Introduction

It’s no secret that greenhouse gas emissions are on the rise. Since the industrial revolution, atmospheric traces of methane alone have more than doubled, and now exceed 1875 parts per billion. (Methane is increasing in the atmosphere by 12 ppb each year.)¹ Most of this increase has been attributed to man-made, or anthropogenic, behavior. The impact of methane emissions on climate change has been well-documented and established in the scientific community, although what exactly the impact is and how to communicate it is still up for debate.

Rising levels of methane emissions represent both a problem and an opportunity. The problem implied by methane emissions is fairly straightforward: as a greenhouse gas, methane’s warming ability is much more potent than carbon dioxide’s. For example, methane has a global warming potential (GWP20) of about 84, whereas carbon dioxide has a GWP of 1.² This means that, over 20 years, methane is more than 80 times as effective as carbon dioxide at absorbing energy in Earth’s atmosphere and thereby warming the planet.³ Humans emit much more carbon dioxide into the earth’s atmosphere, but the methane that is emitted has a stronger effect on global warming.

But reducing methane emissions also represents an opportunity. That opportunity has to do with methane’s average lifespan in the atmosphere. Since methane only lasts, on average, about 12 years in our atmosphere, a meaningful reduction in atmospheric methane could have an outsized effect in reducing global temperatures in the short term. Some sources attribute as much as 25% of anthropogenic warming to methane emissions.⁴ That’s why methane emissions are sometimes called the “low-hanging fruit” of greenhouse gas mitigation.

What is a methane budget?

Scientists often refer to a “methane budget” when cataloguing the sources and sinks of methane emissions globally. Sources are responsible for producing methane, and can either be natural or anthropogenic. Sinks are responsible for absorbing or destroying methane, and mostly occur as chemical reactions in the atmosphere.

As with conventional budgets, a healthy balance usually means you take in more than you spend. The 2020 methane budget showed that global sources of methane emissions outweighed global sinks, with sources accounting for 592 teragrams of CH 4 per year, and sinks accounting for 571 teragrams of CH4 per year – a “deficit” of 21 teragrams.⁵ The same report found that overall methane emissions rose 9%, by about 50 million tonnes, in 2017 compared to 2000-2006.

The two biggest man-made sources in the latest methane budget, reported in 2020, were agriculture and fossil fuel production.⁶ In particular, livestock management practices (especially ruminants) contribute about 30% of the total methane budget globally, putting pressure on both consumers and producers of meat to find more sustainable solutions.

Understanding methane emissions in up- and mid-stream oil and gas

Methane emissions at O&G firms are generally classified in three ways: (1) vented emissions, which are intentional, direct releases; (2) fugitive emissions, which involve unintentional loss of containment; and (3) incomplete combustion. Although much is still unknown about methane emissions in O&G production, there is a blueprint for understanding common problems in each of these cases. For the purposes of this article, we’ll focus mostly on understanding vented and fugitive emissions.

First, much of the O&G industry relies on pneumatic control devices to regulate pressure, set liquid levels, and manage valves. Across production, processing, and transmission sectors, pneumatic control devices perform different jobs. However, many pneumatic devices bleed methane either by design, age, or degradation. Replacing pneumatic control devices with electrical or compressed air devices can be beneficial both in cost-savings and energy storage; alongside retrofitting kits to low-bleed standards, it is one of the most effective ways to defray costs associated with vented emissions.⁷

One pathway for improving emissions leaks is tackling the issue of compressors. In compressors with wet seals, the seal oil that creates a pressurized environment around the compressor shaft often leaks gas through the inboard labyrinth seal. EPA estimates that wet seals can leak methane at a range of 1.1 to 5.7 m 3 /minute.⁸ Transitioning compressors with wet seals to dry seals improves methane leaks by a factor of 6. Additionally, other compressor maintenance may be undertaken to address fugitive leaks, in particular fixing those from scrubber dump valves as well as leaks when taking compressors offline.

The good news is that captured methane saves operators money, both at point of sale and in repairs, as well as generating revenue in the form of carbon offsets. One EPA study noted a 3.5 year payback period when a Mexican O&G operator converted several compressor wet seals at a production site.⁹ Additionally, some vented and incomplete combustion emissions are taxed, so retrofits can reduce the carbon tax burden. Financial, operational, and ecological alignment mean that if vents can be improved and leaks can be detected, there’s business rationale in upgrading, or even overhauling, dated practices.

LDAR for methane emissions

Aside from periodic maintenance and retrofits, LDAR (leak detection and repair) programs are the crucial component in curbing fugitive emissions. Federal and provincial regulations guide operators on how and where to monitor, as well as how to repair leaks. Having a system set up for accurately detecting leaks helps establish baseline readings, routinize repairs, and track progress over time (for regulatory purposes or otherwise). Across the globe, more and more regulators are making compliance a matter of law.

¹⁰Nascent monitoring technologies continue to grow in the LDAR space. Aerial surveillance has seen some promising implementation, with drones, planes, and satellites being used to scan for leaks. While aerial surveillance is helping shed light on the global magnitude of methane emissions from large point sources, they may be less accurate for smaller sources. Another drawback is that these “snapshot” approaches demonstrate extreme temporal variability in emissions studies. Other vexing problems persist in this niche, such as translating atmospheric data into actionable intelligence about what’s happening on the ground, or monitoring emissions accurately in snowy or marshy areas.

Arguably, handheld surveillance is still the most popular means of LDAR.¹¹ Many different methodologies exist. One common approach is a “sniffing” device, which is a hand-held wand outfitted with hydrocarbon detectors. Other optical gas imaging, or OGI, solutions use infrared imaging to pinpoint leaks. The main drawbacks of handheld systems are threefold. They tend to be costly, given that they need a trained operator, and the cameras themselves are expensive. They may be prone to inaccuracies when operators are inexperienced, as some studies have found a correlation between operator experience and reading accuracy.¹² And they are also intermittent; measurements provide insights, but if those measurements occur periodically, utility and understanding are degraded.

The case for continuous methane monitoring

The International Energy Agency recommends both aerial and handheld monitoring to ensure data-driven approaches to fugitive methane, plotting a pathway for an emissions reduction of 75% in 2030.

Unfortunately, it isn’t always feasible for companies to adopt both, whether it’s a cost consideration or time. Furthermore, “snapshot” measurements from handheld surveys and aircraft may miss large leaks for many months at a time. Continuous monitoring solutions, like Qube, offer both scale and economy for small, medium, and large O&G firms.

Continuous stationary monitoring relies on the installation of devices with sensitive gas sensors on-site. Each sensor is placed strategically and coordinates a host of environmental data in real time, continuously. As more data passes through, artificial intelligence can be used to strengthen inferences and even guide predictions. Because sensors work around the clock, and AI does the heavy lifting of identifying leaks, operators can expect an accurate assessment that only gets better over time and cuts costs by reducing manual inspections.

Continuous monitoring is not without its issues. It takes time to train an algorithmic model, and several devices are usually needed to coordinate an accurate reading, but the upside of continuous monitoring is clear: not only is Qube 80% cheaper than average OGI surveys, but also up to 50% more effective in reducing emissions than tri-annual OGI.

Taking Stock of Global Methane Emissions

Introduction

What is a methane budget?

Understanding methane emissions in up- and mid-stream oil and gas

LDAR for methane emissions

The case for continuous methane monitoring

Understanding LDAR Requirements for Oil and Gas Operators

Qube Sits down with CBC to Talk Problems and Opportunities of Continuous Emissions Monitoring