Subpart YY Information Sheet
Overview
Subpart YY of the Greenhouse Gas Reporting Program (GHGRP) (40 CFR 98.510 – 98.518) applies to any facility that produces caprolactam (C6H11NO), glyoxal (C2H2O2), or glyoxylic acid (C2H2O3) and meets the Subpart YY source category definition. Some subparts have thresholds that determine applicability for reporting, and some do not. To decide whether your facility must report under this subpart, please refer to 40 CFR § 98.511 and the GHGRP Applicability Tool.
This Information Sheet is intended to help facilities reporting under Subpart YY understand how the source category is defined, what greenhouse gases (GHGs) must be reported, how GHG emissions must be calculated and shared with EPA, and where to find more information.
On this page:
- How is This Source Category Defined?
- What GHGs Must Be Reported?
- How Must GHG Emissions Be Calculated?
- What Information Must Be Reported?
- What Records Must Be Maintained?
- When and How Must Reported Be Submitted?
- When Can a Facility Stop Reporting?
- For More Information
How is This Source Category Defined?
The Subpart YY source category applies to any facility that produces caprolactam (C6H11NO), glyoxal (C2H2O2), or glyoxylic acid (C2H2O3), but excludes the production of C2H2O2 through the LaPorte process (i.e., the gas-phase catalytic oxidation of ethylene glycol (C2H6O2) with air in the presence of a silver (Ag) or copper (Cu) catalyst).
What GHGs Must Be Reported?
Under Subpart YY, facilities must report nitrous oxide (N2O) process emissions from the production of C6H11NO, C2H2O2, and C2H2O3.
If multiple Greenhouse Gas Reporting Program (GHGRP) source categories are co-located at a facility, the facility may need to report greenhouse gas (GHG) emissions under a different subpart. Please refer to the relevant information sheet for a summary of the rule requirements for any other source categories located at the facility. For example, facilities that produce C6H11NO, C2H2O2, or C2H2O3, must report carbon dioxide (CO2), methane (CH4), and N2O emissions from each stationary combustion unit under Subpart C (General Stationary Fuel Combustion Sources), found at 40 CFR 98.30 – 98.38.
How Must GHG Emissions Be Calculated?
Under Subpart YY, facilities that produce C6H11NO, C2H2O2, or C2H2O3, must report:
- Annual N2O process emissions from each C6H11NO, C2H2O2, or C2H2O3 process line using the appropriate default N2O generation factor(s) from Table YY-1,
- Site-specific N2O destruction factor(s) for each N2O abatement device, and
- Site-specific production data (as applicable):
- Determine the annual amount of C6H11NO, C2H2O2, or C2H2O3 produced (product i) on each process line t (metric tons product) by summing the respective monthly quantities. To determine total monthly amounts produced, use one of the two following methods:
- Direct measurement of production (such as using flow meters, weigh scales, etc.); or
- Existing plant procedures used for accounting purposes (i.e., dedicated tank-level and acid concentration measurements).
- If process line t exhausts to any N2O abatement technology j, determine the destruction efficiency (DE) for each N2O abatement technology as follows:
- Use the control device manufacturer’s specified DE; and
- Estimate the DE through process knowledge. Examples of information that could constitute process knowledge include calculations based on material balances, process stoichiometry, or previous test results provided the results are still relevant to the current vent stream conditions. Explain and document how process knowledge (if applicable) was used to determine the DE.
- If process line t exhausts to any N2O abatement technology j, determine the abatement utilization factor for each N2O abatement technology as follows:
- If the abatement technology j has no downtime during the year, use 1.
- If the abatement technology j was not operational while product i was being produced on process line t, calculate the abatement utilization factor according to Equation 1 of YY.
- Equation 1 of YY: 𝐴𝐹𝑗 =𝑻𝒊,𝒋 /𝑻𝒊
- 𝐴𝐹𝑗 = Monthly abatement utilization factor of N2O abatement technology j from process line t (fraction of time that abatement technology is operating).
- 𝑇𝑖,𝑗 = Total number of hours during month that product i (C6H11NO, C2H2O2, or C2H2O3), was produced from process line t during which N2O abatement technology j was operational (hours).
- 𝑇𝑖 = Total number of hours during month that product i (C6H11NO, C2H2O2, or C2H2O3), was produced from process line t (hours).
- Calculate N2O emissions for each product i from each process line t and each N2O control technology j according to Equation 2 of YY.
- Equation 2 of YY: 𝑬𝑵𝟐𝑶𝒕 = Σ𝒊,𝒋 [𝑬𝑭𝒊 ∗ 𝑷𝒊 ∗ (𝟏 − (𝑫𝑬𝒋 ∗ 𝑨𝑭𝒋))] ∗ 𝟎. 𝟎𝟎𝟏
- 𝐸𝑁2𝑂𝑡 = Monthly process emissions of N2O, metric tons from process line t.
- 𝐸𝐹𝑖 = N2O generation factor for product i (C6H11NO, C2H2O2, or C2H2O3), kilograms (kg) of N2O/ metric tons of product produced, as shown in Table YY-1.
- 𝑃𝑖 = Monthly production of product i, (C6H11NO, C2H2O2, or C2H2O3), metric tons.
- 𝐷𝐸𝑗 = DE of N2O abatement technology type j, fraction (decimal fraction of N2O removed from vent stream).
- 𝐴𝐹𝑗 = Monthly abatement utilization factor for N2O abatement technology type j, fraction, calculated using Equation 1 of this subpart. 0.001 = Conversion factor from kg to metric tons.
