Charging utilization rate measures how much a charging station is actively used over a defined period. It shows the share of time a charger (or connector) is delivering energy compared to the total time it is available. Utilization is one of the most important KPIs for CPOs (charge point operators) and site hosts because it directly impacts revenue, charging ROI, and network expansion decisions.
What is the Charging Utilization Rate?
Charging utilization rate is typically expressed as a percentage:
– Utilization (%) = active charging time ÷ total available time × 100
Depending on how a network defines it, utilization may be calculated at:
– Connector level (most accurate for multi-connector stations)
– Charger level (can hide connector-level imbalances)
– Site level (useful for capacity planning)
Utilization is different from “occupancy” because a bay can be occupied without charging (idle blocking), which does not increase delivered energy.
Why Charging Utilization Rate Matters
Utilization determines whether a charger is underused, optimally used, or constrained by demand. It drives:
– Charging revenue benchmarks and expected income
– Profitability and CAPEX recovery
– Decisions on adding more connectors or increasing power capacity
– Grid and load management strategy
– Operational priorities for uptime and user experience improvements
High utilization is good—up to the point where queues and poor availability start to harm customer experience.
Key Ways Utilization Is Measured
Networks use several utilization-related metrics, each useful in different contexts:
Time-Based Utilization
Tracks the percentage of time the connector is actively delivering energy.
– Best for understanding real demand and capacity needs
– Sensitive to charger power level and typical session duration
Energy-Based Utilization (Throughput)
Tracks energy delivered per period, such as:
– kWh per connector per day
– kWh per site per month
This is useful for revenue forecasting and electricity procurement planning.
Session-Based Utilization
Tracks the number of sessions per period:
– Sessions per connector per day
– Sessions per site per week
This is useful for understanding traffic and driver behavior patterns.
What Drives Utilization Rate
Utilization is a function of both demand and operational performance:
Demand and Location Factors
– Site type (workplace, retail, hotel, municipal, highway)
– EV density and traffic flow near the site
– Parking convenience and dwell time
– Pricing competitiveness and payment simplicity
– Visibility in apps and maps, including charging roaming
Operational and Technical Factors
– Uptime and fault frequency
– Start success rate (authorization and payment reliability)
– Power constraints from load balancing or grid limits
– Connector mix (Type 2, tethered vs socketed) and user preference
– Site layout (easy access, signage, bay marking)
Utilization vs Occupancy vs Dwell Time
These terms are often confused:
– Utilization: time actively charging (energy flowing)
– Occupancy: time the bay is physically blocked (charging or not)
– Dwell time: total time a vehicle remains connected/parked
A site can have high occupancy but low utilization if users leave vehicles connected after charging completes.
What “Good” Utilization Looks Like
A “good” utilization rate depends heavily on charger type and site purpose:
– Destination and workplace AC charging often targets steady moderate utilization over long dwell times
– High-turnover public sites aim for higher utilization but must manage queues and bay blocking
Rather than one universal target, many operators benchmark utilization by site archetype and compare against similar locations.
How to Improve Charging Utilization Rate
Common levers to increase utilization include:
– Improve discoverability (maps, signage, roaming presence)
– Reduce friction (simple payment, reliable RFID/app access)
– Maintain high uptime with proactive monitoring and fast service
– Optimize pricing and consider demand-based pricing
– Prevent bay blocking using idle fees or parking integration
– Right-size the site (add connectors where demand is already strong)
Common Pitfalls When Using Utilization as a KPI
– Measuring utilization at charger level instead of connector level
– Ignoring uptime (a charger can’t be utilized if it is offline)
– Comparing AC and DC utilization without normalizing for session length and power
– Focusing on utilization without monitoring customer experience (queues, failed starts)
– Confusing occupancy with utilization, leading to incorrect expansion decisions
Related Glossary Terms
Charger Utilization
Charger Utilization Rate
Charging Session Analytics
Charging Dwell Time
Charging Revenue Benchmarks
Charging Revenue Models
Charging ROI
Uptime
Load Balancing
Charging Roaming