道路车辆用沼气技术简介（英文版）_62页_1mb

Biogas for Road Vehicles: Technology Brief Summary

Core Content Overview

Biogas can be produced from various biomass sources through anaerobic digestion (AD), and when upgraded to biomethane (natural gas quality), it can be used as a vehicle fuel. The process involves several stages: feedstock collection and pre-treatment, anaerobic digestion, upgrading and purification, and distribution. Biogas vehicles, including natural gas vehicles (NGVs) and dual fuel vehicles, offer environmental and economic benefits over conventional diesel and gasoline vehicles.

Main Points

1. Biogas Production and Feedstock

• Biogas is produced from organic materials such as wastewater, sludge, manure, industrial and municipal organic waste, energy crops, and landfill gas.
• Feedstock availability and characteristics influence the choice of anaerobic digestion technology (wet, solid, continuous, or batch systems).
• Energy crops can compete with food production for land and water, prompting sustainability standards in the EU.

2. Biogas Upgrading and Purification

• Upgrading removes CO₂ and impurities like H₂S and VOC to produce biomethane (≥90% CH₄).
• Technologies for CO₂ removal include absorption, adsorption, and membrane separation.
• H₂S is removed during or before the upgrading process using biological methods or chemical agents.
• Water vapour is removed via refrigeration or drying agents like silica gel.

3. Biogas as Vehicle Fuel

• Biogas can be used in NGVs and dual fuel vehicles, offering lower emissions, fuel costs, and similar driving performance.
• The GHG reduction potential is between 60% and 80% compared to gasoline, with higher savings when using waste instead of energy crops.
• Biogas can be distributed via gas grids, local pipelines, or trucks, depending on infrastructure.

4. Cost Analysis

• Production costs for biogas from manure range from USD 0.22/m³ to USD 0.39/m³, while from industrial waste, it ranges from USD 0.11/m³ to USD 0.50/m³.
• Total supply costs for biomethane (including distribution) range from USD 0.28/m³ to USD 0.88/m³ for large-scale plants, and USD 1.00/m³ to USD 1.55/m³ for small-scale.
• Biomethane production from energy crops is more expensive due to higher feedstock costs.
• Biogas is currently more expensive than fossil natural gas (USD 0.13/m³ in 2016), making cost reduction a key challenge.

5. Performance and Sustainability

• Biogas production efficiency varies depending on feedstock and process conditions.
• Digestate, a by-product, can be used as organic fertilizer, closing local nutrient cycles and reducing methane emissions.
• Biogas can also help reduce nitrogen oxide (NOₓ) emissions compared to diesel vehicles.

6. Potential and Barriers

• Biogas production for transportation is mainly concentrated in Europe, but many countries have significant potential.
• Barriers include lack of centralized biomass availability, high costs, changing regulations, and limited awareness of biogas benefits.
• In some countries, biogas is not widely used as vehicle fuel, despite good NGV infrastructure.

7. Current Applications

• Biogas is increasingly used for public transport and waste collection, such as in Berlin (150+ biogas-powered waste vehicles) and Lille (biogas-powered urban buses since 1990).
• Germany leads in biomethane production, but only 1.4% is used as vehicle fuel. Sweden uses 97% of its biomethane as vehicle fuel.

8. Technology and Future Outlook

• Research is ongoing to improve process efficiency and reduce costs through innovations like power-to-gas and gasification.
• A cost reduction of 30–40% is expected in the near future.
• Biogas technology is mature and reliable, with standardized, prefabricated modules for upgrading and purification.

Key Information

• Biogas definition: Product of anaerobic digestion with 50–70% CH₄ and 25–45% CO₂.
• Biomethane definition: Upgraded biogas with ≥90% CH₄ and low impurities.
• Biogas yield: Varies with feedstock, with municipal waste and animal manure yielding the highest amounts.
• Transport and storage: Biogas can be transported via gas grid, local pipeline, or high-pressure cylinders (200–250 bars) or liquefied for long-distance use.
• Challenges: High costs, lack of feedstock availability, and policy support.
• Opportunities: Synergies with power-to-gas and gasification, and growing use in public transport.

Summary of Benefits

• Environmental: Significant GHG reduction (60–80% vs. gasoline), lower NOₓ emissions, and nutrient recycling.
• Economic: Lower fuel costs compared to diesel and gasoline, potential for cost reduction with scale and technology improvements.
• Sustainability: Supports circular economy and reduces competition with food production when using waste feedstocks.

Best Practices and Examples

• Germany: Leading in biogas production and upgrading.
• Sweden: Uses 97% of its biomethane as vehicle fuel.
• Italy: High NGV adoption and infrastructure.
• Berlin: Uses biogas for waste collection vehicles.
• Lille: Pioneered biogas-powered urban buses.

Conclusion

Biogas represents a promising renewable energy source for transportation, with well-established technologies and significant GHG reduction potential. While challenges like cost and feedstock availability persist, the combination of policy support, technological advancements, and existing NGV infrastructure in many countries suggests a viable path for its expansion as a sustainable vehicle fuel.