Energy and Environment in Alberta: Directive 060, Flaring and Air Quality

Why does Alberta regulate flaring, venting and solution gas?

In Alberta, Energy and Environment can sound like a giant subject. It is.

A producing facility has to deal with energy production, economics, public safety, air quality, emissions, engineering, conservation and a surprisingly large collection of regulatory requirements.

Energy and environment

Few activities demonstrate that balancing act better than flaring and incineration. A flare is useful equipment. It can safely destroy gas that cannot be recovered or handled another way. But burning gas also produces emissions, uses a valuable resource and can affect air quality.

So Alberta has rules governing when gas can be flared, incinerated, enclosed-combusted or vented and what operators must do to reduce the resulting impacts. The principal AER rule is Directive 060: Upstream Petroleum Industry Flaring, Incinerating and Venting.

This directive is frequently updated. It applies broadly across AER-regulated upstream petroleum activities and also includes requirements relevant to certain pipelines, geothermal developments and brine-hosted mineral developments.

This webpage explains the practical ideas behind the Directive and where energy and environment decisions turn into an air-quality modelling problem. It is intended to make a complicated subject easier to navigate. It is not a replacement for reading the current Directive 060 when making a regulatory decision.

Why does Directive 060 exist?

Directive 60 protects public safety, air quality, and valuable resources

A good place to start is 1982. In October of that year, a sour-gas well near Lodgepole, Alberta blew out of control. The uncontrolled release continued for about 67 days. Two workers died and the event became a major turning point in Alberta's approach to sour-gas safety and regulation.

The modern Directive 060 covers far more than the specific circumstances of Lodgepole, but the history makes one principle easy to remember: A gas release is an engineering problem, an air-quality problem and a public-safety problem at the same time.

That is why Alberta's energy and environment framework does more than say don't flare too much. It asks operators to consider what the gas is, what alternatives are available, how the gas will be handled and what environmental and safety consequences could result.

The basic idea: conserve, control, combust or vent

The current Directive 060 decision tree is useful because it turns a huge regulatory document into a sequence of decisions.

For routine and nonroutine gas handling, the AER says operators must evaluate the available alternatives and document how they were considered. The Directive describes conservation as the best alternative for reducing flare, incineration, enclosed-combustion and vent volumes, followed by combustion where venting must be reduced.

Think of the hierarchy this way:

Can the gas be conserved or used?

↓

Can the release be eliminated or reduced?

↓

Can the gas be safely combusted?

↓

If venting is proposed or unavoidable, does it satisfy the applicable requirements?

This is one of the simplest ways to understand Alberta's energy and environment philosophy around flaring.

The regulation can become complicated quickly because the answer depends on the facility, gas composition, volumes, location, operating circumstances and type of event.

What is solution gas?

Some oil contains natural gas dissolved in the produced liquids. As pressure falls during production, some of that gas comes out of solution. That gas is called solution gas.

An operator may be able to:

• use it as fuel
• send it to another facility
• recover it for sale
• inject it
• otherwise conserve it

Or, where permitted and necessary, the gas may be combusted in a flare, incinerator or enclosed combustor. The question for energy and environment is not simply how much gas exists. It is what can reasonably be done with it.

When does Alberta require solution-gas conservation? 

The current Directive 060 uses several criteria. At a general level, conservation requirements can apply where combined flare and vent volumes exceed 900 m³/day and the decision-tree and economic evaluation produce a net present value greater than C$55,000 (in 2026).

Building at a Sour Gas Plant's compressor station

A gas-oil ratio greater than 3,000 m³/m³ also triggers conservation requirements under the Directive.

The AER can also direct conservation regardless of economics. There are additional provisions for facilities near residences and other circumstances. Conserving facilities are required to be designed for 95% conservation efficiency with a minimum annual in-service operating time of 90%.

Those numbers are useful. They are also exactly the kind of numbers that can become dangerous when copied from an old web page into a new project.

