A couple of years ago 2 Brookhaven National Laboratory scientists developed bacteria to recover methane from coal in an environmentally more friendly manner.
NEW YORK, NY — Scientists at the U.S Department of Energy’s Brookhaven National Laboratory are exploring the use of bacteria to increase the recovery of methane, a clean natural gas, from coal beds, and to decontaminate water produced during the methane-recovery process.
Methane gas, which burns without releasing sulfur contaminants, is becoming increasingly important as a natural gas fuel in the U.S. But the process of recovering methane, which is often trapped within porous, unrecovered or waste coal, produces large amounts of water contaminated with salts, organic compounds, metals, and naturally occurring radioactive elements. “Our idea is to use specially developed bacteria to remove the contaminants from the wastewater, and also help to release the trapped methane,” says Brookhaven chemist Mow Lin.
Lin’s team has developed several strains of bacteria that can use coal as a nutrient and adsorb or degrade contaminants. They started with natural strains already adapted to extreme conditions, such as the presence of metals or high salinity, then gradually altered the nutrient mix and contaminant levels and selected the most hardy bugs (see details).
In laboratory tests, various strains of these microbes have been shown to absorb contaminant metals, degrade dissolved organics, and break down coal in a way that would release trapped methane. The use of such microbe mixtures in the field could greatly improve the efficiency and lower the associated clean-up costs of coal-bed methane recovery, Lin says.
This latest report suggests these scientists are still pursuing this line of work. The potential benefits are considerable. The United States has more energy in coal than Saudi Arabia has in oil.
Over half of the electricity produced in the United States is generated by coal-based power plants. Coal is affordable. Supplies are plentiful. And, the United States possesses 275 billion tons of recoverable coal reserves, or about one-fourth of the world's total.
U.S. coal reserves are equivalent to four times the oil of Saudi Arabia, 1.3 times the oil of OPEC and equal to all the world's proved oil reserves.
The development of environmentally friendly and cheaper ways to use coal for more purposes holds out the hope of considerably reducing US dependence on Middle Eastern oil and, by doing so, improving America's strategic position in a number of ways. A total reduction of US dependence on foreign oil would provide a number of benefits for the United States:
Methods to more cheaply extract oil from US oil shale or Canadian oil sands would have most of the same set of benefits though in the case of the Canadian oil sands some of the economic benefits would of course flow to Canada rather than to the US. Still, the resulting lower world oil prices and reduction in the need for defense spending would yield substantial benefits for the US economy as well.
In my view there are very large compelling reasons of grand national strategy for the US government to push the development of a broad range of technologies to provide cost-competitive replacements for oil. That the US government has been and continues to be willing to spend hundreds of billions per year on national security and yet so little on meaningful energy research seems unwise when we consider that a substantial portion of defense and even foreign aid spending is due to the presence of so much oil in the Middle East.
Look at it this way: some day methods to extract energy from coal, oil shale, and oil sands will be found. Why not make that day come sooner? Some day methods to make orders of magnitude cheaper photovoltaics by using nanotechnology fabrication methods and materials will be developed. Why not make that day come sooner too? Some day we will have lithium polymer batteries light enough and sufficiently long lasting to use for powering cars. Again, why not make that day come sooner as well? Similar arguments could be made for new nuclear reactor designs that would be cheaper and safer and that would produce far less nuclear waste and far less material useful for making nuclear bombs. Ditto for a wide range of other energy-related technologies. US national security and US living standards would be improved by the development of these technologies and the development costs would be repaid many times over.
Update: Some may wonder whether we should look for ways to shift to coal for a greater portion of our energy consumption given that coal burning generates more carbon dioxide per amount of energy generated as compared to other fossil fuel energy sources. While it is still debatable whether the effects of the build-up of carbon dioxide in the atmosphere will be a net detriment or benefit to humanity even if it becomes clear at some point in the future that the build-up will have to be stopped and perhaps even reversed this does not mean that fossil fuel consumption will necessarily have to be stopped. Dan Giammar, Ph.D., Washington University in Saint Louis assistant professor of civil engineering, is studying ways to sequester carbon dioxide deep underground by bonding it with silicate minerals in solid form.
"If you make more of it (carbon dioxide), you're going to have to do something with it," said Giammar. "Storing and sequestering is a good option."
Giammar's research may lead to not only storage but also permanent sequestration of carbon dioxide. He has found that when combined with silicate minerals containing either calcium, magnesium, or iron, carbon dioxide will precipitate, or change, into a carbonate solid.
"If you just have gaseous carbon dioxide stored underground, it becomes problematic when you think about leakage. But the carbonate mineral is a solid. It can't leak."
If carbon dioxide were injected into deep saline aquifers, several reactions would occur. The minerals would begin to dissolve as the pH of the saltwater became more acidic. The porosity of the rock would increase, allowing for the addition of more carbon dioxide. Eventually, carbonate solids would precipitate. This last phase is the most important in this model.
"Reactive transport models now make assumptions based on calculations that carbonates will precipitate at a certain time," said Giammar. "If that 's not what is really happening in the environment, we should know that. If we can understand this process, potentially it could give us the ability to control when and where these minerals form."
Carbon dioxide sequestration is still in its infancy. Giammar began his work on the project as part of the Carbon Mitigation Initiative at Princeton University. The United States Department of Energy (DOE) currently is planning a heavily monitored system to inject carbon dioxide into a sandstone aquifer on the Texas Gulf Coast. Another project in the North Sea has been storing carbon dioxide in an aquifer beneath the ocean for several years. And most recently, drilling began in July 2003 on a 10,000-foot well to evaluate underground rock layers in New Haven, W. Va.. as part of a DOE carbon sequestration research project now underway at the American Electric Power Mountaineer plant there.
|Share |||Randall Parker, 2003 September 12 02:47 PM Energy Tech|