Project Astra
Advancing Next Generation Methane Innovation

Frequently Asked Questions

Project Astra has multiple interdependent activities underway including a methane sensor inter-comparison, the development of a digital twin of the pilot region and the demonstration of the Project Astra concept in a ~100 km2 pilot region. These Frequently Asked Questions are divided into sections addressing the overall structure of the study, the methane sensor inter-comparison, the digital twin development, and the demonstration project. Within these sections, general questions and technical questions are addressed.

Project Astra organization and sponsorship
General Questions
Can other organizations join Project Astra?
Organizations have participated in Project Astra as signatories to the Project’s Memorandum of Understanding (MoU) and as supporters of individual project phases.

Signatories to the MoU (Chevron, Environmental Defense Fund, ExxonMobil, GTI, Microsoft, Pioneer Natural Resources, and the University of Texas) have committed to participating in the multiple phases of Project Astra. These phases include the sensor inter-comparison, the development of the digital twin and the pilot. Other organizations, including the Collaboratory to Advance Methane Science and AT&T, have participated in individual phases of the project.

Methane sensor inter-comparison
General Questions
Which sensors are being tested?
A total of seven sensors are being tested. The sensors are being provided by Aeris, Project Canary, Eco-esolutions, Quanta3, Scientific Aviation, Teledyne, and Troposhere. More details about individual sensors are available at the Project Astra web site.

How were the sensors selected? What criteria were used in selecting the sensors?
The Project Astra team solicited applications to participate in the sensor inter-comparison from providers of fixed point sensors. The project team alerted known sensor manufacturers about the opportunity to participate in the inter-comparison. Potential participants completed an application, which was reviewed by the sponsors of the inter-comparison. Review criteria included instrument characteristics (detection limit, precision, sampling frequency, and other factors), the ability to operate under their own power and with their own communications, cost, and technology readiness level.

Technical questions
How are the sensors being evaluated?
Sensors have been deployed at a tank battery site in the Permian Basin. Sensors are located approximately 75 meters from the nearest emission source on the site and are deployed in a row oriented perpendicular to the primary wind direction. Within 2 meters of each sensor is an air inlet, which provides a continuous flow of ambient air into a nearby trailer. In the trailer, a Quantum Cascade Tunable Infrared Lased Differential Absorption Spectrometer (QC-TILDAS) system periodically analyzes the ambient air composition from the vicinity of each sampler. The QC-TILDAS system has a precision of 1 ppb for methane when operating at 1 Hz. The performance of the QC-TILDAS system is evaluated using certified gases at least daily and the measurements from each of the sensors is continuously compared to the QC-TILDAS measurements. In addition, approximately every 2 weeks, certified gases from cylinders are delivered to the inlet point for each sensor and the response of the sensors are compared to the known gas composition. In addition to these evaluations, information on the fraction of time the sensor systems are operating properly is being collected.

What are the results from the sensor tests?
The results from the sensor test will be made public in the spring of 2021. Data that will be reported include comparisons of the sensors against the certified gases and the QC-TILDAS instrument, and the data capture efficiency of the sensors.

Digital twin development
General questions
What is a “digital twin”?
In the context of Project Astra, the digital twin is a simulation of atmospheric concentrations of methane in the Project Astra pilot region associated with both normal and abnormal emissions from oil and gas production activities. The simulation predicts concentrations minute by minute for extended periods (weeks to a year), and at very fine spatial resolution (concentrations predicted roughly every 100 meters). The predicted concentrations are based on minute by minute simulations of normal and abnormal emissions, and an atmospheric dispersion model.

What is the overall purpose of a “digital twin”?
The goal of Project Astra is to demonstrate the operation of a shared, continuous methane monitoring network over an area of approximately 100 km2. A successful demonstration will require strategically placed sensors with sufficient precision to detect abnormal methane emissions. The first use of the digital twin will be to design the sensor network, identifying the selection and placement of sensors that will quickly and reliably detect abnormal emissions, at the lowest cost. The second use of the digital twin will be to test data analytics systems. Once deployed, the data from the sensor network will need to detect and determine the location of abnormal emissions. The digital twin will be used to evaluate approaches to these anomaly detection systems.

Technical questions
What types of abnormal emissions are you considering in the digital twin?
Abnormal emissions accounted for in the digital twin will include, but will not be limited to, unlit flares, flares and other combustion devices with poor combustion efficiency, unintended venting (e.g., stuck separator dump valves and open thief hatches), leaks, and malfunctioning pneumatic controllers. Abnormal emissions do not necessarily need to be included in the digital twin in order to be detected by the Astra network, once it is deployed. However, some abnormal emissions have characteristic frequency patterns, so including specific types of abnormal emissions in the digital twin will allow the Project Astra team to evaluate approaches to data analytics that search for these fingerprints of abnormal emission sources.