Always check the current Directive.

What about the economics?

Alberta recognizes that gas conservation can require capital and operating costs. The Directive therefore includes an economic evaluation process.

Pipeline infrastructure commonly seen in Alberta energy industry.

This is one place where an old copy of Directive 060 can send you in the wrong direction. The economic threshold, for instance, does increase with inflation at times. It is to your advantage to know and use that.

The practical lesson is more important than memorizing the number: The economic case for conservation has to be evaluated using the methodology currently required by the AER.

A project team may already have completed that evaluation before an air-quality consultant becomes involved. That's perfectly reasonable.

From the air-quality side, we still need to understand what the proposed operating scenario means for emissions and impacts.

What about routine, planned and emergency flaring?

This is where terminology becomes important. A flare can be operating under normal conditions, during maintenance or testing, during a process upset or during an emergency.

The current Directive distinguishes different types of events and provides different requirements for them. Emergency combustion can occur when safety systems depressurize equipment to avoid potential injury, fire, explosion or catastrophic equipment failure. Upset events involve operating conditions outside normal allowable limits that require combustion to bring the process back under control.

The simplest way to remember the distinction is:

This is an important energy and environment distinction because the same flare can be subject to different requirements depending on why it is operating. Here's the full text of Directive 60 - http://www.aer.ca/documents/directives/DraftDirective060.pdf

When does air-quality modelling enter the picture?

This is where the regulatory document starts to overlap with the work Calvin Consulting actually does. Directive 060 section 7.12 covers dispersion modelling requirements for sour and acid gas combustion.

For combustion of sour or acid gas in process equipment, flares and incinerators, dispersion modelling is required to demonstrate compliance when the gas contains 10 mol/kmol H₂S or more or when the sulphur emission rate during the combustion event is 1 tonne per day or more.

Below those thresholds, modelling is encouraged as an environmental consideration and additional evaluation can be required for facilities subject to an EPEA approval.

That gives us a useful dividing line: 

Below the threshold - Modelling may still be useful or recommended depending on the situation.

At or above the threshold - The Directive requires an air-quality evaluation using the specified modelling approach.

And there is an important qualification: The thresholds do not eliminate professional judgement. A project still has to determine what the actual release scenario looks like and whether the selected modelling approach is appropriate.

AERflare-incin: the starting point for flare modelling

Directive 060 requires the use of AERflare-incin for applicable SO₂ dispersion modelling from flares and incinerators. The AER provides the spreadsheet and supporting material through the Directive 060 page.

The current Directive establishes a practical screening-first approach. The AERflare-incin spreadsheet provides screening analysis for SO₂ and H₂S dispersion from permanent and temporary flares, incinerators and enclosed combustors.

If the screening-level maximum predictions meet the applicable AAAQOs, no further analysis is required. If they do not, additional refined dispersion modelling is required. That is a very useful concept.

You don't automatically start with the biggest modelling exercise. You first determine whether the screening approach is sufficient.

When can a routine flare need refined modelling?

This is one of the most useful current details for someone actually working on a facility. For routine flaring, incineration or enclosed combustion, refined modelling is required when the screening results do not meet the applicable AAAQOs.

There is another important trigger. If continuous SO₂ emission sources are present within 10 km of the proposed source or within the isopleth representing one-third of the one-hour SO₂ AAAQO, whichever distance is less, the cumulative effects need to be assessed.

In the cumulative assessment, the radius of influence is established from the one-third-AAAQO isopleth, other continuous SO₂ sources are identified within that radius up to a maximum of 20 km and their emissions are included in the assessment.

That means a flare cannot always be evaluated as though it were floating in an empty landscape. The atmosphere already contains other sources.

What happens when the flare is temporary?

Temporary events have their own pathway. Directive 060 section 7.12.4 covers temporary and well-test flaring, incineration and enclosed combustion.

The AERflare-incin spreadsheet must be completed. The spreadsheet's modelling may be sufficient when screening is adequate. Temporary events can also use specific risk-based criteria because they are short-term activities.

