Battery Energy Storage System (BESS)

As demand on the grid increases, along with interest in using more intermittent renewable energy resources, battery energy storage systems (BESS) continue to become critical to providing affordable, reliable power. Global BESS deployments rose 53% in 2024. This growth trajectory is expected to continue in 2025, rising to more than 26% year over year. A BESS has many applications, including use on electric vehicle charging sites. EV charge point operators who invest in an onsite BESS can benefit from increased sustainability, reliability, and optimized energy costs.

What is a BESS?

A battery energy storage system works like a giant rechargeable battery that can store electricity from the grid or from onsite renewable energy sources like solar or wind power.

Here are some of the components of a BESS:

• Battery cells and modules: Battery cells, grouped into modules (or racks), store electrical energy. Lithium-ion chemistry is often used due to its high energy density and efficiency. Batteries are housed in a protective enclosure to guard against environmental elements while ensuring safe and reliable charging.
• Power conversion system: An inverter is critical for bidirectional energy flow. It converts direct current (DC) from the batteries into alternating current (AC) to deploy to the grid or to use for EV charging. Batteries can also recharge with AC power from the grid or onsite renewables like solar.
• Battery management system: The battery management system oversees the health, safety, and efficiency of the battery cells to ensure long-term performance and safety. It continuously monitors the voltage, current, temperature, and charge levels of each module to prevent issues like overcharging or thermal runaway.
• Energy management system: Energy management software serves as the brain of the BESS, making real-time decisions to direct energy. This system manages when and how batteries charge or discharge based on grid demand, electricity prices, available renewable energy, EV charging patterns, and other factors. By integrating with site meters, sensors, and other energy assets, the system optimizes energy flow to save costs, improve resiliency, and enable grid participation.
• Thermal management system: The thermal management system keeps the BESS running safely and efficiently by maintaining optimal operating temperatures regardless of weather conditions. It helps cool or warm as needed to prevent overheating and extend battery life—especially in high-use EV environments.

Battery energy storage systems can be deployed either behind the meter—serving on-site energy loads—or in front of the meter to provide services directly to the grid. Behind-the-meter battery energy storage systems are a natural fit for EV charging sites, where energy demand can be both high and dynamic.

How can a BESS be used on an EV charging site?

Adding a BESS to an EV charging site can help charge point operators (CPOs) manage peak demand, reduce energy costs, and improve charging reliability. But to unlock the full value of the system, a BESS must be paired with a smart energy management platform. Smart energy management optimizes how all energy sources at a site (the grid, renewables, and local battery storage) are used to accommodate EV charging while considering unmanaged loads and the varying cost of energy from the grid.

Here’s a look at some functions of smart energy management software that involve a BESS on an EV charging site.

Renewable load shifting

Smart energy management systems utilize a battery energy storage system as a low-cost, readily available onsite energy source by controlling battery charging and discharging. The BESS can be charged when onsite renewable energy is abundant and discharged when demand peaks, grid energy costs are high, and renewable energy is scarce. During times of peak demand or demand response events, smart energy management can shift loads to renewables and BESS to reduce costs and alleviate strain on the grid.

Peak shaving

Utility demand charges depend on a site’s greatest level of grid use during a billing period. Switching to using battery power when nearing the grid limit can lower peak demand. As with renewable load shifting, smart energy management can replace grid energy by discharging a local onsite BESS to provide power for EV charging, thus “shaving” the peak. Once demand recedes, the platform can use that time to recharge the BESS from the grid and store that energy until demand peaks again. Using resources more efficiently and avoiding utility charges helps reduce operating costs and improve network profitability in the long run.

Ancillary services

Smart energy management also employs a battery energy storage system to enable CPOs to bid on ancillary services in energy markets. During grid frequency imbalances, charge point management systems reduce consumption from the grid for EV charging and may then use renewables or a BESS to provide supplemental power back to the grid for balancing while generating additional revenue for the service. One U.S. utility reported that batteries provided an average of 8.6% of its balancing area’s energy during late afternoon and early evening hours in 2024—evidence of growing grid operator reliance on these programs.

In all, integrating a BESS into your smart energy management system offers a variety of benefits, including:

• Greater sustainability
• Decreased energy costs
• Increased energy resilience
• New revenue generation

Why use Driivz smart energy management with a BESS?

Driivz EV charging management software features industry-leading smart energy management capabilities that result in a win-win for site owners, network operators, drivers, and utilities. From energy shifting and automated time-of-use scheduling for better efficiency, to value stacking for increased profits, and advanced technology that bypasses weak cells to maximize energy storage throughput, Driivz is the smart energy management system of choice for battery energy storage systems on EV charging sites.