As electric vehicle (EV) adoption continues to expand, businesses are looking for more efficient and flexible ways to develop charging infrastructure. Commercial EV charging stations, fleet depots, and public charging hubs often require significant electrical capacity, particularly when multiple vehicles charge simultaneously.
Energy Storage Systems (ESS) offer one approach to managing electricity supply and demand. By storing electrical energy and coordinating its use with charging equipment, energy storage can support different charging strategies, including peak demand management, renewable energy integration, and microgrid operation.
However, integrating an ESS into an EV charging project requires more than choosing a battery with a large capacity. Businesses must evaluate their charging demand, grid connection, energy consumption patterns, and operating requirements.
This guide explains how Energy Storage Systems work with EV charging infrastructure and the key factors businesses should consider when planning an integrated energy solution.
1. What Is an Energy Storage System (ESS)?
An Energy Storage System (ESS) is a system designed to store electrical energy and release it when needed. Battery Energy Storage Systems (BESS) are one widely used type of ESS, using rechargeable batteries to store and deliver electricity.
A commercial battery energy storage system may include several integrated components:
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Battery modules and battery racks
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Battery Management System (BMS)
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Power Conversion System (PCS)
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Energy management controls
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Electrical distribution equipment
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Thermal management systems
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Safety monitoring and protection equipment
Each component has a different function. The battery stores energy, while the power conversion equipment manages the conversion between electrical forms required by the system. The BMS monitors battery operating conditions, and energy management controls coordinate system operation according to configured strategies.
Commercial ESS designs vary depending on the required storage capacity, power output, installation environment, and application.
For EV charging infrastructure, the ESS may operate alongside grid-connected chargers, photovoltaic systems, and energy management platforms.
2. How Does an ESS Work With EV Charging Stations?
An EV charging station draws electricity to charge vehicle batteries. Depending on the installation, electricity may come directly from the grid, from on-site solar generation, from an energy storage system, or from a combination of these sources.
An integrated charging and energy storage system coordinates these energy sources according to the system's design and operating strategy.
A simplified energy flow may include:
Grid / Solar Generation → Energy Management System → ESS / EV Chargers → Electric Vehicles
The actual energy flow depends on the system configuration, electrical architecture, and control strategy.
For example, a commercial site may use solar power during the day to supply charging demand. When solar generation exceeds immediate consumption, the system may direct surplus energy to battery storage. At another time, stored energy may be discharged to support charging loads, subject to system power limits and operating conditions.
This type of integration can provide additional flexibility in how energy is generated, stored, and consumed.
However, an ESS does not automatically eliminate grid demand or guarantee lower electricity costs. Its benefits depend on the system's capacity, power rating, operating strategy, and local energy conditions.
3. Why Is Energy Storage Relevant to Commercial EV Charging?
Commercial EV charging infrastructure can create concentrated periods of electricity demand. This is particularly relevant to sites with multiple high-power chargers or vehicles that need to charge within a limited operating window.
For example, a fleet depot may need to charge several vehicles before their next scheduled departure. A public charging hub may experience higher demand during certain hours of the day.
The electrical supply available at the site may influence the number and power rating of chargers that can be installed.
Energy storage can be considered as part of a broader strategy for managing these requirements.
Potential applications include:
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Peak demand management
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Load shifting
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Renewable energy utilization
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Support for charging infrastructure expansion
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Microgrid integration
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Coordinated energy scheduling
The relevance of each application should be evaluated based on the specific site and project objectives.
4. Peak Shaving and Load Management
Peak shaving is an energy management strategy that aims to reduce the amount of electricity drawn from the grid during selected periods of high demand.
In a charging application, an ESS may discharge stored energy to support part of the charging load while limiting grid power consumption.
For example, a site may have a predefined grid power limit. When charging demand increases, the energy management system can coordinate the available grid power and battery output according to the configured operating strategy.
A Simplified Example
Consider a commercial charging site with the following illustrative conditions:
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Available grid power for charging: 200 kW
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Charging demand during a peak period: 300 kW
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Required additional power: 100 kW
If the energy storage system has sufficient available power and energy, it may supply part of the additional demand, subject to system limitations.
The example is intended to explain the operating principle, not to represent a guaranteed system performance level.
Actual results depend on battery state of charge, discharge power, system efficiency, protection settings, and the site's electrical design.
What Are the Potential Benefits?
Peak shaving may help businesses:
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Manage selected grid demand limits
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Coordinate charging loads
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Reduce the need for simultaneous high grid draw
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Evaluate alternatives to immediate electrical infrastructure expansion
Whether peak shaving provides financial benefits depends on the applicable electricity tariff, demand charges, battery operating costs, and project economics.
5. Energy Storage and Renewable Energy Integration
Photovoltaic (PV) systems generate electricity from sunlight. When combined with energy storage and EV chargers, PV generation can become part of an integrated charging and energy management system.
A PV + ESS + EV charging system may operate through several energy pathways.
