New Year, New Fuel: Recommendations for the Cville Gas Decarbonization Study
Why is Gas Leaking and Who’s Affected? (Blog Three)
Natural Gas Leaks, Overview
Natural gas infrastructure is well documented to leak at every stage of production, from well extraction to pipeline transmission, local distribution, and appliance usage. The natural gas that leaks, unburned, from throughout the system is primarily comprised of methane gas, which has a warming potential 20–30 times greater than carbon dioxide.
Recently, a national U.S. study found that just from main lines in local distribution systems, there are 0.69 million tons of methane escaping annually [1]. That’s the emissions equivalent of roughly 4 million cars in a year, or the annual emissions of more than 40 natural gas power plants. (For context, when we talk about the local distribution system, that’s the local natural gas grid.)
Climate change, exacerbated by these methane leaks, is first and foremost an issue of social justice. The impacts of climate change (floods, food scarcity, increased vector-borne diseases) are already being felt by those who (1) have contributed the least to the climate crisis, and (2) who often have the fewest resources to handle crises. The patchwork of climate impacts on a global scale is mirrored by gas leaks on a local scale. In Massachusetts, a recent study of distribution-level natural gas leaks found that “marginalized populations are disproportionately exposed to natural gas leaks.” Does the same trend exist in Charlottesville? (spoiler alert: Yes!)
Research Highlights from the Charlottesville Community
For the past ~15 years, the Charlottesville Gas distribution system has averaged 126 leaks, annually.
The number of reported leaks from 2011 to 2021 has remained mostly the same, which suggests that the number of leaks is stagnant (a.k.a. not improving!).
Leaks are positively correlated with census tracts that experience the worst cases of energy burden.
There have been an average of 126 leaks annually in the Charlottesville Gas (“the Utility”) distribution system from 2010 to 2022, with no apparent trend (positive or negative) in the leak frequency across that period. In a Charlottesville Gas utility rate report, it was stated that after the “Dig With Care” campaign was instituted, “there was a 33% reduction in gas line damage caused by third-party excavators” from 2013 to 2020. While that can be true for that particular category (when a line is damaged due to excavations), the number of leaks reported between 2013 and 2022 actually increased by 9% when compared to the average between 2010 to 2013. On that topic, Miss Utility tickets [3] observed that the “number of leaks reported” is a much more useful metric to assess the state of leaks across the Utility than “line damage”
Of the Charlottesville Gas leaks from 2020–2022, the majority (51%) were classified as “Grade 1”, which is the most hazardous classification (Figure 1) [4]. Unfortunately, leak classification into categories, a standard practice across the industry, tells community stakeholders very little about the nature and intensity of the leaks. Alternatively, recording the concentration of gas in terms of the percentage of “lowest explosive level” (%LEL) from several distances to the leak source would be far more informative. Charlottesville Gas has the means to measure gas concentration in a more informative manner. However, it is not required to. Such finer-grain data would help future studies understand patterns in leaks and more effectively inform prevention.
According to conversations between C3 and Charlottesville Gas leadership, currently, gas leaks in the local system are detected in one of three ways: (1) the public finds a leak, (2) the Utility survey crews find a leak, or (3) the Utility team finds a leak in their routine work. Even though Grade 1 leaks are the most common type reported, we suspect that it is more likely that Grade 2 and 3 leaks would go undetected for longer periods. This is because the public often reports leaks by smell, which is related to greater leak intensity and hazardousness. If the leak is relatively small or not too close to places where people work, reside, or walk nearly, the leak might take much longer to be detected and reported.
Figure 1. The classification of leaks is based on their hazard level.
Potential Causes of Leaks
A troubling trend, or perhaps lack thereof, is that there seems to be no reduction in the number of leaks across the past decade. Why have we not seen a decrease in leaks if, presumably, technology and detection methods are advancing?
Charlottesville Gas has almost entirely moved away from older technologies such as cast iron to newer ones like plastic or steel-coated pipes since the 1990s. Where new lines are laid, they are made from newer materials, which means that the overall percentage of lines that are plastic is increasing (that would lead to an expected decrease in leaks), but at the same time, the overall size of the utility is increasing (both in terms of area served and volume of gas supplied) and that might be a force leading to increase in leaks. What ultimately results is no clear trend in the number of leaks throughout the utility over time.