For temporary events, the current risk-based criteria include: the predicted 99th percentile concentration at a receptor must not exceed the one-hour SO₂ AAAQO and the predicted 99.9th percentile concentration must not exceed 900 µg/m³

Actual exceedances of the applicable AAAQOs are never simply declared acceptable because those criteria exist. The criteria provide a specific regulatory framework for certain temporary events.

This is a good example of why reading one number from a regulation can be misleading. The context around the number matters.

What about nonroutine flaring?

Nonroutine sour-gas events have another set of modelling criteria. Under the current Directive, an ambient air-quality evaluation is required for nonroutine sour-gas flaring, incineration or enclosed combustion when:

• the proposed gas contains 10 mol/kmol H₂S (1% H₂S) or more, or
• 1 tonne of sulphur is released during the event or day for multiple releases.

A single event predicted to last no more than 15 minutes and predicted to emit less than 1 tonne of sulphur over a rolling 24-hour period is exempt from modelling requirements.

Unexpected release

Existing facilities can also trigger reassessment when emissions change, when the AER requests new modelling or when a renewal or amendment requires it. Certain processing facilities subject to the Activities Designation Regulation must remodel upon renewal.

This is a significant change from the old idea that a modelling report can simply sit on a shelf forever.

The facility and its emissions can change. The modelling may need to change with them.

What does the modeller actually need?

A flare is not just a flame on a stack. For modelling, we need to understand things such as:

• gas composition
• H₂S and sulphur content
• flow rate
• operating duration
• flare or incinerator geometry
• stack height
• exit diameter
• exit velocity
• heat release
• combustion efficiency
• assist gas or fuel
• operating scenarios
• terrain
• nearby sources
• receptors
• meteorological data

This is where energy and environment becomes wonderfully interdisciplinary. Chemistry tells us what is being burned. Engineering tells us how the equipment behaves. Meteorology tells us what the atmosphere is doing. Regulation tells us what must be demonstrated.

Dispersion modelling connects those pieces.

Why the flare design matters

A common misconception is that the model is simply asking: How much SO₂ is being released?

The release rate matters enormously. So do the conditions under which the release occurs. Flare height, diameter, exit velocity, heat release and combustion characteristics all affect the way the release behaves in the atmosphere.

AERflare-incin also evaluates exit velocity and downwash considerations and provides diameter ranges based on recommended exit velocities. The current Directive says the spreadsheet can help optimize flare, incinerator and enclosed-combustor design and verify parameters used in temporary-flaring applications.

That is where air-quality modelling becomes more than a compliance exercise. It can help engineers make the design better.

A Calvin example: when a complicated model may be the wrong answer

Calvin has experience with both AERflare and the CALPUFF-based ABflare approach. A regulator who helped develop these approaches once asked Calvin why we had used the CALPUFF-based approach in a particular situation.

The question was useful. It reinforced an important professional lesson: A more complicated modelling system needs a reason to exist.

If AERflare and AERMOD can defensibly answer the question, introducing another modelling chain creates additional data preparation, processing and quality-control work without necessarily producing a better answer.

At Calvin, AERMOD is our default model for most conventional industrial dispersion work and AERflare is an important specialized application of that modelling approach.

Other models are used when the physics, chemistry, terrain, regulatory requirements or specific project circumstances provide a strong reason. That is an energy and environment judgement call worth making before the modelling starts.

The famous flowcharts are actually useful

Regulations are rarely accused of being bedtime reading. Directive 060 is substantial. The flowcharts are one of its more useful features.

The current Directive contains decision trees and flowcharts for:

• routine and nonroutine flaring, incineration, enclosed combustion and venting
• temporary flaring and incineration permits
• nonroutine sour-gas management
• flare, incineration and enclosed-combustion management

The AER explicitly requires operators to use the general decision tree for applicable new and existing routine and nonroutine sources and document how the alternatives were considered.

