Liberty Environmental Secures Air Quality Permit For Coal Mine Methane Greenhouse Gas Abatement
In September 2024, Liberty secured an air quality construction permit in Pennsylvania for one of the largest single carbon offset projects in the U.S. – the installation of an RTO oxidizer to abate VAM emissions from an underground coal mine located in southwestern Pennsylvania. Coal mines require large ventilation air methane (VAM) systems to maintain safe underground hygiene conditions, and these VAM exhausts are large sources of methane emissions. By installing multiple highly efficient regenerative thermal oxidizers (RTOs) on a large VAM exhaust, this project will achieve one of the largest reductions in greenhouse gas emissions achieved in the U.S. from a single methane abatement project.
Liberty has also provided air permit assistance for other, smaller, coal mine voluntary methane abatement projects, notably installation of flares to control coal mine borehole methane emissions. These are relatively small exhausts that have high methane concentrations, and that can be controlled by small enclosed flares instead of large oxidizers. Liberty has prepared air permit exemptions for these projects and in 2023 participated in the development of the current General Permit (GP-21 for “Coal Mine Methane Enclosed Flare”) that is now used in Pennsylvania to streamline air permitting for these projects.
Liberty’s permitting efforts included preparation of air emissions inventories, evaluating “best available technology” (BAT) for air pollution control options, and negotiating an air permit for the one of the largest VAM methane control projects in the U.S., which we believe will encourage future development of similar projects.
Note that PA DEP recently announced guidance for their Reducing Industrial Sector Emissions in Pennsylvania RISE PA program which identifies fugitive emissions reduction technologies at coal mine VAM exhausts as eligible projects for federal funding. The following article provides additional information:
https://paenvironmentdaily.blogspot.com/2024/11/dep-some-guidance-now-available-to.html
Liberty’s air permitting services extend to a wide variety of industrial sources including building products, metal parts fabrication and surface coating, fabric and vinyl coating, cleaning products and chemicals, recycling, and wood products. Liberty’s climate and sustainability services include greenhouse gas (GHG) emissions inventories, mandatory US EPA Part 98 GHG reporting, voluntary GHG reporting through the Carbon Disclosure Project (CDP), and carbon credit project evaluations.
Background
Methane is one of the pollutants that comprise GHG and methane is more than 25 times more potent as a greenhouse gas than carbon dioxide (CO2). By capturing and controlling methane emissions through oxidation, the methane (CH4) is converted to CO2, thereby significantly reducing overall GHG emissions on a “carbon dioxide equivalent” (CO2-e) basis.
Because methane is a flammable gas (“natural gas” is primarily comprised of methane), controlling methane using oxidation or combustion can be cost effective provided methane concentrations are sufficiently high. Flares can be used to control methane emissions from sources with high methane concentrations like anaerobic digesters processing animal manure and food wastes, or from coal mine boreholes. RTO oxidizers use large stone/ceramic heat exchange beds to achieve high thermal efficiencies in the range of 95%, which can effectively control lower concentration methane sources like coal mine VAM exhausts without the need for auxiliary fuel and consequent additional GHG emissions.
Further information about coal mine methane emissions can be found at U.S. EPA’s Coalbed Methane Outreach Program: