Natural Gas Green Role

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Some people believe that all energy related problems can be resolved with renewable sources such as solar power or wind power. Maybe in the long term future this will be so. However, in the short term what is the best option for those fuels (energy sources) that we have? MIT (Massachusetts Institute of Technology) has issued a report that states that natural gas will play a leading role in reducing greenhouse-gas emissions over the next several decades, largely by replacing older, inefficient coal plants with highly efficient combined-cycle gas generation. That’s the conclusion reached by a comprehensive study of the future of natural gas conducted by an MIT study group comprised of 30 MIT faculty members, researchers, and graduate students. The findings, summarized in an 83-page report, were presented to lawmakers and senior administration officials this week in Washington. The two-year study, managed by the MIT Energy Initiative (MITEI), examined the scale of U.S. natural gas reserves and the potential of this fuel to reduce greenhouse-gas emissions. Based on the work of the multidisciplinary team, with advice from a board of 16 leaders from industry, government and environmental groups, the report examines the future of natural gas through 2050 from the perspectives of technology, economics, politics, national security and the environment.

Some people believe that all energy related problems can be resolved with renewable sources such as solar power or wind power. Maybe in the long term future this will be so. However, in the short term what is the best option for those fuels (energy sources) that we have? MIT (Massachusetts Institute of Technology) has issued a report that states that natural gas will play a leading role in reducing greenhouse-gas emissions over the next several decades, largely by replacing older, inefficient coal plants with highly efficient combined-cycle gas generation. That’s the conclusion reached by a comprehensive study of the future of natural gas conducted by an MIT study group comprised of 30 MIT faculty members, researchers, and graduate students. The findings, summarized in an 83-page report, were presented to lawmakers and senior administration officials this week in Washington. The two-year study, managed by the MIT Energy Initiative (MITEI), examined the scale of U.S. natural gas reserves and the potential of this fuel to reduce greenhouse-gas emissions. Based on the work of the multidisciplinary team, with advice from a board of 16 leaders from industry, government and environmental groups, the report examines the future of natural gas through 2050 from the perspectives of technology, economics, politics, national security and the environment.

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There are two major ways to make a significant difference in the near term in reducing carbon emissions. One is conservation/using less energy. The other is replacing the oldest, least-efficient coal plants with the most-efficient modern combined-cycle gas plants.

The study found that there are significant global supplies of conventional gas. How much of this gas gets produced and used, and the extent of its impact on greenhouse gas reductions, depends critically on some key political and regulatory decisions.

In the United States, for example, there is a substantial amount of low-hanging fruit available by displacing inefficient power generation with more efficient, lower CO2 emitting gas plants. "That kind of substitution alone reduces those carbon emissions by a factor of three. It does however raise complicated regulatory and political issues that will have to be resolved to take advantage of this potential."  Moniz (one of the authors) said.

Some of the study’s findings:

1. The United States has a significant natural gas resource base, enough to equal about 92 years’ worth at present domestic consumption rates. Much of this is from unconventional sources, including natural gas bearing shales. While there is substantial uncertainty surrounding the producibility of this gas, there is a significant amount of shale gas that could be produced.

Globally, baseline estimates show that recoverable gas resources probably amount to 16,200 trillion cubic feet — enough to last over 160 years at current global consumption rates. Further, this global resource figure, excluding the U.S. and Canada, does not include any unconventional gas resources, which are largely not clearly known in the rest of the world. Russia, the Middle East, and the U.S. have the highest concentration of global gas reserves.

In the U.S., unconventional gas resources are rapidly overtaking conventional resources as the primary source of gas production. The U.S. currently consumes around 22 trillion cubic feet per year and has a gas resource base now thought to exceed 2,000 trillion.

2. Environmental issues associated with producing unconventional gas resources are manageable but challenging. Risks include: Shallow freshwater aquifer contamination with fracture fluids; surface water contamination by returned fracture fluids; excessive demand on local water supply from fracturing operations; and surface and local community disturbance, due to drilling and fracturing activities.

3. In the longer term, the reliability of a system in which renewables assume a baseload role in power generation will require additional flexible natural gas peaking capacity, although this capacity may be utilized for only short periods of the time. Renewables as baseload power, firmed by natural gas generation, will require new regulatory structures to ensure reliability of the system and incentivize the building of flexible gas capacity.

4. The overbuilding of natural gas combined cycle plants starting in the mid-1990s presents a significant opportunity for near term reductions in CO2 emissions from the power sector. The current fleet of natural gas combined cycle units has an average capacity factor of 41 percent, relative to a design capacity factor of up to 85 percent.

Modeling of one large region (largely Texas) suggests that CO2 emissions could be reduced by as much as 22 percent with no additional capital investment and without impacting system reliability by requiring a dispatch order that favors natural gas generation over coal generation; preliminary modeling suggests that nationwide CO2 emissions would be reduced by over 10 percent. At the same time, this would also reduce air pollutants such as oxides of sulfur and nitrogen.

5. A global market in natural gas in which supply sources are diverse and gas prices are transparent, set by supply and demand with price differences based on transportation costs, is desirable for U.S. consumers.

The study makes many recommendations regarding the role of natural gas in a carbon-constrained world, suggesting that policy makers should consider supportive policies in the following areas:

Supply

Power generation

- Natural gas for coal

Transportation

-Remove policy and regulatory barriers to natural gas as a transportation fuel.

Global markets

While the new report emphasized the great potential for natural gas as a transitional fuel to help curb greenhouse gases and dependence on oil, it also stresses that it is important as a matter of national policy not to favor any one fuel or energy source in a way that puts others at a disadvantage. The most useful policies, the authors suggested, are ones that produce a truly level playing field for all forms of energy supply and for demand reduction, and thus let the marketplace, and the ingenuity of the nation’s researchers, determine the best options.

Illustrating the role of natural gas as a bridge to a low carbon future, the study’s authors stressed that it would be a mistake to let natural gas crowd out research on other low- or no-carbon energy sources, but it would also be a mistake to let investments in such alternatives crowd out the expansion of natural gas resources in the near term.

For further information: http://web.mit.edu/press/2010/natural-gas
Photo: http://www.topnews.in/files/Natural-gas11.jpg