- Determine the annual emissions combined from each process line at your facility using Equation 3 of YY.
- Equation 3 of YY: 𝑵𝟐𝐎 = Σ 121𝑬𝑵𝟐𝑶𝒕
- 𝑁2O = Annual process N2O emissions from each process line for product I (C6H11NO, C2H2O2, or C2H2O3) (metric tons).
- 𝐸𝑁2𝑂𝑡 = Monthly process emissions of N2O from each process line for product i (C6H11NO, C2H2O2, or C2H2O3) (metric tons).
- Equation 3 of YY: 𝑵𝟐𝐎 = Σ 121𝑬𝑵𝟐𝑶𝒕
- Determine the annual amount of C6H11NO, C2H2O2, or C2H2O3 produced (product i) on each process line t (metric tons product) by summing the respective monthly quantities. To determine total monthly amounts produced, use one of the two following methods:
| Product | N2O Generation Factor* |
|---|---|
| Caprolactam | 9.0 |
| Glyoxal | 520 |
| Glyoxylic acid | 100 |
*Generation factors in units of kg of N2O emitted per metric tons of product produced.
A checklist for data that must be monitored is available here: Subpart YY Monitoring Checklist.
What Information Must Be Reported?
In addition to the information required by the General Provisions in Subpart A, found at 40 CFR 98.3(c), facilities that produce C6H11NO, C2H2O2, or C2H2O3 must report the following:
- Process line identification number.
- Annual process N2O emissions from each process line as follows:
- N2O from C6H11NO production (metric tons);
- N2O from C2H2O2 production (metric tons);
- N2O from C2H2O3 production (metric tons).
- Annual production quantities from all process lines at the C6H11NO, C2H2O2, or C2H2O production facility as follows:
- C6H11NO production (metric tons);
- C2H2O2 production (metric tons);
- C2H2O3 production (metric tons).
- Annual production capacity from all process lines at the C6H11NO, C2H2O2, or C2H2O production facility, as applicable, as follows:
- C6H11NO production capacity (metric tons);
- C2H2O2 production capacity (metric tons);
- C2H2O3 production capacity (metric tons).
- Number of process lines at the C6H11NO, C2H2O2, or C2H2O production facility, by product, as follows:
- Total number of process lines producing C6H11NO;
- Total number of process lines producing C2H2O2;
- Total number of process lines producing C2H2O3.
- Number of operating hours in the calendar year for each process line at the C6H11NO, C2H2O2, or C2H2O3 production facility (hours).
- N2O abatement technologies used (if applicable) and date of installation of abatement technology at the C6H11NO, C2H2O2, or C2H2O3 production facility.
- Monthly abatement utilization factor for each N2O abatement technology for each process line at the C6H11NO, C2H2O2, or C2H2O3 production facility.
- Number of times in the reporting year that missing data procedures were followed to measure production quantities of C6H11NO, C2H2O2, or C2H2O3 (months).
- Annual percent N2O emission reduction per chemical produced at the C6H11NO, C2H2O2, or C2H2O3 production facility, as applicable, as follows:
- Annual percent N2O emission reduction for all C6H11NO production process lines;
- Annual percent N2O emission reduction for all C2H2O2 production process lines;
- Annual percent N2O emission reduction for all C2H2O3 production process lines.
A complete record of all measured parameters used in GHG emissions calculations is required. Whenever a quality-assured value of a required parameter is unavailable, a substitute data value for the missing parameter must be used in the calculations as specified below:
- For each missing value of C6H11NO, C2H2O2, or C2H2O3 production, the substitute data must be the best available estimate based on all available process data or data used for accounting purposes (such as sales records).
- For missing values related to the N2O abatement device, assuming that the operation is generally constant from year to year, the substitute data value should be the most recent quality-assured value.
What Records Must Be Maintained?
Reporters are required to retain records that pertain to their annual GHGRP report for at least three years after the date the report is submitted. Please see the Subpart A Information Sheet and 40 CFR 98.3(g) for general recordkeeping requirements. Specific recordkeeping requirements for Subpart YY are listed at 40 CFR 98.517.
When and How Must Reports Be Submitted?
Reporters must submit their annual GHGRP reports for the previous calendar year to the EPA by March 31st, unless the 31st falls on a Saturday, Sunday, or federal holiday, in which case reports are due on the next business day. Annual reports must be submitted electronically using the electronic Greenhouse Gas Reporting Tool (e-GGRT), the GHGRP’s online reporting system.
Additional information on setting up user accounts, registering a facility, and submitting annual reports is available on the GHGRP Help webpage.
When Can a Facility Stop Reporting?
A facility may discontinue reporting under several scenarios, which are summarized in Subpart A (found at 40 CFR 98.2(i)) and the Subpart A Information Sheet.
For More Information
For additional information on Subpart YY, please visit the Subpart YY webpage. For additional information on the GHGRP, please visit the GHGRP website, which includes additional information sheets, data previously reported to the GHGRP, training materials, and links to Frequently Asked Questions. For questions that cannot be answered through the GHGRP website, please contact us at: [email protected].
This Information Sheet is provided solely for informational purposes. It does not replace the need to read and comply with the regulatory text contained in the rule. Rather, it is intended to help reporting facilities and suppliers understand key provisions of the GHGRP. It does not provide legal advice; have a legally binding effect; or expressly or implicitly create, expand, or limit any legal rights, obligations, responsibilities, expectations, or benefits with regard to any person or entity.