Case Studies

Translating project experience to lessons learned and recognizing the needle-movers that affect your compliance


Case Study 1: Permitting Efficiencies via Modeled Emission Factors


Between 2017 and 2019, Amerigo received a steady stream of requests to provide upstream clients with permitting strategies and emission forecasts that accounted for the production increases associated with active drilling programs. Despite differences between client geographic locations and the relevant state permitting authority, including Oklahoma, New Mexico, North Dakota, and Texas, we identified an immediate need to create efficiencies that would speed the effort behind emission calculations, and reduce opportunities for user error.

The emission forecasts were incorporated into operational and permitting strategy.  Depending on the strategy options and market outlook, operators would make capital-intensive investments for new, increased or modified emission controls or significant design changes to large gathering facilities.  In some scenarios, the forecasts were critical to an operator’s decision to build temporary facilities authorized to handle production when pipeline capacity was low or permanent facility modifications were not economically feasible.

Case Study 2: The Role of Glycol Circulation Rates in HAP PTE Calculations

Glycol Dehydrators are an integral tool used in natural gas dehydration and are common in upstream, gas production facilities or midstream, gas transmission and storage facilities.  The unit removes water content from gas streams to prevent hydrate formation and corrosion.

Both hydrate formation and corrosion are risks to upstream and midstream facilities as they can block pipelines, deteriorate instrumentation/reliability, and create leaks.  As a common piece of equipment found throughout oil and natural gas production facilities, glycol dehydration units are regulated under 40 CFR Part 63 National Emission Standards for Hazardous Air Pollutants (NESHAP).  Both major and area sources of HAPs are subject to Subpart HH.  For major HAP sites, the affected sources are dehydration units, storage vessels with flash emissions, ancillary equipment in HAP service, and compressors in HAP service.  For area sources with HAPs, the affected source is specific to dehydration units utilizing triethylene glycol (TEG).


Case Study 3: Emission Inventories - The Case for Accurate Actual Emissions 

Year over year, state agencies set and review updated emission inventory (EI) guidelines for sites subject to reporting.  The published guidelines or memos include updated methodologies to calculate and report accurate emission actuals.

Most guidance documents have a tiered or preferred calculation methodology that places emphasis on preferred and generally, more accurate approaches to completing actuals.Unlike permitting where applicability and authorization types are based on a facility’s total potential to emit (PTE), the EI is designed to support a state’s actual emission inventory in support of the state’s US EPA approved State Implementation Plans (SIPs).  SIPs must regulate and maintain the EPA published National Ambient Air Quality Standards (NAAQS).

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