Buyer’s guide · 12 minute read

What is a microgrid?

A microgrid is a local electrical system that coordinates defined loads and distributed energy resources as one controllable entity. Depending on its design, it can operate with the utility grid, independently in island mode, or entirely off-grid.

Definition

A microgrid is a controllable electrical system with a defined boundary, local loads, and one or more distributed energy resources. It can coordinate power production and consumption and may be designed to disconnect from and reconnect to the larger grid.

What are the core microgrid components?

Every project is different, but most systems combine several of the following layers.

01

Loads and electrical boundary

The buildings, equipment, feeders, or community the system must serve—and the point where it connects to the wider grid.

02

Distributed energy resources

Solar, wind, combined heat and power, fuel cells, diesel or gas generators, batteries, and controllable loads.

03

Controls and communications

The controller monitors system conditions and dispatches resources to meet reliability, cost, emissions, or market objectives.

04

Protection and switching

Relays, breakers, switchgear, and interconnection controls maintain safety and manage grid-connected and islanded operation.

Three common operating types

Grid-connected

Operates alongside the utility and may optimize costs, provide grid services, or support resilience.

Islandable

Can separate from the utility and continue serving selected loads during an outage.

Remote

Has no utility connection and must continuously balance local generation, storage, and demand.

Which type of microgrid company do you need?

A single project can involve several provider types. A turnkey integrator coordinates the whole system; controls companies orchestrate resources; equipment providers supply the physical power assets; and energy-as-a-service developers may finance, own, and operate the project.

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A practical project sequence

  1. 1

    Define the outcome

    Specify critical loads, outage duration, power quality, cost, emissions, growth, and schedule requirements.

  2. 2

    Screen feasibility

    Model load data, tariffs, resources, site constraints, interconnection, incentives, and operating strategies.

  3. 3

    Develop the electrical design

    Complete one-lines, protection studies, controls architecture, equipment selection, permitting, and utility coordination.

  4. 4

    Contract, build, and commission

    Align performance guarantees and acceptance tests with the desired operating modes before construction.

  5. 5

    Operate and maintain

    Monitor assets, test islanding, patch controls, maintain fuel and batteries, and update dispatch as tariffs and loads change.

Questions to ask a prospective provider

  • Which project roles do you perform directly, and which are subcontracted?
  • Have you commissioned systems at our voltage, scale, and required islanding speed?
  • Which third-party DERs, relays, meters, and communications protocols are supported?
  • Who owns the utility interconnection, protection studies, permitting, and incentive applications?
  • What resilience, fuel, efficiency, availability, or savings guarantees are contractual?
  • How are controls secured, updated, monitored, and recovered after a communications failure?
  • What are the warranty, battery augmentation, O&M, and end-of-term obligations?

Common questions

Can a microgrid operate without the utility grid?

Yes. A remote microgrid is designed to operate without a utility connection. A grid-connected microgrid can operate with the utility and may disconnect into island mode when its design, controls, generation, storage, protection, and interconnection agreement support that operation.

Is a solar-and-battery system automatically a microgrid?

Not necessarily. A microgrid coordinates defined loads and energy resources as a controllable system. Solar and batteries can be components, but the electrical architecture, controls, protection, and operating modes determine whether the system functions as a microgrid.

Who builds a microgrid?

A project may involve an owner’s engineer, developer, controls provider, electrical equipment vendors, generation and storage suppliers, an EPC contractor, the local utility, financiers, and an operator. A turnkey integrator may coordinate several of these roles.

How should companies be compared?

Compare demonstrated experience at the required voltage and project scale, resource and controls compatibility, islanding experience, cyber and protection design, interconnection scope, financial model, warranties, performance guarantees, and long-term service.