Replacing and Retrofitting Natural-Gas Powered Pneumatic Devices is an Important Way for Oil and Gas Companies to Address Scope 1 Emissions

 

     EQT, the largest natural gas producer in the U.S., released their annual sustainability report in late June 2023 and highlighted that they have completed elimination of 100% of natural gas-powered pneumatic devices from its operations, removing approximately 9000 of these devices that vent natural gas into the atmosphere. Changing out these devices for those that do not emit methane is considered to be the ‘low-hanging fruit’ of methane emissions abatement in the upstream oil and gas sector. Natural gas-powered pneumatic devices are the biggest source of methane emissions from U.S. oil and gas E&P companies, so this is a monumental achievement. The effort cost EQT $28 million and took less than two years to accomplish. They dedicated 23,000 work hours to the effort and accomplished it a year ahead of schedule. Wood MacKenzie reports that other oil & gas operators are following suit, noting that Chesapeake Energy has retrofitted 19,000 devices thus far and Antero removed or converted over 5,900 of them.

     As I noted a few years ago, energy analysts are tracking which companies are replacing pneumatic controllers and which companies are not replacing them. This is acting as a kind of peer pressure to compare companies' efforts to reduce Scope 1 emissions. EQT notes that replacing pneumatics gives a reputational advantage.

     EQT notes on their website: “Pneumatic devices are pervasive in the oil and natural gas production industry, serving as a primary method for managing produced fluids in separators, scrubbers, and filters.” These pneumatic devices and controllers use pressurized natural gas to activate valves and controls. Estimations are that there are over 1 million of these devices running in the U.S. representing 35% of methane emissions from the oil and gas sector. EQT describes pneumatic controller replacement as a strategic opportunity: “the quickest and lowest-cost opportunity to reduce methane emissions.”

     The first thing emphasized in EQT’s informative white paper on the subject is to get an accurate count of these device across operations. This allows for accurate cost estimations for replacement. They mention three alternatives to natural gas-powered pneumatic devices: compressed air, nitrogen, and electric drive. A compressed air pneumatic controller requires an adequate power source, a gas dryer to dry the air which also reduces freezing, a tank, and a filter. Costs can be significantly higher for compressed air per unit, but it can be an economic choice when there are many pneumatic devices at a single location since an air compressor can be shared among devices. It does require adequate electric power to run. This can be the best choice where grid power is available. The three main types of compressed air pneumatic systems are scroll, screw, and reciprocating. EQT prefers the reciprocating system because “it has a higher discharge pressure to provide additional stored air volume, can run intermittently, has high efficiency, lower initial cost, and minimally invasive maintenance.”

 

Compressed Air Pneumatic Controller System. Source: EQT

     Nitrogen is an option for remote areas where no grid power is available. Nitrogen has lower initial costs (about $20,000) and low maintenance costs but higher operating costs (up to $1500/month) due to the need to continuously supply nitrogen from bulk cylinders, nitrogen tanker trucks, or MicroBulk. Some nitrogen is lost continuously during the process. Like dried compressed air, nitrogen won’t freeze, which is a plus. It can be dangerous in confined spaces. EQT sees well pads producing 0-50 barrels per day of fluids as good candidates for nitrogen pneumatic controllers.

     The third alternative is electric drive actuators. These have a higher upfront cost, and that cost does not go down with the amount of devices as it does with compressed air. These systems rely on small electric motors to actuate valves and controls. One advantage of these is that they can be operated remotely and throttled to respond to downstream pressure variations. EQT recommends them for use on well pads with a low valve count and high production such as sites with greater than 50 barrels per day of fluid production and less than 24 pneumatic devices. This setup has become the best practice standard for EQT for new well pads. They note that wet gas (condensate) facilities favor compressed air or nitrogen. Low well-count dry gas facilities with no dehydration or ancillary equipment favor electric drive actuators since they often have a lower count of total pneumatic devices. Higher well-count dry gas facilities with dehydrators and other ancillary equipment favor compressed air or nitrogen. The table below shows some operating parameters for each system:

 

 Pneumatic Controller Solutions by Operating Parameters. Source: EQT

References:

EQT changes the table stakes on emissions reduction timelines: Energy Pulse: in brief. June 30, 2023. Wood MacKenzie. Energy Pulse: in brief | | Wood Mackenzie

Pneumatic Device Replacement: Low-Cost Opportunity for Methane Abatement. EQT. January 2022. PNUEMATIC DeVICE REPLACEMENT (eqt.com)