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2012 Distinguished Lecturers

In 2008, GCEP established a distinguished lecturer program where our leading principal investigators travel to each of the sponsor's research centers for a day-long visit. The lecturers present their research highlights and engage in dialogue with members of the sponsor's in-house R&D team.

Kate Maher Photo

Distinguished Lecturer: Katharine Maher
Department of Geological and Environmental Sciences
School of Earth Sciences
Stanford University

Presentation Title: The Reactivity of CO2 in the Subsurface (PDF, 49.6 Mb)

Abstract:  Injection of large volumes of CO2 into the subsurface is an essential strategy for both enhanced energy extraction and the disposal of waste products derived from energy generation. As the CO2 interacts with mineral surfaces and dissolves into local fluids, the ensuing chemical reactions transform the subsurface environment and impact the fate and transport of CO2 and other fluids. In this talk, Professor Kate Maher presented results from experimental studies, geochemical modeling and field observations that provide important insights into the reactivity of CO2-bearing fluids with mineral surfaces in two key types of geologic reservoirs: crystalline rocks associated with enhanced geothermal systems and direct mineral carbonation, and sedimentary formations associated with hypersaline aquifers. In addition to providing an overview of key reactions occurring at mineral surfaces, she will discuss approaches to both enhance the kinetics of mineral dissolution and carbonation, and to control the evolution of porosity and permeability of natural rocks proposed as repositories for CO2.

GCEP: Maher is the lead principal investigator on the GCEP research program entitled, "The Reactivity of CO2 in the Subsurface." She recently completed work on the GCEP effort "Geological Sequestration of CO2 - An Exploratory Study of the Mechanisms and Kinetics of CO2 Reactions with Mg-Silicates."

Biography: Maher is an assistant professor in the Department of Geological and Environmental Sciences at Stanford. She received her B.A. from Dartmouth College in Environmental Earth Science in 1999, her M.S. in Civil and Environmental Engineering from U.C. Berkeley in 2001, and her Ph.D. in Earth and Planetary Sciences from U.C. Berkeley in 2005. Prior to coming to Stanford in 2007, she was a Mendenhall Postdoctoral Fellow with the U.S. Geological Survey in Menlo Park, CA.

John Ralph Photo

Distinguished Lecturer: John Ralph
Department of Biochemistry
DOE Great Lakes Bioenergy Research Center
University of Wisconsin, Madison

Presentation Title: Efficient Biomass Conversion: Delineating the Best Lignin Monomer-Substitutes (PDF, 89.3 Mb)

Abstract: Lignin remains one of the most significant barriers to the efficient utilization of cellulosic substrates in processes ranging from natural ruminant digestibility to pulping and biofuels production. The observed resilience and metabolic plasticity of the lignification pathway suggests that lignin can be engineered and more readily extracted. Incorporating new phenolics into lignin produces a polymer with a different structure and therefore different chemical and physical properties. Some of these modifications allow for improved biomass conversion efficiencies or alternatively can be considered for improved carbon sequestration.

In this lecture, Professor John Ralph described his GCEP investigations into various approaches toward identifying viable sets of lignin monomer-replacements, demonstrating the logic behind some promising approaches, such as introducing "zips" into the lignin backbone to significantly simplify delignification, that could reduce the processing costs and improve the net energy balance of biomass conversion.

GCEP: Ralph is the lead principal investigator for the GCEP research program, "Efficient Biomass Conversion: Delineating the Best Lignin Monomer-Substitutes."

Biography: Ralph, a professor in the Department of Biochemistry at the University of Wisconsin and the Plant Improvement Group Leader for the DOE Great Lakes Bioenergy Research Center, has been engaged in cell wall chemistry/biochemistry, with an emphasis on lignins, for some 38 years. He has published more than 230 papers and is recognized by the Institute for Scientific Information as one of the most highly cited authors, having "exceptional citation count in the field of Agricultural Science." A highlight of his career has been the ability to productively collaborate on 31 publications with GCEP partners. In 2005, he was elected a fellow of the American Association for the Advancement of Science.

