AER ERCB Applications and Air Quality Modelling in Alberta

Alberta energy projects can involve a surprisingly large stack of regulatory requirements. Air emissions are only one part of an application, yet they can influence equipment selection, stack design, flare design, operating restrictions and whether additional regulatory work is required.

People still searching for ERCB Applications are looking for what are now Alberta Energy Regulator ERCB applications. The Energy Resources Conservation Board name disappeared in 2013, although the old term remains common in older reports, websites and searches.

For facilities, pipelines and wells, AER Directive 056: Energy Development Applications and Schedules contains the current technical requirements. The application procedures and forms are now primarily contained in Manual 012: Energy Development Applications; Procedures and Schedules. Both are updated on a regular basis.

Air-quality requirements can also come from Directive 060, Alberta Environment and Protected Areas requirements, the Environmental Protection and Enhancement Act, federal regulations and conditions specific to a project.

That overlap is one reason an apparently simple application can become complicated quickly.

The short version

For an operator preparing an AER application, the main air-quality questions are usually:

The objective is to establish the correct regulatory pathway early enough that air-quality requirements do not become a late design surprise.

ERCB Applications became AER applications

ERCB applications: what makes them work

Older ERCB Applications frequently referred applicants directly to Directive 056 for application forms and technical requirements.

The system has evolved. Directive 056 now contains technical requirements for applications to construct or operate facilities, pipelines and wells. Manual 012 contains the associated procedural instructions and forms for ERCB applications. The AER also notes that other government approvals may still be required.

This distinction matters when using an older regulatory guide. A technically correct statement written ten years ago may now point to the wrong document, regulator name, form or procedure.

Key Alberta air-quality documents

Alberta currently requires regulatory air-quality modelling to follow the Air Quality Model Guideline 2021. Alberta also introduced supplemental guidance for interpreting regulatory air-quality model assessments in 2025.

When does an AER application need air dispersion modelling?

There is no useful one-line answer such as every compressor station needs modelling or anything below a particular emission rate is safe. The facility type, emissions, equipment, approval pathway and surrounding environment all matter. 

For NOx, however, Directive 056 provides some important thresholds. For facilities with total NOx emissions below 16 kg/h, Directive 056 requires documentation showing that each applicable source stack is at least 1.2 times the peak building height.

Part of your AER D56 Application

Where dispersion modelling has been conducted, the directive specifies information that must be documented, including source parameters, locations, elevations, NOx emission rates, predicted maximum ground-level NO₂ concentrations, the model used, meteorological data and terrain.

Facilities above 16 kg/h and certain gas plants require additional documentation to demonstrate compliance with Alberta Ambient Air Quality Objectives before approval. 

That 16 kg/h value is important. It is not a universal dividing line between air quality matters and air quality does not matter. A smaller facility can still deserve modelling when nearby buildings, terrain, unusual operating conditions or other factors create potential air-quality concerns.

NOx and NO₂ - a common Alberta facility issue

Combustion equipment such as compressor engines, heaters and boilers can emit nitrogen oxides. Alberta regulatory assessments commonly evaluate their effect on ambient nitrogen dioxide concentrations.

For relevant compressor stations, pumping stations and category B gas-processing facilities, Directive 056 requires registration before operation when total NOx emissions exceed 16 kg/h. The directive also specifies that new and additional natural-gas-driven reciprocating engines greater than 600 kW at full load must not emit more than 6 g NOx/kWh.

That provincial requirement should be checked alongside any applicable federal requirement. A modeller normally needs:

• engine manufacturer and model
• rated power
• NOx emission factor or manufacturer guarantee
• exhaust flow
• exhaust temperature
• stack height
• stack diameter
• equipment location
• building dimensions
• expected operating loads
• simultaneous operating scenarios

Even apparently minor input errors can affect plume rise and predicted ground-level concentration.

At Calvin Consulting, we've seen that increasing stack height or exhaust velocity, removing rain caps, or adjusting the stack’s location or orientation often leads to significantly lower predicted ground‑level concentrations.

Flares, SO₂ and Directive 060

Flaring is one of the areas where professional judgement can have particularly large consequences.

The current Directive 060: Upstream Petroleum Industry Flaring, Incinerating, and Venting (2026). It applies broadly to AER-regulated upstream petroleum wells and facilities along with specified pipeline installations and other developments within its scope.

For sour-gas combustion, Directive 060 contains specific dispersion modelling requirements.

Temporary events such as well testing, well cleanup, servicing, underbalanced drilling and some sour pipeline blowdowns can require completion of the AERflare-incin spreadsheet. Screening modelling may be sufficient in some cases. Refined modelling can be required when screening cannot demonstrate an acceptable result. 

That is considerably more specific than older advice that SO₂ modelling will probably be needed.

Why flare modelling can behave unexpectedly

A flare is a poor candidate for simplistic more emissions equals more ground-level concentration reasoning. Flow rate, gas composition, heat release, flame characteristics, effective plume rise, wind and terrain interact. And a design change that sounds beneficial can produce an unexpected modelling result.

