COBB EMC - MANAGED EV CHARGING STRATEGY

EXECUTIVE SUMMARY

To prepare for the expected growth of EV adoption and related increase in kWh sales through our distribution system, Cobb EMC has established an EV Working Group. The EV Working Group has been working on developing an enterprise-level EV strategy which has resulted in the creation of several initiatives such as supporting EV home charger adoption, deploying a charger business model for commercial members, positioning Cobb EMC as the Trusted EV Advisor for our members, transitioning operational fleet to EVs, and ensuring grid infrastructure readiness to support future EV load growth while maintaining the reliability of the system and achieving its carbon reduction goals.

A managed EV Charging program can play a pivotal role in supporting these initiatives by mitigating the impact of EV charging on the grid infrastructure and deferring any costly infrastructure upgrades that might be necessary to deal with the increase in load demand due to the high penetration of EVs.  A managed EV charging program coupled with one of our time-of-use (TOU) rate plans, like the NiteFlex rate plan, benefits members by reducing their monthly energy usage and helping the cooperative manage its peak demand. Currently, on our system, we project that there are over 5,000 EVs on our system. This projection comes from self-reporting by members, registration data, and algorithms evaluating load patterns. According to the EPRI study, it is projected that by 2030, approximately 25,000 to 55,000 EVs will be operating in our service area based on their Medium and High EV forecast models, respectively. Even though this significant increase in the number of EVs and their corresponding load may not pose any imminent threat to the reliability of our distribution system, it is important that we take this opportunity to make our grid infrastructure ready, reduce our transmission capacity charges as well as manage any potential increase in power supply capacity needs and thereby improve the load factor and the reliability of the system.

This document provides an overview of managed EV charging, outlines its objectives, describes its current state, and presents a pilot program Cobb EMC plans to implement in 2024. By taking proactive measures now, Cobb EMC can ensure a smooth transition to increased EV adoption, optimize grid infrastructure, and continue delivering reliable and sustainable energy services to its members.

MANAGED CHARGING

The importance of managed charging becomes evident when considering key findings from the EPRI study. It reveals that approximately 81% of charging occurs at home using level 2 chargers, and EV charging is often a key component of peak loads.

So, what is the difference between managed charging and unmanaged charging? Unmanaged EV charging means the members can charge their EVs at any time of the day, which can potentially strain the distribution system when the EV adoption reaches a certain threshold. As a result, the cooperative could be negatively impacted in two ways. First, it may result in the overloading of circuits during peak hours, necessitating rapid capacity increases, especially in equipment like transformers. Second, it can increase transmission peak demand charges and power supply capacity needs.

In contrast, managed charging focuses on changing consumers' behavior by enabling them to shift EV charging from on-peak hours to off-peak hours. The objective of this program is to reduce the peak demand, which may otherwise be increased due to the increase in EV load. Therefore, instead of increasing the hosting capacity of the distribution grid by investing more in grid upgrades, shifting the load to times of day when the grid is underutilized can effectively provide additional capacity. The question then arises how do we facilitate this behavioral change, and how do we find out if our members are willing to charge their EVs during off-peak hours when the energy rates are low or the demand on the system is low? This is where the Pilot Managed EV Charging program comes into play. It aims to accomplish the following:  

• Discover how and when members charge their EVs.
• Understand the degree to which they can shift charging to off-peak periods of the day.
• Evaluate various EV managed charging vendors to learn different charge control platforms and communication technologies.
• Understand what incentives may be appropriate in addition to rates to encourage smart usage for EV charging.
• Assess the costs of implementing and managing a program.
• And finally, measuring member satisfaction with EV charge management.

We can collect this information and gain experience through piloting managed EV charging. We can use this information to develop robust future EVSE programs and rate structures to support EV adoption further.

The pilot program aims to influence members' charging behavior.  Members will be rewarded with incentives for voluntarily participating in the program. It is important to note that the pilot program does not involve direct control of members' EV charging. Instead, members can set up their charging schedule on their EV, app, or EVSE to define charging time.

