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Triennial Minor Source Emissions Inventories Due in 90 Days

The Wyoming Department of Environmental Quality (WDEQ) monitors and collects actual emissions data in accordance with federal regulations. State-wide minor source emissions inventories are collected every three years. As part of the Triennial Minor Source Emissions reporting cycle, each minor source located in Wyoming must submit an inventory of the estimated actual emissions for the 2020 calendar year by April 30, 2021.

How do I report my emissions inventory?

WDEQ prefers that operators use the Air Quality Division’s (AQD’s) Inventory, Monitoring, Permitting, And Compliance Tracking (IMPACT) data system to report their emissions.  Operators can work directly within the web portal or enter data into a WDEQ-supplied workbook, pre-populated with facility inventory information to report emissions inventories. AQD’s Legacy Emission Inventory workbook remains available for operators to use, but AQD must be contacted for permission prior to submittal.

The following summarizes 2020 emissions inventory submission guidelines by facility type: 

Oil and Gas Production Facilities:

  • For operators with 25 or fewer production sites, it is likely easier to work directly in IMPACT via the web portal to develop/submit the emissions inventory for each facility.
  • Operators with greater than 25 facilities are advised to use the new batch submittal reporting procedure outlined in WDEQ’s “New Production-Site Batch EI Submission Process Overview_2020 Annual EI" guidance document.

The new batch submittal option extracts facility data from IMPACT with data entry fields awaiting operating parameter information (e.g. operating hours, fuel consumption, production, throughputs, etc.). The batch submittal option also helps mitigate IMPACT’s constraint that limits users to working on one facility at a time.

Reporting forms and other guidance for reporting actual emissions for minor sources can be accessed on WDEQ’s website.

Oil and Gas Midstream Facilities:

Oil and gas midstream facilities are also required to submit triennial emission inventories through IMPACT/IMPACT-extracted workbook when possible.

If unable to submit through IMPACT (e.g. IMPACT facility information is not up to date), the following guidelines apply:

How do I get started?

With the April 30, 2021 deadline fast approaching, facilities should begin compiling their 2020 data now and verify they have collected the necessary information. Completing an accurate emissions inventory can be a cumbersome process. Some operators may not have calculated actual emissions since the previous triennial report was submitted in 2018, meaning data may need to be collected and calculated. Additionally, in certain circumstances, facility information within IMPACT must first be updated before the emissions inventory can be submitted.

Anything else I should know?

Attention to detail is paramount when generating an emission inventory. Inaccurate information can cause confusion and potentially lead to enforcement. It is important to submit accurate, high-quality data because the triennial emissions inventories not only support the National Emissions Inventory, but also have real impacts on facilities. For example, WDEQ will use submitted emission inventories as the basis for determining permit compliance during future site visits.

Questions? Contact us.

Trihydro’s Air Quality and Process Management Team Team has decades of experience working with clients to produce accurate emission inventories and assisted with numerous 2017 reporting cycle WDEQ Triennial Emissions Inventories. With expertise in emission calculations and experience using Wyoming’s IMPACT system, Trihydro is available to answer your reporting questions or provide full-service reporting assistance.

John Pfeffer
Senior Air Professional
(307) 745-7474
[email protected] 

John Pfeffer
John Pfeffer
Senior Air Professional, Golden, CO

John has performed, supervised, and managed environmental projects in the refining and petrochemical industries for over 27 years. His experience includes numerous Clean Air Act compliance projects involving New Source Review (NSR) permitting, Title V Permitting and compliance, Benzene Waste Operations NESHAP (BWON), Consent Decree compliance, leak detection and repair (LDAR) program implementation and management, New Source Performance Standards (NSPS), and Maximum Achievable Control Technology (MACT) regulations.

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