国际能源署-沼气和生物甲烷展望-全球地理空间评估（英）-2025_132页_8mb

International Energy Agency (IEA) Outlook for Biogas and Biomethane Report Summary

1. Definitions and Scope

• Biogases: An umbrella term for biogas (mixture of methane and CO₂ from organic decay) and biomethane (upgraded, near-pure methane).
• Feedstocks: Agricultural residues, animal manure, biowaste, and woody biomass (exclusive of food crops to avoid competition with food systems).
• Key Features: Produced locally from organic waste, supports energy security, waste management, emissions reduction, and rural development.

2. Current State of Development

• 2023 Production: ≈50 billion cubic meters of natural gas equivalent (bcme) globally, with biogas (80%) used for heat/electricity, and biomethane (20%) as a gas-grid substitute.
• Leading Regions: Europe (40% of global demand), China, US, India.
• Emerging Economies: India (5% of potential exploited), China (<10%), Brazil.
• Policy Drivers: ~50 new policies since 2020 (EU blending targets, carbon credits, blending mandates); India’s compressed biogas (CBG) CNG expansion; US inflation reduction act subsidies.

3. Environmental Benefits and Challenges

• Benefits: Avoids methane emissions (50% of global anthropogenic methane), reduces reliance on imported fuels, creates local jobs.
• Drawbacks:
  • Methane leakage during production (2-7% of output, undermining emissions benefits if unmitigated).
  • Emissions depend on feedstock (manure avoided ~80 g CO₂/MJ; natural gas ~500 g CO₂/MJ).
  • Digestate management challenges in some regions.

4. Economic and Technological Considerations

• Costs:
  • Biomethane cost: USD 18/GJ avg. (Lower in Asia: ~10/GJ in best locations).
  • Higher operational costs vs. solar/wind, but competitive at scale ($5/GJ after carbon pricing).
• Technologies:
  • Mature: Anaerobic digestion, landfill gas capture.
  • Emerging: Gasification/pyrolysis, CO₂ capture for mineralization/biochar.
  • Best practices: Closed digestate storage, leak detection reduce emissions (e.g., ~15% cheaper with synergistic feedstocks).

5. Future Outlook (Scenario-Based)

• Scenarios:
  • Stated Policies (STEPS): By 2050, ~200 bcme demand (5x 2023); rapid growth in emerging economies (China, India).
  • Announced Pledges (APS): ~300 bcme by 2050 (10x 2023), driven by net-zero alignment.
• Drivers:
  • Energy security (EU avoids 75 kb/d oil by 2050).
  • Decarbonization (hard-to-abate sectors like shipping, steel).
  • Rural economy boost (10M+ jobs by 2035).
• Policy Recommendations:
  • Standardize feedstock accounting, streamline permitting (e.g., gas-grid injection incentives).
  • Value co-benefits (digestate as fertilizer, CO₂ credits).

Conclusion
Biogases and biomethane offer significant potential for energy security, waste valorization, and emissions reduction at scale. Success requires:

• Tailored policies to overcome feedstock logistics and methane leakage.
• Investment in infrastructure (gas grids) and co-digestion to unlock marginal lands.
• Integration with circular economy (e.g., biochar, synthetic fuels), particularly in Asia and Europe.