Understanding the Mechanisms of Continuous Methane Monitoring

Methane is invisible, odorless in its raw state, and far more potent than carbon dioxide as a near-term driver of warming. For oil and gas operators, that combination makes it both an environmental liability and an operational one — every leak is wasted product, a safety hazard, and a growing compliance risk. The challenge has never been whether to find methane emissions, but how to find them reliably, in real time, and at the source.

That is the problem continuous methane monitoring is built to solve. Rather than relying on periodic surveys that capture a single snapshot in time, continuous methane monitoring keeps watch around the clock, catching intermittent and unexpected releases that a quarterly walkthrough would miss entirely. To understand why it works — and where the technology is heading — it helps to look under the hood at the mechanisms that make it possible.

Why Continuous Monitoring, and Not Just Inspection?

Traditional leak detection has historically relied on scheduled inspections: a technician with a handheld analyzer or an optical gas imaging camera walks a site every few months. Those surveys are valuable, but they share a fundamental weakness. Methane emissions are often episodic. A pressure-relief event, a malfunctioning controller, or a seal that fails between visits can release significant volumes of gas that no one observes until the next scheduled survey — if at all.

Continuous methane monitoring closes that gap. By keeping sensors permanently in place and constantly sampling the environment, it can detect releases as they happen, alert operators quickly, and build a continuous emissions record rather than a series of disconnected data points. The payoffs are concrete: faster leak response, reduced product loss, improved site safety, and far stronger documentation for regulatory reporting. As emissions reporting expectations tighten and markets increasingly reward verified low-methane gas, the ability to demonstrate measured, time-stamped data is becoming a competitive advantage rather than a box-checking exercise.

The Core Mechanisms: How Methane Gets Detected

Almost every methane monitoring system exploits one core fact of physics: methane absorbs infrared light at specific, well-defined wavelengths. The differences between technologies come down to how they use that property — and whether they sample gas directly or sense it across a distance. Broadly, the mechanisms fall into three families.

1. Point Sensors (Contact-Based Detection)

Point sensors measure the methane concentration in the air immediately around them. Common types include:

• Non-dispersive infrared (NDIR) sensors, which shine infrared light through a small sample chamber and measure how much is absorbed at methane’s signature wavelength.
• Metal-oxide semiconductor (MOS) sensors, whose electrical resistance changes in the presence of methane.
• Catalytic (pellistor) and electrochemical sensors, often used where simple threshold alarms are needed.

Point sensors are inexpensive and well understood, but they only “see” gas that physically reaches them. Catching a plume depends heavily on wind direction and sensor placement, which is why fixed installations typically rely on networks of sensors rather than a single unit.

2. Open-Path and Laser Absorption Spectroscopy

Open-path systems sense methane across an extended beam of light rather than in a single chamber. The dominant approach here is laser absorption spectroscopy, which tunes a laser precisely to a methane absorption line and measures the light lost as it travels through the air. Several variations exist:

• Tunable diode laser absorption spectroscopy (TDLAS) offers high accuracy, strong resistance to interference from other gases, and minimal need for recalibration.
• Photoacoustic spectroscopy (PAS) detects the faint sound pulse created when methane molecules absorb pulsed light.
• Cavity ring-down spectroscopy (CRDS) measures how quickly light decays inside a highly reflective optical cavity, achieving extremely low detection limits.

Because these methods integrate measurements over a path, a single sensor can cover much more ground than a point detector — making them well suited to perimeter monitoring and large facilities.

3. Optical Gas Imaging and Spectroscopic Imaging

Optical gas imaging (OGI) renders methane plumes visible on a screen, letting operators see a leak and pinpoint its location. Conventional OGI cameras use broadband infrared imaging, which is excellent for visualization but historically less precise at quantifying exactly how much gas is escaping. The frontier of the field is spectroscopic imaging that combines the locational clarity of imaging with the quantitative rigor of spectroscopy — answering not just where the leak is, but how big.

Fixed Versus Mobile Continuous Monitoring

Continuous monitoring can be deployed in two broad modes. Mobile approaches — drones, vehicles, aircraft, and satellites — are powerful for surveying wide areas and screening many sites quickly, but they sample any given location only when they pass over it. Fixed continuous monitoring installs sensing hardware permanently at a facility so that critical infrastructure is watched without interruption.

For the assets where leaks are most likely and most consequential — high-pressure equipment, storage, and transfer points — fixed continuous monitoring is the approach that delivers true around-the-clock coverage. And this is precisely where newer sensing architectures are reshaping what’s possible.

A Solution for Fixed Continuous Monitoring: Coherent Lightwave Technology

Most established laser-based methods detect methane by measuring the intensity of light absorbed. Coherent Lightwave Technology (CLT), the GeoTeknica solution, takes a different and more information-rich approach by exploiting the full wave nature of light — its frequency, phase, interference, and coherence — rather than intensity alone.

This is the same fundamental shift that transformed fiber-optic telecommunications. Coherent detection was pioneered in the 1980s but only came to dominate optical communications once real-time digital signal processing (DSP) made it practical at scale. GeoTeknica applies that same principle to gas sensing: it pairs proprietary DSP algorithms for coherent gas detection with low-cost fiber-optic components mass-produced for the telecom industry. The result is a compact, scanning laser spectrometer that delivers high sensitivity and sharp frequency selectivity without the cost typically associated with high-end spectroscopic instruments.

For fixed continuous methane monitoring, that combination matters in practical terms. CLT is designed to:

• Monitor continuously and always-on, keeping watch across facilities and infrastructure in real time rather than during scheduled visits.
• Quantify at the source, reporting emissions by individual source location so operators know not just that a leak exists, but exactly where it is and how much is escaping.
• Track tank-level emissions with accurate measurement.
• Detect occluded or hard-to-see leaks that conventional line-of-sight tools can miss.

By delivering reliable, source-level methane monitoring, the system helps operators identify emissions faster, improve safety, and meet regulatory and reporting requirements with greater confidence.

Where Fixed Continuous Monitoring Delivers the Most Value

Not every asset carries the same risk profile. Fixed continuous methane monitoring tends to deliver the strongest return at the points where methane is under pressure, in transit, or concentrated. The facilities and operations that benefit most include:

• Metering stations
• Settling tanks
• Compressor stations
• Gas plants
• Pipeline infrastructure

These are the locations where intermittent releases are both likely and easy to overlook with periodic inspection alone — and where continuous, source-level data turns leak management from a reactive task into a proactive one.

The Bottom Line

Continuous methane monitoring works because methane reveals itself to infrared light, and because modern sensing systems can read that signal in real time across an entire facility. The mechanisms range from simple point sensors to sophisticated laser spectroscopy and spectroscopic imaging — each with its own strengths in sensitivity, coverage, and cost.

For operators who need permanent, source-level coverage of their highest-risk assets, fixed continuous monitoring is the approach that closes the gaps periodic inspection leaves open. And as coherent detection migrates from telecom into emissions sensing, technologies like GeoTeknica’s Coherent Lightwave Technology point toward a future where high-confidence, always-on methane monitoring is both more capable and more accessible than ever before.