Biogas Purification (Biogas Methane) vs Biogas Power Generation

Biogas Purification (Biogas Methane) vs Biogas Power Generation

Comprehensive Comparison of Biogas Purification (Biogas Methane) and Biogas Power Generation

1. Technology Maturity and Applicable Scenarios
Biogas Purification
Technology: Requires carbon dioxide removal (CO₂), dehydration, desulfurization, etc., with high technical barriers.
Applicable Scenarios: Suitable for large-scale production (large-scale biogas projects), and requires nearby natural gas pipelines or transportation refueling stations.
Biogas Power Generation
Technology: Direct combustion for power generation or cogeneration (CHP), with mature technology, and small systems can also be applied.
Applicable Scenarios: Suitable for distributed energy (such as farms, wastewater treatment plants), without relying on pipelines.

2. Economic Benefits
Investment Cost
Purification: Equipment (such as membrane separation, PSA) and pipeline connection costs are high, approximately 1.5-2 times that of power generation.
Power Generation: Internal combustion engines or gas turbines have lower costs, but consideration must be given to grid connection or energy storage costs.
Revenue Sources
Purification: High prices for selling biogas (such as for vehicle fuel or industrial use), possibly enjoying carbon subsidies.
Power Generation: Electricity sales revenue (requires policy support such as FIT), and residual heat utilization (CHP efficiency can reach 80%).

3. Energy Efficiency
Purification: Energy loss is approximately 10-15% (during the purification process), but methane utilization is high (90%+).
Power Generation: Power generation efficiency is typically 35-45% (for gas turbines), and can be increased to 70-80% when cogeneration is involved.

4. Policy and Market Factors
Purification
Dependent on natural gas prices and carbon trading markets (such as EU RED II subsidies).
Requires policy support (such as green gas quotas). Power generation
Depend on feed-in tariffs (FIT) or renewable energy certificates (such as the 0.25 yuan/kWh subsidy for biogas power generation in China).
The difficulty of grid connection may affect the returns.

5. Environmental impact
Enhancement of air quality
Replacing fossil natural gas, with significant emission reduction effects (methane leakage must be prevented). Power generation
Replace coal power with other energy sources, but if the grid becomes cleaner, the marginal benefits will decrease.

6. Operation complexity
Purification: Adsorbents need to be replaced regularly and gas purity must be strictly monitored.
Power generation: Generators (such as spark plugs and engine oil) need maintenance, but the technology is more widespread.

7. Utilization of by-products
Purification: CO₂ can be utilized in a food-grade manner (it needs to be purified) to increase revenue.
Power generation: Waste heat can be used for heating or drying agricultural products to enhance overall benefits.
Overall suggestions
Choose gas extraction: If there are conditions for large-scale production (>500m³/h), convenient pipeline access, and policy support (such as a high carbon price).
Choose power generation: If the demand is scattered, the grid support is good, or a quick return is needed (for small projects).
Mixed mode: Partial purification and partial power generation to balance risks and benefits.