From Feedstock to Power: A Chain Analysis of CNG, LNG, and NG, and Trends in Generator Set Applications

Natural gas, a critical pillar in the global energy structure transition, covers a complete chain from underground extraction to end-user applications. As feedstock, natural gas (NG) is processed into compressed natural gas (CNG) or liquefied natural gas (LNG) before being converted into electricity via generator sets. This article examines the relationships among NG, CNG, and LNG from a产业链 (industrial chain) perspective and explores technological trends and market prospects in generator set applications.

1. Upstream Industrial Chain: NG Extraction and Processing

Natural gas (NG) primarily originates from gas field extraction or unconventional resources like shale gas, with methane as the main component (85%–99%), accompanied by small amounts of ethane, propane, and sulfides. Extracted NG undergoes purification processes such as desulfurization, dehydration, and separation to meet pipeline transportation standards (methane content ≥95%) before entering the midstream sector.

Key Data: Global natural gas production has surpassed 4 trillion cubic meters annually, with Russia, the U.S., and Iran as the top three producers, collectively accounting for over 40%. China’s natural gas production stands at ≈200 billion cubic meters annually, with an import dependency exceeding 40%.

2. Midstream Industrial Chain: The "Morphological Transformation" of CNG and LNG

NG must be physically processed into CNG or LNG to adapt to different transportation and storage needs:

1. CNG Production Process:

• Compression: NG pressure is increased to 200–250 bar using multi-stage compressors.

• Storage: Filled into high-pressure cylinders (made of carbon fiber-wrapped aluminum alloy), with single-bottle capacity ≈200–300 liters.

• Transportation: Short-distance transport via CNG tankers (single-vehicle capacity ≈4,000 m³).

2. LNG Production Process:

• Purification: Further removal of CO₂ and nitrogen to prevent low-temperature freezing.

• Liquefaction: NG is cooled to −162°C via expansion refrigeration or mixed-refrigerant cycles.

• Storage: Filled into double-walled vacuum-insulated tanks (daily evaporation rate ≤0.3%).

• Transportation: Long-distance transport via LNG carriers (capacity 70,000–270,000 m³) or tankers (single-vehicle liquid capacity ≈30 m³).

Cost Comparison: LNG liquefaction consumes ≈850 kWh/ton, accounting for 30%–40% of production costs. CNG compression consumes ≈100 kWh/1,000 standard cubic meters, with lower costs but limited transportation efficiency.

3. Downstream Industrial Chain: Application Scenarios and Technological Trends in Generator Sets

CNG and LNG are converted into electricity via generator sets, with application scenarios and technological paths diverging due to their morphological differences:

1. CNG Generator Sets: The "Capillaries" of Distributed Energy

• Urban distributed energy stations: Forms microgrids with photovoltaics and energy storage to enhance power supply reliability.

• Industrial park combined cooling, heating, and power (CCHP): Uses waste heat for heating or cooling, achieving overall efficiency >80%.

• Transportation sector: Supports charging stations for CNG buses and taxis, enabling "gas-to-electricity" conversion.

• Technological Path: Utilizes gas internal combustion engines or micro gas turbines, with power ranges from 10 kW to 10 MW.

• Application Scenarios:

• Case: Shanghai Disneyland adopts a CNG CCHP system, reducing annual CO₂ emissions by ≈12,000 tons and meeting 40% of the park’s electricity demand.

2. LNG Generator Sets: The "Arteries" of Large-Scale Energy Bases

• Peaking power plants: Compensates for renewable energy intermittency to ensure grid stability.

• Remote area power supply: Replaces diesel generators to lower fuel costs and pollution.

• Offshore platforms: LNG directly fuels gas turbines, enabling "zero-carbon" shipping pilots.

• Technological Path: Employs heavy-duty gas turbines (e.g., 9E, 9F-class), with power ranges from 50 MW to 500 MW.

• Application Scenarios:

• Case: Guangdong Zhuhai LNG Peaking Power Station, with an installed capacity of 2×400 MW, generates 3 billion kWh annually, accounting for 15% of Zhuhai’s electricity consumption.

4. Market Trends: Rising LNG Demand and Accelerated Technological Integration

1. Growing LNG Demand: Global LNG trade volume surged from 220 million tons in 2010 to 390 million tons in 2022, with a compound annual growth rate of 6%. It is projected to exceed 600 million tons by 2030, driving expansion in the LNG generator set market.

2. Technological Integration:

• Hydrogen Coupling: LNG storage tanks can be adapted for liquid hydrogen storage (requiring material modifications), paving the way for future "blue hydrogen" and "green hydrogen" applications.

• Digital Operations and Maintenance: IoT monitors tank pressure and temperature for predictive maintenance, reducing unplanned downtime risks.

3. Policy Drivers: China’s 14th Five-Year Plan emphasizes "expanding natural gas utilization," targeting 150 GW of natural gas-fired power capacity by 2025, with LNG generator sets expected to account for over 60%.

5. Conclusion: The "Dual-Form" Future of Natural Gas Power Generation

CNG and LNG, as two forms of NG, play core roles in distributed and centralized power generation, respectively. As LNG costs decline and technologies upgrade, its application boundaries will continue to expand, while CNG will remain competitive in specific scenarios due to its flexibility. In the future, both may deeply integrate with hydrogen energy and renewables, jointly building a clean, efficient, and flexible modern energy system.