Continuous Monitoring Systems and Proactive Workflows

Continuous monitoring systems can detect, localize, and quantify methane emissions in real time with a high degree of accuracy. Continuous monitoring systems are also relatively inexpensive, easy to use, and easy to deploy and scale. EPA noted in the recent OOOOb/c ruling that advanced detection technologies, such as continuous monitoring systems, “have the ability to detect fugitive emissions quickly, cost-effectively, and in a manner that may be less susceptible to operator error or judgment than traditional leak detection technologies”.

By Dave Levy, Marketing Manager – Qube Technologies

However, continuous monitoring out­puts alone do not fix leaks, nor teach operators how to improve emission responses in the future. Leak detec­tion and repair (LDAR) workflows must be proactive and methodical to capture the full benefit of real-time emissions data from continuous monitoring systems.

Historically, LDAR workflows have em­phasized scheduled physical inspec­tions in search of leaks irrespective of the presence of a leak. Depending on the regulatory jurisdiction, program and facility type, physical inspections must typically be performed 2 – 12 times per year. But even regulatory programs with high frequency inspec­tion requirements such as Colorado’s Regulation 7 are not sufficiently in­structive for operators to make sys­temic operational improvements that result in fewer and less severe emis­sion events over time.

Proactive workflows are distinguished from reactive workflows by first de­termining if sites are operating as de­signed by comparing measured emis­sions against estimated emissions. Operators can use continuous moni­toring data in combination with emis­sion estimates to identify root causes of fugitive emissions before they occur, rather than simply respond to emis­sions when they occur, and implement more effective systems that prevent or limit similar leaks in the future.

Over time, these root-cause improve­ments can lead to significant emis­sion reductions and lower operations and maintenance costs associated with LDAR.

Continuous monitoring systems pro­duce continuous emissions data that are essential to proactive workflows because the data continually informs the workflow, which in turn continual­ly improves all related emissions man­agement processes and outcomes.

Alarms and Typical Alarm Review Workflows in a Continuous Monitoring System

Continuous monitoring system alarms are notifications sent to key operator personnel when a potential leak has been detected. Most contin­uous monitoring systems allow op­erators to set their own parameters for triggering alarm notifications, such as when specific emission vol­umes or emission rates over time are reached, and most enable the opera­tor to define alarm parameters on a site-by-site basis.

Continuous monitoring alarms will trigger operations and maintenance workflows designed to confirm the presence, severity, and source of an emission, and drive the appropriate remedial response. A typical alarm review workflow may look something like this:

Illustration of a typical continuous monitoring system alarm review and response workflow.

Once an emission is detected, a prompt evaluation is made to either clear the alarm if the emissions falls within the range of normal operations, or to investigate further. If the cause of the alarm falls within normal operations and will be resolved in due course, no additional action is needed.

If further investigation is required, then a root cause analysis should be performed. If that analysis does not yield an explanation for the detected emission (an exception to the norm), then management should become involved, and the operator should continue with an AVO/OGI inspec­tion. Once the cause of an alarm is determined and remedial steps are taken, an operator should annotate the event in the continuous monitor­ing system’s log.

Proactive Versus Reactive Emissions Management Workflows

While a reactive workflow will effec­tively resolve a one-off alarm and emis­sion, it may not necessarily improve how operations and maintenance teams respond to or prevent similar events in the future. In effect, this reac­tive workflow does not make the oper­ator any better the next time around.

A proactive workflow determines if sites are operating as designed by comparing measured emissions against estimated emissions every month. The workflow uses that anal­ysis to improve the accuracy of emis­sion inventories and various aspects of site design, operations, and LDAR practices for better emission reduc­tion outcomes.

A proactive workflow is illustrated below.

Illustration of a proactive workflow that leverages continuous monitoring systems to determine if sites are operating as designed by comparing measured emissions against estimated emissions.

In this workflow, continuous monitor­ing sensors are installed and collect data to determine the site’s emissions from normal operations (the emission baseline). Then, continuous monitor­ing data is used to create a measured monthly emissions inventory.

At the same time, a calculated inven­tory is developed using established emission factors for the site’s equip­ment and design. These inventories are then compared and analyzed through reconciliation. Reconciliation is an ongoing process of cumulative source-level emission inventories with independent site-level measure­ments to produce a more definitive emissions inventory. The reconcilia­tion process helps improve the accu­racy, thoroughness, and reliability of reported emissions, as well as work­flows aimed at minimizing emissions.

In a proactive workflow, if measured emissions exceed calculated inven­tories, an operator should develop and implement operational and site design improvements before busi­ness-as-usual monitoring resumes. For example, an operator may imple­ment design changes to conserve gas or send gas to flare as opposed to at­mospheric venting during maintenance procedures, and by doing so limit the number of actionable emissions that occur at the site in the future.

This is an important branch in the workflow with financial consequences because an operator can make proac­tive changes based on learnings from data reconciliation instead of reactive changes to a major emissions event that is subject to the new methane fee.

However, if calculated inventories from emission factors exceed mea­sured emissions, then an operator should review their emission fac­tors and revise them where need­ed so they align more closely with measured emissions. EPA defines emission factors as “a representa­tive value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associat­ed with the release of that pollutant”. More simply, an emission factor is the pollutant emission rate relative to the level of source activity.

Emission factors are commonly used to prepare emission inventories and help operators identify and resolve operational inefficiencies. Since emis­sion factors are calculated from aver­ages of industry-wide data they may not, by themselves, produce accurate estimates for site-specific equipment and designs.

Continuous monitoring data can sharpen site-specific emission fac­tor estimates and align them more closely with measured emissions to produce more accurate inventories. Accurate emission inventories enable operators to see the root causes of emissions more clearly and develop preventative practices and more ef­ficient LDAR responses based upon that knowledge.

Continuous Monitoring Data Leads to Continual Operational Improvements and Better Emission Reduction Outcomes

Continuous monitoring data must be applied to operations on a strategic level to have a material impact on broader emission reduction goals over time. By implementing proac­tive workflows that compare contin­uous monitoring data with calculated emission estimates on an ongoing basis, operators can identify root causes of emissions and develop preemptive practices that yield accu­rate emission inventories, maximize LDAR approaches, and adjust alarm parameters to reflect actual site-level emission trends. Together, continu­ous monitoring data and proactive workflows help operators learn from instance to instance to improve oper­ations and reduce overall emissions and regulatory exposure.


ABOUT THE AUTHOR: Dave Levy is the Marketing Manager at Qube Technologies. In this role Dave develops policy and product-focused content for internal and external stakeholders. Prior to Qube, Dave was the Program Director for MobilityNext, where he developed and led mobility programs that trial new technologies and programmatic innovations to reduce GHG emissions and road network congestion. Dave has a bachelor’s degree in psychology from Emory University and a master’s degree in environmental policy from the University of Colorado, Boulder.
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