Fighting Cow Flatulence…
It is difficult to get a handle on the amounts of “natural” greenhouse gas release (typically from things like volcanos, forest fires, and trapped methane) versus “human” release (called anthropogenic sources). A rough estimate might be 40/60, with a growing natural release being part of the “cascade effect” of the human release (ie accelerated arctic methane release due to anthropogenic fossil fuel burning). Can these natural greenhouse gases be contained utilizing biomass techniques?
I know, I know, some are lining me up for a Fox News “liberal” talking point, such as “and they want to put a giant cork on volcanoes and plastic diapers on whales!” sort of a thing. But all I’m really advocating here is the minimization of forest fires and mining of leaking natural methane deposits, so as to reduce greenhouse gases. Frankly, the problem is beyond the point of blame-game over whether nature or humans are at fault. Obviously, some greenhouse gas is good (otherwise you have Mars…brrrrr!) and too much is bad (Venus is a 700 degree hell), so let’s get to work! I’ve always felt that if nothing else, renewables were going to be more efficient, cleaner, and cheaper than fossil fuel (becoming more true every day) and this alone makes them worthwhile. I also have a sneaking hunch that renewables alone won’t reverse global warming, and we may eventually have to build machines (or organisms) that remove ambient carbon and methane, if not “mine” them at their natural sources (after the anthropogenic sources have been eliminated). This article will be about this source mining and the biomass conversion potential.
Briefly, and for the record, CO2 levels have risen 41% compared to pre-industrial (before 1750) levels (280 to 395 ppm) and Methane 170% (700 to 1,893 ppb) in the same period. It is speculated that prior to the industrial anthropogenic era, natural CO2 and methane releases were largely absorbed by other forces, such as carbon-soaking plants and natural fires (which can volatilize methane). Scientists are aware of this data by studying polar ice samples, associated with different eras. It is estimated that 60% of greenhouse gas is anthropogenic, but recent discoveries of methane release under melting polar ice means that human activities are helping liberate ever more natural greenhouse gas. As such, the 60% number may prove to be much higher when all is known. (LeTreut, Somerville, Cubasch, Ding, Mauritsen, et al, n.d.)(Gray, 2018)
I wrote a previous article about the spate of recent “superfires” in California and Australia, and the need to reduce dead forest fuel (usually dead trees, leaves, and pine needles), thin trees, and/or perform controlled burns. Though there is controversy on this front (involving habitat and endangered species), one can only imagine the amount of trapped carbon released to the atmosphere during one of these events. Since forest biomass strategies include using this forest biomass for energy, this is thought to be a net-carbon neutral process. Ironically, the “Smokey the Bear” politics of the last century may have helped get us into this mess, since preventing fires has set the stage for superfires. Of course the subject of CO2 minimization, absorption, and “scrubbing” has been well-covered by other articles. (Scott, 2020), (Scott, 2020)
Trapped methane release may be the biggest problem/opportunity for natural greenhouse gas minimization. Recent articles have sounded the alarm over receding polar ice and exposing of methane pockets, previously “capped”. In addition, methane “ice” previously trapped deep in the ocean, may “melt” and come to the surface due to warming oceans. Since methane is similar to natural gas, there may soon be a scenario of rogue natural methane extraction and use, if only to keep this leaky methane from escaping into the atmosphere. Somewhat fortunately, many of these methane deposits are close to being point-sources (many are the sites of ancient swamps, which behave more or less like modern landfills). Perforated pipes can be placed in these sites, which enables the methane gas to travel to some sort of gathering point. What happens after that may be a matter of emerging technology and economics. (Borunda, 2019)
Methane capture has been around a long time, but traditionally it has been “flared” (burned off) so as to remove the danger of flammable gases around a more important operation (usually an oil well, landfill, or wastewater treatment plant). In addition to methane there are contaminants, often sulfuric compounds and CO2. To be sold commercially, the raw methane gas is often “refined” (into renewable natural gas, or RNG), so as to remove these contaminants, which can inhibit combustion and are hard on engines. One obvious solution would be to refine and compress the methane gas at the source, bottle it and transport it to market, if not to run it in a pipeline. Since there is a vast natural gas pipeline network all over the world, it would make sense to blend this “biogas” with natural gas and/or hydrogen to create a “green gas”. Many are advocating for full-electrification and the “banning” of natural gas, and in this scenario biogas methane may be utilized (with carbon capture) at the power plant.
Fracking (the production of oil and gas by forcing a watery slurry into shale fissures) has created another troublesome release point for methane. Studies show that since 2006 (when fracking began, largely in the US and Canada), methane releases are up measurably (perhaps 50% due to fracking, an estimated 2–5% of production). It appears also that a few fracking operations are to blame, notably in the North Texas Barnett Shale region, where better management practices may need to be enforced to reduce leakage. Many want to shut down fracking altogether for this reason, but for the moment, there is only talk of banning it on Federal lands. Since Dick Cheney helped make fracking regulation free in 2005 (ironically under the Safe Drinking Water Act) it is hard to both monitor and regulate operations. If natural gas is to be allowed as a transition fuel, methane releases need to be contained and gas/methane burning accomplished using carbon capture. (Leahy, 2019),(scientificamerican.com, 2011)
The coal and oil industries are familiar with the presence of methane, and depending on markets, have either flared (wasted) the gas, or refined, compressed, and sold the product. In these cases, the methane was only escaping due to man-made activities (the quest for coal and oil), and for the most part was a nuisance. Since we as a society will likely ramp-down or discontinue coal and oil, this leaves the naturally-occurring methane product, and this provides an opportunity for the coal and oil industry to find another similar commercial avenue. Leaky methane deposits under pressure can be released commercially from vertical shafts and/or pumps. Amorphous escaping deposits under less pressure (more typical of “swamp gas”) can require assistance from another element (usually forced air) to direct methane to processing. Steam extraction to “coax” methane hydrate (“methane ice”) out of deposits is another possibility. (Clarkson, Moore, Saurabh, Harpalani, Singh, et al, n.d.)(prnewswire.com, 2019)
The economics are tricky, since in many cases, the extraction of this methane may not be profitable (compared to other energy sources) and thus subject to subsidies or other inducements. It would help if we knew exactly what we were dealing with…if escaping natural methane were half of the world’s problem, and cost twice as much to correct as the 50% man-made problem (soon-to-be resolved with renewable replacement?), we may be forced to pay a “tax” to mine the excess. This levy might be similar to the way we pay to get rid of garbage via recycling (not much profit, but at least we’d get some return while cleaning house). There will doubtless be political pressure from the companies that accomplish all this, to create pipelines and/or ship product (always subject to spills or explosions) from these mostly remote places (generally the north and south polar regions).
An interesting side note is the article you often see about cows and some dairies that increasingly recapture methane from cattle wastewater ponds (now required to reduce pollution in streams in many areas), or perhaps the cows themselves. Since many people like cows, this is a kind of “aww” and makes one believe that we don’t actually have to get rid of our bovine friends to save the earth. I suppose the ultimate truth is somewhere in between. Diets are changing so that people are less reliant on beef and dairy products, and in fact there is probably less profitability in “mining” methane from cow pies. However, future dairies may be required to capture this methane, and will certainly pass those costs on to those willing to pay extra for their milkshake and Big Mac. In the dairy example, the wastewater lagoons will likely have plastic covers that direct the bio “moo-gas” to a direct burn for hot water heating (good because biogas tends to wreck engines due to the aforementioned impurities). Excess gas might be compressed, bottled, and sold as a low-grade fuel, the way propane is currently sold. (Betz, 2020)
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