Anaerobic digestion of livestock manure offers a pathway for Iran to mitigate seasonal energy imbalances. During the four- month, thermal power plants' methane consumption rises by an average of 85 Mcm/day (2,650 Mcm/month), peaking at 309 Mcm/day. This study identifies a national biomethane potential of approximately 12.7 Mcm/day from 92.1 Mt of annual collectible manure. If stored and dispatched seasonally, this capacity could offset nearly two months of the incremental peak demand observed in thermal power plants.

Economically, the research advocates for a strategic shift from biogas-to-electricity toward biogas-to-renewable natural gas (RNG) injection. decoupling power-generation infrastructure reduces capital expenditure by 51.52%, boosting the internal rate of return from 9.2% to 29 % and shortening the payback period to four years.

To the best of the authors’ knowledge, this research represents the first application of the Livestock Standard Unit Equivalent (LSUe) framework to Iranian provincial livestock distribution. This methodology yields an estimated 50.6 m3 of biomethane per tonne of fresh manure. Integrating these results with economic screening identifies Mazandaran and Golestan as primary provinces for targeted bioenergy expansion