<h2>In the United States, which is thought to have 3.2 million wells that are either abandoned, with no owner or operator or deserted by identified owners, methane gas leaks are becoming an increasing phenomenon.</h2>
The University of California Berkeley (Lawrence Berkeley Laboratory) commissioned ABB, funded by the California Energy Commission, to conduct measurements over an abandoned gas well with HoverGuard™ 60 miles north of San Jose.
The objective was to show how effective ABB’s system is for measuring gas leaks in real-world applications. ABB employed its drone-based HoverGuard™ detection system as the primary analysis method.
The company also deployed its MicroGuard™ (hand portable) and MobileGuard™ (vehicle-based) to display how effective each system can be while gathering data about how they function in a real-world scenario.
HoverGuard™ demonstrated the capacity to find and characterize the suspected leak but also discovered another, much larger leak. This second, larger leak was previously unknown, originating far from the road but having a considerably greater emission rate.
Detection of Methane Gas Emissions
Natural gas remains a key part of the energy mix, and many see it as a valuable fuel for the transition of electricity generation between highly polluting coal and more permanent non-fossil energy sources such as wind and solar power.
It also plays a crucial role in balancing out demand when renewable sources are not able to operate effectively. Although there will be a reduction in the demand for gas in the coming years, consumption by 2024 will need to be greater than what the IEA considers ideal if net-zero targets set for 2050 are to be met.2
Natural gas mostly consists of methane, in combination with lower percentages of other hydrocarbons. It is also comprised of water, carbon dioxide, nitrogen, oxygen, and some sulfur compounds.
Carbon dioxide receives the majority of the attention for its atmospheric warming potential, yet methane is the second main greenhouse gas and is of increasing concern. Despite having a shorter lifespan than CO2, the potential of methane’s heating is up to 84 times greater over a 20-year period.
In 2019, atmospheric methane hit record levels, at more than two and a half times the level of pre-industrial times. Primary sources of methane emissions include coal mining, landfill, livestock, manure, and natural gas, with natural gas production and distribution accounting for the majority, at over 30 percent of all emissions.
Government and environmental agencies have recognized the need to curb such methane emissions: this is the main objective of the Global Methane Pledge. Signed at COP26 by over 100 countries, the aim of the pledge is to reduce methane emissions in the atmosphere by 30 percent by 2030.
It is believed that such a reduction has the potential to achieve at least a 0.3 °C reduction in global warming by 2040. More efficient use of natural gas is a way to reduce its environmental impact, and the IEA advises the gas industry to act quickly and effectively to reduce nonessential methane emissions.
As well as meeting environmental concerns, the ability to detect and fix a gas leak quickly also makes for common sense from an economic and safety perspective. Pipelines from which gas leaks represent a loss of billions of dollars of revenue every year, from direct product loss and the work and costs required to replace it.
Data from the US government’s Pipeline and Hazardous Materials Safety Administration (PHMSA) indicates that between 2000-2019, 686 serious incidents occurred on gas pipelines, contributing to 253 fatalities and 1,111 injuries.3
This means that those responsible for operating gas wells and pipelines need to become better at detecting gas leaks from their facilities. As well as limiting monetary losses from the escaping gas into the atmosphere, they will also be contributing to the reduction of methane’s contribution to global warming.
To facilitate this, a rapid, effective and efficient method of detecting leaks is a must. So far, conventional methods employed to detect gas leaks have not been fully fit for this purpose. As well as being slow, they lack the accuracy and sensitivity required and, even more so, they lack the ability to detect leaks efficiently and reliably.
These techniques are dependent on handheld analog detectors that technicians have to carry across the suspected gas leak area. The devices used in these techniques require sufficient time to calibrate on-site and also have a low detection rate, which means users must tread slowly over the investigation site.
The test data needs to be manually added to systems, further increasing the time necessary for an effective evaluation of a potential leak. Recently, technological advances have ushered in improvements in sensing, analytics, and mobile technology. These advances facilitate the development of enhanced techniques that perform considerably better than conventional methods.
These systems are able to detect methane from natural gas leaks at concentrations of 1 part per billion (ppb).
ABB leads the innovation in this field, having produced a range of gas detection applications based on its LGR-ICOS™ technology. The latest, known as off-axis integrated cavity output spectroscopy (OA-ICOS), employs a tunable laser that generates light at a selected wavelength to interact with the methane and ethane gases that need to be detected.
This can achieve a sensitivity more than 1,000 times greater than traditional technologies and detect leaks at distances of around 100 meters. The laser passes into a highly reflective mirrored cavity, which is reflected thousands of times before its egress onto a photodetector.
This results in the laser following an extremely long optical path of several kilometers, generating an increased measurement sensitivity and creating strong absorption of the infrared light by the gas. Adjusting the wavelength of the laser enables the gas concentration to be measured with high precision and accuracy.
The method is able to detect the targeted gas in single parts per billion. This ensures that variations in atmospheric concentrations can be rapidly measured from long distances, a feat that other technologies find hard to emulate.
