Resources

BESS Glossary

The BESS glossary defines the terms used to size, specify, integrate and operate battery energy storage systems.

BESS (Battery Energy Storage System)

A system that stores electrical energy in batteries and delivers it when needed for applications such as peak shaving, backup power, and energy shifting.

LFP (Lithium Iron Phosphate)

A lithium-ion battery chemistry used in energy storage, known for safety, long cycle life, and stable thermal performance.

BMS (Battery Management System)

A control system that monitors voltage, current, and temperature at the cell and module level, and protects the battery during operation.

PCS (Power Conversion System)

Equipment that converts DC power from the battery to AC power and controls charge and discharge. Enables integration with the grid or facility.

EMS (Energy Management System)

Software that controls battery operation based on load profile, tariffs, and system objectives.

SCADA (Supervisory Control and Data Acquisition)

A monitoring and control system used to manage energy systems in real time at the facility or grid level.

Round-Trip Efficiency (RTE)

The percentage of energy returned from the battery compared to the energy used to charge it. Example: charging 100 kWh and discharging 92 kWh results in 92% efficiency.

C-Rate (Charge/Discharge Rate)

The rate at which a battery is charged or discharged relative to its capacity.

1C equals a full charge or discharge in 1 hour.
0.5C equals a 2-hour discharge.
0.25C equals a 4-hour discharge.

Cycle Life

The number of charge and discharge cycles a battery can complete before its capacity decreases to a defined level.

Depth of Discharge (DoD)

The percentage of the battery’s usable capacity that is discharged during a cycle.

State of Charge (SoC)

The current charge level of the battery, expressed as a percentage of usable capacity.

Degradation

The gradual reduction in battery capacity over time due to cycling, temperature, and operating conditions.

DC (Direct Current)

The type of electrical current used within the battery system.

Thermal Management

Systems that control battery temperature to ensure safe operation and maintain performance.

Peak Shaving

Using the battery to reduce the highest power demand (kW) at a site to lower demand charges.

Load Shifting

Charging the battery during low-cost periods and discharging during high-cost periods.

Demand Charge

A component of an electricity bill based on the highest level of power used during a billing period.

Time-of-Use (TOU)

An electricity pricing structure where rates vary depending on the time of day.

Grid-Forming (PCS Mode)

An operating mode where the system establishes voltage and frequency, enabling independent operation.

Grid-Following (PCS Mode)

An operating mode where the system synchronises with the grid and injects or absorbs power.

How to use the BESS glossary

The glossary defines the terms used when sizing, specifying and operating a battery energy storage system. Power and energy are different: kW or MW describe output, while kWh or MWh describe stored energy. The BMS monitors cells, the PCS converts power and the EMS schedules operation. Keep the terms that matter to your project in a short brief before contacting BX.

Review the BESS guide and system platforms for related information.

Project information to bring to the next step

When reviewing a system, separate the outcome from the equipment list. A battery may be asked to deliver a short, high-power response, several hours of backup or a daily charge and discharge cycle. Those duties affect the usable energy, inverter rating, reserve state of charge and expected operating schedule.

Site conditions matter as well. Confirm the electrical service, available installation area, access for delivery, ambient temperature and the control signals the system must exchange with existing equipment. Include safety, maintenance and commissioning responsibilities in the project scope.

Good project information makes the next conversation more productive. Keep the source of each number, note assumptions that still need checking and identify the person who can provide missing records. BX can then outline the next engineering step without treating a generic example as a promise.

Read related BESS applications, review the system platforms and contact BX when you are ready to discuss your site.

Supporting technical resources

BX battery energy storage system — BX battery energy storage platform

For independent technical background, see the U.S. Department of Energy’s energy storage research and resources. Use that reference alongside your site data when reviewing system choices.

Contact BX Energy Systems when you are ready to discuss the application, operating schedule and project constraints.

BESS glossary planning

The BESS glossary defines the terms used to size, specify, integrate and operate battery energy storage systems.

Use the BESS guide and DOE energy storage resources to frame the next step.