Solar-to-Vehicle Charging
When solar generation is available, electricity may be used directly to support EV charging, depending on the system configuration and charging demand.
Solar-to-Battery Storage
If generation exceeds immediate demand and the system is configured for charging the battery, surplus electricity may be stored for later use.
Battery-to-Vehicle Charging
Stored energy may be discharged to support EV charging when solar generation is lower or when the system's operating strategy calls for battery use.
Grid Integration
The grid may remain an important energy source, particularly when renewable generation and stored energy are insufficient to meet charging demand.
The actual operating modes depend on the system architecture, control settings, and applicable electrical requirements.
Why Does PV + ESS Matter?
Combining solar generation with energy storage can provide flexibility in matching energy supply with charging demand.
However, the value of a PV + ESS system depends on several factors, including solar availability, charging schedules, battery capacity, electricity tariffs, and installation costs.
Businesses should conduct a site-specific assessment rather than assuming that solar and storage will provide the same benefits in every location.
6. Understanding Battery Capacity and Power Rating
Two important specifications when evaluating an Energy Storage System are energy capacity and power rating.
Although they are related, they describe different characteristics.
Energy Capacity: kWh
Energy capacity is commonly expressed in kilowatt-hours (kWh). It indicates how much energy a battery system can store under the specified conditions.
For example, a battery system with a rated capacity of 215 kWh is described in terms of its nominal energy capacity. The amount of usable energy available during operation depends on system specifications, operating limits, and other conditions.
Power Rating: kW
Power rating is expressed in kilowatts (kW). It indicates the rate at which the system can charge or discharge electricity under specified conditions.
A battery system may have a high energy capacity but a comparatively lower power rating. Conversely, a system designed for high-power applications may require a suitable power conversion and battery configuration to support its intended discharge rate.
Why Do Both Specifications Matter?
For EV charging infrastructure, businesses need to consider both:
| Specification | What It Describes | Why It Matters |
|---|---|---|
| Energy capacity (kWh) | Stored energy | Influences how long the system can supply energy at a given load |
| Power rating (kW) | Charge or discharge power | Influences how much power can be delivered at a given moment |
| Operating duration | Time at a particular load | Helps determine whether the system can meet the intended demand |
| Efficiency | Energy conversion and storage losses | Affects usable energy and operating economics |
A suitable ESS configuration should match the charging site's power requirements and expected energy consumption profile.
7. How to Select an ESS for Commercial EV Charging Projects
Choosing an ESS for commercial charging requires a structured evaluation of the site's electrical and operational needs.
7.1 Assess Charging Demand
First, businesses should understand how much charging demand the site is expected to handle.
Important questions include:
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How many vehicles will charge each day?
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How many chargers may operate simultaneously?
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What is the expected peak charging load?
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How long do vehicles remain at the site?
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Are charging periods concentrated at specific times?
A fleet depot with predictable charging schedules may have different requirements from a public charging station with variable demand.
7.2 Evaluate Grid Capacity
The existing electrical infrastructure should be assessed before determining the role of an ESS.
Relevant considerations may include:
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Available grid connection capacity
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Transformer capacity
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Distribution equipment
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Maximum demand
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Electrical protection requirements
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Local grid connection rules
An ESS can be part of a power management strategy, but it does not replace the need for proper electrical design or required grid approvals.
7.3 Determine Required Energy Capacity
The required energy capacity depends on the amount of energy the system is expected to store and deliver.
Businesses should assess the intended operating duration, expected discharge requirements, charging schedules, and battery operating limits.
A larger capacity is not necessarily the most appropriate choice for every project. The system should be sized according to actual demand and operating objectives.
7.4 Determine Required Power Output
The ESS must also be evaluated according to the required charge and discharge power.
A project involving multiple DC fast chargers may have different power requirements from a site primarily using AC chargers.
The power rating of the ESS, chargers, and other electrical equipment should be considered as part of the overall system design.
7.5 Consider Installation Environment
Commercial ESS installations require appropriate consideration of environmental conditions and safety requirements.
Depending on the equipment and installation site, businesses may need to evaluate:
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Temperature and humidity
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Protection against environmental exposure
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Cooling requirements
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Fire safety provisions
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Maintenance access
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Local regulatory compliance
The equipment specifications and installation requirements should be reviewed with qualified technical personnel.
8. The Role of EMS in Integrated Charging and Storage Systems
An Energy Management System (EMS) helps coordinate energy-related equipment and operating strategies.
In an integrated EV charging system, an EMS may communicate with charging equipment, energy storage systems, photovoltaic systems, and other electrical assets.
Potential functions include:
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Monitoring energy consumption
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Coordinating charging schedules
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Managing energy storage operation
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Monitoring operating conditions
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Supporting load management
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Coordinating multiple energy sources
The specific functions of an EMS depend on the system design and available control interfaces.
EMS and Dynamic Load Management
Dynamic Load Management (DLM) is another technology used to manage charging demand.
A DLM controller can monitor charging station power consumption and adjust charging loads according to configured power limits.
