Contact: Bob Ratliff
As scorching heat across much of the nation puts tremendous strains on energy supplies, Mississippi State University scientists are studying how a substance similar to common ice can help ease the situation.
Using gas hydrates--essentially ice--to store natural gas near high-demand areas offers a promising solution, said MSU chemical engineering professor Rudy E. Rogers.
"Gas hydrates can be used to store a lot of natural gas in a small space," he said. "For example, more than 180 standard cubic feet of gas can be stored in one cubic foot of hydrate."
In 1990, Rogers was among the first American scientists to research the industrial use of hydrates. Since 1997, his work has received support from the U.S. Department of Energy. At present, he is examining the feasibility of storing natural gas in hydrates near power plants that use the gas to generate electricity.
Rogers said hydrates are formed when gas is used to put water under pressure and the temperature lowered to freezing. The pressure causes two reactions--water solidifies at a temperature higher than 32 degrees Fahrenheit and the gas becomes trapped in soccer ball-shaped molecules within the frozen mass.
"When there's a big peak electrical demand, power plants can't pull enough gas out of pipelines fast enough to meet their needs," he said. "The delivery limitations of pipelines can be overcome, however, if supplies are stored nearby."
In addition to space considerations, hydrates offer a safer way to store large quantities of natural gas. "Hydrates can be stored under relatively low pressure," Rogers said.
"Should a storage tank rupture, there wouldn't be a sudden release of gas because it is trapped inside the hydrates at low temperatures," he explained. "This type of storage can be especially useful in heavily populated areas of the Northeast where there is often heavy energy demand and no natural storage sites such as depleted gas fields or the salt domes in South Mississippi."
Gas hydrates form naturally on the ocean floor at depths greater than 1,000 feet where natural gas seeps from the earth's crust or is formed by microbes. Rogers said there is growing interest in tapping into this source of energy.
During the past year, a group of students directed by Rogers and MSU microbiologist Lewis R. Brown researched aspects of ocean-floor hydrates, including what happens when gas suddenly released by the hydrates rises to the surface.
Rogers said some scientists theorize that the sudden release of massive amounts of methane and carbon dioxide--both greenhouse gases--from ocean-floor hydrates have triggered the end of previous ice ages and could again affect worldwide weather patterns.
While speculation about climate change and other theories involving hydrates may be more sensational, Rogers said he believes their real value is in preventing widespread power outages in heavily populated areas.
"The practical ways of using gas hydrates also is something Congress is interested in," he said. "Earlier this year, it passed the Methane Hydrate Research and Development Act to promote long-term studies."