On Calvin Consulting flare projects, measures that have improved predicted concentrations have included:

1. Adding supplemental fuel, where the additional heat improves plume behaviour and ground-level radiation criteria can still be met
2. Increasing flare-stack height, particularly while a facility is still in the design phase
3. Adding air or lift gas where appropriate for the flare system
4. Reducing the effective exit diameter in some sour-gas cases to improve exit conditions and plume rise
5. Changing the flow rate or refining the assumed gas composition where the revised case more accurately represents the expected operation
6. Relocating the flare when receptors, terrain or facility configuration make location an important factor.

These measures are project-specific. A taller flare is not automatically the best answer and a lower flow rate rarely (if ever) reduces the predicted concentration in proportion to the lower emission rate.  In fact, Directive 060 specifically cautions that reducing a flare rate does not produce a proportional reduction in predicted concentrations.  Our experience agrees.

This is why flare modelling benefits from examining the physics as well as the output table. To cover variability, we automatically model three flow rates for a flare case in Alberta; one at the maximum rate and two lower rates.  Any of these can yield the highest predicted concentration.

Non-routine flaring and Alberta's risk-based criteria

Non-routine flaring needs special treatment because an event that occurs for a few hours each year has a different frequency profile from a continuously operating stack.

Alberta maintains Non-Routine Flaring Management: Modelling Guidance specifically for these assessments. The guidance provides modelling methods and risk-based criteria for planned and unplanned non-routine flare events. Alberta continues to list this document as part of its current air-quality modelling guidance.

The idea is important. Risk-based criteria allow the modelling assessment to consider the frequency of a temporary or non-routine event rather than treating every possible modelled hour as though the flare operates continuously all year.

Current Directive 060 also contains explicit risk-based criteria for planned temporary events. The 99^th-percentile prediction at a receptor must remain at or below the one-hour SO₂ AAAQO and the 99.9^th-percentile prediction must remain at or below 900 µg/m³. The directive makes clear that these criteria apply to model predictions and do not authorize an actual AAAQO exceedance.

For non-routine events at permanent facilities, Directive 060 also refers back to the annual flaring-hour limits in Alberta's non-routine modelling guidance. Exceeding the applicable annual hours or experiencing an SO₂ AAAQO exceedance can trigger post-event dispersion modelling and immediate contact with the AER. That creates real operational consequences.

Where predicted conditions remain problematic, Directive 060 allows the regulator to consider an air-quality management plan. Possible controls can include meteorological restrictions, changes to operating rates, supplemental fuel and ambient monitoring.

For operators preparing ERCB Applications from older templates, this is one of the areas where copying a historical assessment can produce a poor result. The present regulatory framework distinguishes among continuous flaring, temporary events and non-routine events and the modelling treatment needs to match the actual operation.

What information should be ready before modelling starts?

Good modelling begins with good source information. A useful initial package usually contains:

A consultant will often spend considerable time checking whether these inputs agree with each other. That work is easy to underestimate.

What happens when the model predicts an exceedance?

An exceedance should trigger investigation before it triggers panic. A practical review normally asks:

• Is the emission scenario physically possible?
• Are the source inputs correct?
• Is the controlling source obvious?
• Which meteorological condition produced the maximum?
• Where is the maximum receptor?
• Is terrain or building downwash contributing?
• Would a realistic design change materially improve the result?
• Does Alberta's current interpretation guidance affect how the prediction should be evaluated?
• Does the regulatory pathway permit an operating or management control?

Alberta released specific Guidance for Interpreting Regulatory Air Quality Model Assessments effective 2025. That guidance is now an important companion to the 2021 Air Quality Model Guideline.

An experienced modeller should be able to explain why the model predicts the concentration it does and what engineering variable actually controls the result. Simply rerunning the model until the number becomes smaller is poor practice.

Federal MSAPR requirements

Federal Multi-Sector Air Pollutants Regulations, usually shortened to MSAPR, deserve a separate check.

MSAPR does not regulate every air pollutant from every industrial facility. It sets specific requirements for certain gaseous-fuel-fired boilers and heaters, stationary spark-ignition engines and cement manufacturing facilities.

Air pollution in Alberta?

For oil and gas operators, stationary engines are particularly relevant. For regular-use pre-existing engines of at least 250 kW within the applicable oil and gas sectors, the federal framework provides a 4 g NOx/kWh flat-limit option or a 4 g/kWh yearly-average option for qualifying engine groups.

For qualifying modern regular-use engines, the federal limit is generally 2.7 g/kWh, subject to the definitions, exclusions and compliance provisions in the regulation.

This means a provincial equipment requirement does not by itself establish MSAPR compliance. An Alberta operator may therefore need to consider:

AER licence requirements + Alberta environmental requirements + federal equipment requirements

during the same project.

MSAPR also covers specified boilers, heaters and cement manufacturing. Calvin Consulting has not relied on cement-industry project experience for this article. The federal rules remain relevant for future work in sectors where the applicable equipment or facility falls within MSAPR.

H₂S, odours and related requirements

Sour facilities raise issues beyond routine NO₂ and SO₂ dispersion modelling.

