{"id":"AIBD-0910","title":"EPA approves trained Pavilion8 models in place of hardware NOx analyzers on seven Arkansas turbines after they passed its accuracy tests","summary":"EPA found that trained Pavilion8 models matched hardware NOx analyzers on seven Arkansas turbines, with relative accuracy of 1.38% to 3.15%. It approved them in their place.","date_observed":"2012-11-21","date_basis":"source publication","date_precision":"day","benefit_status":"intended","source_collection":null,"source_entry":null,"account":"The Arkansas Electric Cooperative Corporation owns the Harry L. Oswald Generating Station, a 510 MW combined-cycle plant in Pulaski County, Arkansas. Federal rules require it to monitor NOx emissions from its seven combustion turbines continuously. It did so with certified hardware analyzers. In July 2010 the cooperative installed Pavilion8 software PEMS, which predict emissions from operating data, on all seven turbines. Each was trained on sensor readings while NOx was measured, and a model for each turbine was built from the training data. The models then ran alongside the analyzers for at least 720 operating hours per turbine. In a letter dated 21 November 2012, EPA found that each model passed all three required statistical tests. Relative accuracy against the analyzers ranged from 1.38% to 3.15%. EPA approved the models in place of the analyzers, with conditions for quality checks and retraining. EPA relied on data that the cooperative submitted, and the letter reports no saving.","category":"aggregate result","unexpected":false,"purpose":"Rockwell Automation built the Pavilion8 software PEMS to predict a combustion turbine's NOx emissions from its operating data.","system":"Pavilion8 Software PEMS (predictive emission monitoring systems) on Units G1 through G7","model_version":null,"developer":"Rockwell Automation (maker of Pavilion8, which the letter names only as a product)","deployer":"Arkansas Electric Cooperative Corporation (AECC), Harry L. Oswald Generating Station","location":"Pulaski County, Arkansas, United States","domain":"Air emissions monitoring (power generation)","segment":null,"benefit_type":"Improved Task Accuracy","work_activities":["4.A.1.b.3","4.A.1.a.2"],"taxonomy_note":"The models matched the accuracy of the hardware analyzers that they replace, and the letter reports no gain over the analyzers or any saving.","registry_ids":{},"ratings":[{"group":"organizational","depth":null,"reason":"EPA approved the models on a demonstration against the analyzers, and the letter reports no saving or other outcome for the cooperative."}],"ai_role":{"status":"assessed","statement":"Each model's hourly NOx predictions were compared with the hardware analyzer on the same turbine, so the accuracy figures are the models' own. EPA writes that each PEMS was trained on operating data and that a model for each turbine was developed from the training data."},"evidence":[{"kind":"regulatory document","citation":"U.S. Environmental Protection Agency, Clean Air Markets Division. Letter to the Arkansas Electric Cooperative Corporation approving alternative monitoring systems (PEMS) for Units G1 through G7 at the Harry L. Oswald Generating Station (ORISPL 55221), signed by Reid Harvey, Director, 21 November 2012.","title":"Request for Approval of Alternative Monitoring Systems for Units G1 through G7 at the Arkansas Electric Cooperative Corporation's Harry L. Oswald Generating Station (Facility ID (ORISPL) 55221)","url":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf","date":"2012-11-21","written_by":"independent","quote":"Tables 1 through 4 also summarize the results of AECC's statistical analyses of the paired PEMS and CEMS data, which show that the NOx lb/mmBtu output from each PEMS passed all three required statistical tests."},{"kind":"regulatory document","citation":"U.S. Environmental Protection Agency, Clean Air Markets Division. Letter to the Arkansas Electric Cooperative Corporation, 21 November 2012. Background.","title":"Request for Approval of Alternative Monitoring Systems for Units G1 through G7 at the Arkansas Electric Cooperative Corporation's Harry L. Oswald Generating Station (Facility ID (ORISPL) 55221)","url":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf","date":"2012-11-21","written_by":"independent","quote":"A model for each combustion turbine was then developed from the training data."}],"replication":{"produced_by":["Each PEMS was trained on sensor readings of turbine operation while NOx was measured at the same time.","Each model predicted hourly NOx emission rates from inputs such as gas flow, steam injection and humidity."],"must_hold":["Input values stay within the operating envelope of the training data.","Daily checks, monthly audits and periodic accuracy tests continue, with retraining when operations change."],"echoes":[]},"paired_incident":null,"headline":"EPA lets *Pavilion8 PEMS* stand in for NOx analyzers in Arkansas","metric":"relative accuracy of 1.38% to 3.15%","comparator":{"against":"Certified hardware NOx analyzers (CEMS) on the same turbines","before":null,"after":"Relative accuracy of 1.38% to 3.15% across the seven units, with all three statistical tests passed","basis":"measured","quote":"in which hourly NOx emission rates predicted by the PEMS are compared directly against measurements made with either a certified CEMS or a reference method","url":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf"},"later":null,"value":null,"developer_country":"United States","deployer_country":"United States","unrated_because":"EPA approved the models on a demonstration against the hardware analyzers, and the letter reports no outcome after the approval.","brief_notes":null,"brief":null,"revisions":[{"date":"2026-10-31","change":"Added the record from the finding of the U.S. Environmental Protection Agency.","source":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf","editor":"AIBD"}],"confidence":"found","shade":"high","claim_status":"Found by a regulator","claim_basis":"Sources: one independent regulatory document. The cited evidence includes