What is a Microgrid? Benefits, Types and Applications Explained

Today, with the growing penetration of renewable energy sources and the global need to reduce CO2 emissions, microgrids are becoming increasingly popular. But what exactly is a microgrid, how does it work, and why does it matter for the energy transition?

Definition of a microgrid

A microgrid is a localised and self-contained energy system that can operate independently from the main power grid — known as off-grid or island mode — or as a controllable entity connected to the main power grid, known as on-grid mode. 

It consists of distributed energy resources (DERs) such as solar PV plants, wind turbines, battery storage systems and conventional generators, all integrated and coordinated by advanced software tools and communication technologies. Microgrids can serve an energy community, a building complex or even a single home, and are increasingly designed to improve energy resilience, reduce operating costs and lower carbon emissions. 

What is a microgrid controller ? 

A microgrid controller is a device capable of monitoring and managing the energy resources and loads connected to the microgrid, turning all connected assets into a single controllable entity. 

Its core functions include maintaining local grid stability, reducing operating costs through least-cost dispatch of assets, and managing real-time power flows to adapt to all operating circumstances. A microgrid controller can also receive optimised planning inputs from an Energy Management System (EMS), enabling a predictive approach to energy dispatch. In emergency situations — such as a blackout — the controller is able to analyse the situation rapidly, balance energy production with load consumption, and maintain power supply to critical loads. 

How to manage a microgrid system?  

In a microgrid, where the local electrical network cannot depend on the external transmission network, a real-time control system is essential. A Power Management System (PMS) calculates and applies an optimal power dispatch for all assets to ensure grid stability, manage black start procedures — which means repowering the entire system after a blackout — and deliver grid services such as frequency and voltage support. 

The PMS uses input forecasts, including weather data, to anticipate operating conditions for the upcoming hours. For more efficient optimisation, the local controller receives operational planning from an Energy Management System (EMS), which collects multiple forecasts and simulates future asset behaviour over the following days. 

When the microgrid is connected to the main grid, control focuses on respecting the constraints of the connection point and transformer, maximising financial returns, and supporting the main grid in case of frequency or voltage deviations through ancillary services. 

How microgrids work and what are the benefits? 

Being connected to the main grid ensures a stable electricity supply in most countries. However, in some locations — remote areas, islands or regions with unreliable infrastructure — interconnection is not possible or cost-effective. In these cases, an isolated microgrid is the solution. 

A microgrid can operate while connected to the grid, but it can also disconnect and rely entirely on its own local energy sources, especially during emergencies such as storms, maintenance periods or asset failures. Energy communities increasingly adopt microgrids to maximise self-consumption and self-production from locally installed solar panels and battery storage systems. 

The main benefits of building a microgrid include: 

• Power reliability: A microgrid provides a reliable source of electricity in areas with frequent outages or unreliable grid infrastructure. With its own generation capacity and storage, it ensures that critical loads remain powered at all times. 

• Energy cost savings: By combining renewable energy sources such as solar or wind power with storage systems, a microgrid reduces reliance on traditional fossil fuel sources and lowers energy costs. 

• Environmental sustainability: A microgrid reduces carbon footprint by generating and storing renewable energy on-site, helping organisations meet their sustainability and decarbonation goals. 

• Energy independence: By generating and storing its own power, a microgrid provides energy independence — particularly valuable in remote or off-grid locations. 

• Resilience: In the face of natural disasters, extreme weather events or grid disruptions, a microgrid can continue to supply power to critical loads even when the larger grid is down. 

• Electrification of isolated areas: Currently around 10% of the global population has no access to electricity. Isolated microgrid systems offer a practical and scalable solution to this challenge. 

On-Grid Microgrid vs Off-Grid Microgrid: Key Differences 

Off-grid microgrids, also called islanded microgrids, are designed to operate entirely independently from the main electrical grid. They are commonly used in remote areas or situations where connecting to the main grid is technically unfeasible or cost-prohibitive. They are also increasingly adopted to provide power resilience and independence for communities far from centralised infrastructure. 

On-grid microgrids are integrated with the main grid and can supplement or replace power from it. In some cases, they can also generate excess power that is sold back to the grid, creating a revenue stream for microgrid owners. One of the key challenges of on-grid microgrids is ensuring proper integration with existing grid infrastructure, which requires careful project planning and coordination with the local utility company. 

Is a Home Energy System Equivalent to a Microgrid?

A home energy system can be considered a type of microgrid, but it is not equivalent to a community microgrid in terms of scale, generation sources, management complexity or resilience. 

A home power system is a single-building energy solution using a limited set of energy sources and serving only the building in which it is installed. A community microgrid, by contrast, serves a larger area with multiple buildings, integrates diverse generation sources and requires more complex coordination and management. 

While both are part of the broader microgrid ecosystem, their differences in scale, coverage and complexity make them distinct solutions for distinct needs. 

Real-World Microgrid Examples

One concrete example of a microgrid operating in island mode in a remote area is Energy Pool's project in New Caledonia. Energy Pool provides an Energy Management System to manage and decarbonise the power supply across several islands. Read the story here !

Energy Pool's Microgrid Technology

Energy Pool's microgrid solution includes a Power Management System (PMS) embedded within an Energy Management System (EMS), enabling local monitoring of customer assets and combining cloud-based setpoints with local real-time data to optimise asset-level performance and dispatch decisions. 

The PMS coordinates asset behaviour to closely follow forecast-based optimised operating schedules provided by the EMS, while making real-time adjustments to adapt to deviations. It also manages voltage and frequency stability of local systems and networks, particularly in islanded or stand-alone configurations. 

For on-grid microgrids, Energy Pool's EMS can provide ancillary services — including frequency regulation, voltage control and reactive power support — generating additional revenue for the microgrid community while contributing to grid stability. The system uses intelligent models developed by Energy Pool's specialists to determine the optimal energy strategy, lowering energy bills and minimising CO2 emissions. 

The continuous feedback loop between the predictive EMS and the real-time PMS ensures constant optimisation of both operating costs and carbon footprint.