Update: Due to DOE project cancellations, we are reevaluating our projects and will update the website when we have additional information.


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:

SABER Study Design

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 Interim Report

SABER: Site‐Air‐Basin Emissions Reconciliation ‐ Towers (August 2024)

Funding Provided by:

National Energy Technology Laboratory – Department of Energy

Collaborators:

Bridger Photonics

Center for Air Quality (CAQ) at the University of Wyoming 

Earth-Atmosphere Interactions Lab at The Pennsylvania State University

SABER Schedule

#ActivityStarting QuarterDuration (Quarters)Start DateEnd Date
Section 1: Project Management and Planning
1Project Management and Planning1128/01/238/01/26
1.1Finalize DJ agreements128/01/232/01/24
1.2Finalize UGR agreements2211/01/235/ 01/24
Section 2: Denver-Julesberg Basin
2.1DJ Field campaign planning2211/01/235/ 01/24
2.2Develop tower network for DJ138/01/235/ 01/24
2.3Assemble modeling for tower estimates2311/01/238/ 01/24
2.4BU model for DJ342/ 01/242/01/25
2.5DJ Field campaign435/ 01/242/01/25
2.6Operate DJ tower and create TD estimates465/ 01/2411/01/25
2.7Tune BU model inputs using field data732/ 01/2511/01/25
2.8Compare DJ BU with TD estimates825/ 01/2511/01/25
2.9Community outreach/ educationOngoing
M1Ready for DJ Field campaign5/16/24
M2DJ Field campaign Complete2/17/25
M3DJ Emissions Comparison Complete11/17/25
Section 3: Upper Green River Basin
3.1UGR field campaign planning42
3.2Develop tower network for UGR33
3.3Fall UGR Field campaign61
Spring UGR Field campaign81
3.4Replicate tuning from DJ in UGR92
M4Ready for UGR Field campaign11/15/24
M5UGR Trial Complete2/16/26
Section 4: Synthesis and Finalization
4.1ID learnings and generalize process10211/01/255/ 01/26
4.2Set up tower networks for long term1122/ 01/268/ 01/26
4.3Final report and synthesis paper(s)1122/ 01/268/ 01/26
M6Project Complete7/31/26

Results:

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. (2025, in prep). Laboratory and field assessment of multiple mid-infrared absorption (MIRA) analyzers’ performance for in-situ methane and ethane.

Opportunities to Participate:

Interested in participating?  Contact [email protected] for further information.