no independent study or report.","case_jurisdictions":["United States"],"profile":{"case_id":"AIBD-0910","catalog_version":"1.0.0","source_fingerprint":"c04fd9c5376436ade55de36ae443a0c6286caed75506d915f310f7ff4b14ba1d","collection_refs":[{"collection_id":"aibd","version":"2026-10-31"},{"collection_id":"querist","version":"2026-10-25"}],"source_ids":["AIBD-0910-source-0001","AIBD-0910-source-0002"],"families":{"strategic assessments":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"Editorial assignment.","review_state":"not_assessed","coverage":"partial","record_ids":[]},"evaluations":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"Editorial assignment.","review_state":"not_assessed","coverage":"partial","record_ids":[]},"monetary observations":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"Editorial assignment.","review_state":"not_assessed","coverage":"partial","record_ids":[]},"institutional decisions":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"Editorial assignment.","review_state":"not_assessed","coverage":"partial","record_ids":[]}},"fields":{"actors[]":{"state":"value_present","value":{"kind":"record_fields","fields":{"developer":"Rockwell Automation (maker of Pavilion8, which the letter names only as a product)","deployer":"Arkansas Electric Cooperative Corporation (AECC), Harry L. Oswald Generating Station"}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["developer","deployer"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"actors[].ownership_control":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"ai_contribution":{"state":"value_present","value":{"kind":"record_fields","fields":{"ai_role":{"status":"assessed","statement":"Each model's hourly NOx predictions were compared with the hardware analyzer on the same turbine, so the accuracy figures are the models' own. EPA writes that each PEMS was trained on operating data and that a model for each turbine was developed from the training data."}}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["ai_role"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"ai_relationship":{"state":"value_present","value":{"kind":"record_fields","fields":{"category":"aggregate result","ai_role":{"status":"assessed","statement":"Each model's hourly NOx predictions were compared with the hardware analyzer on the same turbine, so the accuracy figures are the models' own. EPA writes that each PEMS was trained on operating data and that a model for each turbine was developed from the training data."}}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["ai_role","category"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"assessments[].alternatives":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"assessments[].assessor_date":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"assessments[].depth":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"assessments[].display_confidence":{"state":"value_present","value":{"kind":"structured","data":{"confidence":"high","evidence_word":"found","claim_status":"Found by a regulator","basis":"Sources: one independent regulatory document. The cited evidence includes no independent study or report.","interpretation":"Existing display rule preserved; the richer outcome-specific confidence question still needs review."}},"provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"assessments[].rationale":{"state":"value_present","value":{"kind":"record_fields","fields":{"ratings":[{"group":"organizational","reason":"EPA approved the models on a demonstration against the analyzers, and the letter reports no saving or other outcome for the cooperative."}]}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["ratings"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"assessments[].rubric_version":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"assessments[].status_basis":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"assessments[].target":{"state":"value_present","value":{"kind":"record_fields","fields":{"ratings":[{"group":"organizational","reason":"EPA approved the models on a demonstration against the analyzers, and the letter reports no saving or other outcome for the cooperative."}]}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["ratings"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"availability":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"brief":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"case_kind":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"case_links[]":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"claims[].evidence_links":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"claims[].evidence_strength":{"state":"value_present","value":{"kind":"structured","data":{"answer":"Found by a regulator. Sources: one independent regulatory document. The cited evidence includes no independent study or report.","evidence_word":"found","claim_status":"Found by a regulator"}},"provenance":{"kind":"source_review","basis":"Editorial assignment.","record_fields":["evidence"],"source_refs":["AIBD-0910-source-0001","AIBD-0910-source-0002"],"reviewed_on":"2026-10-29"},"review_state":"reviewed","coverage":"complete","display":{"answer":"Found by a regulator. Sources: one independent regulatory document. The cited evidence includes no independent study or report.","inferred":false}},"claims[].missingness":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"claims[].proposition":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"cross_border_flows[]":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"decisions[].action_outcome":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"institutional decisions"},"decisions[].grounds":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"institutional decisions"},"decisions[].institution_task":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"institutional decisions"},"decisions[].success_criterion":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"institutional decisions"},"deployment_stage":{"state":"value_present","value":{"kind":"structured","data":{"classification":"pilot","answer":"The system was used in a pilot. The cooperative ran the models alongside its hardware analyzers on the seven operating turbines before EPA approved them for compliance monitoring.","scope":"The period and activity described in the case."