Kamran Mushtaq
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Electrical

DG & DS

Added: July 27, 2026

Definition

DG (Distributed Generation) and DS (Distributed Storage) are the two types of DER (Distributed Energy Resources):

  • DG produces electricity (e.g., rooftop solar panels, small wind turbines).
  • DS stores electricity for later use (e.g., batteries). Together, they make local energy generation and storage possible.

The Problem That Led to It

DER tells us that energy resources are spread across the grid, but it doesn't distinguish between resources that generate electricity and those that store it. Engineers needed clearer categories because generation and storage play different roles.

What Problem It Solves

Separating DER into DG and DS helps engineers:

  • Decide which resources produce electricity.
  • Decide which resources save electricity for later.
  • Better plan and manage the power grid.

What Happens If Not Used

Everyone would simply call everything "DER," making it harder to understand whether a device is creating electricity or just storing it.

Easy Wording

DG makes electricity, while DS saves electricity for later.

Layman Example

Think of your phone:

  • DG is the charger that supplies power.
  • DS is the battery that stores power until you need it.

Both are needed, but they do different jobs.

Technical Example

Before DG/DS Classification

  • A neighbourhood has solar panels and batteries.
  • Both are simply labelled "DER."
  • Operators don't immediately know which devices generate or store power.

After DG/DS Classification

  • Rooftop solar panels → DG (generate electricity).
  • Community battery → DS (stores excess electricity).
  • During the day, DG powers homes and charges DS.
  • At night, DS supplies stored electricity when solar panels are no longer generating.

Limitation

DS is only a general category for energy storage. It does not describe what kind of storage system is being used.

Solution

The next concept is BESS (Battery Energy Storage System), the most common type of Distributed Storage (DS) used in modern power grids. It explains how batteries store and release electricity when the grid needs it.