Could there be a huge reserve of untapped methane, the main component in natural gas, deep in the Earth’s crust? Could energy be cheap again?

Not so quick. According to a report released in the fall in the Proceedings of the National Academy of Sciences (PNAS) that possibility is being explored.

IU South Bend physics and geology professor Henry Scott was the lead author of the PNAS study that included scientists from Carnegie Institution’s Geophysical Laboratory, Washington, D.C.; Harvard University; and the Lawrence Livermore National Laboratory.

As a postdoctoral fellow for the National Research Council, Scott developed a collaborative relationship with this distinguished group of scientists at the Carnegie Institution’s Geophysical Laboratory in Washington, D.C. Their research involves the formation of hydrocarbons, and he continues this work as a faculty member at IU South Bend.

The team of researchers found that there is a possibility of an inorganic source of hydrocarbons deep within the Earth from a simple reaction between water and carbon-bearing rock. The traditional theory is that fossil fuel is formed over millions of years from the breakdown of plants and animals. These fossil fuel reserves exist close to the Earth’s surface, no deeper than three to five miles down.

The experiments show that methane can form independently of living organisms and remain chemically stable at pressures and temperatures similar to conditions at 120 to 180 miles beneath the Earth’s surface. The team used a diamond anvil cell (two gem-quality diamonds with flattened tips that are pressed together) to squeeze materials common on the Earth’s surface such as iron oxide, calcite, and water to pressures many thousands of times the pressure of the Earth’s atmosphere. The scientists heated the mixture with a resistive heating method and by focusing laser light up to 2,700 degrees Fahrenheit and produced methane.

These experiments point to the possibility of an inorganic source of hydrocarbons at more than 100 miles down where the pressures and temperatures are extremely high. "This is an interesting step forward," Scott said. "Although it is well established that commercial petroleum originates from the decay of once-living organisms, these results support the possibility that the deep Earth may produce abiogenic hydrocarbons of its own under high pressure chemical reactions. These initial results do not prove the extent to which this occurs within the Earth, but they spark the imagination regarding the origin of natural gas and petroleum and what that means to the future supply of natural resources."

Scott cautioned that their findings do not offer a quick cure for high gas prices or oil politics. "They do suggest that additional research is needed to fully understand how hydrocarbons form in the Earth," Scott said.