A microgrid is a localized power network that supplies electricity to a specific facility, community, or group of users. Unlike a conventional power system that relies entirely on the main grid, a microgrid combines local power generation, energy storage, and intelligent control to manage electricity closer to where it is consumed.
A microgrid can operate in grid-connected or islanded mode, making it useful for improving power resilience, integrating renewable energy, and supplying critical or remote loads.
Core Components of a Microgrid
A microgrid typically combines several technologies to generate, store, convert, and manage electricity.
- Distributed Generation: Local generation provides power within the microgrid. Depending on site conditions and energy requirements, sources may include solar PV, small wind turbines, combined heat and power (CHP), fuel cells, and backup generators. Multiple generation sources can also be combined to improve energy availability.
- Energy Storage: Battery energy storage systems store surplus electricity and release it when generation is lower than demand. Storage can help smooth renewable energy fluctuations, shift energy use, and provide backup power during grid interruptions.
- Power Conversion: Inverters and converters manage electricity between generation sources, batteries, the utility grid, and electrical loads. They support functions such as DC-to-AC and AC-to-DC conversion and allow different energy resources to work together.
- Energy Management System (EMS): The EMS acts as the control center of the microgrid. It monitors generation, electricity demand, battery status, and grid conditions, then coordinates available resources according to real-time conditions and operating priorities.
Two Operating Modes of a Microgrid
A key feature of a microgrid is its ability to operate either with the main grid or independently from it.
Grid-Connected Mode
- Grid Connection: The microgrid operates alongside the utility grid while managing its local generation, storage, and loads.
- Power Exchange: When local generation exceeds demand, surplus electricity may be exported to the grid where permitted. When local generation is insufficient, electricity can be imported from the utility grid.
- Energy Management: The EMS coordinates generation, storage, and loads to improve renewable energy utilization, manage peak demand, and control energy costs according to project requirements.
Islanded Mode
- Grid Disconnection: During a utility outage or in locations without grid access, the microgrid can disconnect from the main grid and continue operating independently.
- Local Supply: Local generation, energy storage, and backup generation work together to supply connected loads.
- Load Priority: If available power is limited, the system can prioritize critical loads and reduce or disconnect non-critical loads. This helps maintain essential services during emergencies or extended grid interruptions.
How Does a Microgrid Work?
Generation and electricity demand can fluctuate continuously, especially when renewable energy is used. The EMS coordinates local generation, energy storage, and loads, adjusting power distribution based on real-time supply and demand.
- Real-Time Monitoring: The EMS continuously tracks power generation, electricity demand, battery state of charge, and grid conditions.
- Generation > Demand: When local generation exceeds demand, the surplus can be stored in the battery or exported to the utility grid in grid-connected systems.
- Generation < Demand: When generation is insufficient, the battery can discharge to cover the power gap. This reduces dependence on external power and helps maintain supply stability.
- Storage Insufficient: If local generation and stored energy cannot meet demand, a grid-connected microgrid can draw additional electricity from the utility grid. An islanded microgrid may use backup generation or reduce non-critical loads.
- Critical Load Protection: During an outage, available energy can be prioritized for essential equipment and services. This allows limited generation and storage capacity to support the most important loads.
Types and Typical Applications of Microgrids
Microgrid operating modes and microgrid configurations describe different aspects of a system. Operating modes define how the microgrid interacts with the utility grid, while configuration describes how generation, storage, and backup resources are arranged for a specific project.
Microgrids can be classified according to their connection to the utility grid and the way local energy resources are configured.
- Grid-Connected Microgrids: These operate alongside the utility grid and are commonly used for commercial and industrial facilities, campuses, and other sites that need greater control over local energy resources.
- Off-Grid Microgrids: These operate independently without a permanent utility connection. They are suitable for remote communities, islands, communication facilities, and other locations where extending the conventional grid is difficult or uneconomical.
- Hybrid Microgrids: These combine multiple energy resources, such as solar, wind, battery storage, and backup generation. The specific combination depends on local resources, load profiles, and reliability requirements.
Typical Applications: Microgrids are used in remote communities, communication base stations, commercial and industrial facilities, mining sites, hospitals, emergency facilities, and other locations where reliable local power is important.
How to Select the Right Microgrid Configuration?
The appropriate microgrid configuration shall be determined according to the project’s actual power demand, site conditions and available energy resources. Assessment is normally carried out from the following aspects:
- Site Conditions: Determine suitable local power generation methods and system configurations based on local solar and wind resources, available space, climatic conditions and grid connection status.
- Load Requirements: Calculate the required generation and energy storage capacity according to total power consumption, peak load, critical equipment, operating hours and backup duration, and rationally allocate critical and non-critical loads.
- Grid Connection: Determine the microgrid operating mode based on whether the project requires connection to the public power grid. If grid-connected operation is needed, grid access conditions and switching requirements between grid-connected and off-grid operation should also be considered.
- Backup Power: Decide whether to equip backup power sources according to the project’s requirements for power supply reliability. Select battery energy storage, diesel generators or other backup power sources by taking critical loads, backup duration and power outage risks into account.
- Energy Mix: Select a single power generation method, or combine multiple energy sources such as PV, wind power and energy storage in accordance with local energy resources and power supply demand, to improve system flexibility and power supply stability.
- Expansion Requirements: If the project expects future power consumption growth or system capacity expansion, choose configurations with modular design to facilitate the subsequent addition of generation or energy storage capacity.
Choose YG ENERGY for Custom Microgrid Solutions
YG ENERGY designs tailored microgrid solutions based on your site’s power requirements. We integrate PV, wind power, battery energy storage, EMS and other equipment according to site conditions, load requirements and project objectives.
If you have project requirements, contact YG ENERGY to further discuss the suitable system configuration.