How many digital twins of the atmosphere will be constructed? Will multiple scenarios of abnormal emissions be added on top of the normal emissions?
Multiple “pairs” of digital twins will be constructed, recognizing that the locations, durations and magnitudes of normal and abnormal emissions may vary. For each pair of normal and abnormal emissions, all of the individual sources of methane emissions will be tracked in the digital twin, so that the ability of the sensor network to detect specific types of abnormal emissions can be evaluated. Some of the pairs will be used to develop the network design and data analytics. Other pairs will be used to evaluate the performance of the sensor network designs and data analytics.

Atmospheric inversions are computationally expensive; are you assessing the possibility of generating a database of inversions for each receptor (sensor) for ranges of wind speeds and wind directions, to reduce the computational burden by just looking up the contributions from sites under certain conditions at certain locations?
Multiple types of data analytics approaches will be evaluated, ranging from full atmospheric inversions, to much less computationally intensive pattern recognition. Part of the pattern recognition could use the characteristic temporal patterns of certain types of abnormal emissions. Additional information could be provided by examining the information from multiple sensors. For example, if a sensor detects an apparent abnormal emission, and sensors upwind of the sensor with an abnormal emission detection do not show evidence of abnormal emissions, then the location of the abnormal emissions can be limited to sites between the sensor with the detection and the sensors that show no abnormal emissions. Similarly, if wind directions change while the abnormal emission is occurring, the location of the emission source can be triangulated.

Astra demonstration project
General Questions
Where will the “large scale pilot” deployment be?
The pilot will be conducted in Midland County, in the Permian Basin.

When will the “large-scale pilot” deployment begin, and when will full deployment be achieved?
Deployment is expected to begin in the fall of 2021, with full scale deployment anticipated in early 2022.

Who will operate the pilot?
To be determined.

Will Astra monitor air pollutants other than methane?
Some of the sensors being evaluated for use in Project Astra measure multiple pollutants. If these sensors are deployed as part of the pilot demonstration then it is possible that the network will detect multiple pollutants, but that is not the primary intent.

How will the public be able to see data from the “large scale pilot” monitoring network? And how frequently?

Will the learnings from project Astra be useful for other basins that have completely different geography, topography, and meteorological conditions?
To maximize the probability of success, Project Astra is initially being demonstrated in a region with dense oil and gas assets, and with relatively few topographic features. If successful in the initial test region, the project team’s expectation is that initial expansions will be to other parts of the Permian Basin. For these, and other regions that may wish to replicate the approach taken in Project Astra, the project team will prepare a “playbook” that describes the process that was taken in developing the pilot region.

Technical questions
What are the success criteria for the “large-scale pilot” network deployment?
Multiple criteria will be used to test the pilot network. These include:
The ability of the network to detect and identify sites with releases, ranging from <10 kg/hr of methane to >100 kg/hr.
The ability of the network to quickly detect abnormal releases from sites within the network.
The ability of the network to distinguish between normal and abnormal emissions (minimizing false positive detections of abnormal emissions).
The ability of the network to operate at a cost comparable to current leak detection and repair programs and other emission detection methods.
The ability of the network to quantify total regional emissions from the test region with an accuracy comparable to aircraft based surveys.

Will Astra be able to replace regulatory requirements like OOOOa or voluntary Leak Detection and Repair programs?
The goal of Project Astra is to develop and demonstrate a sensor network that rapidly detects abnormal emissions and notifies operators of those emissions. If the operators rapidly mitigate the abnormal emissions, emissions reductions may be greater than for conventional LDAR programs. Whether this alternative approach can be used as a replacement for required programs is a regulatory decision. The Project Astra team is committed to communicating the results of the program to regulators, but the ultimate decision about whether a sensor network can replace more traditional LDAR programs will be made by regulatory agencies.

Can Astra be used for regional methane emission quantification?
Yes. To rapidly detect abnormal emissions, the Project Astra sensor will need to be able to estimate emissions at individual sites. These individual site estimates can be aggregated in various ways to produce regional estimates of methane emissions for a single company or for a particular region.

What parameters will the sensor mesh network be optimized for?
As the network is driven to more rapid detection of smaller and smaller emissions, the probability of having “false positive” detections becomes greater. One of the goals of the pilot demonstration will be to characterize this trade-off.

Are there benefits besides cost that could be obtained by having a mesh of sensors rather than having sensors at every site?
Additional information is provided by sensors at multiple sites. For example, if a sensor detects an apparent abnormal emissions, and sensors upwind of the sensor at other sites do not show evidence of abnormal emissions, the location of the abnormal emissions can be limited to sites between the sensor with the detection and the sensors that show no abnormal emissions. Similarly, if wind directions change while the abnormal emission is occurring, the location of the emission source can be triangulated.

Could the mesh of networks detect fugitive emissions from pipelines that are in between production sites?
In principle, multiple types of abnormal emission sources can be detected and their location determined.

How will you determine the cost effectiveness of the test deployment?
Costs and operator time requirements will be carefully tracked.