Transcript Photosynthesis - University of Tennessee

Sustainability and Technology: Are They
Compatible?
Our Energy Future as a Case Study
Paul Frymier
Dept. of Chemical and Biomolecular Engineering
University of Tennessee, Knoxville
[email protected]
Evolution of a Research
Engineer
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Graduated from NC State in 1985 with a BS in Aerospace Engineering,
again in 1987 with an MS in Aerospace Engineering
Joined the US Peace Corps and spent 2 years teaching mathematics
at a junior high level in The Gambia, West Africa
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Spent time thinking and reading about the interaction of technology, civilization, and
energy
Investigated the state of alternative energy research in graduate schools in the US
Started graduate school in Chemical Engineering at the
University of Virginia in 1990, working on bioremediation
related problems.
Graduated from UVa with a PhD in ChemE in 1994.
Received appointment in Chemical Engineering at UTK in
1995. Research work as evolved from bioremediation, to
bioprocessing, to toxicity monitoring to biological
mechanisms for generating fuels
What is Technology?
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Technology is the process by which humans modify nature to meet their
needs and wants.
Technology artifacts: computers and software, aircraft, pesticides, watertreatment plants, birth-control pills, microwave ovens, etc.
Technology includes the infrastructure, knowledge and processes used to
create and to operate technological artifacts
Technology is a product of engineering and science
Engineering is "design under constraint," with
science-the laws of nature-being one of a number
of limiting factors engineers must take into
account.
Other constraints include cost, reliability, safety,
environmental impact, ease of use, available
human and material resources, manufacturability,
government regulations, laws, and even politics.
National Academy of Engineering , “ What is Technology? ”, 2009.
Quality of life
Quality of life
Quantity of tech. artifacts
The Interaction of Technology
and Quality of Life
Technology
Quantity tech. artifacts
Technology
Axiom: Sustainability of human enterprise leads to higher
quality of life.
Three Dimensions of
Sustainability
• Environmental sustainability: maintaining a stable resources base,
avoids over-exploitation of renewable resource systems or
environmental sink functions, and depletes non-renewable
resources only to the extent that investment is made in adequate
substitutes
• Economic sustainability: producing goods and services on a
continuing basis, maintaining manageable levels of government
and external debt, avoiding sectoral imbalances that damage
agricultural or industrial production.
• Social sustainability: fairness in distribution and opportunity, and
adequate provision of social services including health and
education, gender equity, and political accountability and
participation.
Harris JM, Goodwin NR. A survey of sustainable development: social and economic dimensions,
frontier issues in economic thought, 2001.
Social Sustainability
• A case study of social acceptance of four alternative energy
technologies conducted in the municipality of Kil in west central
Sweden
• Assessed knowledge, perception, and fear associated with four
chains of energy technologies
• Indicated that respondents have such a low level of information
and knowledge about new energy technologies that they are
unable to discriminately rank them.
• Hampered participation in discussions and
decision making about technologies for which
public funds would be spent.
• Öresund Bridge connecting southern Sweden
and Copenhagen: implemented in 5 years after
discussions regarding its plan lasted for 100
years.
Assefa ,G and Frostell, B, Technology in Society, 2007.
Questions for Consideration
• Over time, has technology led to an
increase in the sustainability of fuel
production?
• How will future technological advances in
the production and utilization of fuels impact
their sustainability?
• What are the potential energy senarios
for the future?
• How can research engineers provide
for a sustainable future?
• Are “more sustainable” technologies
good enough?
What Do Engineers Do?
• Engineers respond to society’s expressed needs by
creating new technology
• They attempt to understand the expressed needs in terms
of a problem to be solved and the constraints to which the
solution is subject
• Their objective is to create the most optimal solution
(within reason) subject to physical, environmental,
economical, societal, and legal constraints.
• The product of their work is usually technology and
technology artifacts
Fuels, Energy, and Power
• “Energy” is the ability to do work, the measure of the
amount of work done or energy used (kW-hr). Power is
the rate at which work is done or energy is used (kW) .