To give Charlottesville Gas some credit, while there has not been a reduction in the number of annual leaks, C3’s preliminary research indicates the intensity of leaks (and therefore, the volume of gas escaping into the atmosphere) may have been decreasing as a share of the total natural gas received by the Utility. At least, that has been the trend of the “Lost or Unaccounted For (LAUF) gas”, the difference between the total gas sold by the local Utility from the total gas purchased by it, between 2012 and 2022 [5].
Overall, there is very little detailed information about leaks in the local gas system. There are likely a mirid of natural gas leak causes. However, without precise data on where leaks are occurring, it’s hard to draw many conclusions. Could it be that near major thoroughfares the ground is rumbling more, and the pipes spring more leaks? Do we need to therefore monitor more along heavily trafficked corridors? The point is, without more data, we cannot answer these questions and we cannot expect to meaningfully reduce environmental and safety risks of gas leaks throughout the Utility’s system. The Charlottesville Gas decarbonization study is an excellent opportunity to compile and create more data, analyze it meaningfully, and develop actionable solutions.
Distribution of Charlottesville Leaks
Studying the trends of leaks across the Utility as a whole presents additional problems, as it is insufficient to understand the localized impacts of leaks in specific neighborhoods and communities. For example, our preliminary study of the pattern of leaks across Charlottesville found that Rose Hill and Venable have the highest leaks per 10,000 people.
When comparing the rate of extreme energy burden per census tract (a marker of financial stability and energy security: a household with a higher energy burden spends a bigger share of their income on energy) with the most natural gas leaks per 10,000 people. With less income left over after paying energy bills, hazards and disruptions can be extremely damaging to someone’s ability to sustain their livelihood. The relationship between higher energy burden rates and the incidence of gas leaks tells another chapter of the story of climate injustice. It also showcases the importance of targeted leak interventions and prevention in places where leaks are likely to cause the most disruption.
Therefore, the Charlottesville Gas decarbonization study must also be an opportunity to better understand the nature of and explore the best ways to address climate injustices in the local natural gas system of the Utility. As such, C3 urges that Charlottesville’s City Councilors and key decision-makers request the Charlottesville Gas leadership and the consultants of the decarbonization study to also follow the recommendations below:
Third Set of Recommendations for the Cville Gas Decarbonization Study
Research best practices for reporting leaks and reducing the cumulative time they leak
Determine how many fewer leaks per year are expected when the Utility transitions the last remaining cast iron pipes to plastic
Conduct an in-depth analysis of the geographic distribution of leaks (with precision beyond census-tract level) to understand and address inequitable exposure to leaks
Calculate and create mechanisms for regularly reporting the cost of gas leaks (volume of gas leaked and repair costs) to Charlottesville Gas ratepayers
Include community engagement throughout the study process to hear local perspectives to ensure relevant and fair participation of community members in the ideation and shaping of solutions.
References
[1] Weller, Z. D., Hamburg, S. P., and von Fischer, J. C. (2020), “A National Estimate of Methane Leakage from Pipeline Mains in Natural Gas Local Distribution Systems.” Environmental Science and Technology. Available at: https://pubs.acs.org/doi/10.1021/acs.est.0c00437
[2] Environmental Protection Agency [EPA] (2023), “Greenhouse Gas Equivalencies Calculator.” Available at: https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator#results
[3] The City of Charlottesville (2023), “Fiscal Year 2023 Utility Rate Report.” Available at: https://www.charlottesville.gov/ArchiveCenter/ViewFile/Item/236
[4] The U.S. Pipeline and Hazardous Materials Safety Administration within the Department of Transportation classifies leaks from grade 1 to grade 3. Grade 1 leaks are considered to be hazardous because of their gas concentration or proximity to populated areas. See more here: https://www7.phmsa.dot.gov/regulations/title49/interp/PI-78-017
[5] Some of the LAUF gas is the result of billing errors or other inaccuracies, so the volume itself is not helpful on its own. However, the trend in how this LAUF is changing over time can help us understand patterns in the volume of leaks over time.