Bill Scanlon, NREL
January 21, 2014 | 8 Comments
In the annals of impressive eating, there was The Cat That Swallowed the Canary and The Eggplant That Ate Chicago. Now, add The Microbe That Consumes the Methane.
A microbe capable of digesting methane could save countless tons of greenhouse gas from reaching the atmosphere during the hydraulic fracturing process. Hydraulic fracturing, also known as fracking, uses pressurized water to fracture rock to release natural gas. It's been a boon to local economies and a source of inexpensive fuels — but if nothing is done to capture the byproduct methane, which is typically flared in the air, it can also contribute heftily to greenhouse gases in the atmosphere.
Scientists and engineers at the Energy Department's National Renewable Energy Laboratory (NREL) are working with colleagues at the University of Washington (UW), LanzaTech, and Johnson Matthey to develop microbes that convert the methane found in natural gas into liquid diesel fuel. If successful, the Biological Gas to Liquids (BioGTL) process could also lower our dependence on foreign oil.
NREL scientist Qiang Fei examines a fermenter containing microbes that can consume methane at NREL's Integrated Biorefinery Research Facility. NREL is working with partners to see if the microbes can eat the methane vented or flared off gas wells in the fracking process. Photo by Dennis Schroeder, NREL
The amount of natural gas simply flared or vented from oil wells globally is enormous—six trillion cubic feet, equal to one-third of the amount of petroleum used in the United States each year, which adds up to $12 billion in lost potential revenue annually. This adds greatly to global greenhouse gas emissions because every molecule of methane vented to the atmosphere in the fracking process has the global-warming capacity of 20 molecules of carbon dioxide.
"Fracking for oil has led to huge increases in the amount of natural gas that is flared or vented," said Philip Pienkos, principal manager of the Analytical Chemistry and Life Sciences Group of the National Bioenergy Center at NREL. "Look at nighttime satellite shots of the upper Midwest [see second image to the right]. You see Chicago, you see Minneapolis, and you see North Dakota, just as bright." The first two show the lights from big cities; the third reveals the flare from fracking wells in rural North Dakota.
Today, with 600,000 fracking wells in the United States alone, pressure to use the technology to reach untapped petroleum reserves is greater than ever. But each of those wells flares or vents the equivalent energy of 2,000 barrels of oil per day because it just isn't economical to bring the natural gas to market. If that stranded natural gas can be turned into a liquid, then it can be piped along with the petroleum to refineries where it can be turned into diesel suitable for trucks and cars, or even jet fuel for use in planes.
Energy Department's ARPA-E Provided Funding
Backed by a $4.8-million Advanced Research Projects Agency – Energy (ARPA-E) award from the Energy Department, the scientists are making progress. The goal of the project is to transform the current landscape of the energy and raw materials markets by producing a scalable, low-cost, low-temperature, and low-environmental-impact way of converting that wasted methane into a transportation fuel.
In the night sky, a satellite image captures the sources of light in the Midwest. The light seen over the Bakken Oil Fields comes from fracking operations as the flaring of methane into the atmosphere lights up the sky—shining nearly as bright as the city lights in Minneapolis and Chicago. Photo from NASA Earth Observatory
Historically, oil wells have typically been situated in locations where the natural gas could be captured and sold as a chemical feedstock or as a fuel for heating and electricity generation. The amount of natural gas that was flared or vented was not considered to be such a concern. However, as we become more aware of the impact of greenhouse gas emissions, and as fracking has led to huge increases in domestic oil production in areas too remote for effective and economical natural gas capture and transport, natural gas flaring has become a dilemma for the domestic energy industry.
At the same time, fracking in other areas specifically for natural gas has increased the volumes produced and lowered prices so much that there is even less incentive to capture it at an oil well. But by happy accident, the average well is about the right size to accommodate a fermentation and conversion facility to grow the methane-eating bacterium (known as a methanotroph) and to convert the natural gas into liquid fuels. The microorganisms can be grown in fermenters with the help of nutrients such as nitrogen, phosphorous, and salts. The same water that comes out of the ground with the oil or that is available from nearby seawater can be used to operate these fermenters.
Microbe Has Novel Qualities; Can Use Methane as a Carbon Source
The scientists chose a novel microbe, Methylomicrobium buryatense 5GB1, which is one of just a few bacteria that have a high natural potential for producing lipids (a good biological feedstock for hydrocarbon-based fuels) from any carbon source. Within that small subset, 5GB1 is a rare species that can use methane to produce lipids — the precursor to fuel.