}},"provenance":{"kind":"source_review","basis":"Editorial assignment.","record_fields":["account","evidence"],"source_refs":["AIBD-0910-source-0001"],"reviewed_on":"2026-10-29"},"review_state":"reviewed","coverage":"complete","display":{"answer":"The system was used in a pilot. The cooperative ran the models alongside its hardware analyzers on the seven operating turbines before EPA approved them for compliance monitoring.","inferred":false}},"economics[].amount":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].costs[]":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].counterfactual":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].currency_price_basis":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].gross_net":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].measure_type":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].period_unit":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].realization":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].recipient_payer":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].return_payback":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"economics[].valuation_method":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"monetary observations"},"evaluations[].ai_uplift":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].comparator":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].design":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].effect":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].exposure":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].id":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].measurement_method":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].metric":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].reproduction_materials":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].setting_sample":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"evaluations[].uncertainty_limitations":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"evaluations"},"external_references[]":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"follow_up[]":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"human_oversight":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"id":{"state":"value_present","value":{"kind":"record_fields","fields":{"id":"AIBD-0910"}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["id"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"infrastructure_dependencies[]":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"outcomes[].beneficiaries":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"outcomes[].beneficiary_count":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"outcomes[].benefit_type":{"state":"value_present","value":{"kind":"record_fields","fields":{"benefit_type":"Improved Task Accuracy","taxonomy_note":"The models matched the accuracy of the hardware analyzers that they replace, and the letter reports no gain over the analyzers or any saving."}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["benefit_type","taxonomy_note"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"outcomes[].claim":{"state":"value_present","value":{"kind":"record_fields","fields":{"account":"The Arkansas Electric Cooperative Corporation owns the Harry L. Oswald Generating Station, a 510 MW combined-cycle plant in Pulaski County, Arkansas. Federal rules require it to monitor NOx emissions from its seven combustion turbines continuously. It did so with certified hardware analyzers. In July 2010 the cooperative installed Pavilion8 software PEMS, which predict emissions from operating data, on all seven turbines. Each was trained on sensor readings while NOx was measured, and a model for each turbine was built from the training data. The models then ran alongside the analyzers for at least 720 operating hours per turbine. In a letter dated 21 November 2012, EPA found that each model passed all three required statistical tests. Relative accuracy against the analyzers ranged from 1.38% to 3.15%. EPA approved the models in place of the analyzers, with conditions for quality checks and retraining. EPA relied on data that the cooperative submitted, and the letter reports no saving.","benefit_type":"Improved Task Accuracy"}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["account","benefit_type"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"outcomes[].distribution":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"outcomes[].duration":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"outcomes[].id":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"outcomes[].stakeholder_group":{"state":"value_present","value":{"kind":"record_fields","fields":{"ratings":[{"group":"organizational","reason":"EPA approved the models on a demonstration against the analyzers, and the letter reports no saving or other outcome for the cooperative."}]}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["ratings"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"outcomes[].status":{"state":"value_present","value":{"kind":"record_fields","fields":{"benefit_status":"intended"}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["benefit_status"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"outcomes[].tradeoffs":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"outcomes[].unexpected":{"state":"value_present","value":{"kind":"record_fields","fields":{"unexpected":false,"purpose":"Rockwell Automation built the Pavilion8 software PEMS to predict a combustion turbine's NOx emissions from its operating data."