Methane is an interesting gas. It is the Dr. Jekyll and Mr. Hyde of greenhouse gases, but, in recent years, it’s been turned to a laughing matter by some news reporters, and that is not very helpful. We should understand how dangerous the Mr. Hyde side of methane really is for our environment, but we also can learn that at the same time, methane has a potential to save us — at least in the short run.
Let’s clarify this immediately: although one of the ways to create methane is by food digestion that is not the only way. Furthermore, not all humans produce flatus that contains methane. For example, in one study of the feces of nine adults, only five of the samples contained archaea capable of producing methane. *1
What do you need to know about methane’s GWP?
Evil Mr. Hyde’s side of methane is that his lifetime is 12.4 and it has a GWP of 86 over 20 years, and a GWP of 34 over 100 years. Methane is a much more potent greenhouse gas than CO2, but there is over 200 times more CO2 in the atmosphere. CO2 levels are 380 ppm (parts per million), while methane levels are 1.75ppm.
Hence, the amount of warming methane contributes to large percent of the global warming.
What is GWP?
Global warming potential (GWP) *2 is a relative measure of how much heat a greenhouse gas traps in the atmosphere. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by CO2 (carbon dioxide gas).
Who are the main contributors of methane?
The largest contributors to atmospheric methane gas are Natural Gas and Petroleum Systems, along with coal mining industry, contributing with 39% of all CH4 emissions in the United States. Certain amounts of CH4 are emitted to the atmosphere during the production, processing, storage, transmission, and distribution of natural gas. Because gas is often found alongside petroleum, the production, refinement, transportation, and storage of crude oil is also a source of CH4 emissions.*6
The second largest contributor is domestic livestock, such as cattle, buffalo, sheep, goats, and camels, which produce large amounts of CH4 as part of their normal digestive process. Of these, the largest methane contributors are dairy cows and beef cattle. Cows produce 50-100 times more methane than pigs in the digestive process. *8
Where up to 95% of the emissions comes from the cow’s mouth, rather than its behind. Additionally, bovine manure decomposition also produces large quantities of methane gas,
The third largest contributor of methane emission is waste from homes and businesses. Methane is generated in landfills, largely from food waste decomposing, and in the treatment of wastewater. ^
Potentially huge danger from methane
Methane exists in one more naturally-occurring form called methane clathrate *4, or methane hydrate. It is a solid form, in which large amounts of methane are trapped within a crystal structure of water. Clathrates are stable at -20oC and are generally found at depth in sediment or in the sea bed. Increasing ocean temperatures, due to climate change, could cause the sudden release of large amounts of natural gas from methane clathrate deposits. This could cause runaway climate change that cannot be halted.
How to reduce the amount of methane in environment ?
There are many things that can be done.
First, we should decrease — if not stop — drilling and mining, especially hydraulic fracturing of shell gas deposits. Reasons to do that are many, and the recent case of bad handling in California *9 that caused an environmental catastrophe — while they still do not know what caused it — strengthens my point. An even bigger problem is that the California leak is not the only one, and the negative impacts are huge. *7
Furthermore, the reduction of food waste, which is approximately one-third of all food we produce, would also significantly reduce methane emission.
Also, scientists are conducting new studies, in order to decrease the amount of methane produced by cattle. One of these is the “Project Clean Cow” *10. In other instances, scientists studied the impact of different diets on methane production, including putting garlic into cows’ feed. According to BBC News, “Garlic directly attacks the organisms in the gut that produce methane,” and, so far, results have been positive.
Additionally, numerous United Nations reports on climate change said that we should reduce consumption of meat or stop eating meat completely, in order to tackle climate change. Although this sounds logical, it is very difficult to implement. Although I personally would not mind doing it, there are number of arguments why I do not favor this method.
Is there a good side of methane?
Yes, there is the Dr. Jekyll side of methane: methane is a fuel.
Let me say that again. Methane is a fuel!
Unlike CO2, which does not react much with anything, methane (CH4) is a fuel, and we can burn it. We can use it to heat our homes, run our cars with it instead of gasoline, and we can even use it in power plants instead of coal to produce electricity.
But, methane is not clean. *5 When we burn CH4, we get CO2 (CH4 + 2O2 -> CO2 + 2 H2O). It is important to keep in mind that methane is 25 times (over 100 years) more potent as a greenhouse gas than CO2, so, by using it as a fuel, and by burning it, we are actually helping nature .
In other words, for each burned molecule of methane (CH4), we get one molecule of carbon-dioxide and two molecules of water. So, by burning it, we are not getting rid of CO2 completely, but we are making the greenhouse effects from methane 25 times (over 100 years) less dangerous.
Additionally, if we use methane as our primary fuel, instead of coal and gasoline, we would not create additional CO2 emissions from those sources. But, that is only if we use methane from natural sources: livestock and the waste we produce.
The important thing is to stop digging for natural gas and methane and to start harvesting it.
Instead of trying to suppress cows’ methane emissions, as previously mentioned [^], we should collect that methane on a mass scale and use it as fuel.
Currently, there are 1.2 billion vehicles on the world's roads *16, and there is a similar number — ranging between 1.3 and 1.5 billion of cows. Beef cows will produce between 150 and 250 liters of methane each day, and dairy cows will emit around 500 liters of methane. *3 *10
On average, that means that each cow produces around 130kg of methane per year. If we convert this to cubic meters 180 m3, and if we assume an average range of 14 km per cubic meter of methane, we can calculate that extracting this gas would allow one car to travel around 2500 km a year.
Additionally, cows produce an average of 30 kilograms of dung each day, and each kilogram of dung (in bio reactor) can produce a total of 35 liters of methane over 63 days. Dung from a single cow can produce 35 lpkg x 30 kg = 1050 liter of methane a day (over 63 days), giving an additional range of about 5000km for our average car. *18
The average mileage for four-wheeled vehicles was 7,900 miles (12,700km) in 2013 in the UK, meaning that we would need 2 cows to fuel one vehicle. If we would scale this method significantly, we could power around 700 million cars in this way, and, by switching to methane, reduce total gasoline or diesel usage, respectively.
Different fuel types produce carbon-dioxide at different rates per kilowatt-hour when generating electricity. For instance, coal (Lignite) produces 2.17, natural gas (methane) 1.21, and distillate oil 1.67 pounds of CO2 per kWh. Even if methane would produce an equal amount of CO2 to coal, which is not the case, we would still benefit from burning it, as we would make it 25 (over 100 years) times less harmful. Keep in mind that this is only if we harvest methane from naturally bio-occurring resources (cows, manure, and landfill waste). If we would use sea bed deposits or mine for it, we would do more harm than good.
Methane and CO2 are already in the atmosphere. Methane, accounts for large percent of global warming because it is more potent greenhouse gas than CO2 (between 72 to 84 times more potent over 20 years and between 25 to 34 times more potent over 100 years). By burning it as a replacement for other fuels (not an addition), we would almost erase its effects, and that is huge. However, what is said can be misleading: these calculations account only for future emissions that would be collected and processed. If we do not find a way to extract methane from the atmosphere, we would need to wait 12.7 years these deposits fall apart.
The technology of converting dung in anaerobic digesters is fully known and easy to implement. *12 The only things needed are the understanding that it is available and a bit of investment, which has a quick return. Collecting methane directly from cows, on the other hand, would be challenging but not impossible. A project from Argentina's National Institute of Agricultural Technology has shown in a proof-of-concept study that it is possible. *11 Researchers put plastic backpacks on cows, and inserted tubes into their rumens (their biggest digestive tract) trough a fistula made by surgery *13 *14 *15. In this way, they were able to extract the methane at the rate of about 300 liters a day.
Regarding fistulated cows’ lifespan, in one of the interviews with Dr. Edward DePeters, who ran through the entire process at the end, he noted that the cows have a longer life span, due to the care extended to them. This can be misleading, as the lifespan of cattle is determined by their economic factors: beef cows are slaughtered at 18 months and dairy cows at 4 years. Thus, the importance of his note is more in the way that the procedure is safe, that the animal will not suffer, and that it does not cause the premature death of the cow, because of infection, for instance.
In conclusion, I would like to stress again to stop calling methane “fart gas,” as that single word of ignorance can cause many investors to draw back from an investment that could potentially save the environment and civilization.
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Notes & References:
2. Global warming potentialhttps://en.wikipedia.org/wiki/Global_warming_potential
3. Do Cow Farts Really Significantly Contribute to Global Warming?http://www.todayifoundout.com/index.php/2014/04/cow-farts-really-significantly-contribute-global-warming/
4. Methane clathratehttps://en.wikipedia.org/wiki/Methane_clathrate
5. Gas is not clean energyhttps://sites.google.com/site/gasisnotcleanenergy/gas-is-dirty-energy
6. Overview of Greenhouse Gases - U.S. Methane Emissions, By Sourcehttp://www3.epa.gov/climatechange/ghgemissions/gases/ch4.html
7. Methane Leaks from North American Natural Gas Systems – higher than previously estimated.http://www.novim.org/images/pdf/ScienceMethane.02.14.14.pdf
8. Animal methane makershttp://news.bbc.co.uk/1/hi/magazine/8329612.stm
9. 5 Facts to Know about the California Methane Leakhttp://www.scientificamerican.com/article/5-facts-to-know-about-the-california-methane-leak/
Researchers find nearly 6,000 natural gas leaks in District’s aging pipe systemhttps://www.washingtonpost.com/national/health-science/researchers-find-nearly-6000-natural-gas-leaks-in-districts-aging-pipe-system/2014/01/15/f6ee2204-7dff-11e3-9556-4a4bf7bcbd84_story.html
10. Project Clean Cowhttp://www.dsm.com/corporate/science/competences/chemical-sciences/project-clean-cow.html
11. These Backpacks For Cows Collect Their Fart Gas And Store It For Energyhttp://www.fastcoexist.com/3028933/these-backpacks-for-cows-collect-their-fart-gas-and-store-it-for-energy
12. Production: Powered by poo: Somerset dairy farm enjoys biogas boomhttp://www.bbc.co.uk/news/uk-england-somerset-35482839
13. Rumen fistula surgery for the private practitionerhttp://www.damninteresting.com/hole-y-cow/