Colorado Ongoing Basin Emissions Study (COBE)
Summary:
This is an environmental project that serves to support the Colorado Department of Public Health and Environment (CDPHE), Air Pollution Control Division (APCD) in facilitating the state of Colorado’s efforts to enact greenhouse gas (GHG) reduction measures with the goal of limiting future climate warming. CSU will develop a measurement-informed inventory for methane emissions from the statewide upstream O&G segment utilizing site-level aircraft measurements. This project will support the implementation of the Intensity Verification Rule enacted by the Colorado Air Quality Control Commission (AQCC) in July 2023.
CSU (in collaboration with aerial survey participants and research participants) shall conduct a series of aerial surveys to scan upstream O&G facilities and quantify observable methane emissions throughout the state of Colorado. Emission observations collected from the aerial survey participants shall be sent to the Contractor for attribution of emission sources to specific facilities. CSU will share these emission observations with O&G operators who agree to participate in non-disclosure agreements for bi-directional data sharing. The sharing of emission observations with O&G operators is needed for assessment of maintenance operations occurring on site at the time of observation. The emissions data collected by the aerial survey participants as well as operational metadata collected from O&G operators for each measurement campaign shall be analyzed by the CSU and its partners to create a statistical model to develop measurement-informed emission factors for a series of classes of O&G facilities throughout the state from the data collected by aerial survey participants. The resulting model shall assess the total methane emissions from the upstream O&G segment in comparison to the state Oil and Natural Gas Annual Inventory Emission Report (ONGAIER) database for use within the development of the state default factor(s) for the implementation of the Intensity Verification Rule.
Objectives:
Goal: To improve and protect the air quality in Colorado through the development and implementation of cost-effective and efficient air pollution control measures that are consistent with the requirements of state and federal law.
Objective: Collect site-level aircraft measurements performed at a subset of facilities to develop a measurement-informed inventory of methane emissions from the upstream O&G sector throughout the state of Colorado.
Project Plan:
1. Broad multi-basin sampling with many hours of aircraft time
a. Repeat sampling, as funding allows, to help with persistence numbers
b. Aircraft have ‘context cameras’ to help identify activities on facilities
2. Establish a ‘pipeline’ to allow participating operators to review aircraft detections:
a. Identify plumes from maintenance actions
b. React to / correct fugitive emitters
c. Establish a dialog about what & why
3. Use data from (2) to identify maintenance emissions
a. Note that matching aircraft plumes to maintenance does not indicate that the maintenance emissions were reported accurately.
4. Use data from (1)-(3) to estimate emissions for major gas basins in Colorado
Why Does Maintenance Impact Estimates?
- Common scaling method for aircraft detections:
- Sum up plumes: Estimated size X <some estimate of persistence>
- Above sum = emission rate of basin
- Basin rate is implicitly scaled to 24×7 emissions
- Common scaling works if:
- Emitter duration is similar for all sources, and persistence assumption is correct
- Sampling is unbiased to times with more/fewer emitters
- But …
- Aircraft resampling too infrequent to identify persistence (duration) of maintenance releases
- Aircraft sampling is biased to daylight weekday periods
What does operator/CSU participation look like in COBE?
- Agree to participate: CSU/Operators covered by an NDA.
- CSU only releases results based on aggregation and anonymization
- Expect operators to join in stages as more hear about project
- NDA will define how information will be exchanged – depends on legal counsel’s recommendations
- Operators provide email and phone contact for POC for CSU to send detections on their facility
- CSU provides window of flight campaigns (few months span but operators will not be informed of exact flight plans)
- CSU sends detections to POC using our best estimate of who owns the facility
- Operator returns best estimate of cause – maintenance, known problem – to CSU …sometimes reiteration needed here
- CSU/Operators have regular working group meetings
- CSU provides all aggregated and anonymized data in reports to CDPHE; scientific analysis reported in peer-reviewed journals
Schedule:
Project timeline:
March 2024 – June 2025
Flight campaigns:
1. Campaign 1: Spring 2024
2. Campaign 2: Summer 2024
3. Campaign 3: Fall 2024
Results:
TBD
Opportunities to Participate:
Operators interested in participating, please contact PI Anna Hodshire, anna.hodshire@colostate.edu.
Funding Provided by:
Study Partners:
- Colorado School of Mines – statistical scaling to basin level
- University of Texas at Austin – additional modeling support
- Aerial surveys (companies still under contracting)