}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["unexpected","purpose"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"places[]":{"state":"value_present","value":{"kind":"record_fields","fields":{"location":"Pulaski County, Arkansas, United States","developer_country":"United States","deployer_country":"United States"}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["location","developer_country","deployer_country"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"purpose":{"state":"value_present","value":{"kind":"record_fields","fields":{"purpose":"Rockwell Automation built the Pavilion8 software PEMS to predict a combustion turbine's NOx emissions from its operating data."}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["purpose"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"record_dates":{"state":"value_present","value":{"kind":"record_fields","fields":{"date_observed":"2012-11-21","date_basis":"source publication","date_precision":"day","revisions":[{"date":"2026-10-31","change":"Added the record from the finding of the U.S. Environmental Protection Agency.","source":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf","editor":"AIBD"}]}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["date_observed","date_basis","date_precision","revisions"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"replication.attempts[]":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"replication.conditions":{"state":"value_present","value":{"kind":"record_fields","fields":{"replication":{"produced_by":["Each PEMS was trained on sensor readings of turbine operation while NOx was measured at the same time.","Each model predicted hourly NOx emission rates from inputs such as gas flow, steam injection and humidity."],"must_hold":["Input values stay within the operating envelope of the training data.","Daily checks, monthly audits and periodic accuracy tests continue, with retraining when operations change."],"echoes":[]}}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["replication"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"revision_history[]":{"state":"value_present","value":{"kind":"record_fields","fields":{"revisions":[{"date":"2026-10-31","change":"Added the record from the finding of the U.S. Environmental Protection Agency.","source":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf","editor":"AIBD"}]}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["revisions"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"sector":{"state":"value_present","value":{"kind":"record_fields","fields":{"domain":"Air emissions monitoring (power generation)"}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["domain"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"sources[].access_version":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"sources[].citation_locator":{"state":"value_present","value":{"kind":"record_fields","fields":{"evidence":[{"kind":"regulatory document","citation":"U.S. Environmental Protection Agency, Clean Air Markets Division. Letter to the Arkansas Electric Cooperative Corporation approving alternative monitoring systems (PEMS) for Units G1 through G7 at the Harry L. Oswald Generating Station (ORISPL 55221), signed by Reid Harvey, Director, 21 November 2012.","title":"Request for Approval of Alternative Monitoring Systems for Units G1 through G7 at the Arkansas Electric Cooperative Corporation's Harry L. Oswald Generating Station (Facility ID (ORISPL) 55221)","url":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf","date":"2012-11-21","written_by":"independent","quote":"Tables 1 through 4 also summarize the results of AECC's statistical analyses of the paired PEMS and CEMS data, which show that the NOx lb/mmBtu output from each PEMS passed all three required statistical tests."},{"kind":"regulatory document","citation":"U.S. Environmental Protection Agency, Clean Air Markets Division. Letter to the Arkansas Electric Cooperative Corporation, 21 November 2012. Background.","title":"Request for Approval of Alternative Monitoring Systems for Units G1 through G7 at the Arkansas Electric Cooperative Corporation's Harry L. Oswald Generating Station (Facility ID (ORISPL) 55221)","url":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf","date":"2012-11-21","written_by":"independent","quote":"A model for each combustion turbine was then developed from the training data."}]}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["evidence"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"sources[].id":{"state":"value_present","value":{"kind":"identifiers","identifiers":["AIBD-0910-source-0001","AIBD-0910-source-0002"],"role":"Existing evidence items, in their original order"},"provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"review_state":"record_mapped","coverage":"complete"},"sources[].language":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"sources[].relationship":{"state":"value_present","value":{"kind":"record_fields","fields":{"evidence":[{"kind":"regulatory document","citation":"U.S. Environmental Protection Agency, Clean Air Markets Division. Letter to the Arkansas Electric Cooperative Corporation approving alternative monitoring systems (PEMS) for Units G1 through G7 at the Harry L. Oswald Generating Station (ORISPL 55221), signed by Reid Harvey, Director, 21 November 2012.","title":"Request for Approval of Alternative Monitoring Systems for Units G1 through G7 at the Arkansas Electric Cooperative Corporation's Harry L. Oswald Generating Station (Facility ID (ORISPL) 55221)","url":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf","date":"2012-11-21","written_by":"independent","quote":"Tables 1 through 4 also summarize the results of AECC's statistical analyses of the paired PEMS and CEMS data, which show that the NOx lb/mmBtu output from each PEMS passed all three required statistical tests."},{"kind":"regulatory document","citation":"U.S. Environmental Protection Agency, Clean Air Markets Division. Letter to the Arkansas Electric Cooperative Corporation, 21 November 2012. Background.","title":"Request for Approval of Alternative Monitoring Systems for Units G1 through G7 at the Arkansas Electric Cooperative Corporation's Harry L. Oswald Generating Station (Facility ID (ORISPL) 55221)","url":"https://www.epa.gov/sites/default/files/2015-05/documents/harry_l._oswald_generating_station_0.pdf","date":"2012-11-21","written_by":"independent","quote":"A model for each combustion turbine was then developed from the training data."