• Fuels are sources of concentrated energy.
• Nearly all sources of energy and crude fuels on Earth
are forms of solar energy; exceptions are geothermal
energy and radioactive material (uranium).
• Nearly all technology artifacts and
the generation of technology require
a concentrated source of energy.
Evolution of Fuels and Energy
Use
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Fire was used by early human ancestors in northern China more than
400,000 years ago.
The cost of energy limited the growth of technology until fossil fuels
came into use, a little less than three hundred years ago. Currently fossil
fuels supply 75% of the energy used in the world.
Coal
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The Romans were mining coal from England over 2000 years ago.
The first documented mining of coal in the US was in 1748. Today we produce over one
billion tons per year.
Natural Gas
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The ancient Persian"eternal fires" around 100 to 125 A.D. probably were from natural gas
ignited by lightning
In 1821 in Fredonia, New York, William A. Hart drilled a 27 foot deep well in an effort to
get a larger flow of gas from a surface seepage of natural gas. This was the first well
drilled to obtain natural gas.
Evolution of Petroleum
• American Indians used petroleum for paint, fuel, and medicine.
• In 1859 George Bissell and a group of businessmen founded the
Seneca Oil Company. Kerosene had become valuable because
of an 1885 whale shortage.
• The Seneca Oil Company hired Edwin Drake to drill for oil in
Titusville , Pennsylvania. Found oil at a depth of 69 feet,
produced thirty-five barrels a day, sold for $20 a barrel.
• Early kettle stills produced 3 “cuts”
• Initially, only the middle (kerosene) “cut” was considered to have
any value. The portion which contained the heavier oils and the
lighter compounds in gasoline were discarded by pouring on the
ground
Dawn of the Era of Petroleum
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Oil market fell with the invention of the light bulb. 1882: Edison started
the first commercial electrical generating plant, fueled by coal. By the
turn of the century, there were over 18 million lightbulbs in use in the
U.S.
Interest in light “cut” in early 1900s as a transportation fuel.
In 1910, there were about 8,000 registered vehicles, and by 1920 there
were 23 million cars. (Note: in the early 1900s, most cars were electric.)
When WWI began, horse was the primary mode of transportation; one
horse for every three soldiers, horses required 10x food.
At start of war, Britain it had only about 800 motor vehicles devoted to
war.
By the end of the war, Britain had 56,000 trucks and 36,000 cars. U.S.
shipped over 50,000 vehicles to Europe and built 15,000 planes.
Previous to WWI, oil was a commodity brought to market by a few
entrepreneurs; after WWI, it was a strategic mineral for which supplies
had to be ensured.
The Nuclear Age
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1939: Bohr comes to America and announces HahnStrassman-Meitner discoveries (calculated the energy
associated with pushing two positively charged nuclear
fragments apart to be approximately 200 million
electron volts (MeV) per uranium atom. By comparison,
the most energetic chemical reactions release
approximately 5 eV per atom.)
1942: The experimental nuclear reactor Chicago Pile1 demonstrates the first
fission “ignition”
1951: The Experimental Breeder Reactor I (EBR I) goes critical in the desert of
Idaho, atomic energy was successfully harvested for the first time. It lit 4 light
bulbs.
The Soviet nuclear power station Obninsk 110 km SW of Moscow started on June
1, 1954, and was connected to the grid on June 26, 1954.First nuclear reactor to
be connected to a power grid, in Obninsk,. It would power 2000 homes today.
In Dec, 1957, the Shippingport Atomic Power Station, in Beaver County,
Pennsylvania (25 miles from Pittsburgh) was started.
In 2007, there were 104 nuclear reactors generating power in the US.
The Concept/Reality of “Peak Oil”
Note: there is also a “Peak Coal” scenario, measured reserves
for coal are longer lasting, peaks on the order of 100 years.
