Business Opportunities at the Forefront of Scientific Research 5 th - - PowerPoint PPT Presentation

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Business Opportunities at the Forefront of Scientific Research

5th Annual Alumni Business Conference “Hot Topics in Business” March 26, 2010

• Dr. Raymond L. Orbach

Director, Energy Institute University of Texas at Austin

• rbach@energy.utexas.edu

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Essential Role of Basic Science

• Today’s energy technologies and infrastructure are rooted in 20th Century

technologies and 19th Century discoveries—internal combustion engine, incandescent lighting.

• Current fossil energy sources, current energy production methods, and current

technologies cannot meet the energy challenges we now face.

• Incremental changes in technology will not suffice. We need transformational

discoveries and disruptive technologies.

• 21st Century technologies will be rooted in the ability to direct and control matter

down to the molecular, atomic, and quantum levels.

Watt Steam Engine, 1782 Four-stroke combustion engine, 1870s Bio-inspired nanoscale assemblies – self-repairing and defect-tolerant materials and selective and specific chemical reactivity.

Mn Mn Mn Mn O O O O O O Mn Mn Mn Mn O O O O 2H2O 4H+ + 4e-

photosystem II Quantum Control of Electrons

Separating electrons by their spin for ―spintronics‖ and other applications of electron control.

Forefront of Scientific Research

Three Opportunities That Matter:

Sunlight to Fuels – production of H2 without generation of CO2 (Bard) Electrical Energy Storage at baseload levels (Goodenough) Offsetting the cost of CO2 capture & pressurization by production of natural gas (Pope)

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Sunlight to Fuels – Production of H2 without generation of CO2

Imagine: Direct conversion of sunlight to chemical fuels without use of plants or microbes: artificial photosynthesis

• Sunlight provides by far the largest of all carbon-neutral energy sources – more

energy from sunlight strikes the Earth in one hour (4.6 x 1020 joules) than all the energy consumed on the planet in a year.

• Despite the abundance, less than 0.1% of our primary energy derives from

sunlight.

• Sustainable energy will involve the conversion of solar energy economically and

efficiently to chemical fuels and electricity.

• Identification of new materials that can efficiently absorb sunlight and then use that

energy to catalyze a) splitting water into clean hydrogen fuel, and b) converting CO2 to fuels.

• Professors Allen J. Bard and Buddie Mullins are examining novel semiconducting

metal oxides as promising photoelectrocatalysts.

• Fabrication of columnar films at the nanoscale to generate a large contact surface

area between the active electrode material and the electrolyte, and a short path for electrons to travel in order to minimize electron-hole recombination.

Photosystem II uses solar energy to break two molecules

• f water into one oxygen

molecule plus four hydrogen ions, meanwhile freeing electrons to drive other reactions. A multi-layered triple- junction solar cell designed to absorb different solar photons.

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• Traditional photoelectrochemical water splitting is limited by

a cumbersome planar, two electrode configuration for light absorption and H2 and O2 generation. Current generation of semiconductors used for absorbing visible solar spectrum are intrinsically unstable. Precious metals (Pt, Pd) are needed for H2 evolution.

• One key constraint in photon absorbers for solar energy

conversion is that the samples need to be thick enough for sufficient absorption, yet pure enough for high minority carrier length and photocurrent collection.

• New nanorod configuration was recently developed to
• rthogonalize the directions of light absorption and charge

carrier collection, i.e. it separates longitudinal light absorption from transverse carrier diffusion to reactive surface.

• The short diffusion paths to reaction broadens usable

materials to include earth abundant, resistive

• semiconductors. Opposing nanorod configuration with

conductive ion membrane allows for compact device with inherent separation of O2 and H2 gas.

• High surface-to-volume ratio of nanostructure decreases

current density and permits use of broad range of new metals as sites for H2 and O2 evolution.

Sunlight Driven Hydrogen Formation

ligh t

n-WO3 p-Si Solar powered water splitting scheme incorporating two separate semiconductor rod-array photoelectrodes that sandwich an electronically and ionically conductive membrane.

Spurgeon JM, Atwater HA, Lewis NS, Journal of Physical Chemistry C, 112, 6186-6193 (2008).

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Baseload Electrical Energy Storage

• Many renewable energy sources such as wind and solar

are intermittent — To make these energy sources truly effective and integrate them into the electrical grid, we need significant breakthroughs in electrical energy storage technologies.

