by Tina Casey: Scientists at the Department of Energy’s Pacific Northwest National Laboratory have developed a new system to convert methane into a deep green, energy-rich, gelatin-like substance…
that can be used as the basis for biofuels and other bioproducts, specialty chemicals — and even feed for cows that create the gas in the first place.
From Meadow Muffins To Renewable Energy
The new technology can also apply to fossil natural gas and industrial gases, but CleanTechnica is much more interested in the renewable energy angle.
The PNNL team discovered that a unique combination of two microbes exposed to methane gas in one bioreactor does the trick.
One is the methanotroph Methylomicrobium alcaliphilum 20Za, a microbe that thrives in methane-rich soil under rice paddies and landfills.
The other is Synechococcus species 7002, a strain of the familiar cyanobacteria.
The first microbe consumes the methane gas to produce a carbon-rich biomass that can be used as fuel or feed.
The cyanobacteria uses light to produce oxygen, which the first one needs to survive.
It all boils down to a “productive metabolic coupling,” as PNNL puts it.
So, Why Do All This?
Since methane already is a usable fuel, you may be wondering what’s the point.
The problem is that in their original states, methane biogas and other waste gases contain hydrogen sulfide and other undesirable impurities.
The PNNL breakthrough provides an economical way to purify methane gas while converting it into a liquid or solid, which provides for ease of transportation and a wider variety of options for use.
One important aspect of the system is its flexibility. It can be adjusted to maintain the necessary balance between the two microbes when the availability of methane falls or rises:
When there’s methane to convert, the cyanobacteria absorb light and use carbon dioxide as fuel to produce oxygen, fueling the methane-munching bacteria. When there is not much methane, researchers dim the lights, reducing the oxygen, which slows the action of the methanotrophs.
In addition to capturing methane from livestock operations, the system could also be used to reclaim fugitive emissions from landfills, and from oil and gas operations.
So far PNNL has run the system continuously for about two months, using methane culled from a dairy farm and from an oil field.
Meanwhile, Over At The EPA…
No word yet from the White House about the significance of this latest development, but take a look at this infographic from US EPA and you can see how biogas recovery has become a significant feature in the agricultural sector:
EPA promotes biogas recovery through its AgStar program, which offers this laundry list of bottom line benefits to American livestock farmers and their communities:
Provide a source for distributed energy generation in rural areas
Produce renewable energy to generate electricity and be used as a fuel for boilers or furnaces, offsetting fossil fuel use
Yield pipeline quality gas or compressed natural gas that can be sold as a renewable fuel
Provide a potential revenue source from the sale of energy, carbon credits or coproducts
Improve relationships with neighbors due to reduced odor levels from manure storage and spreading
Generate products for use on the farm, such as animal bedding and high quality fertilizer
That’s on top of reducing greenhouse gas emissions, an important feature considering the generous contribution of domestic livestock to the global GHG load.
As for whether or not AgStar will survive the budget axe, the prospects look dim but on the other hand, the program has been chugging along since 1994 so here’s hoping.