Battery storage is the use of batteries to store electrical energy and release it later when needed. In EV charging infrastructure, battery storage is typically deployed as a Battery Energy Storage System (BESS) to increase effective site capacity, reduce operating costs, improve reliability, and support smart energy strategies such as peak shaving, load shifting, and power boosting.
What Is Battery Storage?
Battery storage captures electricity at one time and makes it available at another. A battery storage solution usually includes:
– Battery modules (energy storage)
– Battery Management System (BMS) for safety and control
– Inverter/PCS to manage charging and discharging power
– Protection devices, switchgear, and isolation equipment
– Monitoring and control software, often an Energy Management System (EMS)
Battery storage is described by:
– Energy capacity (kWh/MWh)
– Power rating (kW/MW)
– Duration (how long it can discharge at a given power)
Why Battery Storage Matters in EV Charging
EV charging can create large, short-duration peaks that exceed a site’s available import capacity or trigger high demand charges. Battery storage helps by:
– Enabling more chargers on a limited grid connection
– Reducing peak demand and electricity cost exposure
– Stabilizing site load and improving operational reliability
– Increasing self-consumption of on-site renewables (solar PV)
– Reducing the need for immediate grid upgrades
– Supporting limited backup power operation in resilience-focused sites
For fleet depots and public charging hubs, battery storage can improve utilization and speed up site deployment.
How Battery Storage Works at an EV Charging Site
A battery storage system is controlled to balance site import, on-site generation, and charging demand:
– The battery charges during low-demand periods or low-tariff windows
– The battery discharges when EV charging demand rises
– The EMS caps grid import to a defined threshold and uses the battery to cover spikes
– Chargers may coordinate with load management to respect site limits
Common operating modes include:
– Peak shaving to limit maximum demand
– Load shifting to move energy use to cheaper time windows
– Power boosting to temporarily increase charging output
– Renewable shifting to store solar energy for later charging
– Load smoothing to reduce rapid demand swings
Typical Use Cases
– Workplace sites adding chargers without upgrading the grid connection
– Retail locations reducing demand peaks during busy hours
– Fleet depots managing overnight charging schedules and demand limits
– Public charging hubs where multiple sessions overlap
– Sites with solar PV aiming to reduce energy costs and CO₂ footprint
Key Benefits of Battery Storage
– Higher effective charging capacity on constrained connections
– Lower energy bills through demand and tariff optimization
– Faster deployment by reducing dependency on utility upgrades
– Improved uptime through stabilized site power
– Better sustainability performance when paired with renewables
– Optional resilience capability for critical loads
Limitations to Consider
– Higher upfront cost and added system complexity
– Battery degradation reduces performance over time
– Correct sizing is essential to achieve meaningful savings
– Safety, permitting, and fire protection requirements can add lead time and cost
– Round-trip efficiency losses reduce net energy returned
– Not a permanent substitute for grid upgrades if sustained high power is required continuously
Related Glossary Terms
Battery Energy Storage System (BESS)
Battery Buffer Storage
Energy Management System (EMS)
Battery Management System (BMS)
Available Import Capacity
Peak Shaving
Battery Load Shifting
Power Boosting
Smart Charging
Microgrid