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Emission Standards

Canada: Stationary Spark-Ignition Engines


In 2016, Environment Canada has published the final Multi-Sector Air Pollutant Regulations (MSAPR) [3528] that established requirements for the following emissions: (a) NOx from boilers and heaters in various industrial sectors; (b) NOx from stationary spark-ignition engines that combust gaseous fuels in various industrial sectors; and (c) NOx and SO2 from cement manufacturing facilities.

The regulation defines two sets of engine emission standards, applicable to modern engines and to pre-existing engines used in certain industrial sectors. The definitions and applicability of the standards are summarized in Table 1. The standards are further differentiated for regular-use and low-use engines (Table 2).

Table 1
Engine categories and applicability of MSAPR performance standards
Modern EnginesPre-existing Engines
DefinitionManufactured on or after September 15, 2016Manufactured before September 15, 2016
Regulated sectorsAluminum and alumina, base metals, cement manufacturing, chemicals, iron ore pelletizing, iron, steel and ilmenite, nitrogen-based fertilizer, oil sands, petroleum refining, potash, power plants, pulp and paper, and oil and gasOil and gas—defined as upstream oil and gas, natural gas transmission pipelines and related underground storage facilities in those two sectors

The regulation affects some estimated 6,300 “pre-existing” engines in Canada, with more than 95% of these engines located in the upstream oil and gas sector and the natural gas transmission pipeline sector.

The standards include exclusions for engines owned and operated by small businesses that meet certain criteria specified in the regulation.

Emission Standards

The emission requirements are summarized in Table 2. The emission standards for modern engines—which are comparable in stringency with the US EPA NSPS standards—become effective with the publication of the regulation. The emission requirements for pre-existing engines are phased-in from 2021 to 2026 and include two alternative compliance options: (1) per-engine standards (flat limit) or (2) engine group standards (yearly average limit).

Table 2
MSAPR performance standards for SI gas fueled engines
Modern EnginesPre-existing engines
Regular-use Engines
Engine size threshold≥75 kW≥250 kW
NOx emission limits 2.7 g/kWh or 160 ppmvd at 15% O2 Per-engine approach: 4 g/kWh or 210 ppmvd at 15% O2 (engines comprising 50% of total power as of 2021; 100% by 2026) or
Yearly-average approach: 8 g/kWh or 421 ppmvd at 15% O2 as of 2021; 4 g/kWh or 210 ppmvd at 15% O2 as of 2026
Emission testing Baseline performance test; ongoing tests for engines ≥375 kW Baseline performance test; ongoing tests for some engines ≥375 kW
Low-use Enginesa
Engine size threshold ≥100 kW ≥250 kWb
NOx emission limits 160 ppmvd at 15% O2 None
Emission testing None None
a Low-use engines are defined as those used less than 5% of the time based on a three-year average
b Engines must be registered and are subject to engine hours record and reporting requirements

Registration and Reporting Requirements. The regulation includes engine registration and reporting requirements for engine owners.

  • For modern engines, the engine must be registered and the results of emission testing submitted annually starting one year after the engine begins to operate. However, there are no emission testing requirements for modern, low-use engines.
  • For pre-existing engines, registration is required as of January 1, 2019, and annual reports must be submitted as of 2022.

Control Technologies. Environment Canada envisions a number of technologies that can be used to reduce NOx emissions from stationary SI gas engines, including rich-to-lean engine management systems, non-selective catalytic reduction (NSCR = three-way catalyst) in conjunction with air-to-fuel ratio controllers, replacement with lean-burn engine with pre-combustion chamber, and improvements to the ignition system.