Raw biogas typically consists of 50% to 65% methane by volume, with the remaining balance composed primarily of carbon dioxide (35% to 45%) along with trace amounts of water vapor, hydrogen sulfide, and ammonia. This high methane concentration serves as the primary combustible energy carrier, while advanced upgrading and purification facilities can scrub away inert gases to elevate methane purity above 95% to produce pipeline-grade renewable natural gas.