Gas Technology Institute (GTI), with project partners AECOM, GHD Services, Inc., and Washington State University will improve the characterization of methane emissions from the natural gas distribution system. The project will focus on emissions from industrial meters in the natural gas distribution system, differences between vintage and new plastic pipelines, and gather data to compare steel and cast iron pipelines with and without plastic liners. The project team will conduct an unprecedented assembly of existing and new field data on methane leaks that will feed advanced statistical methods to offer a new perspective on methane emissions, the metrics/categories used to estimate emissions, and techniques used to curb those emissions.
Gas Technology Institute, Des Plaines, IL 60018
To meet the Nation’s Climate Action Plan goal of reducing emissions 40-45% below 2012 levels by 2025 requires a comprehensive understanding of the emissions profile from the entire natural gas infrastructure to enable cost-effective and efficient identification and control of methane emissions. This project will contribute to one piece of the research needed to provide input into a cohesive strategy for greenhouse gas reduction. The EPA Greenhouse Gas Inventory (GHGI) estimates are used to drive environmental policy and regulations at the federal level, which directly impacts individual natural gas customers, rate payers. By reducing uncertainty and improving the characterization of methane emissions from the gas industry, appropriate regulations will be made, the cost of compliance will be reduced, and the savings will be passed on to the rate payers.
The research will have a significant impact on the national estimates of methane emissions from the natural gas industry. It is intended that the improved Emissions Factors and activity data will be incorporated into EPA’s annual GHGI. The proposed project will also identify specific metrics to be tracked at a company level so operators can prioritize the repair of their non-hazardous leaks to maximize the reduction of methane emissions. Studies have shown fat-tailed emissions can be responsible for up to 50% of total emissions. By identifying these leaks, operators can more efficiently reduce the environmental impacts of their system. The results from the study will also improve the activity data estimates for specific sources such as industrial meters and distribution pipelines. This can help individual companies develop targeted leak repair programs for non-hazardous leaks to optimize emissions reductions. Specifically, the data collected on emissions from cast iron and unprotected steel with plastic liners will help determine if this is an effective practice for reducing leaks. It could then be made into practice in the field and possibly support the creation of a different classification for this type of pipeline to promote the use of these liners as a method of reducing emissions. A reduction in leaks also improves safety for customers and the public.
Currently, GTI is involved in the extensive field data collection section of the project. At this point, GTI has completed seven of eight weeks of measurements of industrial meters in five of six regions nationally, with the eighth week of measurements in the sixth region scheduled for January 2018. For that sampling, GTI has visited nearly 330 sites, conducting detailed leak surveys and component counts. During four of the sampling weeks, GTI focused on maximizing the number of sites visited, so they only quantified leaks that presented at the 45% LEL concentration or higher. For three of the sampling weeks, GTI quantified every leak that presented at 100ppm or higher to better understand all leaks coming from this category. Additionally, GTI has completed seven of ten weeks of measurements of new vs. vintage plastic pipe in four of six regions nationally, and is actively working out the logistics for the final three weeks of sampling in early spring 2018. During that time, GTI has visited 200+ sites and quantified 70+ individual leaks. Finally, GTI has conducted one field campaign to survey 10,031 ft cast iron and steel mains lined with cured in place plastic liners. GTI did not locate any leaks on the specific segments of plastic lined pipe. GTI has begun setting up the basic statistical analyses of the data and will be developing advanced statistics in the next two quarters.