Stationary Energy Storage Systems (SESS)

Definition of Stationary Energy Storage Systems (SESS)

Stationary Energy Storage Systems (SESS) are energy storage solutions designed to store electricity at a fixed location for later use. Unlike mobile storage systems such as electric vehicle batteries, stationary energy storage systems are permanently installed and used to support grid stability, renewable energy integration, backup power and energy optimization.

These systems store energy – typically generated from renewable sources or the grid – and discharge it when demand is high, supply is limited, or during power outages. Stationary energy storage systems are a foundational component of modern energy infrastructure, EV charging networks and smart grids.

How do stationary energy storage systems work?

Stationary energy storage systems operate by capturing electrical energy and storing it in a suitable medium, then releasing it when required. A typical system includes:

• Energy Storage Medium – Batteries (lithium-ion, flow batteries), thermal storage or mechanical storage
• Power Conversion System (PCS) – Converts energy between AC and DC
• Energy Management System (EMS) – Controls charging, discharging and optimization
• Battery Management System (BMS) – Monitors battery health, safety and performance
• Thermal Management System (TMS) – Regulates operating temperatures

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Together, these components ensure energy is stored efficiently, discharged safely and managed intelligently.

Why are stationary energy storage systems important?

Stationary energy storage systems play a critical role in the energy transition by:

• Improving grid reliability and resilience
• Enabling higher penetration of renewable energy
• Reducing peak demand and energy costs
• Supporting EV charging infrastructure
• Providing backup power for critical facilities

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As energy systems become more decentralized, stationary storage bridges the gap between energy generation and consumption.

Key applications of stationary energy storage systems

1. Renewable Energy Integration

Stores excess solar or wind energy and releases it when generation is low.

2. Grid Stabilization & Frequency Regulation

Helps balance supply and demand and maintain grid stability.

3. EV Charging Infrastructure

Supports high-power EV charging stations by reducing grid strain and improving uptime.

4. Backup Power & Energy Resilience

Used in hospitals, data centers, industrial facilities, and commercial buildings.

5. Peak Shaving & Load Shifting

Reduces electricity costs by managing energy use during peak demand periods.

Types of stationary energy storage systems

• Battery Energy Storage Systems (BESS) – Most common form of stationary storage
• Thermal Energy Storage – Stores energy as heat or cold
• Mechanical Storage – Includes pumped hydro and flywheels
• Chemical Storage – Hydrogen and other emerging storage technologies

Stationary energy storage systems vs BESS

While BESS is a type of stationary energy storage system, the term stationary energy storage systems is broader and includes non-battery technologies such as thermal, mechanical, and chemical storage. BESS is currently the most widely deployed due to its efficiency, scalability, and suitability for EV and renewable applications.

Maintenance challenges in stationary energy storage systems

Managing stationary energy storage systems involves challenges such as:

• Preventive maintenance scheduling
• Monitoring asset health across multiple sites
• Managing spare parts and consumables
• Ensuring safety and regulatory compliance
• Tracking performance degradation over time

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Without structured maintenance, system reliability and lifespan can be significantly reduced.

Managing stationary energy storage systems with CMMS & field service software

Digital CMMS and field service management platforms help operators:

• Automate preventive maintenance and inspections
• Track asset performance and lifecycle data
• Manage inventory and spare parts
• Coordinate field technicians and service teams
• Ensure SLA compliance and regulatory adherence

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This centralized approach improves uptime, safety and long-term operational efficiency.

Stationary energy storage systems: Powering a resilient energy future

As EV adoption, renewable energy generation and grid decentralization accelerate, stationary energy storage systems are becoming essential infrastructure. Their ability to store, manage and deliver energy reliably makes them a cornerstone of sustainable, future-ready energy ecosystems.