(natural gas and ethanol give off 40% as much carbon dioxide as coal
when burned), and carbon-free fuels and technologies (nuclear power;
hydrogen fuel cells; and renewable sources such as solar energy, wind
power, and biomass fuels). Both approaches have long been studied by
ORNL researchers and other DOE national laboratories.
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Mike
Karnitz (left) and David Stinton chat in the High Temperature
Materials Laboratory exhibit area during the Distributed Generation
Showcase held June 19 and 20, 2000, at ORNL.
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Today, for example,
ORNL is studying distributed generation—electricity produced on
site using fuel cells and microturbines (which operate on natural gas)
and renewable energy systems such as wind turbines and solar electric
cells to meet specific energy needs for factories, hospitals, and office
and commercial buildings. ORNL researchers are devising better ways
to combine microturbines with fuel cells, which provide waste heat that
help run the turbines. According to Tony Schaffhauser, manager of ORNL's
Energy Efficiency and Renewable Energy Program, microturbines could
be combined with ORNL-developed heat pump chillers that may be marketed
as air conditioners. If ORNL-developed desiccant systems are used to
pull out the excess humidity, less air conditioning will be needed,
decreasing energy use 15 to 20% and reducing carbon emissions. The desiccant
material that absorbs moisture from the inside air before it is chilled
will give it off to the outside air when the material is warmed by waste
heat from a microturbine.
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Solomon
Labinov prepares to measure air flow in a microturbine at ORNL's
Buildings Technology Center while Jeff Christian looks on. The
velometer Labinov is studying is next to the turbine, which drives
the generator at right.
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The third and
newest way to manage carbon is carbon sequestration. In this proposed
approach, carbon will be captured from the atmosphere and from stack
emissions of fossil-fuel combustion facilities. Some of the carbon may
be transformed into useful products. The rest will be transferred to
aboveground terrestrial ecosystems such as forests, to belowground terrestrial
ecosystems such as underground coal seams, and to the ocean.
DOE has established
two carbon sequestration centers, one of which is co-led by ORNL researchers.
It is the DOE Center for Research on Enhancing Carbon Sequestration
in Terrestrial Ecosystems (CSiTE), and its co-manager is Gary Jacobs
of ORNL's Environmental Sciences Division (ESD). (For details, see the
"Capturing
a Role in Carbon Storage Studies" article in the Review,
Vol. 32, No. 3, 1999.) The other is the DOE Center for Research on Ocean
Carbon Sequestration (DOCS). ORNL researchers David Cole (Chemical and
Analytical Sciences Division) and Gerry Moline (ESD) participate in
one of DOE's geologic sequestration projects.
In evaluating
ORNL's emerging role as a leader in carbon management research, Farrell
says, "We found that ORNL's missing pieces included analytical
capabilities to determine the potential of geological and ocean systems
to store pumped-in carbon, to predict how long it would be stored, and
to assess if the sequestration methods are safe. We also need to determine
the best mix of energy-producing technologies in terms of cost, energy
production, and carbon dioxide emissions."
Carbon Management
Model
Farrell and his
colleagues see the need for a carbon management model, and they recently
won internal funding to develop one. "We plan to build a carbon
management model to evaluate different carbon management strategies
and options," Farrell says. The team of ORNL researchers who have
received funding to build the model are Tony King of ESD, Kathy Yuracko
of the Life Sciences Division (LSD), Paul Leiby of the Energy Division,
Mike Taylor of the Computational Physics and Engineering Division (CPED),
and Brian Worley of the Computer Sciences and Mathematics Division (CSMD).
They are conducting the research in collaboration with Pacific Northwest
National Laboratory.
"We will
be doing cost-benefit analyses of a mix of energy and sequestration
technologies and predict their impacts on atmospheric carbon dioxide
levels," says King, an expert in the global carbon cycle who will
analyze natural impacts on carbon dioxide levels such as volcanoes,
forest fires, and El Niño. "For example, we will compare
terrestrial and ocean sequestration in terms of cost and the expected
carbon storage time. We will analyze the risks of sequestration options
and other carbon management strategies. We will do life cycle analysis
and uncertainty analysis.
"Our model
will update and combine existing global carbon cycle models, energy
technology models, and economic models. The model will be modernized
so that it can use different programming languages across platforms
and make complex calculations on parallel supercomputers such as the
IBM SP at ORNL."
"The model
will be used to ask 'what if' questions," Farrell says. "For
example, what if it was decided to introduce hydrogen fuel cell cars
in the United States to greatly reduce carbon dioxide emissions from
the transportation sector, which represents about one-third of total
U.S. carbon emissions? What are the risks and uncertainties with respect
to building an infrastructure to support these vehicles?"
In building such
a model, the developers are following DOE assumptions, as explained
by Farrell.
"We can reduce
energy intensity through energy efficiency improvements between now
and 2010," he says. "We can reduce carbon intensity by substituting
clean energy sources for coal combustion by 2020.
Because we have
abundant supplies of coal, we can once again burn it in large quantities
to produce energy by introducing carbon capture and sequestration technologies
by 2030. Right now we can enhance carbon sequestration naturally by
planting trees and grasses on marginal farmlands that can be converted
to biomass fuel."