}]}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["evidence"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"sources[].upstream_sources":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"strategic_assessments[]":{"state":"unresolved","review_state":"not_assessed","coverage":"partial","family":"strategic assessments"},"summary":{"state":"value_present","value":{"kind":"record_fields","fields":{"summary":"EPA found that trained Pavilion8 models matched hardware NOx analyzers on seven Arkansas turbines, with relative accuracy of 1.38% to 3.15%. It approved them in their place.","account":"The Arkansas Electric Cooperative Corporation owns the Harry L. Oswald Generating Station, a 510 MW combined-cycle plant in Pulaski County, Arkansas. Federal rules require it to monitor NOx emissions from its seven combustion turbines continuously. It did so with certified hardware analyzers. In July 2010 the cooperative installed Pavilion8 software PEMS, which predict emissions from operating data, on all seven turbines. Each was trained on sensor readings while NOx was measured, and a model for each turbine was built from the training data. The models then ran alongside the analyzers for at least 720 operating hours per turbine. In a letter dated 21 November 2012, EPA found that each model passed all three required statistical tests. Relative accuracy against the analyzers ranged from 1.38% to 3.15%. EPA approved the models in place of the analyzers, with conditions for quality checks and retraining. EPA relied on data that the cooperative submitted, and the letter reports no saving."}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["summary","account"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"systems[].autonomy_permissions":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"systems[].component_role":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"systems[].deployment_configuration":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"systems[].inputs_outputs":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"systems[].model_name":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"systems[].model_version":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"systems[].product_name":{"state":"value_present","value":{"kind":"record_fields","fields":{"system":"Pavilion8 Software PEMS (predictive emission monitoring systems) on Units G1 through G7"}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["system"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"systems[].provider":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"taxonomy_crosswalks[]":{"state":"unresolved","provenance":{"kind":"curatorial","basis":"Editorial assignment.","record_fields":[],"source_refs":[]},"reason":"This is an explicit unresolved assignment: the sources on record do not settle this question.","review_state":"not_assessed","coverage":"partial"},"title":{"state":"value_present","value":{"kind":"record_fields","fields":{"title":"EPA approves trained Pavilion8 models in place of hardware NOx analyzers on seven Arkansas turbines after they passed its accuracy tests","headline":"EPA lets *Pavilion8 PEMS* stand in for NOx analyzers in Arkansas"}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["title","headline"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"},"version":{"state":"value_present","value":{"kind":"identifiers","identifiers":["c9487b481dfcbb3706559f799a5b3a93178b0c069a3546299d9e1723222a2dcf"],"role":"SHA-256 of the complete public record and its assessments"},"provenance":{"kind":"curatorial","basis":"SHA-256 of the public record, its assessments, and its displayed answers and notes, excluding its own identifier and the derived coverage summary.","record_fields":[],"source_refs":[]},"review_state":"record_mapped","coverage":"complete"},"workflow":{"state":"value_present","value":{"kind":"record_fields","fields":{"account":"The Arkansas Electric Cooperative Corporation owns the Harry L. Oswald Generating Station, a 510 MW combined-cycle plant in Pulaski County, Arkansas. Federal rules require it to monitor NOx emissions from its seven combustion turbines continuously. It did so with certified hardware analyzers. In July 2010 the cooperative installed Pavilion8 software PEMS, which predict emissions from operating data, on all seven turbines. Each was trained on sensor readings while NOx was measured, and a model for each turbine was built from the training data. The models then ran alongside the analyzers for at least 720 operating hours per turbine. In a letter dated 21 November 2012, EPA found that each model passed all three required statistical tests. Relative accuracy against the analyzers ranged from 1.38% to 3.15%. EPA approved the models in place of the analyzers, with conditions for quality checks and retraining. EPA relied on data that the cooperative submitted, and the letter reports no saving.","replication":{"produced_by":["Each PEMS was trained on sensor readings of turbine operation while NOx was measured at the same time.","Each model predicted hourly NOx emission rates from inputs such as gas flow, steam injection and humidity."],"must_hold":["Input values stay within the operating envelope of the training data.","Daily checks, monthly audits and periodic accuracy tests continue, with retraining when operations change."],"echoes":[]}}},"provenance":{"kind":"legacy_record","basis":"Editorial assignment.","record_fields":["account","replication"],"source_refs":[]},"review_state":"record_mapped","coverage":"partial"}},"summary":{"total":91,"addressed":91,"known":28,"reviewed":2,"reviewed_complete":2,"reviewed_partial":0,"record_mapped":26,"review_not_assessed":63,"not_assessed":0,"complete":false,"by_state":{"value_present":28,"not_reported":0,"unresolved":63,"not_assessed":0,"not_applicable":0,"withheld":0,"source_unavailable":0}}},"presentation_version":"8189309cb4c743815e9eb97930534c9d81a49a3122bcc300eaaf27f53d6918f6"}