The world will need to make maximum use of every available source of energy to satisfy the sharp increase in energy demand over the next quarter-century, according to experts addressing a two-day workshop here on energy and the environment.
And to mitigate the environmental impact of energy use, the U.S. and other nations must achieve greater efficiency in electrical power generation, while switching as much as possible from fossil-fuel to renewable energy sources.
“Total energy generation worldwide over the next 25 years,” said Ed Levy, director of Lehigh’s Energy Research Center
, “is projected to rise by as much as 44 percent, because of population growth and greater use of electrical devices.
“To accommodate that demand, we will need to make use of every electrical generating option available. Windmills, hydroelectric, biomass, solar—we’ll need them all.
“And we will have to build more nuclear-power plants.”
Levy was one of two dozen national experts, including six from Lehigh, to give presentations at “Balancing Energy and the Environment: An Exploration of Future Research Needs,” a workshop held Oct. 31 and Nov. 1 in Iacocca Hall. More than 180 people attended.
The event was sponsored by the P.C. Rossin College of Engineering and Applied Science
and the College of Arts and Sciences
. Levy served as co-chair of the workshop, along with Bruce Koel
, vice provost for research, and Dork Sahagian
, director of Lehigh’s Environmental Initiative.
Levy’s comments were echoed by Trang Nguyen, director of the National Science Foundation’s Energy for Sustainability Program, who spoke of a more distant future.
“If the human race is to last until the next millennium,” said Nguyen, “the only viable source of energy will be nuclear fusion, because no fossil fuels will be left.
“In the near term, however, we have to become more efficient in existing energy-generation processes and look for other sources of renewable energy, including wind, solar and biomass. We have to do things wisely and worry about the environment.”
Improving on a successful record
Levy, who spoke on clean coal technologies, said the U.S.’s 1,500 coal-fired power plants have made significant progress in the past 35 years in curbing pollution, especially precipitates, sulfur-dioxide and nitrogen oxides (NOx), while tripling the total amount of power generated.
The plants, which generate 50 percent of the nation’s electricity, have made reduction of carbon-dioxide emissions their top priority, Levy said. CO2 emissions are projected to double by 2030, he added, if no changes are made to plant operating conditions.
To limit CO2, the electrical power plants are relying on two techniques known as carbon capture and carbon sequestration, Levy said.
“These techniques have the potential to get nationwide CO2 emission levels below the point they were at in 1990. They will both cost an enormous amount of money and time but we have to make that investment.”
Carbon capture, or the removal of CO2 from power-plant flue gas, can be accomplished by improving combustion efficiency, usually with oxygen, by physically separating CO2 from flue gas with scrubbers or sorbents, and by gasifying coal with oxygen. Carbon sequestration involves the pumping of CO2 into geological formations below the earth’s surface.
Pollution emissions can also be reduced, Levy said, by improving the overall efficiency of power plants, a feat that can be achieved by increasing steam pressure and temperature, by optimizing combustion with sensors and controls technology, and through other innovative techniques.
“The goal is to use less coal to produce more energy,” said Levy. “To do that, we need contributions from mechanical engineers, materials scientists, chemical engineers, computer scientists, physicists, chemists and electrical engineers—in short, just about everyone in science and engineering.”
The role of materials
A major factor complicating the quest for greater efficiencies, said John DuPont, the ERC’s associate director, is that many coal-fired power plants in the U.S. were built in the 1950s and 1960s and have exceeded their design lifespan of 30 years. In addition, the cost of building a typical new coal-fired plant runs about $2.4 billion—or $3 billion if it is equipped with carbon-sequestration capabilities.
Age, combined with the demands imposed by pollution-control equipment, causes severe stress to the miles of metal routing tubes contained in a power plant, said DuPont. Altering a plant to fulfill NOx standards, for example, can accelerate corrosion to pipes and tubes, causing them to fail, and sometimes necessitating shutdowns that cost plants $250,000 to $850,000 a day.
A crucial factor in optimizing the performance of plant boilers is the selection of the material used to coat boiler tubes and pipes, said DuPont, who is a professor of materials science and engineering. But even the best materials and alloys are vulnerable to pressure, high temperatures and several types of fatigue.
Better materials, said DuPont, are a “key enabling technology” not only for improved coal-fired plants, but also for next-generation nuclear-power plants and the safe storage of spent nuclear fuel. DuPont said his research group is evaluating the performance of new materials and alloys, developing long-term life-prediction models and studying safe nuclear-waste containers.
Arnold Kritz, Lehigh professor of physics and an internationally renowned expert in nuclear fusion, said fusion promises to provide clean, safe, abundant energy—once scientists and engineers learn how to produce it economically.
An international consortium called ITER
, which consists of the U.S., the European Union and five other nations, is building a $10-billion reactor in southern France, Kritz said, with the goal of producing 10 times as much fusion energy as the amount of energy required to run the reactor. The reactor will be completed in 10 years.
Fusion, the process by which the sun produces energy, occurs when isotopes of hydrogen combine under great pressure to produce helium. Kritz and Eugenio Schuster
, assistant professor of mechanical engineering and mechanics, head up Lehigh research groups that work with scientists at the world’s major fusion research centers.
Posted on Friday, November 02, 2007