TCEQ Air Quality 101 Blog Series – Continuous Monitoring Systems (CMS)

Close your eyes and imagine you are the conductor of a symphony orchestra.  Now open them and come to grips with the fact that your orchestra is a Data Acquisition and Handling System (DAHS)!  So have some fun with it…you are the conductor of an orchestra of probes/analyzers, umbilical lines, condensers, gas dilution equipment, other hardware, all while sending communication responses to software systems.

Now imagine you are a Plant Manager, or Responsible Official.  For all those annual, semiannual, and quarterly reports that rely on Continuous Emissions Monitoring System (CEMS) data, you must certify the emissions information in each report is complete, accurate and true, beyond your reasonable inquiry.  Do you have the confidence in your quality assurance/quality control (QA/QC) procedures, your calibration audits, or general work practice standards to ensure that recorded data is valid, beyond reasonable inquiry?  Can you be assured that your Texas facility is protected from the risk of noncompliance with the cacophony of regulations that govern data reporting?  Managing continuously measured data in increments (i.e., 10-second, 1-minute, 1-hour, etc.) may seem like a lot of pressure–almost bottom of the ninth, bases loaded, type of pressure (for all you Astros fans), but rest assured, if you are informed and understand your CEMS, using CEMS for reporting, recordkeeping, purposes can be an asset instead of a burden.

Whether your facility is subject to the emissions inventory reporting requirements of 30 TAC §101.10, the utility electric generation reporting requirements identified in 30 TAC §117.3045(d)(5), the emissions events reporting and recordkeeping requirements pursuant to 30 TAC §101.201 or even Federal Information Collection Requests (ICRs) or the Standards of Performance for New Stationary Sources (NSPS) reporting requirements of 40 CFR §60.7(c)-(d), you most likely are relying on the accuracy of your facility’s CEMS to submit data.  You might even be relying on CEMS to demonstrate compliance with emission rates identified in your permit’s maximum allowable emission rates table (MAERT).  Whatever regulation, administrator request, or permit condition it may be, the validity of your CEMS data is critical.

Some of ALL4’s experience with TCEQ CEMS reporting requirements has led us to reporting annual emissions, and qualifying downtime and exceedance events throughout the year to ensure the continuously recorded data is in fact being reported correctly.  It is vital to know how your DAHS works.  It is vital to be transparent and foster a trusting relationship with the regulator who reviews your reports (e.g., emissions inventory or downtime/excess emissions events reports).  It is vital to know how valid averages are calculated (e.g., how valid minute data creates a valid hourly average).

Did you know that according to TCEQ’s 2016 Emissions Inventory Guidelines, published January 2017, “actual measurement with continuous CEMS is the preferred method of calculating emissions from a source” (pg. 6)?  Therefore, TCEQ prefers that reported annual emissions data be quantified using CEMS.  Since CEMS are typically used as a tool for continuously collecting emissions data for air compliance purposes, the data being reported using CEMS must be valid.  Having a CEMS that is not calibrated correctly, or is not certified, exposes your facility to unnecessary risk.  TCEQ reviews annual emissions inventory data and may reach out with questions upon reviewing those reported emissions.  Remember, for emissions reported via CEMS, TCEQ requires sheets that summarize the Relative Accuracy Test Audits (RATA) or other similar audits that were performed during the reporting year.  Make sure routine preventative maintenance activities are conducted on your CEMS, and make sure you have an ample supply of calibration gases on site, just to name a few action items that can support your CEMS in producing valid data.

For any of your facility’s submitted reports, find out how your regulator reviews your data.  For the person reviewing your facility’s reports, transparency in your data is key.  In our conversations with regulatory contacts throughout the state, transparency is one of the most valued criteria when building trust with a facility and its operations staff.  In addition, consistency in reporting your data is also key.  Through our conversations with state staff members and through our own experience, we have found that regulators review historical reports alongside of current reports, looking for trends, inconsistencies, or discrepancies between reporting periods.  Submitting consistent reports allows regulators to more efficiently perform his or her review, which makes your life easier.  For example, from a consistency standpoint, make sure you define any excess emissions event at your facility using exactly the same language on your excess emissions event notifications, excess emissions and monitoring systems performance detailed reports, semiannual deviation reports, etc.  It is important to have the information on these reports quality assured, as eventually the submitted data will become available to the public.

A day in the life of an Environmental Manger can be tricky, especially when it comes to managing CEMS.  As highlighted throughout this blog, there are notification, reporting, recordkeeping and best management practices required to maintain a compliant and healthy CEMS in TX.  Know the rules, and try to understand your regulator’s expectations and what he or she may focus on.  From CMS to COMS all the way to CPMS and PEMS, ALL4 has you covered in TX.  Equipped with extensive experience, ALL4 has a robust CMS team that can alleviate CMS stresses, or even provide company-wide CMS trainings through webinars.  Please reach out to me at fdougherty@all4inc.com, 281-937-7553 x302 if you have any CMS related questions.