Take Charge of CEMS Data Review in 2024
January is the perfect time for organizing – from straightening your closet to cleaning up your desktop to following resolutions to stay on top of reviewing your CEMS data. There are many data points to track at different times of the year. To help make this process easier, we’ve created a series of CEMS Data Review Checklists to keep it all straight.
Data Review CEMS Checklist Types
To help you review your CEMS data at the optimal time of year, we’ve created checklists for the following:
Each checklist makes recommendations for Daily and Weekly, Monthly, Quarterly, Semi-annual/Annual data reviews for your CEM system.
Full CEM System Checklist
In general, coal-fired units or stacks use a full CEM (or COM) system. Full CEM System monitoring components usually include opacity, SO2, NOx, CO2/O2, CO, volumetric stack flow, a sample probe, an umbilical sample bundle, and Data Acquisition System (DAS). This configuration is the most complicated. Note this checklist does not address Mercury Air Toxin Standards (MATS) issues.
Appendix D CEM System Checklist
A unit that is using the Appendix D protocol for emission monitoring does not need to monitor for SO2 in units that combust fuel oil (diesel fuel or other grades) or gaseous fuels (pipeline natural gas, natural gas, or other grades) because the sulfur content in these fuels is consistent. Facilities use a routine sampling program of combusted fuel to determine sulfur content and Gross Caloric Values (GCV). Operators can then use default values for these two characteristics. Operators must accurately measure and record hourly fuel combustion rates and track two sets of gas monitoring systems (NOx and diluent [CO2/O2] monitors along with a sample probe). They must also measure the two pollutants using an umbilical sample bundle and a Data Acquisition System. The DAS records the fuel flow so periodic accuracy checks are necessary for the fuel flow meters or transducer transmitters. Primary Element Inspections (PEI) are required every five years. The DAS also calculates hourly SO2, NOx, and CO2 mass totals, along with quarterly and year-to-date totals.
Appendix E CEM System Checklist
Operators can only use the Appendix E protocol for gas or oil-fired units with an average capacity factor of ≤ 10.0% averaged over three consecutive years, with no single year measuring >20.0%. No emission monitors are needed, but the system accurately measures the fuel flow rates following the Appendix D protocol. Periodic accuracy checks are necessary for the fuel flow meters or transducer transmitters. Primary Element Inspections (PEI) are required every five years. The Data Acquisition System uses a specialized configuration to estimate the hourly NOx emission rates based on hourly heat input rates. The DAS also calculates hourly SO2, NOx, and CO2 mass totals, along with quarterly and year-to-date totals.
LME System Checklist
A Low Mass Emitting (LME) system is used on units that infrequently operate, typically with an operating history of approximately 100 operating hours or less per year. Operators do not monitor the actual emissions. Monitoring Plan records define default emission factors (lb./MMBtu) for SO2, NOx, and CO2. LMEs do not need a typical Data Acquisition System (DAS) because operators can generate the operating records from other operating systems and use these records to generate the corresponding EDR files in ECMPS. The regulations required that a facility’s records include information on when the unit operates, the duration of operation in each hour (minutes per hour), and the load generated (MW/hr. or steam flow in K lb./hr.). The data system or ECMPS calculates hourly SO2, NOx, and CO2 mass totals using the default emission rates and hourly operating data. It also calculates quarterly and year-to-date totals.
Make CEMS Data Review a Priority
With so much on your plate, from changing regulations to reporting to team management and demands from other departments, it’s hard to make time to run the periodic reviews needed to keep you audit ready (read our Quick CEMS Audit Prep Checklist and Guide to Part 75 Audit Preparation for more guidance). Setting aside the time in the present will keep you from running into problems in the future.
We’re Here to Help
If you need assistance, please reach out to our ESC Spectrum experts. From Data Acquisition Systems to high-quality CEM systems, equipment, or services to Stack testing, Reporting, Engineering, IT, and Regulatory teams – we have everything you need to help you meet air emissions monitoring and compliance requirements.
Interested in learning a more comprehensive overview of how CEM Systems work? Read Understanding Continuous Emissions Monitoring Systems (CEMS): A Comprehensive Guide. This guide will give you a complete understanding of all the components in the flow of a CEMS.