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On November 13, 2019, Air Pollution Control Division (APCD) published the Oil and Gas Industry Emissions Calculation & Regulatory Analysis Workbook and associated guidance document. The Emissions Calculation & Regulatory Analysis Workbook is intended to assist operators in applying for permits by following approved calculation procedures, ensuring uniformity and supporting regulatory requirement determinations. The workbook has been worked on by the Division over the last 4.5 years and has been used by permit engineers to verify calculations supplied by the applications, therefore usage of this workbook although voluntary, is highly encouraged in order to facilitate the permit application review process.

The workbook comes with a guidance document which provides details on using the workbook for applications and for integrating it with other tools and facility workbooks. The workbook includes a “project summary” tab and separate tabs for estimating emissions from common oil and gas equipment like condensate storage tanks, crude oil storage tanks, produced water storage tanks, hydrocarbon loadout, separator venting, natural gas fired heaters, dehydration units and amine units. There are also separate tabs within the workbook to complete the regulatory analysis for each equipment type (this includes typically applicable federal standards and Colorado specific standards). The guidance document specifies that if the structure, calculations or standard language of the worksheet is modified, a detailed discussion of the changes must be provided. Note the workbook does not have any embedded calculations for estimating working/breathing/flash losses from storage tanks and as such, copies of process simulations and/or analytical reports must be provided with the workbook. Also note that this workbook does not include calculation or regulatory applicability tabs for internal combustion engines. It is expected that a facility may want to maintain their own emission calculations and analysis, but supplement with the APCD tools to align expectations with the agency and expedite the review process. The workbook will be printed and submitted in hard copy along with rest of the permit application, however applicants are encouraged to maintain an electronic file which can be provided upon request to the assigned permit engineer.

The division has stated that it will periodically update the workbook to add new features and functionality.

For additional information on the usage of this workbook, permitting implications, or air permit application support, please contact Hari Krishna Bharadwaj in Trinity's Denver office at (720) 638-7647, x116.