Investigating the Quality of Carbon Credits from Nitrous Oxide Abatement in Nitric Acid Manufacturing

Nitric acid is primarily used in the chemical manufacturing industry to produce synthetic fertilizers and is one of the largest anthropogenic sources of Nitrous Oxide (N2O) emissions. Working with Calyx Global’s Renewable Energy and Industrial Gas team under an NDA, we sought to adapt their existing ratings framework to best evaluate the greenhouse gas (GHG) integrity of ‘N2O abatement in Nitric Acid Production’ carbon credit projects. Potential GHG integrity risks were categorized into six standardized factors - Additionality, Baseline, Project Emissions, Leakage, Permanence, and Overlapping Claims. We first independently studied the nitric acid manufacturing industry and individual carbon credit methodologies to identify sectoral and methodology-level GHG integrity risks. From this, we produced a combined sectoral and methodology-level assessment framework to determine the quality of carbon credits. Finally, we rated select N2O abatement projects and awarded them a letter grade corresponding to the GHG integrity of their carbon credits. These ratings will inform potential investors about the reliability of a credit’s claim on its climate impact.