• Current lithium batteries use a liquid electrolyte and solid

insertion-compound electrodes. They suffer from limitations in the amount of energy than can be stored in the battery per unit weight and volume, as well as high cost and safety concerns.

• Professors Goodenough and Manthiram are exploring the

use of a solid Li+ -ion or Na+ -ion electrolyte that separates a non-aqueous solution from an aqueous cathode.

• Electrical energy can be converted into chemical energy in

the cathode, that can then be pumped into tanks and stored until needed. The liquid can then be pumped back into a fuel cell, converting chemical energy into electrical energy, providing electricity when needed.

Imagine: Storing electrical energy generated by intermittent sources (wind, solar) at baseload

magnitude, enabling usage when needed most and reducing the need for “peaking” generation

Energy and power densities of various energy storage devices. Electrochemical capacitors bridge between batteries and conventional capacitors.

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Nanomaterials are Key to Improved Battery and Capacitor Storage

• Current battery consists of 2-dimensional structures of electrodes separated by electrolytes in a planar geometry. Nanostructured

architectures for power storage (batteries, fuel cells, ultracapacitors, photovoltaics) provide many advantages over existing technologies to minimize power losses, improve charge/discharge rates and enhance energy densities.

• Three-dimensional structures can further revolutionize the ability of these devices to accumulate, store and release charge at

unprecedented levels. Electrodes in these architectures will consist of interconnected ~10nm domains and mesopores (10-50nm). Ultrathin, conformal and a pinhole-free separator/electrolyte are electrodeposited onto the electrode nanoarchitecture. Low melting point metals (mp<200°C) or colloids fill the remaining mesoporous volume. These designs have the potential for higher performance by separating the length scales for electronic and ionic transport, thereby accessing previously unachievable power and energy densities.

• In addition, new nanoscale materials could be produced by self-assembly. Nature uses self-assembly to produce materials with

specific functionality. These bio-inspired concepts have potential for the development of novel nanomaterials and architectures to enhance the development of chemical energy storage systems. The ability to apply these techniques to the fabrication of battery electrodes could be revolutionary.

Oxide or carbon (electrode)

—

+

~ 10 nm Polymer (separator/ electrolyte) Nanoparticle (electrode)

Current Battery Structure 3-D Nanoscale Electrochemical Battery Cell Structure Positive Electrode Electrolyte/Separator Negative Electrode

Long et al., Chem. Rev 104, 4463–4492, 2004; Fischer et al., Nano Letters, 7, 281, 2007

Offsetting the cost of CO2 capture & pressurization by production of natural gas

• Pulverized coal fired power plants in the U.S. product ~ 2 Gt of CO2

each year. In order to capture and pressurize CO2 to a supercritical liquid, ~ 1/3rd of the of the power plant’s energy is expended, making it uneconomical in today’s market.

• Professor Gary Pope has suggested injecting the supercritical CO2

into geopressured methane saturated aquifers, releasing natural gas that can be either sold or drive a combined cycle generator,

• ffsetting the cost of CO2 capture and pressurization.
• When CO2 is mixed with brine saturated with methane, the CO2 will

dissolve at its equilibrium solubility concentration, and the methane will come out of solution as methane gas. The methane gas will flow to the top of the aquifer and form a gas cap. About 1/3rd of this gas can be produced from wells completed in the gas gap.

• The total in-place volume of methane for Tertiary sandstones below

8,000 ft. in the Texas Gulf Coast is ~ 690 TCF, so ~ 230 TCF is recoverable, sequestering ~ 3,450 TCF of CO2 (~ 170 Gt).

• Compare with ~ 1,700 TCF of methane from all sources in U.S.

Summary: Opportunities that Matter

Sunlight to Fuels – production of H2 without generation of CO2 (Bard): The oil industry uses large amounts of H2 produced from CH4+2H2O=4H2+CO2 . Hence, sunlight- to-fuels would displace a major source of CO2. Electrical Energy Storage at baseload levels (Goodenough): The reserve margin of ~20% can be reduced for wind and solar energy, thereby increasing penetration into the grid of renewable energy. Offsetting the cost of CO2 capture & pressurization by production of natural gas (Pope): Reducing the cost of CO2 capture and pressurization, and storage in saline aquifers, can make sequestration economically possible.

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