Anthropogenic emissions of greenhouse gases, especially carbon dioxide, C[O.sub.2], have led to increasing atmospheric concentrations which are mostly responsible for the roughly 0.8[degrees]C global warming the Earth has experienced since the Industrial Revolution. With industrial activity and population expected to increase throughout the rest of the century, large increases in greenhouse gas emissions are projected, with additional and potentially substantial subsequent global warming predicted. Using a powerful PC-based global climate model, global warming is projected for two business as usual cases, as well as simple yet instructive scenarios in which major programs are initiated to limit C[O.sub.2] emissions. This paper provides a brief overview of the forces driving C[O.sub.2] emissions, how different C[O.sub.2] emission trajectories could affect temperature this century, with a focus on power generation mitigation options, and research and development priorities. While much literature exists on various aspects of this subject, this paper aims to provide a succinct integration of our best knowledge of the projected warming the Earth is likely to experience in the decades ahead, the emission reductions that may be needed to constrain this warming to tolerable levels, and the technologies potentially available to help achieve these emission reductions.
In February 2007, the Intergovernmental Panel on Climate Change (IPCC) concluded that:
* "Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level." (1)
* "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic [greenhouse gas] concentrations." (2)
* "The combined radiative forcing due to increases in [carbon dioxide] ... is very likely to have been unprecedented in more than 10,000 years." (3)
* "The total temperature increase from 1850-1899 to 2001-2005 is 0.76[degrees]C [0.57[degrees]C to 0.95[degrees]C]." (4)
* Depending on the assumed greenhouse gas emission trajectory, warming in 2095, relative to pre-industrial levels, is projected to be 1.6 to 6.4[degrees]C. (5)
Given these findings, this paper will examine the critical energy sector with the aim of evaluating the ability of technologies to moderate projected warming. The author will begin with a discussion of the factors that lead to increasing emissions of C[O.sub.2], (6) the critical greenhouse gas, and the anticipated importance of key countries. Next, C[O.sub.2] emissions will be projected into the future for key sectors. The author will then summarize the state of the art of technologies and research and development priorities for the key power generation sector. Finally, the adequacy of research, development, demonstration (R,D,&D) and deployment will be discussed.
Although the scope of this paper is limited to a consideration of power generation technologies that can play a significant role in reducing C[O.sub.2] emissions, it is important to note that availability of such technologies will be necessary but not sufficient to constrain emissions. Since many of these technologies have higher costs and/or greater operational uncertainties than currently available carbon intensive technologies, robust policies will need to be in place to encourage their utilization.
II. FACTORS THAT DRIVE EMISSIONS OF C[O.sub.2]
The World Resources Institute has examined the factors that have driven C[O.sub.2] emissions for key countries in the 1992 to 2002 time period. (7) The factors considered are: Gross Domestic Product (GDP), growth per capita, population growth, carbon intensity growth per unit of energy (more coal in the mix increases this factor), and the growth of energy usage per unit of GDP. …