Smart charge management (SCM) is a data-rich system that can monitor, control, coordinate and optimize federal fleet (and building) operations. Successful implementation of SCM requires coordination between various stakeholders, including:
- Fleet managers: Are responsible for electric vehicle (EV) scheduling and ensuring operational readiness.
- Facility infrastructure managers: Oversee the site's electrical infrastructure and energy usage.
- Facility energy managers: Provide insights on optimal charging times based on energy rates and grid conditions.
- IT/cybersecurity team: Obtain authorization for SCM cloud software to connect with the facility network, and continuously monitor and manage SCM software to govern risks.
- Local utility: Provide pricing signals for time of use (TOU) rate, request shifting loads depending on grid capacity, and request energy using vehicle to grid (V2G) technology in case of peak demand events.
These stakeholders work together to develop charging schedules that meet fleet needs while optimizing energy use and costs.
Data Requirements
To implement smart charge management, fleets can coordinate with the above-mentioned relevant stakeholders to gather the following data.
Vehicle and EV Charging Equipment Inventory
Data includes the number of existing and to-be-procured EVs (battery electric vehicle/plug-in hybrid electric vehicle and battery capacities), EV charging stations (Level 1, Level 2, or Level 3/DC fast charging), and vehicle operational times/schedule, including dwell periods if available. This can be obtained from the fleet team. Note that analyzing the existing telematics data will offer more accurate insights into the existing vehicle operations.
Utility Rate Structure
Data includes information about applicable pricing models such as TOU, any location-specific pricing, variable peak demand periods to optimize charging conditions while maintaining reduced cost, and vehicle readiness. This information may be acquired by communicating with the local utility or energy provider. Learn more about evaluating your utility rate options.
Building/Grid Data
Data includes building electrical loads (typically shared via smart meters) and, if applicable, projected energy use profiles along with on-site renewable generation profiles. If this is integrated with the local grid, then information on grid signals and their communication protocols will also be helpful. Moreover, the total capacity and the utilization of distribution service transformers is needed to understand the available capacity.
SCM Communication Protocols
Communication among smart charge management systems (EVs, EV charging stations, management systems, distributed energy resources [DERs], electric grid, and others) is crucial for SCM implementation. Open standards like Open Automated Demand Response (OpenADR) and Open Charge Point Protocol (OCPP) (owned by Open Charge Alliance) offer interoperability advantages across different EV charging station vendors, including remote control, monitoring, and future expansion without proprietary lock-in.
Applications for SCM Communication Protocols and Standards
A few of the commonly known protocols with their typical use cases are listed in the sections below and shown in Figure 1. Some of the key smart charging applications for these communication protocols include:
- Enabling communication among SCM systems.
- Enabling an aggregator to determine and implement optimized charging profiles based on the control objective.
- Enabling bi-directional EV charging stations for V2G services.
Aggregators: Third parties that coordinate and manage multiple EVs charging across various locations, optimize energy use, and provide grid services. They may act as intermediaries for fleets, charging infrastructure, and the electricity grid.
Control Objective: Defines the optimization target, such as minimizing capital cost, reducing operational cost, or maximizing vehicle readiness. It guides the decision-making process to find the best possible solution within the defined parameters.
Open Charge Point Protocol Applications
OCPP enables smart charging functionalities such as distributing power based on available capacity limits among various charging stations—either individually or for a group of chargers. OCPP also allows adaptive smart charging capabilities with input from energy management systems and enables charging schedules and profiles.
- Setting charge limits: In a fleet of five L2 chargers of 7 kW maximum power each, the total consumption can be 5x7 kW = 35 kW. However, in times when the available capacity is less than 45 kW (e.g., 30 kW), the SCM standard can set the charge limits to 30 kW/5 = 6 kW each.
- Prioritizing vehicles: It can also prioritize vehicles with a lower state of charge or shorter dwell period.
- Setting time and power ceiling limits: The control objective can limit the time and power ceiling at which the user can charge.
- Setting charging schedules: Facilitate EV charging needs based on departure times to ensure vehicle readiness.
ISO 15118 Standard Applications
The ISO 15118 Standard enables data input from EVs such as charging demand and V2G, in addition to plug and charge capabilities.
- Enabling data inputs: ISO 15118 facilitates vehicle charge profiles, allows EVs to be used as DERs, or enables EV V2G charging.
- Enabling plug and charge capabilities for user convenience: No credit card, RFID tag, QR codes, or mobile apps are needed to initiate the EV charging session. Simply plug in the charging cable and the EV sends its digital certificate. Once verified, charging begins automatically without any further driver’s action.
Open Automated Demand Response Applications
OpenADR facilitates automated demand response and enables participation in demand response (DR) programs with utilities, allowing utilities to request reduced power consumption in extreme events.
Figure 1. Potential communication pathways and protocols between EVs, EV charging stations, aggregators, buildings, distribution systems, and bulk power transmission systems. There may be several other possible pathways and configurations. Illustration adapted from the Lawrence Berkeley Laboratory report, Survey and gap prioritization of U.S. electric vehicle charge management deployments.
Bulk Transmission Systems: High-voltage power lines and associated equipment that move large amounts of electricity over long distances from generation sources to local distribution systems.
Distribution Systems: Lower-voltage power lines and equipment that deliver electricity from the transmission system to end-users, including homes, businesses, and EV charging stations.
Action Items/Implementation Pathway
By Step 10 of the ZEV Ready Center process, the number of charging stations, power level, and location needed to support fleet operations should be well defined. At this point in the process, the fleet may identify smart charge management solutions to reduce costs or increase the number of EV charging stations that can be installed in the project without surpassing the electrical capacity for the available electrical assets.
Figure 2. Implementation pathway for deploying SCM in an EV fleet. Illustration by Fred Zietz, NREL
Define the SCM Objective
Identify goals for SCM such as capital or operational cost reduction, emissions reduction, or working within limited grid and transmission capacity and extended installation timelines.
Coordinate With Utilities
Coordinate with local utilities or energy providers to understand any capacity constraints, and to ensure that the identified SCM goal can be achieved with their capabilities, such as relevant communication protocols.
Assess Flexibility of Fleet Charging
Understand fleet EV charging needs and the potential for charging flexibility to ensure that EVs will be able to meet their mission operations within the SCM solution. For this step it is important to understand vehicle operations, including when the vehicle needs to charge and the required state of charge after a charging session.
Identify EV Charging Stations/SCM Solutions
Identify EV charging stations and SCM procurement solutions that integrate with cloud platforms and support required capabilities and communication protocols based on the defined control objectives.
Implementing SCM Solutions
In the ZEV Active Phase of the ZEV Ready Center process, which covers the steps that fleets acquire, install, maintain EVs and EV charging stations, there are a few additional considerations for fleets implementing SCM solutions.
Commission the System
Verify that the SCM system is properly integrated with the charging stations, fleet management software, and any utility demand response programs. Ensure that it can receive inputs from fleet management systems such as vehicle schedule, route plans, and energy requirements. Test various charging scenarios and ensure the system responds as expected based on the defined SCM objective.
Communicate to Drivers
Provide training and guidance to drivers on how the SCM system works and what they can expect in terms of charging behavior.
Maintain the System
Monitor the performance of the SCM system and charging infrastructure to identify and address any issues promptly.