That suggests a good way to read Directive 060: Don't read 109 pages straight through unless you really want to.

Find the decision tree that describes your situation. Then follow the branches. That is a much more civilized way to approach energy and environment regulation.

What happens when the model predicts too much?

This is where modelling becomes useful to engineers.

Suppose the screening assessment predicts an SO₂ concentration that does not meet the applicable requirement. The answer is not automatically: The project is impossible.

The model can become a design tool. Potential responses may include:

• increasing stack height
• changing flare or incinerator geometry
• adjusting operating conditions
• controlling flow or duration
• increasing heat release where appropriate
• using makeup gas to increase plume rise
• developing an air-quality management plan where permitted
• using refined modelling to understand the controlling conditions

The current Directive specifically recognizes design optimization and, in certain situations, operating controls and additional gas to increase heat release and plume rise as potential responses.

This is one reason early modelling can be valuable. You want to discover the design problem while there are still design choices available.

Why 'just run the model' is a poor project strategy

A client can often obtain software. An engineering team may already have good flare specifications.

A technically minded employee may be perfectly capable of following a modelling tutorial. The difficulty is that the model is only one link in the chain. Someone still has to decide:

• What scenario should be modelled?
• Are the input data representative?
• Is screening enough?
• What happens if screening fails?
• Are other SO₂ sources relevant?
• Is the flare design creating downwash?
• Which flow conditions matter?
• What does the maximum concentration actually mean?
• Does the regulatory comparison use the correct statistic?
• What should happen if the result is too high?

A model can produce a perfectly formatted answer to an incorrectly framed question. That is one of the more expensive ways to save money.

What a specialist adds

At Calvin, our role is often to connect the regulation, the equipment and the atmosphere.

1. We can review the proposed approach before a full assessment is built.
2. We can check source information against available data.
3. We can work with engineering teams on flare and incinerator parameters.
4. We can use AERflare and other appropriate modelling tools.
5. We can assess terrain, receptors, meteorology and nearby sources.
6. We can run refined dispersion modelling when the screening assessment requires it.
7. We can help interpret why a predicted maximum occurs where it does.
8. And senior Calvin modellers carry out QA/QC so that another experienced person examines the work before it becomes a regulatory deliverable.

That is particularly useful when the technical directions become dense. Even experienced professionals can spend a surprising amount of time tracing a regulation through several sections, exceptions and flowcharts.

A specialist who does this work regularly can help turn the maze into a sequence of decisions.

The bigger energy and environment lesson

Flaring looks simple from a distance. Gas goes in. Fire comes out.

In reality, a flare sits at the intersection of several systems:

Reservoir → production → process equipment → gas management → flare design → combustion → atmosphere → receptors → regulation

That is the interesting part. The flare itself is only one piece.

A good environmental decision considers what happens before the gas reaches the flare and what happens after the combustion products enter the atmosphere.

That is energy and environment in its most practical form.

Need help with the air-quality side?

Your engineering or regulatory team may already understand the conservation requirements. They may already have worked through the Directive 060 flowchart. They may even have the flare specification sitting on someone's desk.

The question we often get is the next one: What does all of this mean for the air?

That is where Calvin Consulting Group comes in.

We work with operators and engineering firms on flare and incinerator air-quality assessments, emissions characterization, dispersion modelling and regulatory applications.

Calvin's work includes AERflare and flare-design evaluations, refined dispersion modelling, terrain and receptor assessments, meteorology, cumulative-source assessment and QA/QC review.

And we do not begin by assuming that the most complicated model is the best one. We begin with the regulatory question, the physical situation and the information available.

The earlier that question is asked, the more design choices you usually have. Getting a specialist involved before the flare has been designed around an untested assumption can prevent expensive rework later.

The goal is more than simply to produce another modelling report. It is to help the project make the right technical decision while there are still choices left to make.