Directive 056 includes specific requirements related to H₂S, vapour recovery and off-lease odours. For example, current facility requirements distinguish between gas streams above 10 mol/kmol H₂S for certain vapour-control provisions and transported fluids above 0.01 mol/kmol H₂S for off-lease odour controls during transport.

Release-rate assessment, emergency planning and AERH2S requirements can also become relevant for some sour developments. Those are separate technical disciplines from the air-quality modelling described on this page.

Calvin has not used AERH2S on a contracted project to date, so this page does not present AERH2S as a project-experience claim.

Why professional modelling usually costs less than fixing the wrong design

Software makes it possible to run a dispersion model.

Professional practice requires considerably more. A competent assessment involves:

• understanding which regulation applies
• assembling a defensible emissions inventory
• identifying realistic operating scenarios
• selecting the correct modelling method
• checking stack and process data
• preparing representative meteorology
• evaluating terrain
• assessing building downwash where relevant
• interpreting predicted concentrations
• investigating unusual results
• identifying workable mitigation
• documenting the assessment so another technical reviewer can follow it

An error near the beginning can propagate through everything that follows.

• Wrong gas composition can produce the wrong SO₂ emission rate.
• An unrealistic simultaneous-operation assumption can create a fictitious worst case.
• A bad stack flow value can distort plume rise.
• A missed building can change near-field concentrations.
• Poorly chosen meteorology can make a technically elaborate calculation irrelevant to the actual project.

That is where experience becomes valuable.

Experience behind the modelling

Barry J. Lough, B.Sc., P.Phys., P.Met., EP has a background in physics and meteorology from the University of Alberta and has worked as a meteorologist with Environment and Climate Change Canada. His environmental consulting work has focused primarily on air-quality modelling in Canada.

The conscientious Energy industry in Action

His dispersion-modelling experience includes upstream and midstream energy facilities, chemical and petrochemical operations, oil storage, cogeneration and power facilities, fertilizer plants, refineries, pipelines, large industrial complexes and unusual emission sources.

That background matters when a regulatory model produces a result that appears technically valid yet makes little physical sense. For more...

Please contact Barry J. Lough at Calvin Consulting Group Ltd. at 

References:

I have collected these here rather than scattering raw URLs through the copy:

1. AER Directive 056: Energy Development (ERCB applications) and Schedules
2. AER Manual 012: Energy Development Applications; Procedures and Schedules
3. AER Directive 060: Upstream Petroleum Industry Flaring, Incinerating, and Venting
4. Alberta air-quality modelling guidance
5. Alberta Ambient Air Quality Objectives and Guidelines
6. Federal MSAPR overview for engines

 Thank you.

Preparing an AER application?

Today's AER process is more structured than the old ERCB Applications many operators still find in archived reports and search results.

A good air-quality assessment should answer four questions clearly:

• What is emitted?
• What happens to it in the atmosphere?
• How does the predicted concentration compare with the applicable criteria?
• What should the project team do about the result?

When those questions involve NOx, SO₂, flares, incinerators, complex operating scenarios or dispersion modelling, early specialist involvement can save considerable redesign and regulatory delay.

Calvin Consulting Group Ltd. provides air emissions assessment, dispersion modelling and regulatory support from Calgary for industrial projects in Alberta and elsewhere in Western Canada.

If an AER application has reached the point where you are wondering whether modelling is required, that is usually the right time to ask. Contact Calvin Consulting before equipment, flare geometry or operating assumptions become expensive to change.

For readers who arrived here searching for ERCB Applications, the regulator's name has changed. The value of getting the emissions, modelling and technical interpretation right has not.

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AAAQOs and AAAQGs

Alberta Ambient Air Quality Objectives and Alberta Ambient Air Quality Guidelines are important regulatory reference concentrations for ambient air.

For regulatory modelling, Alberta indicates that assessments should consider:

• applicable AAAQOs
• applicable AAAQGs where a local concern can reasonably be expected

These criteria apply to ambient concentrations rather than directly to stack concentrations or worker exposure.

That distinction matters. Emission limits, ambient objectives and occupational exposure limits answer different questions.

A facility can satisfy an equipment emission limit while still needing to demonstrate acceptable ambient concentrations.

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Do you have concerns about air pollution in your area??

Perhaps modelling air pollution will provide the answers to your question.

That is what I do on a full-time basis.  Find out if it is necessary for your project.

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Thank you to my research and writing assistants, and the author remains responsible for the content.

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What an experienced modeller checks first

An emissions spreadsheet can be beautifully formatted and still describe the wrong facility.

Before running a model, an experienced air-quality practitioner asks questions such as:

• Can all listed sources physically operate at their maximum rates at the same time?
• Does the emission rate represent normal operation, maximum operation, startup or an upset condition?
• Is a ten-minute release being treated as though it occurs continuously?
• Are exhaust temperature, flow and stack diameter internally consistent?
• Could nearby structures cause building downwash?
• Does the selected meteorological dataset reasonably represent the facility?
• Are background concentrations being handled appropriately?
• Is the maximum modelled concentration physically plausible?

A model can perform the requested mathematics perfectly while answering the wrong engineering question.

That distinction is central to credible ERCB Applications carried forward into today's AER process.