THE CURRENT STATE OF MANAGED CHARGING

Currently, Cobb EMC does not have an operational EV Managed charging program in place other than its popular NiteFlex rate plan. The NiteFlex rate plan allows members to charge their EVs for free up to 400 kWh per month between 12:00 am and 6 am. This encourages members to shift their EV charging from on-peak to off-peak hours. This benefits members using the free energy available through the NiteFlex rate plan and the cooperative benefits by reducing the peak load.  Currently, Cobb EMC has 1,800 members enrolled in the NiteFlex rate. 

Similarly, the Smart Choice rate plan is another TOU rate plan that essentially works the same way, discouraging members from charging EVs during peak hours and helping them to reduce their monthly demand charges.

Cobb EMC has developed an in-house model that utilizes kWh usage data from the Meter Data Management (MDM) system to predict EV charging patterns. The engineering team is also working on identifying any overloading of service transformers. As a proactive measure, we are currently replacing 25 KVA transformers that are overloaded by 90-100%. Additionally, we are also performing a detailed analysis of the capacity of existing lines, equipment, station banks, and identifying locations where upgrades are necessary to accommodate projected EV load growth.

To further enhance our capabilities, we are actively exploring vendor solutions for effectively identifying EVs within our service area. This will enable us to have a comprehensive understanding of the EV landscape and have a comprehensive plan for future EV growth. 

OBJECTIVES

The objectives outlined below support Cobb EMC's overall EV Mission of leading the charge toward building a better EV ecosystem in the South:

1. Defer or avoid costly infrastructure upgrades that might be necessary to manage the increase in future EV load growth.   
2. Understand different technologies related to EV charging and available telematics solutions.
3. Explore non-wires alternatives (NWA) solutions to manage expected EV load growth.
4. Reduce transmission capacity cost by shifting charging from on-peak hours to off-peak hours.
5. Minimize impact on Southern Power's capacity requirements by avoiding the need for additional capacity purchases.
6. Prevent thermal overloading of the feeders during peak hours.
7. Promote the NiteFlex rate plan to encourage members to charge their EVs at nighttime.
8. Gain insights into members' charging behavior and opt-in and opt-out rates in the Managed EV Charging program.
9. Evaluate the effectiveness of various control strategies – direct or indirect load control, rate plan, peak notification, etc.
10. Develop a comprehensive and robust managed charging program based on the pilot program's results.

CONCLUSION

The rapid adoption of EVs presents both challenges and opportunities for Cobb EMC. By implementing an effectively managed EV charging program, the cooperative can mitigate potential negative impacts on the grid and leverage the benefits of shifting charging from on-peak to off-peak hours.

By utilizing the predictive models, undertaking necessary infrastructure upgrades, and seeking advanced technologies, Cobb EMC aims to stay ahead of the EV charging demand, ensure grid reliability, and provide exceptional service to our members.

Through this pilot project, the cooperative aims to learn: 1) the acceptance of the managed charging program for reducing the cooperative's peak demand, 2) the selection by members of a TOU rate versus other incentives for selecting when they charge, 3) what other strategies need to be developed to increase members' participation.   

Also, as Cobb EMC is expanding the deployment of distributed energy resources (DER) on its distribution system, it is important to seamlessly integrate these devices with utility operations at all levels for management and monitoring purposes. This integration is challenging as the OEM of each DER device is different, and there is no standard interface or communication information model available. Cobb EMC views Distributed Energy Resource Management System (DERMS) technology as a potential solution that can simplify the integration by consolidating the capabilities of various DER devices into manageable grid services. It will enable to optimize, schedule, and dispatch resources based on the market price signals, essentially creating a Virtual Power Plant (VPP). In addition, it can also streamline internal processes so that we can manage the life cycles of each DER resource and demand response program more efficiently and effectively.