Biogas Purification Technologies: A Comparative Review of Methods and Accessibility for Sustainable Energy Applications

Biogas, a renewable energy source, is generated through anaerobic digestion and consists of methane (CH4) and carbon dioxide (CO₂) as main components, together with small amounts of hydrogen sulfide (H₂S), ammonia (NH₃), siloxanes and water vapour. The contaminants reduce heating capacity of biogas and cause operational issues and equipment deterioration in downstream applications. The study evaluated contemporary purification methods used to generate highly pure biomethane. The priority was to achieve necessary guidelines for energy manufacturing, automotive fuel and grid entry standards alongside cost-effective operations and environmentally friendly solutions. The analysis focused on four widespread upgrading techniques: membrane separation (MS), cryogenic upgrading, pressure swing adsorption (PSA) and water scrubbing. The evaluation process of each method depends on operational effectiveness combined with CH₄ output rates alongside development capacities and industrial pricing factors. The analysis demonstrated that one purification solution does not fit all cases, and therefore, proper approach selection requires an evaluation based on gas composition together with specific use targets. The combination of MS and PSA permits scalable operation and produces significant CH₄ yields, yet cryogenic and water scrubbing processes yield high purity at the cost of initial expense and energy consumption requirements. Technical performance must remain balanced against investment costs, together with environmental considerations, according to the study findings. Specific purification methods improve the sustainability potential of biogas as an alternative power source. The review demands specific solutions for each application to attain maximum operational efficiency and reduce expenses. This study will assist developers in making informed technological choices and support ongoing research by guiding efforts toward the global integration of biogas systems within renewable energy markets.