Why Sequester Carbon?
Farrell says that
if the Kyoto conference recommendations for controlling greenhouse gas
emissions are followed, the United States can continue major use of
fossil fuels only if we can capture, transport, and dispose of carbon
in an economical way. "Right now the technologies are there,"
he says, "but studies suggest that it would double the cost of
electricity from fossil fuel plants." For most Americans, that's
too many greenbacks to reduce greenhouse gases.
People will sequester
carbon only if a value is placed on this action, Farrell says. "Let's
suppose that the government imposed a carbon tax of $50 per ton of carbon
discharged. Then it might be economical to capture the carbon and convert
it to useful products or dispose of it permanently by injecting it into
a geological formation or the ocean. The higher the carbon tax, the
more capture and sequestration technologies will be valued."
It will be costly to build
a fossil plant, a capture plant, and a natural gas-like infrastructure
to pipe half a gigaton of captured carbon gas to special facilities
for injection into geological formations or the ocean.
The most economical
approach, Farrell says, is to delay the mitigation response for coal-fired
power plants because new technology should allow us to capture and sequester
carbon emissions more economically in the next three decades. In the
meantime, we can switch from high-carbon to lower-carbon or carbon-free
fuels and introduce energy efficiency technologies.
Challenges to Carbon
Management
One challenge
to carbon management is plant and animal biomass. Schaffhauser calls
plant biomass "carbon neutral" because, while they give off
carbon dioxide when burned, plants absorbed and sequestered the same
amount of the greenhouse gas before they were harvested. "Green
plants are a gift," Schaffhauser says, "because they provide
us with food, fuel, chemicals, building products, and a way to sequester
carbon." But biomass can be a large source of carbon dioxide to
the atmosphere if large tracts of forest are burned because of drought
and demands to clear the land for agriculture and development.
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Landfills
are rich sources of methane.
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Biomass and other
materials disposed of in landfills decay to form landfill gas, which
is mostly methane. The release of landfill methane to the air boosts
greenhouse gas levels. But landfill gas can be captured and run through
gas turbines to produce electricity, turning trash into treasure.
Animal waste is
also a challenge to carbon management. According to ORNL's John Sheffield,
who is also director of the Joint Institute for Energy and Environment
at the University of Tennessee, U.S. farms for raising cattle, poultry,
and swine to help feed the world have 1.4 billion tons of wet manure,
which annually emits almost 3 million metric tons of methane, a greenhouse
gas. Because the United States has about 15% of the world's manure,
it is apparent that animal waste worldwide is a significant contributor
to greenhouse gas levels.
"Manure is
commonly used as a fertilizer," Sheffield says, "but it also
is a large, generally untapped, source of energy. Cleverly applied technological
solutions could allow farmers to sell manure as a feedstock for producing
methane for energy and for making other products. Income from the animal
waste feedstock will help farmers offset the costs of controlling pollution
from farm chemicals such as fertilizers, pesticides, pathogens, antibiotics,
and hormones."
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Burning
gas from methane hydrate ice.
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Another challenge
to carbon management is methane hydrates, which harbor a huge amount
of natural gas in the ocean and Arctic permafrost. The problem is that
harvesting these hydrates for energy might result in the release of
the methane to the atmosphere, raising the greenhouse gas levels enough
to change the climate (see "Methane Hydrates:
A Carbon Management Challenge" article).
"As a key
resource for science and technology, we hope to support DOE's mission
of fostering a secure and reliable energy system that is environmentally
and economically sustainable," Farrell says. "Our goal is
to be DOE's major resource of carbon management science and technology.
"We hope
to expand our leadership in energy efficiency R&D by increasing
our R&D on distributed energy power, buildings, and transportation.
We plan to expand our clean power R&D by increasing our R&D
on fuel cells, gas turbines, reciprocating engines, hydrogen production
and storage, agricultural biomass genetics, and methane hydrates. Through
CSiTE we hope to increase our ability to estimate the potential for
terrestrial carbon sequestration. We want to invest in fundamental R&D
to advance the development of chemical, biological, and engineering
technologies for capturing and sequestering carbon."
David Reichle,
who recently retired from ORNL as an associate director, is in charge
of helping ORNL leverage its capabilities through partnerships with
the other Battelle-managed labs—Brookhaven National Laboratory,
Pacific Northwest National Laboratory, and the National Renewable Energy
Laboratory. These labs and ORNL have formed a DOE carbon management
network. The network will work with core universities and industrial
firms to form an R&D consortium. By broadening the network's skill
base, its R&D proposals for funding in the area of carbon management
should be increasingly competitive.
With such a plan,
ORNL hopes to capture a leading role in DOE's research program for managing
carbon.
Beginning
of Article
Related Web
sites
The
DOE Center for Research on Enhancing Carbon Sequestion in Terrestrial
Ecosystems
ORNL's Buildings
Technology Center
ORNL's Center for
Global Energy and Environmental Studies
ORNL's
Energy Efficiency and Renewable Energy Program
ORNL's Environmental
Sciences Division
