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Views: 0 Author: Site Editor Publish Time: 2025-08-18 Origin: Site
Biogas is a clean and renewable bioenergy produced through anaerobic fermentation of organic waste, such as livestock manure, crop straw, kitchen waste, and sewage sludge. Its main components are methane (CH₄, accounting for approximately 50%–70%) and carbon dioxide (CO₂), with small amounts of hydrogen, hydrogen sulfide, and other gases. Using biogas for power generation is one of its most core and efficient applications, while it can also be extended to multiple fields. Below is a detailed introduction to the main uses of biogas and its power generation technology.
Biogas power generation converts the chemical energy in biogas into mechanical energy through internal combustion engines (such as biogas generator sets) or gas turbines, which then drive generators to produce electricity. The technology is mature, with an efficiency of 30%–45%, and can operate both on-grid and off-grid.
Renewability: Biogas raw materials are widely available and can be continuously supplied, reducing dependence on fossil fuels.
Environmental friendliness: The carbon dioxide emissions from burning biogas for power generation are much lower than those from coal combustion. Moreover, it prevents methane (with a greenhouse effect 25 times that of CO₂) from being directly released into the atmosphere.
Economic efficiency: It transforms waste into energy, lowering waste treatment costs. Additionally, it saves electricity bills through self-consumption or generates revenue by selling electricity, achieving the goal of "turning waste into treasure."
Stability: Biogas production can be regulated, and the power generation process is less affected by weather conditions, making it suitable as a base-load power source or for peak shaving.
Rural areas: Utilizing livestock manure and crop straw for power generation helps solve rural electricity supply issues while reducing environmental pollution.
Industrial sector: Organic wastewater from food processing plants and breweries can be used for biogas power generation to achieve energy self-sufficiency.
Urban waste management: Landfills or kitchen waste treatment plants can reduce greenhouse gas emissions through biogas power generation.
Distributed energy: Biogas power stations can be built in remote areas or islands to replace diesel generators, lowering operational costs.
Direct combustion for heating: Biogas can be burned in boilers to provide hot water or steam for heating residential buildings, greenhouses, or industrial plants.
Combined heat and power (CHP): By combining power generation with waste heat utilization, the overall system efficiency can reach 70%–85%, significantly higher than that of power generation alone.
Absorption refrigeration: The waste heat from biogas combustion can drive absorption chillers to meet cooling demands in summer.
Cooking and lighting: After purification (desulfurization and decarbonization), biogas can replace liquefied petroleum gas (LPG) or natural gas for household cooking, hot water supply, and lighting.
Transportation fuel: Through purification technology, the methane concentration in biogas can be increased to over 95% to produce bio-compressed natural gas (Bio-CNG), which can be used as fuel for buses, trucks, and other vehicles.
Chemical production: Methane in biogas can be used to produce hydrogen through steam reforming or to synthesize chemicals such as methanol and ammonia.
Carbon capture and utilization: Carbon dioxide separated from biogas can be used for food preservation, dry ice production, or greenhouse cultivation.
Organic fertilizer production: The residues (biogas slurry and sludge) from biogas fermentation are rich in nutrients such as nitrogen, phosphorus, and potassium and can be used as high-quality organic fertilizers for farmland.
Integration with livestock farming: Constructing biogas projects on livestock farms enables the realization of an ecological cycle model of "livestock farming - biogas - planting," reducing environmental pollution.
Raw material pretreatment: Remove impurities and adjust the pH value and temperature to improve fermentation efficiency.
Anaerobic fermentation: In a closed reactor, microorganisms decompose organic matter to produce biogas.
Biogas purification: Remove impurities such as hydrogen sulfide and moisture to prevent equipment corrosion.
Power generation and waste heat utilization: Biogas drives generator sets to produce electricity, and the waste heat is recovered through heat exchangers for heating or cooling.
Treatment of biogas residues and slurry: After solid-liquid separation of the fermentation residues, the biogas sludge is used for composting, and the biogas slurry is returned to the fields as liquid fertilizer.
Biogas power generation in Germany: Germany is one of the countries with the most advanced biogas power generation technology in the world. By 2020, its installed biogas power generation capacity reached 5.3 GW, accounting for about 7% of the country's renewable energy power generation. Its model is mainly based on agricultural biogas, combined with combined heat and power generation to achieve efficient energy utilization.
Rural biogas projects in China: China has promoted the "one pool with three reforms" (biogas digester, reform of toilets, kitchens, and livestock sheds) model in rural areas, using household biogas digesters to solve domestic energy needs and agricultural waste treatment problems. For example, a large-scale livestock farm in Sichuan Province, China, built a biogas power station with an annual power generation capacity of 2 million kWh, meeting its own electricity demand while selling surplus electricity to the grid.
Challenge: Seasonal fluctuations in organic waste may affect biogas production.
Countermeasure: Establish a diversified raw material supply system by combining crop straw, kitchen waste, and industrial wastewater to balance seasonal variations.
Challenge: The initial investment in biogas projects is relatively high, especially for large-scale projects.
Countermeasure: Reduce investment risks through government subsidies, carbon trading revenues, or energy management contract (EMC) models.
Challenge: In some regions, policies regarding feed-in tariffs or grid connection for biogas power generation are incomplete.
Countermeasure: Promote legislation to clarify the priority grid connection rights and subsidy standards for biogas power generation and improve market mechanisms.
Through multiple applications such as power generation, heating, civil fuel, and industrial raw materials, biogas achieves the coordinated development of energy, the environment, and the economy:
Energy level: It provides clean and renewable electricity and heat, reducing dependence on fossil energy.
Environmental level: It lowers greenhouse gas emissions, improves soil and water quality, and promotes ecological cycles.
Economic level: It reduces waste treatment costs, creates energy revenues, and drives the development of related industries.
In the future, with technological advancements and policy improvements, the application potential of biogas will be further unlocked, becoming an important pillar for global energy transformation and carbon neutrality goals.
