Three Major Operational Modes for Power Generation of Gas Engine-based Power Generation Units

Three Major Operational Modes for Power Generation of Gas Engine-based Power Generation Units

Against the backdrop of energy structure transformation and the "Dual Carbon Goals" (peaking carbon emissions and achieving carbon neutrality), gas engine-based power generation, as an efficient, clean, and flexible distributed energy technology, is garnering increasing attention.

When exploring gas engine-based power generation projects, many people often encounter three technical terms: "Islanded Operation," "Grid-connected without Export," and "Grid-connected with Export." These essentially represent three fundamental operational modes defining the unit's relationship with the power grid. What are their differences, and which scenarios are they respectively suitable for?

Today, we will provide a detailed breakdown of these three modes to help you make more informed energy decisions.

Ⅰ. Islanded Operation:

The Self-sufficient "Island Power Supply" Mode

Islanded Operation, also known as isolated operation, refers to a mode where the gas engine-based power generation unit operates completely separated from the public grid, independently supplying power to the load. In this mode, the generator set acts as the "supreme commander," solely responsible for maintaining voltage and frequency stability.

Key Characteristics:

1. Complete Independence: Has no electrical connection to the utility grid, is unaffected by grid fluctuations, and does not rely on the grid.

2. Self-controlled Voltage and Frequency: The unit must possess excellent regulation capability, adjusting output in real-time based on load changes to ensure power quality.

Applicable Scenarios:

1. Remote areas not covered by the grid: Such as islands, border outposts or remote mining areas.

2. Locations with extremely high requirements for power supply continuity: Critical loads that cannot tolerate interruption even during a grid outage.

3. Industrial plants: The electricity generated by the gas engine-based unit can be fully consumed on-site, directly supplying the factory's production systems, power equipment, and auxiliary facilities.

Ⅱ. Grid-connected without Export:

The "Self-generation for Self-consumption" Mode for Utilizing Surplus Power

Grid-connected without Export is currently the most common and mainstream operational mode for domestic gas-fired distributed energy projects (Combined Cooling, Heating, and Power - CCHP). The generator set operates in parallel with the grid on the user side but only "takes" and does not "give" – the generated power is supplied for self-use. When generation is insufficient, power is purchased from the grid; when there is a surplus, sending the excess power back to the grid is not permitted.

Key Characteristics:

1. Flexible Switching, Ensured Stability: Relies on the large capacity of the main grid to stabilize voltage and frequency, resulting in smoother unit operation and longer lifespan.

2. Load Following: The unit typically operates at an economically efficient full-load state. The system automatically adjusts when the user's load changes.

Applicable Scenarios:

1. Large commercial complexes, hotels, data centers: Have large and stable electricity loads, suitable for utilizing waste heat from generation for cooling or heating (CCHP).

2. Industrial parks: In regions with significant peak-valley electricity price differentials, using self-generation for self-consumption reduces electricity costs.

3. Areas with high grid security requirements: Avoids potential impact on the public grid from user-side power sources.

Ⅲ. Grid-connected with Export:

"Self-consumption + Surplus Power Export" for Maximized Revenue

In this mode, the gas engine-based power generation unit operates in parallel with the grid and transmits all or surplus electricity generated to the public grid for use by other consumers, effectively acting as a small-scale "private power plant."

Key Characteristics:

1. Bidirectional Flow: Electricity can flow in both directions; the user acts as both a consumer and a supplier.

2. Grid Participation: The unit needs the capability to participate in grid peak shaving and frequency regulation, responding to dispatch instructions from the grid.

3. Revenue Model: Generates economic income by selling electricity to the grid.

4. Stringent Standards: Requires extremely high power quality (voltage, frequency, harmonics, etc.), complex control systems and protective devices, and must obtain strict approval and grid-connection permission from the local grid company.

Applicable Scenarios:

1. Dedicated gas-fired power stations: Act as power sources for the grid, with large-scale electricity sales as the primary profit model.

2. Gas resource production areas: Such as oil fields, shale gas fields, etc., where generation costs are lower than grid electricity prices, allowing full utilization of gas resources for power generation and sale to meet internal production needs and increase enterprise economic benefits.

3. Grid peak-shaving power sources: Serve as supplementary capacity during peak demand periods, responding quickly to supply power to the grid and balance the load.

4. Factories with surplus gas: Such as steel plants, chemical plants, tire pyrolysis plants, etc., that utilize industrial by-product gas for power generation. This achieves pollution reduction and energy savings while generating revenue from electricity sales, realizing multiple benefits.

In summary, Islanded Operation does not rely on the grid and is completely self-sufficient; Grid-connected without Export uses the grid as a backup, focusing on economical self-use; Grid-connected with Export participates in the electricity market to achieve revenue from power sales. The choice of mode depends on the project's resource conditions, electricity demand, and commercial objectives.

Kelinyuan can provide you with full-process professional services from solution design to grid-connection support, helping enterprises build cost advantages, ensure safe operation, and achieve sustainable development.