Site-Aerial-Basin Emissions Reconciliation (SABER)
Update: Due to DOE project cancellations in October 2025, all work was stopped on this project.
Summary:
Top-down/bottom-up (TD/BU) studies attempt to compare two disparate scales of measurements in order to provide an accurate-as-possible emissions estimate for a given region. BU (inventory) measurements (e.g. OGI scans, on-site measurements, fenceline monitoring) tend to be at the facility level and can provide emissions for specific processes. BU must be scaled upwards with statistical methods to estimate the emissions for an entire region. TD methods (e.g. larger emitter flight, satellites, tower networks) tend to view a larger region at a time, such as entire facilities or regions (e.g. satellite measurements). While the spatial coverage is greater, TD methods do not always provide mechanistic causes for emissions. Comparisons of the emissions estimates from TD/BU have historically disagreed. BU may underestimate through missing emitters or incorrect emissions factors. TD may overestimate due to the relatively short time-scale most TD measurements are taken over or incorrect source attribution.
The SABER study team is currently leading a smaller coordinated campaign in the DJ basin, the Colorado Coordinated Campaign (C3). C3 has focused on understanding large emitters. A particularly successful and informative piece of C3 has been engagement with operators to understand what portion of plumes from aircraft flights can be attributed to maintenance events and other known emission sources. We aim to take all learnings from C3, including the key operator engagement piece to SABER, which will be a significantly larger effort.
At its core, SABER is a top-down/bottom-up reconciliation of emissions, and we will use the Denver-Julesburg Basin (DJ) in northeastern Colorado as our method development and validation study. To show that these methods can be applied elsewhere, we will run a second campaign in the Upper Green River Basin (UGR) in western Wyoming. SABER is a study lead by Colorado State University (CSU; PI: Dan Zimmerle), with project partners of Pennsylvania State University (PSU; PI: Ken Davis), University of Wyoming (UW; PI: Shane Murphy), and Bridger Photonics (PI: Asa Carre-Burritt).
Objectives:
We aim to demonstrate that:
(a) high frequency sampling can be used to create inventory emissions estimates that accurately represent emissions in a basin; and
(b) the proposed method can be replicated in other basins.
At its core, SABER is a top-down/bottom-up reconciliation of emissions, and we will use the Denver-Julesburg Basin (DJ) in northeastern Colorado as our method development and validation study. To show that these methods can be applied elsewhere, we will run a second campaign in the Upper Green River Basin (UGR) in western Wyoming. SABER is a study lead by Colorado State University (CSU; PI: Dan Zimmerle), with project partners of Pennsylvania State University (PSU; PI: Ken Davis), University of Wyoming (UW; PI: Shane Murphy), and Bridger Photonics (PI: Asa Carre-Burritt).
Project Plan:
The design of this study is summarized below:
Box 2 focuses on updating the BU inventory with Bridger Photonics flights (1a) over the DJ basin in three intensive campaigns in 2024 (spring, summer, and fall). Given Bridger’s relatively low detection limit, it can be used to understand mid-to-large emitters for BU estimates. We will also run on-site measurements (1c) using tracer-release methods (CSU, UW). Operator engagement and activity data from facilities (1b) will help the study team understand causes and sources of detected plumes. All data will help improve the study team’s BU model (MEET) that supports temporally and spatially resolved inventory estimates. Independently, PSU will run tower networks (3) that can separate O&G emissions from other sources through ethane channels to form the TD estimate.
The DJ basin aircraft campaign is anticipated to take place over spring, summer, and fall of 2024, requiring project planning with the study team and participating operators in late 2023/early 2024 (anticipated around November and December of 2023). The UGR basin aircraft campaign will be staggered to allow for lessons learned from the DJ work and is anticipated to run in fall of 2024 and spring of 2025. Project planning with the study team and operators for UGR is anticipated to take place spring and summer of 2025.
