Microgrids are localized energy systems that can operate connected to the utility grid and, when designed for it, can also operate independently (islanded). They combine distributed energy resources such as solar PV, battery energy storage (BESS), and backup generation with controllable loads like EV chargers, using intelligent control to balance supply and demand within a defined site.
What Are Microgrids?
A microgrid is a “mini power system” serving a specific area, such as:
– Commercial and industrial facilities
– Campuses (hospitals, universities, business parks)
– Residential developments and mixed-use districts
– Logistics depots, ports, and municipal sites
Microgrids typically include:
– Local generation (PV, wind, CHP, generators)
– Storage (BESS)
– Loads (buildings, HVAC, process loads, EV charging)
– Switchgear, protection, and metering infrastructure
– A microgrid controller to coordinate operation
Why Microgrids Matter for EV Charging
EV charging can significantly increase maximum demand and strain site connections. Microgrids help EV charging projects by:
– Supporting more chargers without immediate grid upgrades through peak shaving and load control
– Improving resilience so critical charging can continue during grid outages
– Increasing renewable self-consumption by aligning charging with PV generation
– Reducing demand charges and improving energy cost predictability
– Enabling advanced managed charging strategies for fleets and workplaces
For fleet depots, microgrids can ensure vehicles are charged reliably while keeping site demand within the maximum site demand limit.
How Microgrids Operate
Grid-connected mode
– Imports and exports power while optimizing cost, carbon, and peak demand
– Uses storage and load control to smooth peaks and manage constraints
Islanded mode (if enabled)
– Disconnects from the grid during outages or planned islanding
– Supplies prioritized loads using onsite generation and storage
– May shed non-critical loads to maintain stability
Not all microgrids are built for islanding; some are designed only for grid-connected optimization.
Key Microgrid Components
– Microgrid controller / energy management system (EMS)
– Point of common coupling (PCC) switchgear and protection
– Inverters for PV and BESS with monitoring and control
– Site metering and sub-metering (often via meter cabinets)
– Load control interfaces (including EV charger control via OCPP and CPMS)
– Optional backup generation (diesel, gas, CHP) for resilience
EV Charging Use Cases for Microgrids
– Fleet depots using BESS to reduce peak demand and ensure morning readiness
– Campuses combining PV + BESS + managed charging across multiple car parks
– Real estate sites adding chargers without increasing main connection size
– Municipal resilience hubs where EV charging supports emergency operations
– Industrial sites balancing EV charging with production loads under strict limits
Benefits and Trade-Offs
Benefits
– Lower peak demand and better control of maximum demand
– Higher renewable utilization and potential emissions reduction
– Increased uptime and resilience for critical loads
– Greater hosting capacity for EV chargers on constrained connections
Trade-offs
– Higher CAPEX and design complexity (controls, protection, integration)
– Interconnection and regulatory requirements can be strict
– Ongoing monitoring, cybersecurity, and maintenance are essential
– Benefits depend on tariffs, load patterns, and correct sizing of PV/BESS
Related Glossary Terms
Microgrid controller
Energy management system (EMS)
Battery energy storage system (BESS)
Managed charging
Load balancing
Dynamic load management
Maximum demand
Maximum site demand limit
Peak shaving
Renewables integration