California's manure methane-to-gas program faces accounting concerns

California’s climate‑action framework includes a long‑standing incentive program that compensates dairy producers for capturing methane from manure and converting it into renewable natural gas (RNG). Launched in the early 2010s under the state’s Low‑Carbon Fuel Standard, the scheme offers payments based on the volume of RNG generated, with the goal of reducing greenhouse‑gas emissions by displacing fossil‑derived natural gas in transportation and electricity markets. Since its inception, the program has enrolled hundreds of farms across the United States, and the California Air Resources Board reports that the captured methane has been quantified at several hundred thousand metric tons of carbon‑dioxide‑equivalent reductions annually.

Recent analyses by environmental watchdogs and academic researchers have raised questions about the net climate benefit of the initiative. Critics point to the lifecycle emissions of RNG, the potential for double counting of carbon credits, and the relatively high cost per ton of CO₂ avoided compared with other mitigation strategies. A 2024 audit indicated that a portion of the credited RNG is exported to markets outside California, where it may be burned without the same emissions accounting, thereby diluting the intended state‑level impact. The findings have prompted state officials to consider revisions to the verification process and to evaluate alternative pathways for reducing agricultural methane emissions.

The California Air Resources Board has announced that it will review the program’s methodology and reporting requirements in the coming months, aiming to ensure that future incentives deliver measurable and verifiable climate outcomes. Adjustments could include stricter eligibility criteria, revised credit calculations, and increased transparency for RNG sales. The review is expected to inform potential policy updates slated for the 2025 regulatory cycle.