Chapter 7. Metrics for Tracking Charger Deployment

This chapter provides context, metrics, and strategies for monitoring EVSE as airports begin to deploy new charging infrastructure. It is important to track not only the number and level of chargers available, but also the performance of charging infrastructure across a variety of measures using data from EVSE, EVSPs, and utilities over time. Effective monitoring of EVSE will significantly improve airports’ ability to make informed decisions about future charging infrastructure deployment.

What data should be tracked to monitor the performance of chargers?

Managing charging infrastructure performance saves money and improves user satisfaction. As detailed in Chapter 2, networked chargers typically come with an online portal allowing airports to monitor key metrics. There are several common metrics for tracking EV chargers:⁷⁵

• Energy usage: Daily, monthly, or annual energy use is important to track to monitor growth in charging demand or unexpected energy losses (due to malfunction). For a networked charger, the EVSE owner/operator should compare energy use from the charger with that from the electric meter (assuming the charger has its own meter).
• Charger utilization: Utilization does not have a standard industry definition but is typically the fraction of time an EVSE port is actively charging an EV out of a 24-hour period. In general, utilization of 20% or more is a high utilization.
• Idle time: Vehicle idling is when a vehicle is plugged in but not actively charging. This metric helps inform pricing (if there is a payment system and user fee) and load flexibility (i.e., can the charging be done at a time when electricity is cheaper).
• Revenue: The revenue of a charging station refers to the total income generated by the station. There are several possible revenue streams for charging stations, but it is important to keep track of the overall revenue generated by chargers and the entire charging station to make decisions about future charging infrastructure.
• EVSE uptime: The uptime of a charging station or an individual charger refers to the availability of charging services in a calendar year. Uptime is a critical metric for assessing the reliability of charging infrastructure. The Federal Highway Administration targets an uptime of 97%.

What are the sources of data that can be used to track performance?

Airports can leverage data from EVSPs and utilities to track performance of charging infrastructure. Each is described briefly below.

• EVSP Data. To monitor, control, and visualize charging station data in a central location, management software can provide airports with the ability to view metrics like utilization, revenue, uptime, and energy usage. Management software helps users assess the performance of EV chargers and can provide additional services like payment integration and load management. The management software available to airports will depend on the EVSE provider, whether EV chargers are part of a network of chargers, and whether the EVSE conforms with

• OCPP. Typically, there is some operational cost to use charge management software, and the specific fee structure will depend on the agreement between the airport and the EVSP.
• Utility Data. The final source of charging station data is the local utility, which should provide monthly billing data including energy usage, peak load, and fees paid. If installed EVSE is networked, utility billing data can provide airports with the ability to double-check the performance of charging infrastructure. Comparing energy usage and peak load between utility bills and EVSE management software provides the opportunity to identify faulty equipment or inefficient performance. If installed EVSE is non-networked, utility billing data can provide a way to track important EV charging data in lieu of the more advanced metrics provided by charge management software.

Evaluating EVSE performance with utility data can present a challenge. Unlike charge management software, utility billing data will not provide vehicle- or time-specific data, which limits an airport’s ability to make informed decisions about when to charge vehicles. This challenge is even more significant if EVSE is not installed on a dedicated meter. Without a dedicated meter, it is very difficult to accurately attribute electricity usage and peak load increase to EVSE.