A new study has found that an equipment widely used in identifying the level of methane gas in the atmosphere may have been registering significant errors. The failure was detected after a group of researchers noticed that their study appeared to have underestimated emissions.
Researchers from the University of Texas were aiming to improve the national inventory of the potent greenhouse gas, so they set out on a campaign to measure its levels from U.S. natural gas production locations. They found a trend of measurement errors from the Bacharach Hi-Flow Sampler (BHFS), an equipment extensively utilized in natural gas facilities. The device is said to switch between two sensors that identify low and high strength discharges. Frequent malfunctioning were also noted, signifying the underestimates reported from the genuinely high emissions.
The findings of the report, published in the journal Energy Science & Engineering, found that the main problem of the device lies in its usage of two sensors. The first sensor is used to identify the low levels of methane gas emissions and the second one is meant to read high levels of emission. When the methane content becomes too much to bear for the first sensor, the second sensor catches it.
The handover from the first sampler to the second may suffer frequent failures under several circumstances, unless it is meticulously and timely recalibrated, says Touché Howard, lead author of the report. This error may result in the failure of the sampler to measure the levels of gas emissions that the second sensor was able to collect, leading to underestimates of methane leakages.
The Environmental Protection Agency (EPA) collects national data from these facilities, and with the notable errors the researchers have found, the discovery may be a cause for widespread data inaccuracy.
Bacharach, the sampler manufacturer, responded to Howard after reading the recent paper and an earlier report made at the start of 2015. According to the company, the device was first made in 2003 and underwent initial testings using gas streams that were not similar to the ones used in the paper.
"We believe that some of the primary test results and conclusion of the studies 'are not valid' because the sensor failures reported by Mr. Howard could be caused by other factors," stated Bacharach. The company then recommended that frequent calibration of the sampler and further testings be performed. They also said that they will update their operating manuals accordingly.
Photo: Gene Spesard | Flickr
