Terrestrial carbon disturbance from mountaintop mining increases lifecycle emissions for clean coal

Area of Science:

• Environmental Science
• Geochemistry
• Forestry

Background:

• The Southern Appalachian region, a major U.S. coal producer, faces extensive mountaintop coal mining (MCM).
• MCM is the primary method for extracting remaining high-quality coal reserves.
• Greenhouse gas emissions from coal life cycles are typically assessed without fully accounting for terrestrial disturbance.

Purpose of the Study:

• To quantify greenhouse gas emissions linked to terrestrial disturbance during MCM.
• To assess the impact of disturbed forest carbon on the overall life-cycle emissions of coal energy production.

Main Methods:

• Estimated disturbed forest carbon (soil and non-soil) using EPA and USDA Forest Service data.
• Quantified geogenic organic carbon exposure using published total organic carbon and carbon isotope data.
• Incorporated terrestrial disturbance into coal life-cycle assessments.

Main Results:

• Life-cycle emissions from MCM are significant due to terrestrial disturbance.
• Indirect emissions from MCM terrestrial disturbance are at least 7% for conventional power plants.
• Indirect emissions are approximately 70% for carbon dioxide (CO2) capture and sequestration power plants.

Conclusions:

• Terrestrial disturbance is a critical, underestimated factor in MCM's coal life-cycle emissions.
• Further research is needed on the fate of soil and geogenic carbon at MCM sites.
• Accurate life-cycle assessments must include indirect emissions from land disturbance.