We are all familiar with natural gas. We may use it to heat our home and office, power our water heater and heat our stove. It plays a very important role in our lives.
Methane is the primary component of natural gas. When natural gas (methane) is burned, carbon dioxide is emitted, just like other fossil fuels. But burning natural gas emits only about half the amount of carbon dioxide as coal. Natural gas is sometimes considered a “transition” fuel in the process of moving from coal and oil to clean energy such as solar and wind.
However, a problem occurs when natural gas (methane) is not burned but escapes into the atmosphere. This can occur when a pipeline leaks. An example is Aliso Canyon in California where a leak led to the escape of over 100 thousand tons of methane in a four month period.
Methane in the atmosphere is a powerful greenhouse gas. According to EPA, methane is about 120 times more powerful as a greenhouse gas than carbon dioxide. But its lifespan in the atmosphere is only about 12 years (compared to hundreds of years for carbon dioxide). If both power and lifespan are taken into account, methane is still about 25 to 36 times more powerful than carbon dioxide.
Methane is produced and emitted in low oxygen environments like wetlands where the soils are water-logged. Methane is also emitted from landfills.
Cattle have a unique digestive system where fermentation breaks down the feed for digestion. This process produces methane which is exhaled into the atmosphere by the animal.
Livestock manure produces methane when it is stored or treated in anaerobic conditions (without oxygen). This is usually manure in liquid form kept in pits, tanks and slurries. But this manure can be processed by means of “anaerobic digestion” where biogas is produced that can be used as an energy source.
Don Hofstrand is a retired agricultural economist from Iowa State University Extension. During the last few years of his work life, he focused on renewable energy and climate change. He and his wife live in Mason City.