New energy resources to significantly reduce global carbon dioxide emissions by the end of the century is “the grand challenge” of the 21st century, according to energy expert Franklin “Lynn” Orr, a Stanford University chemical engineer and director of the university’s Global Climate and Energy Project.

Left to right: Franklin "Lynn" Orr, Stanford University, Theodore Tsotsis, chairman of the USC Viterbi School Mork Family Department of Chemical Engineering and Materials Science, Paul Hansma, UC Santa Barbara, and Priya Vashishta, a professor in the Mork Family Department.

Orr and Paul Hansma, a leading physicist at the University of California, Santa Barbara, were guest speakers at the second in a series of centennial lectures hosted by the Viterbi School of Engineering to commemorate 100 years of engineering at USC.  Orr presented some of the latest and most promising research in the ongoing worldwide debate on energy alternatives in the coming century. Hansma discussed  the molecular mechanisms that nature uses to control biomineralization, which plays a role in the development of renewable energy resources.  
 
In “Fueling the Future: Opportunities and Challenges in Energy and the Environment,” Orr introduced a variety of research projects in solar energy, hydrogen generation, and other renewables, calling them the pathway to sustaining a planet that will house approximately 9 billion people by the end of the century.    

“Reducing carbon dioxide emissions enough to have an impact is the issue,” he told an audience of USC faculty, staff and students Jan. 26.  “We need a wide-ranging portfolio of energy technologies, improved efficiency, and managed carbon uptake, each contributing in a significant way, to meet that challenge.”

Orr is the Keleen & Carlton Beal Professor of Petroleum Engineering at Stanford University. His research focuses on the interactions of fluid phase behavior with multiphase flow in porous media; the design of gas injection processes for enhanced oil recovery; and C02 sequestration in subsurface porous media.  He joined the Stanford faculty in 1985 and served as dean of Stanford's School of Earth Sciences from 1994 to 2002.

Buildup of Greenhouse Gases
He said the continuing buildup in the atmosphere of greenhouse gases, such as carbon dioxide and methane, will result in a 2-to-6 degree Celsius temperature rise by the end of the century.  Greenhouse gases, produced by the burning of coal and fuels derived from oil, include carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons (CFCs), which are used primarily as refrigerants.

Franklin "Lynn" Orr

Carbon dioxide is the most significant of these gases; there is 25 percent more CO2 in the atmosphere today than there was a century ago, he said.

Researchers at the Global Climate and Energy Project (GCEP) are investigating the most viable energy technologies aimed at greatly reducing these greenhouse gas emissions. GCEP is a collaborative effort of the scientific and engineering community aimed at conducting fundamental, pre-commercial research to support the development of an alternative global energy system to fossil fuels.

Current research falls into a number of technical areas, including solar energy, nanostructured photovoltaics, and a broader range of fuel cells; potential breakthroughs in energy conversion through biological processes; and novel approaches to the area of capture, separation and geologic sequestration of carbon dioxide.  

Among the variety of projects Orr described was one investigation in “biohydrogen generation” that is aimed at “making a cost-effective and environmentally benign biofuel.” The process uses  yeasts that are capable of  producing ethanol from waste plant material.

Studying Biomineralization
In his talk, “Molecular Mechanics of Bone Fracture,” Hansma described some of the processes that can be replicated in the laboratory to develop high-performance micro-laminate composites.  

Using the atomic force microscope, Hansma has analyzed the construction of abalone nacre to gain an unprecedented insight into what makes abalone shell so tough yet so lightweight.  From these studies, he concluded that the “glue” that  holds the nacre tablets together plays an integral role in maintaining the strength and fracture resistance of the shell. That led the team into other, more exciting biocomposites, such as bone, he said.

The durability and fracture resistance of human bone has become a major focus of osteoporosis research, primarily due to an increase in the disease arising from an aging population that is living longer.     

“We are observing, for the first time, on a microscopic scale, what actually happens when bone fractures,” Hansma said.  “And as it turns out, human bone has the same molecular ‘glue’ that we see in abalone shell holding it together.”

 

Paul Hansma

 

At the molecular level, that glue consists primarily of “nanoscale mineral crystals and a complex organic matrix,” which begins to pull apart, causing microcracks, tiny fractures and osteoporosis, he said. That discovery may influence the direction of osteoporosis research and pharmaceutical therapies, which up until now, have concentrated solely on bone remodeling processes that occur over a lifetime.