How to Measure Methane Emissions
Methane is a common gas, found in low background amounts in the atmosphere, and trapped in natural reservoirs such as permafrost and underground deposits. It is non toxic and low level exposure is completely harmless, though risks increase when concentrations are allowed to build up, especially in confined spaces.
A commonly used fossil fuel, methane is highly combustible, meaning it is ideal for industrial and domestic use. It also burns much more cleanly than other fossil fuels such as coal, making it the preferred choice in an environmentally conscious world. Natural gas is found in large underground deposits, often below the sea bed, which can be accessed by drilling and syphoning off the resulting gas.
While methane burns relatively cleanly, if it enters the atmosphere in an unaltered state it can trap 25 times as much solar radiation than carbon dioxide, making it one of the most potent greenhouse gases. As such, leaks and methane emissions from domestic and industrial sources can contribute hugely to the effects of climate change.
Methane is also quite expensive to extract so inefficient handling and accidents which involve leaks are incredibly costly, both in terms of materials lost and repairs to extraction and processing equipment. Measuring gas emissions is therefore vital to maintaining safe and cost effective operations.
What are sources of methane emissions
Methane is a naturally occurring gas which is generated from a number of sources. Permafrost is a huge source of methane, and as climate change melts parts of the world which are usually frozen year-round, the rate of methane emissions from these sources is increasing.
Agriculture, particularly the meat and dairy industry, are known to produce a large portion of total methane emissions. Livestock produces methane as they digest food, and their waste products also provide a source of methane due to bacterial activity.
Methane emissions can also be accidental. In industrial plants that handle, use, or process methane, leaks can cause the loss of large quantities of methane, either over time or in a rapid incident. It is common practice for these incidents to be properly measured through natural gas leak detection and it is important these are reported so that there is accountability within the industry.
Domestic waste is also a sizable contributor to overall global methane emissions. Landfills and waste management systems are localised sources of atmospheric methane which also need to be monitored. As waste decomposes, it releases methane which can then be captured and used in the production of electricity and heat. Read more on how to detect methane gas.
How are methane emissions measured?
Measuring methane emissions is legally required in a lot of instances, and accurate reporting is imperative. Global and national emissions are monitored by the UN and other organisations and committees in an effort to reduce the impact of climate change. Carbon dioxide and methane are two of the most important greenhouse gases when it comes to monitoring atmospheric levels and collecting data. This data is used to assess the impact of measures which are designed to reduce emissions and assists in planning measures to make further reductions.
Point source measurements are taken at fixed points and are based on flow rate and methane concentration. This technique is ideal for assessing methane levels over time in a fixed location, and assists in identifying temporal trends in total methane emissions.
Enclosure chamber measurements are taken when gas is passed through a fixed chamber which monitors the concentration of methane over short periods, giving an accurate picture of ambient levels. This controlled environment makes it possible to sample small areas and even small groups of livestock.
Perimeter facility line measurements are taken by placing monitors along a boundary to measure the methane concentrations within a given source area. This method does not give the most accurate readings as it is exposed to factors outside the perimeter when done in ventilated or outdoor spaces. As such, it can be difficult to use this method to identify specific areas and causes of any changes in methane levels.
Handheld gas analysers and gas detectors can be used to create a long or short term picture of methane emissions in a given area. Their mobile nature makes it easy to pinpoint areas of increased methane emission, and they can also record metrics over time with accurate GPS locations adding valuable insight.