Methane Gas Seeps

Project Summary

Objectives

To evaluate the potential for environmentally responsible development of unconventional natural gas from seeps near the remote Alaskan village of Atqasuk for local space heating and power generation. Research priorities include identifying and evaluating the quantity, quality, and location of natural seeps, as well as determining potential capture and transport mechanisms necessary for future resource development.

Regional map of Northern Alaska showing the location of Atqasuk, a rural village surrounded by natural methane gas seeps

Project Description

Methane (CH₄) in natural gas is a major energy source in the U.S., and is used extensively on Alaska’s North Slope, including the oilfields in Prudhoe Bay, the community of Barrow, and the National Petroleum Reserve, Alaska (NPRA). Smaller villages, however, are dependent on imported diesel fuel for both power and heating, resulting in some of the highest energy costs in the U.S. and crippling local economies. Numerous CH₄ gas seeps have been observed on wetlands near Atqasuk, Alaska, (in the NPRA) and initial measurements have indicated very high flow rates. Gas samples collected in 1996 indicated biogenic origin, although more recent sampling indicated a mixture of biogenic and thermogenic gas. This study will:

1. quantify the amount of CH₄ generated by these seeps and evaluate their potential use as an unconventional gas source for the village of Atqasuk and
2. collect gas and analyze its composition from multiple seeps several miles apart to see if the source is the same, or if gas is being generated locally from isolated biogenic sources, and to identify the source of CH₄ (decomposition of biomass, CH₄ from coal seams, dissociating gas hydrates, or deep conventional gas) and
3. assess the magnitude of natural CH₄ gas seeps for future use in climate change modeling.

Potential Impact

Potential benefits of the project are:

1. Reduction in the consumption of diesel fuel in Atqasuk both for power generation and home heating (approximately 500,000 gallons per year)
2. better understanding of the gas resources in the NPRA area, with potential larger markets
3. on the climate change side, quantifying natural seeps to atmospheric CH₄ sources may change our understanding of the global balance between human and natural sources.

Recent work revealed that seeps may contribute as much as 50-70 million tones of atmospheric CH₄ per year, or ~10% of global sources. Additionally, capture and use of CH₄ from seeps mitigates global climate change in two ways: Combusting CH₄, a potent greenhouse gas (CH₄ is 25 times stronger than CO₂ on a per molecule basis), converts it to the weaker greenhouse gases, CO₂ and H₂O; and use of local CH₄ reduces energy consumption associated with diesel usage and shipping to remote villages.

1. CH4 seeps reported in the Atqasuk area shown as white dots
2. the Qalluuraq Lake Q seep, shown from the air
3. water surface of Lake Q in Auguat 2007 and
4. water surface of Lake Q in January 2008

These seeps are of interest as an energy source given preliminary measurements of high flow rates and CH4 concentration.