His research interests focus on general plant cell wall chemistry/biochemistry with a particular emphasis on lignin biosynthesis (including pathway delineation), lignin chemistry and lignin reactions. Ralph’s research group is also involved in developing syntheses of biosynthetic products, precursors, intermediates, molecular markers, cell wall model compounds; method development in solution-state NMR (particularly of cell wall components, especially lignins); cell wall cross-linking mechanisms; and developing methods for wall structural analysis (chemical/degradative, NMR, GC-MS, etc.).

Ralph received his B.Sc. (Hons) in Chemistry at the University of Canterbury, New Zealand in 1976 and his Ph.D. in Forestry/Chemistry at the University of Wisconsin-Madison in 1982. He has held three long-term appointments at the New Zealand Forest Research Institute (1974-1987), the U.S. Dairy Forage Research Center and the Forestry and Biological Systems Engineering departments at the University of Wisconsin-Madison (1988-2008) and since 2008, the Department of Biochemistry and the Great Lakes Bioenergy Research Center in Madison, Wisconsin.

Michael McGehee Photo

Distinguished Lecturer: Michael McGehee
Department of Materials Science and Engineering
School of Engineering
Stanford University

Presentation Title: Combining Organic and Inorganic Solar Cells to Achieve Power Conversion Efficiencies > 20%

Abstract: There is a need for photovoltaic technologies with power conversion efficiencies (PCEs) exceeding 20% that can be produced with a module cost under $0.50 per Watt. Making hybrid tandems with organic solar cells on top of silicon or CIGS solar cells is one of the most promising approaches to meeting this need. Organic photovoltaics have a significant processing advantage over inorganic alternatives for the top cell in a tandem, because they can be easily deposited by solution processing techniques at or near room temperature without damaging the bottom cell. Furthermore, the cost of the organic layers themselves has been estimated to be less than $10/m2, so that they can be added to a variety of commercial inorganic cells with little addition cost.

The McGehee research group studies the fundamental electronic and chemical processes that occur in organic photovoltaics. The group has modeled hybrid tandems and found that organic photovoltaics are just starting to have the performance that is required to improve silicon or CIGS solar cells. Within a few years, hybrid tandems could be 20% to 35% more efficient than the bottom cells alone. The key challenges to making this approach commercially viable will be increasing the voltage of organic solar cells while maintaining an internal quantum efficiency > 90%, depositing high-quality transparent electrodes without damaging the organic semiconductors, and obtaining > 20-year lifetime.

In his talk, Professor Michael McGehee will discuss how to obtain the desired efficiency and lifetime in organic photovoltaics and demonstrate how spray transparent electrodes based on silver nanowires can outperform conventional electrodes based on indium tin oxide.

GCEPMcGehee is the lead principal investigator on the GCEP project entitled,
Advanced Electron Transport Materials for Application in Organic Photovoltaics (OPV)

He has also been the principal investigator on the following GCEP efforts:

Biography: At Stanford, McGehee is an associate professor in the Materials Science and Engineering Department, director of the Center for Advanced Molecular Photovoltaics and a senior fellow at the Precourt Institute for Energy. His research interests are patterning materials at the nanometer length scale, semiconducting polymers and solar cells. He has taught courses on nanotechnology, organic semiconductors, polymer science and solar cells. McGehee received his undergraduate degree in physics from Princeton University and his Ph.D. in materials science from the University of California -Santa Barbara, where he did research on polymer lasers in the lab of Nobel laureate Alan Heeger. He is the recipient of the 2007 Materials Research Society Outstanding Young Investigator Award, the 2001 DuPont Young Faculty Award and the Mohr Davidow Innovators Award. He is a technical advisor to Nanosolar, PLANT PV and Plextronics. His students have founded three solar cell startup companies.



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