Peak/off-peak tariffs are electricity pricing structures where energy costs vary by time of day (and sometimes by weekday/season). Peak periods have higher prices during periods of high grid demand, while off-peak periods offer lower prices during periods of lower demand. Some tariffs also include a shoulder period between the peak and off-peak periods.
In EV charging, peak/off-peak tariffs can apply to:
– The site’s electricity supply contract (what the operator pays)
– The public or private EV charging tariff (what the driver or fleet pays)
– Both, when charging prices are designed to reflect time-based energy cost differences
Why Peak/Off-Peak Tariffs Matter in EV Charging
Peak/off-peak tariffs are a key tool for controlling costs and site constraints because they encourage charging when electricity is cheaper, and the grid is less stressed. They help:
– Lower operating costs for charge point operators (CPOs), site owners, and fleets
– Reduce peak demand and exposure to demand charges (tariff-dependent)
– Improve site reliability by avoiding overload during high-demand hours
– Support grid-friendly behavior by shifting charging to low-demand periods
– Increase the value of smart charging and scheduled charging strategies
How Peak/Off-Peak Tariffs Work
Peak/off-peak tariffs define time windows and assign different rates:
– Peak window: higher €/kWh (often weekday mornings/evenings)
– Off-peak window: lower €/kWh (often overnight)
– Shoulder window: mid-priced periods in between (if used)
Tariffs may also vary by:
– Weekdays vs weekends
– Seasonal schedules (winter vs summer)
– Separate components such as energy (€/kWh), fixed fees, and capacity-related charges
How They Are Used in EV Charging Pricing
Charging operators may reflect peak/off-peak energy costs in customer tariffs using:
– Time-of-day kWh-based pricing (different €/kWh by hour)
– Scheduled charging options that default to off-peak hours
– Dynamic load balancing rules to protect the site during peak periods
– Time-based fees (connection/parking) to manage bay occupancy when demand is high
– Fleet depot rules that prioritize vehicles based on departure time and target SoC
Common Use Cases
– Overnight charging at homes and residential car parks (maximize off-peak energy)
– Overnight fleet charging at depots (lowest-cost bulk energy delivery)
– Workplace charging (avoid morning building start-up peaks)
– Multi-tenant sites with limited capacity (shift charging away from evening peaks)
– Public destination charging with predictable demand windows (tariff-based demand shaping)
Benefits
– Lower energy costs and improved margin predictability for operators
– Reduced site peaks and fewer overload risks when paired with load management
– Encourages better charging behavior without reducing charger availability
– Supports renewable integration where off-peak aligns with higher renewable output (market-dependent)
– Improves business case for controlled charging and energy optimization
Limitations and Practical Considerations
– Users may prioritize convenience over lower off-peak prices without automation
– Misaligned time windows can fail to reduce billed peaks (utility demand interval rules vary)
– Tariff complexity can confuse users unless displayed clearly at the charger/app
– Time-based fees can feel unfair if charging power varies by vehicle
– Operators must ensure pricing complies with local transparency and consumer rules
Related Glossary Terms
Peak vs Off-Peak Pricing
Time-of-Use (TOU) Tariffs
Peak Demand
Demand Charges
Load Shifting
Peak Shaving
Load Management
Scheduled Charging
Smart Charging
Maximum Site Demand Limit