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Methane Emissions and EPA Method 21

01 July 2024

Global emissions from the fossil fuel industry have been a contentious issue for decades, with methane, also known as natural gas, being a significant concern.

Methane emissions in the United States have been challenging to measure accurately, prompting the EPA to introduce Method 21. The recent passage of the Inflation Reduction Act, the most significant climate legislation in US history, has renewed focus on emissions reduction. Historically, Method 21 has relied on sparse data and incorrect assumptions. Data is currently collected through periodic surveys using drones, aircraft, thermal cameras, and other methods. Despite incomplete data, the Environmental Protection Agency has identified “widespread noncompliance with Leak Detection and Repair.” Experts believe the Inflation Reduction Act provisions will significantly accelerate the decline in US emissions, with a goal to cut emissions by half by 2030 compared to 2005 levels. Given the issue with methane leaks, continuous leak monitoring is essential for reducing methane emissions and supporting the goals of the recent legislation.

What is EPA Method 21?

Introduced in 1981, Method 21 requires the use of a specialized volatile organic compound (VOC) analyzer to detect leaks. It is not designed to gauge the emission rate of greenhouse gases but to identify leaks.

Any analyzer meeting Method 21 requirements can be used, which include:

  • Portability
  • Battery-powered sample pump
  • Intrinsic safety certification
  • Sample probe no larger than 1/4 inch in diameter

While Method 21 aims to identify methane emission sources, various factors make this type of leak detection ineffective. Challenges include the tedious and expensive manual inspection process and the lack of constant monitoring.

For instance, an EPA National Enforcement Center (NEIC) case study showed that the actual percentage of leaks was, on average, four times higher than the number reported by facilities. Additional studies indicate that methane leaks at oil and gas facilities are significantly underreported using Method 21 requirements. A 2020 study found over half a million leaks in local gas distribution systems in the US, with leakage five times greater than EPA estimates.

The Impact of Undetected Methane Leaks

Method 21’s failure to identify leaks accurately has led to increased atmospheric methane levels. These leaks pose immediate public safety risks, such as explosions or fires, and contribute significantly to global warming. Methane traps over 80 times more heat in the atmosphere than carbon dioxide and accounts for approximately a quarter of global warming.

This warming potential leads to more intense and frequent extreme weather events, increased food insecurity, greater infectious disease risk, reduced access to clean water, and deteriorating air quality. Despite Method 21 regulations, significant gas leaks have not declined substantially since 2010.

To address this threat, many countries have committed to the Global Methane Pledge, aiming to cut methane emissions by 30% by 2030. Achieving this goal will require improved leak detection methods beyond those in Method 21.

MPS Extended Range Low Power Methane Gas Sensor

NevadaNano’s Molecular Property Spectrometer™ (MPS™) Extended Range Low Power Methane Gas Sensor offers a solution for open-air methane and natural gas leak detection across various applications. It provides continuous monitoring of methane leaks, surpassing Method 21 requirements, and plays a key role in reducing methane emissions.

This gas detection technology features:

  • Built-in environmental compensation for constant self-testing and fail-safe operation.
  • Standard digital bus sensor readings, requiring no additional electronics.
  • Inherent poison resistance for reliable readings.
  • No calibration required, reducing the total cost of ownership.
  • Long lifespan, with reliability for five or more years.
  • Low power consumption, averaging approximately 15 mW.
  • Intrinsic safety (IS) certification.

Methane emissions are a significant contributor to global warming, making their reduction crucial to meeting the Global Methane Pledge. While Method 21 aims to identify leaks, it has notable flaws. The Inflation Reduction Act necessitates improved leak detection and mitigation. The MPS Extended Low Power Methane Gas Sensor offers a superior solution for continuous methane leak monitoring, effectively reducing emissions.

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