Current and Near Term Total
Energy Picture
Total average worldwide energy
consumption rate: 16 TW
Source: Exxon Mobil: The Outlook For Energy, www.exxon.com
Energy Information Administration, U.S. Department of Energy, “World
Consumption of Primary Energy by Energy Type and Selected Country
Groups, 1980-2004“, 2006.
British Petroleum, "BP Statistical review of world energy June
2006“, 2006.
Alternate Energy Futures
• Back to prehistory- use fossil fuels to
exhaustion, then lights out!
• Global Climate Change: What if Al Gore is an
optimist?
• Nuclear fission
• Sun on Earth- nuclear fusion
• Biomass-derived energy
• Photovoltaics- organics, bio-hybrids, inorganics
• Solar hydrogen
Back to Pre-History
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Real scenario (David Price, Population and
Environment: A Journal of Interdisciplinary Studies,
Volume 16, Number 4, March 1995, pp. 301-19)
Proponents believe no stable carrying capacity exists
Humans evolved ability to exploit energy reserves on
planet, technology drives resource depletion
Coal could meet current US demand (for coal only) for
around 250 years, nat. gas around 100 years.
Technology and energy reserves make it possible to
exploit resources at a dramatically increasing rate (10
cents buys daily energy output of an average human)
Reindeer of St. Matthew Island (Bering Sea). 4 inch
layer of lichen. 29 reindeer introduced in 1944. By
1957; pop. Was 1,350; by winter of 1963, was 6,000,
Lichen depleted, following spring, 41 females and one
apparently dysfunctional male were left alive.
Growth of reindeer herd introduced to St. Matthew
Island, Alaska (After Klein, 1968:352).
Growth of worldwide human population (Adapted from
Corson, 1990:25).
Global Climate Change
Trumps Energy Exhaustion
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New, carbon neutral fuels and energy producing
methods can’t be developed in time to avert
catastrophic global warming
Polar ice cap melts, seas rise (est.1-3 meters)
habitable land is reduced
Shifts in arable land, water resources, disease
patterns will increase global conflict
At the least, there will be serious political, social,
human health consequences.
Carbon-based combustible fuels also have other
issues (NOx, SOx, ash ponds, mercury, etc.)
Nuclear Fission
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Provides 20% of the world’s electricity
Provides 7% of world’s total energy usage
Cost/(KW/hr) is currently similar to fossil fuels
After construction, reactors have essentially zero
emissions of smog or CO2
• There are 440 nuclear power reactors in 31 countries,
with 30 under construction
• They produce a total of 351 billion watts of electricity
• Watts Bar 1, which came on-line in February 7, 1996,
was the last U.S. commercial nuclear reactor to go
on-line as of today.
Nuclear Fission- Prospects
for the Future
• Current average energy consumption rate: 16 TW
• Estimated energy consumption rate by 2050: 32 TW
• Estimated world uranium deposits: Proven, around 80
years; guestimated: a few hundred years? (once-through
reactors)
• Requires ten thousand 1.6
MW reactors in the next 41
years to meet anticipated
additional projected need by
2050 (0.6 reactors/day)
• PR problem
Nuclear Fusion
• Solar fusion: Hydrogen to helium
• Earth fusion: deuterium and tritium to helium
• Tritium bred in reactor from deuterium and
lithium
• World lithium supply about 100 years
assuming all-fusion energy supply
• Inherently safe, can’t “run away”
• Reactor will be radioactive; half-life around
50 years.
• Technology has yet to be practically
demonstrated.
ITER (International Thermonuclear
Experimental Reactor), Cadarache,
France
Biomass-derived Fuels
• Requires relatively moderate
technology developments
• As a vehicle fuel, compatible with
current technology
• Potentially carbon neutral (or nearly
so)
• Can potentially replace up to 30% of current gasoline use
• Relatively low yields per unit land area
• Require large harvesting, transportation, refining
infrastructure that does not exists
Photovoltaics
• Solar insolation at the Earth’s surface is 6000 times the
current world consumption rate
• Potentially lasts as long as the sun lasts
• PVs produce 10 to 30 times as much energy as
required to produce them.