SABER Reports
Funding Provided by:
National Energy Technology Laboratory – Department of Energy
Collaborators:
Center for Air Quality (CAQ) at the University of Wyoming
Earth-Atmosphere Interactions Lab at The Pennsylvania State University
SABER Schedule
| # | Activity | Starting Quarter | Duration (Quarters) | Start Date | End Date |
|---|---|---|---|---|---|
| Section 1: Project Management and Planning | |||||
| 1 | Project Management and Planning | 1 | 12 | 8/01/23 | 8/01/26 |
| 1.1 | Finalize DJ agreements | 1 | 2 | 8/01/23 | 2/01/24 |
| 1.2 | Finalize UGR agreements | 2 | 2 | 11/01/23 | 5/ 01/24 |
| Section 2: Denver-Julesberg Basin | |||||
| 2.1 | DJ Field campaign planning | 2 | 2 | 11/01/23 | 5/ 01/24 |
| 2.2 | Develop tower network for DJ | 1 | 3 | 8/01/23 | 5/ 01/24 |
| 2.3 | Assemble modeling for tower estimates | 2 | 3 | 11/01/23 | 8/ 01/24 |
| 2.4 | BU model for DJ | 3 | 4 | 2/ 01/24 | 2/01/25 |
| 2.5 | DJ Field campaign | 4 | 3 | 5/ 01/24 | 2/01/25 |
| 2.6 | Operate DJ tower and create TD estimates | 4 | 6 | 5/ 01/24 | 11/01/25 |
| 2.7 | Tune BU model inputs using field data | 7 | 3 | 2/ 01/25 | 11/01/25 |
| 2.8 | Compare DJ BU with TD estimates | 8 | 2 | 5/ 01/25 | 11/01/25 |
| 2.9 | Community outreach/ education | Ongoing | |||
| M1 | Ready for DJ Field campaign | 5/16/24 | |||
| M2 | DJ Field campaign Complete | 2/17/25 | |||
| M3 | DJ Emissions Comparison Complete | 11/17/25 | |||
| Section 3: Upper Green River Basin | |||||
| 3.1 | UGR field campaign planning | 4 | 2 | ||
| 3.2 | Develop tower network for UGR | 3 | 3 | ||
| 3.3 | Fall UGR Field campaign | 6 | 1 | ||
| Spring UGR Field campaign | 8 | 1 | |||
| 3.4 | Replicate tuning from DJ in UGR | 9 | 2 | ||
| M4 | Ready for UGR Field campaign | 11/15/24 | |||
| M6 | Project Complete | 7/31/26 | |||
Results (as of July 2025):
- Demonstrated a new approach for basin-scale methane measurement. The SABER project showed that high-frequency atmospheric monitoring combined with facility data can produce reliable emissions estimates for large oil and gas basins such as Colorado’s Denver–Julesburg Basin.
- Early results suggest that different measurement approaches can be reconciled. Independent “top-down” atmospheric measurements and “bottom-up” emissions inventories showed encouraging agreement, indicating that careful modeling and comprehensive data collection can bring these methods into alignment.
- Extensive field campaigns improved understanding of real-world emissions. Aerial surveys, ground inspections, and drone measurements identified emission sources and helped detect abnormal leaks, enabling operators to address issues and providing valuable data for emissions modeling.
- New tools were developed to better represent emissions behavior. The project advanced the Methane Activity Emissions Simulator (MAES), a modeling framework that incorporates operational activity, equipment behavior, and real-world failure events to improve emissions inventories.
- Findings highlight the importance of looking beyond oil and gas sources. Preliminary analysis suggests that non-oil-and-gas sources—such as agricultural operations and landfills—may represent a significant share of total basin methane emissions, emphasizing the need for broader measurement and mitigation strategies.
- The SABER framework provides a scalable model for other regions. The methods developed through this work are designed to be transferable to other basins, supporting more transparent and reliable methane emissions accounting.
Publications:
- Mbua, M., Riddick, S. N., Kiplimo, E. Shonkwiler, K., Hodshire, A., and Zimmerle, D. J. (2025) Evaluating the feasibility of using downwind methods to quantify point source oil and gas emissions using continuously monitoring fence-line sensors; EGUsphere, https://doi.org/10.5https://doi.org/10.5194/amt-18-5687-2025
- Riddick, S. N., Mbua, M., Anand, A., Kiplimo, E., Santos, A., Upreti, A., and Zimmerle, D. J. (2024) Estimating total methane emissions from the Denver-Julesburg basin using bottom-up approaches. Gases, 4(3), 236-252. https://doi.org/10.3390/gases4030014
- Liu, Y., N.L. Miles, S.J. Richardson, D.O. Miller, and B.J. Haupt (2025). Denver-Julesburg Basin: In-situ tower greenhouse gas data. Data set. Available on-line [http://datacommons.psu.edu] from The Pennsylvania State University Data Commons, University Park, Pennsylvania, USA. https://doi:10.26208/ra58-sx41.
- Liu, Y., Miles, N.L., Richardson, S.J., Barkley, Z.R., Miller, D.O., Kofler, J., Handley, P., DeVogel, S., Davis, K.J. (2026). Laboratory and field assessment of multiple mid-infrared absorption (MIRA) analyzers’ performance for in-situ methane and ethane. https://doi.org/10.5194/amt-19-965-2026
Opportunities to Participate:
As project is discontinued, please contact [email protected] for further information.