In an article published in the Nov. 1 issue of the journal Science, scientists at the University of Illinois at Urbana-Champaign and their collaborators evaluate known advanced energy technologies for their capability to supply carbon-emission-free energy and their potential for large-scale commercialization. There are no simple solutions, they say.
During the last century, the concentration of atmospheric carbon dioxide has increased from about 275 parts per million to about 370 parts per million. Unchecked, it will surpass 550 parts per million by the end of this century, the article states. Climate models and paleoclimate data indicate that 550 parts per million of carbon dioxide, if sustained, could eventually produce global warming comparable in magnitude to the global cooling of the last Ice Age.
Primary power consumption today is about 12 terawatts, of which 85 percent is fossil-fueled.
"As world population increases and we strive for a higher standard of living -- particularly in the developing nations -- more energy will be consumed, with an attendant rise in carbon dioxide emissions," said Michael Schlesinger, a professor of atmospheric sciences at Illinois and a co-author of the paper. "We must limit the levels of emissions at some point, and that means we will have to replace fossil fuels with alternative sources that eliminate or significantly reduce the amount of carbon emissions."
The most effective way to reduce carbon dioxide emissions while continuing to support economic growth and equity is to develop revolutionary technologies for energy production, distribution, storage and conversion, the article states.
Although some alternative energy sources exist -- wind power, solar and nuclear fission, for example -- they are more expensive than fossil fuels and therefore less likely to be implemented on a grand scale. "An effective energy policy would not focus on just one of the many possible alternatives," Schlesinger said. "There is no clear winner at this time that could fully replace fossil fuels."
Another possible approach is sequestration -- where carbon dioxide emitted from fossil fuels would be collected and stored in trees, oceans and other potential reservoirs.
"While carbon capture and sequestration could eliminate the carbon dioxide emissions from fossil fuels, the technology is still in its infancy, and much work remains to make it viable," said Atul Jain, a professor of atmospheric sciences at Illinois and a co-author of the paper.
The message presented in the article is clear, Jain said. "To reduce carbon dioxide emissions and stabilize the climate, we must switch to alternative energy sources. We need to invest in new technologies and make them cost effective."
The article concludes: "Combating global warming by radical restructuring of the global energy system could be the technology challenge of the century. É Although regulation can play a role, the fossil fuel greenhouse effect is an energy problem that cannot be simply regulated away."
Researchers collaborating on the project are from Columbia University, Exxon Mobil Research and Engineering Co., Lawrence Livermore National Laboratory, Massachusetts Institute of Technology, McGill University in Canada, the National Aeronautics and Space Administration, the National Center for Atmospheric Research, the Naval Research Laboratory, New York University, University of Arizona, University of California at Irvine and University of Houston. Martin Hoffert of New York University was the lead author of the article.
The U.S. Department of Energy funded the project.