• On my house, I could get about 1,100 kW-hr of capacity
for $90k, which would meet my current electrical
requirements (excluding transportation, heating, and
hot water), on average (www.dovetailsolar.com)
• Long payback periods (on the order of 15-20 years).
• Only works when the sun is up, affected by clouds, rain,
and by season, partially alleviated by grid connection.
Solar Hydrogen
• Projected fuel yield per unit land area is around 20
times that of switchgrass-derived ethanol
• Does not require expensive liquid separation
• Produces a transportable fuel
• Storage does not require expensive, heavy batteries
• Development in very early stages
• Hydrogen is more difficult to store than liquid fuels
• Conversion to electricity requires fuel cells that use
platinum
Suggestions for Reaching
Sustainability
• A little panic may be appropriate
• Extrapolations of increased energy demand, population, etc. lead to
doomsday senarios
• Highly efficient resource utilization will be a key to any sustainable
future
• Diversity of research still required, no winners have emerged
• All current options will have to be exploited
• Resurgence of nuclear power in at least the mid-term.
• Specific fuels for specific tasks
• For many proposed energy solutions, the devil is in the details
• A lot of energy reaches Earth via the sun, but it is dilute. Any
scheme to capture it will cover a lot of area.
Questions Review
• Over time, has technology led to an increase in the
sustainability of fuel production?
– Pandora’s Box was opened with technology but filled with
technology artifacts
– To date, technology has not increased the sustainability of fuel
production because of its potential to generate more technology
artifacts and help increase population
• What are the potential scenarios for the future?
• How can engineers provide for a sustainable future?
– They can’t. However, they do respond to EXPRESSED needs.
– Coordination along all dimensions of sustainability
• Are “more sustainable” technologies good enough?
– Eventually, no. May be beneficial in short- to mid-term, but we don’t
know what that means, objective evaluations are difficult to come by
Biosynthetic Production of
Hydrogen
• Hydrogen is a promising energy carrier and is clean and potentially
renewable
• It can created as an essentially pure compound (no separation costs)
• Phototrophic organisms evolve H2 by using solar energy and water
• H2 yield equivalent to 50 gal. gas /day/acre
– corn based ethanol (0.6 gal/day/acre)
– soy based biodiesel (0.15 gal/day/acre)
– projected yields of switchgrass produced
ethanol (1.8 gal/day/acre)
Overview of e- Transfer in the Light Cycle of
Photosynthesis
In vitro H+ Reduction to Hydrogen
2H+
H2
• ascorbate as a
sacrificial electron
donor
Light
• cyt c553 or PC as a
soluble electron carrier
• platinum nanocluster
catalyst
Pt
2e-
PSI
cyt c553 or
plastocyanin
Asc-
Asc
Sustained H2 Evolution from Platinized PSI Complexes
NaAsc
injection
cyt c6
injection
cyt c6-free platinized PSI was initially added at time t = 0. 1 mM sodium ascorbate was added
at time t = 7.5 h and cyt c6 was then added at time t = 20.09 h.
Long-term Stability of Hydrogen Evolution
600C
Dialyzed to
remove excess
platinate
250C
Stored at 40C
for 64 days
250C
250C
250C
Time (h)
Average values of H2 evolution at 250C
H2 evolution at 600C increased by 80%.
onset
Our PSI preparation maintain operational
end
0
5
10
15
stability for extended time periods.
Biological-Pt Hybrid Nanoparticle for
Solar Energy-to-Fuel Conversion
Pt
EPA-funded Undergraduate
Design Studies
• Production of hydrogen using live
algae
• Hydrogen gate-price of about $40/kg
established, sustainability not certain
• Competed for Phase II funding at
National Sustainable Design Expo on
the National Mall in DC
• Current project: recovery of
waste glycerol from
manufacture of biodiesel by
production of a compost
accelerant