Want go go deeper, reach out to Barry by email:

The most useful way to think about Directive 060

...is not as a giant collection of rules. Think of it as a series of questions:

• Can we avoid the release?
• Can we conserve the gas?
• Can we safely control or combust it?
• What happens to air quality when we do?
• Does the screening assessment answer the question?
• If it doesn't, what should change?
• What does the regulator need to see?

Those questions will remain useful even as individual requirements change.

The numbers, section references and modelling tools will inevitably be updated. The decision-making framework is much more durable.

Related Calvin and Stuff in the Air resources:

What Is a Gas Flare?
How flares work, what they emit and why flare design matters.

AERMOD: Alberta's Workhorse Air Dispersion Model
How the main regulatory dispersion model works and what experienced modellers check.

Which Air Dispersion Model Should You Use?
A practical comparison of AERMOD, CALPUFF and specialized modelling approaches.

Air Quality Dispersion Modelling
The broader technical guide to atmospheric dispersion modelling.

Flare Modelling and AERflare
Specialized information on flare inputs, outputs, design and modelling.

BC Flaring Regulations
A comparison for projects outside Alberta.

What an experienced modeller checks

This is where a regulation and a modelling report start to diverge. The Directive can tell you what must be demonstrated. It cannot inspect your client data.

At Calvin Consulting Group Ltd., we compare the information provided by a client or engineering firm against other available information and against what makes physical sense.

For example, we may ask:

• Does the gas composition make sense?
• Is this flow rate reasonable for the equipment?
• Is the flare diameter consistent with the expected flow?
• Does the exit velocity look plausible?
• Could another operating condition produce a higher impact?
• Are there other SO₂ sources nearby?
• Does the terrain affect dispersion?
• Does the wind pattern make sense?
• Does the predicted maximum occur where we would expect it?

Where equipment information is incomplete, we may consult Alberta emissions inventories and other source information to compare expected parameters for similar source types.

That is professional judgement. The computer cannot do that part for you.

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An energy and environment checklist for operators and project teams

Here's what you can do before a flare or incinerator project gets too far along, gather:

The gas

• Composition
• H₂S concentration
• Sulphur content
• Heating value where relevant

The release

• Flow rate
• Duration
• Operating scenarios
• Routine or nonroutine status

The equipment

• Stack or flare height
• Exit diameter
• Exit velocity
• Temperature
• Assist or makeup gas
• Combustion efficiency
• Nearby buildings

The location

• Terrain
• Residences
• Other industrial sources
• Relevant receptors

The regulatory situation

• Current Directive 060 requirements
• Applicable permit or approval requirements
• Applicable AAAQOs
• Modelling requirements
• Notification requirements

The modelling

• Is screening sufficient?
• Does refined modelling apply?
• Are cumulative SO₂ sources relevant?
• Has a qualified person reviewed the approach?

Getting these answers together early can save considerable rework.

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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A simple Directive 060 decision tree

Here is the practical version.

1. What are you doing?

• Routine operation?
• Well test?
• Planned maintenance?
• Upset?
• Emergency?
• Temporary event?

2. What is being released or combusted?

• Sweet gas?
• Sour gas?
• Acid gas?
• How much H₂S?
• How much sulphur?

3. Can the gas be conserved?

• Evaluate the applicable conservation requirements.

4. Can the gas be safely combusted instead of vented?

• Check the applicable equipment and operating requirements.

5. Does the event require an air-quality evaluation?

• Check the current modelling triggers.

6. Can the AERflare-incin screening assessment demonstrate compliance?

• If yes, the screening may be sufficient.

7. Does the screening indicate a problem?

• Then consider design changes, operating controls or refined modelling as required.

8. Does the refined assessment need cumulative sources?

• For applicable continuous SO₂ sources, check the one-third-AAAQO radius and cumulative requirements.

9. Does the event require notifications, a permit, a management plan or post-event modelling?

• Follow the applicable Directive sections.

This is exactly why a decision tree can be more useful than a page full of regulatory prose.