For example, Gresgying describes its DLM controller as comparing a set maximum power limit with the total active power collected from charging stations through a gateway meter. The controller manages charging station loads to help prevent transformer overload. This is a documented product function, and actual performance depends on the system configuration and operating conditions.
When used alongside an ESS and EMS, load management can form part of an integrated approach to coordinating charging infrastructure.
9. Commercial Applications of ESS-Integrated EV Charging
Energy storage systems can be considered in several commercial charging scenarios.
Fleet Charging Depots
Fleet operators may need to charge multiple vehicles according to scheduled operating requirements.
An ESS may support energy management strategies where charging demand is concentrated or where the site has specific grid capacity constraints.
The appropriate configuration depends on the fleet size, vehicle charging requirements, available electrical capacity, and operating schedule.
Public Fast Charging Stations
Public charging stations may serve vehicles with different charging needs throughout the day.
At sites with high charging demand, energy storage may be evaluated as part of a strategy for coordinating grid power and charging operations.
The suitability of an ESS depends on the station's demand profile, electrical infrastructure, and business model.
Commercial and Retail Properties
Shopping centers, office buildings, and other commercial properties may combine EV charging with solar generation and energy storage.
For these locations, the charging schedule may overlap with building electricity consumption, making energy management an important consideration.
An integrated system may help coordinate charging, energy storage, and other site loads, subject to the system's design.
10. Gresgying's Approach to Commercial Energy Storage
Gresgying's product portfolio includes a 215kWh Commercial ESS designed for commercial energy storage applications.
According to the official product information, the system integrates an energy storage battery, battery management monitoring system, distribution system, environmental control system, and fire control system.
The listed product features include a modular cabinet design, IP54 protection, multiple levels of safety monitoring and protection, and support for multiple units in parallel.
The product documentation specifies a rated energy capacity of 215 kWh and a rated AC power of 100 kW for the listed CESS-100K215AL model. Other specifications include LFP battery technology and communication interfaces such as Ethernet, RS485, and CAN.
These specifications refer to the published product model and should be verified against the latest technical documentation before use in a project.
Gresgying also describes energy storage applications involving peak shifting and valley filling, dynamic capacity addition, and microgrid integration with photovoltaic systems, EV chargers, and EMS controllers.
Businesses evaluating a commercial ESS should review the actual system configuration and determine whether its specifications match their project requirements.
11. Important Safety and Maintenance Considerations
Safety is an essential consideration when planning battery energy storage and EV charging infrastructure.
An ESS should be designed, installed, commissioned, and maintained according to applicable technical requirements and manufacturer instructions.
Key considerations may include:
Battery Monitoring
The Battery Management System helps monitor battery operating conditions and supports battery protection functions according to its design.
Thermal Management
Battery systems may require appropriate cooling and environmental controls to maintain operating conditions within specified limits.
Electrical Protection
The system should incorporate suitable electrical protection and safety measures according to its architecture and applicable standards.
Fire Safety
Fire detection, protection, and response provisions should be considered based on the battery technology, equipment design, installation environment, and local requirements.
Maintenance and Inspection
Regular maintenance and inspection procedures help support reliable operation. The required frequency and scope depend on the equipment, operating conditions, and manufacturer's instructions.
Safety features should not be evaluated only through a single specification. The overall system design and installation practices are important.
12. What Businesses Should Evaluate Before Deployment
Before investing in an ESS-integrated EV charging system, businesses should assess both technical and economic requirements.
A practical evaluation may include:
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Charging demand: Determine the expected energy consumption and peak load.
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Grid capacity: Assess the existing electrical supply and connection limitations.
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Storage requirements: Define the required energy capacity and power rating.
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Operating strategy: Determine how the ESS will be used, such as load management or energy shifting.
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Installation conditions: Review environmental, safety, and maintenance requirements.
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Economic analysis: Compare capital expenditure, operating costs, electricity tariffs, and expected project benefits.
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Future expansion: Consider whether the system can support additional chargers or changing demand.
A detailed assessment can help identify the appropriate balance between charging capacity, energy storage, and electrical infrastructure.
Conclusion
Energy Storage Systems can play a supporting role in commercial EV charging infrastructure by providing additional flexibility in how electricity is stored, managed, and delivered.
Applications such as peak shaving, load management, and renewable energy integration may be relevant to charging stations, fleet depots, and commercial properties. However, the value of an ESS depends on the characteristics of each project, including charging demand, grid capacity, battery specifications, and operating costs.
Businesses should evaluate energy capacity and power rating together, consider the role of EMS and load management, and ensure that safety and installation requirements are addressed.
As EV charging infrastructure continues to develop, integrated solutions combining charging equipment, energy storage, and intelligent energy management may offer businesses additional options for planning scalable and application-specific charging systems.
For companies evaluating commercial EV charging and energy storage projects, understanding the relationship between these technologies is an important step toward making informed infrastructure decisions.
Explore commercial EV charging and energy storage solutions with Gresgying to discuss the requirements of your next charging infrastructure project.