Update on a Global Study Measuring Methane Emissions From Liquid Natural Gas Facilities Using Differential Absorption Lidar

Abstract:

Methane, a potent greenhouse, is the main component of natural gas (NG). Liquefied natural gas (LNG) provides a means for global trade in NG and its use has increased in recent years. The Environmental Defense Fund along collaboration with the Climate and Clean Air Coalition, the Oil and Gas Climate Initiative and European Commission are undertaking a global study into methane emissions. As part of this the National Physical Laboratory (NPL) is undertaking measurements to quantify methane emissions from key stages of the LNG supply chain using a variety of measurement techniques, including NPL’s Differential Absorption Lidar (DIAL).

DIAL is a powerful technique that can be used to track and quantify plumes emitted from complex emission sources including oil and gas sites such as LNG plants. It provides 3D mapping of methane emission concentrations and quantification of emission rates. NPL also deployed optical gas imaging (OGI) camera, portable gas detection equipment and hi-flow sampler to enable individual emissions sources to be identified.

Within this study an initial selection and prioritisation of sites was made and from this shortlist two regassification and two liquefaction plants have been measured so far. Emissions have been quantified for total site emissions and related to the different processes on the sites. Data from the sites has also been collected to enable comparisons between the emissions and for e.g. equipment type, age and throughput.

This talk will describe the objectives and scope of the project, including an overview of the current knowledge on methane emissions from the LNG supply chain. The methodology used to characterise the sites by their functional elements will be given, and benefits in comparing data with this level of granularity will be discussed. The methodology and techniques deployed will be described in detail. The DIAL measurements were conducted using a methodology which is the basis for a draft standard method for fugitive monitoring currently being developed by CEN in Europe. The techniques used, their performance and validation data will be presented. An overview of the measurement campaigns, the methodology and a summary of the current status of the field measurements and a discussion on the preliminary results will be given. Future work and expected outcomes will be discussed.