Co Authors:Â Jay Robertson, Manager, Energy & Utilities & Carolyn Weiner, Senior Manager, Energy & Utilities
While the rapid proliferation of electric vehicles (EVs) is revolutionizing the transportation sector, it is also beginning to present significant challenges for electric distribution utilities. As the number of EVs on the road increases, the demand for charging infrastructure and potential localized strain on the distribution grid become more pronounced. Left unchecked, new EV load could easily double or quadruple the load on transformers, wreaking havoc and causing strain on upstream transmission lines and substations. To navigate this challenge utilities need more robust and integrated and collaborative planning. By integrating EV forecasts with traditional forecasting, enhancing hosting capacity tools, and collaborating with internal and external stakeholders, utilities can proactively identify needed grid upgrades, seek regulatory assurances of investment recovery and continue to ensure delivery of safe and reliable power supply.
The Need for More Integrated and Collaborative Planning to Enable Higher EV Adoption
Traditionally, utilities have been reactionary to new loads, whether from a new apartment building, data center, or EV charging stations – as they have the obligation to serve and, in most instances, are the provider of last resort.
However, treating EVs in the same way by only responding to individual applications for infrastructure upgrades and electric rate changes is not sustainable. Residential customers aren’t accustomed to telling their utility when they purchase a new appliance, whether it be a new air conditioning unit or an electric vehicle, and many utilities aren’t equipped to do anything with that information. This information gap can pose a threat, potentially overloading the grid in high-adoption residential zip codes. It can also result in a poor customer experience for commercial customers aiming to electrify vehicle fleets. While businesses are more accustomed to communicating with their utility when they expand their facilities, they aren’t accustomed to having to wait up to two years to purchase a new vehicle due to utility delays in conducting feasibility studies and/or planning for powerline upgrades. Some utilities are looking at how their new service processes can be made more efficient and look to best-in-class utilities in this space, like Southern California Edison (SCE)[1]. Southern California Edison took the lead to publish a detailed process flow for EV charging construction projects, which several utilities have now followed a similar practice. Also, SCE along with other California utilities have organized dedicated engineering planning teams to collaborate with vendor and/or customers’ engineers along the process from design and construction.
To address challenges and delays in interconnection, improved and more integrated planning is necessary to enable utilities to better anticipate EV growth.  This would require the level of internal and external collaboration to increase substantially. Utilities need the ability to invest in system upgrades before receiving new load applications in residential and commercial areas where EV load growth is forecasted to be the greatest. In addition, by taking advantage of non-wire-alternatives where feasible, including managing EV charging schedules, and potentially using  EV batteries as grid resources, utilities can eliminate or postpone otherwise required long lead-time system upgrades. This shift in mindset can transform the grid into a plug-and-play infrastructure already equipped to support EVs.
External Stakeholder Outreach and Coordination
Utilities are more frequently engaging with regulators, city planners, EV manufacturers, EV charging companies, transportation departments, and fleet operators to share knowledge and collaborate on forecasts. Much like working with internal regulatory and rate analysis groups, working with regulators and transportation departments can shape laws and incentives around using EVs as a resource and that could impact EV forecasts. Furthermore, by using expected city growth, socio-economic forecasts, plans for EV sales and charger installation growth, and plans for fleet conversion to electric, utilities can accurately predict and plan for future EV growth. External coordination and conversations educate all stakeholders on viewing EVs as not only a threat to the existing grid infrastructure, but also an opportunity, emphasizing their potential as a mobile resource to mitigate or postpone grid upgrades.
Stakeholder coordination and outreach is key to improving planning and forecasting in anticipation of EV growth. As part of stakeholder education and outreach, progressive utilities are hosting workshops and forums to discuss emerging trends and upcoming work related to EVs. Open sharing of data should be encouraged so that all stakeholders are aware of ongoing developments.
Collaborating Internally to Improve Planning and Forecasting
Enabling collaboration across multiple utility departments can pay dividends in improving planning and forecasting. Today, utilities facing significant growth in EVs have taken action to include diverse groups, such as regulatory, rate-making, planning, engineering, and operations, in workshops and discussions to surface unconsidered perspectives and enable the utility to operate cohesively. For example, rates teams can change rates that incentivize customers to allow utilities to use EVs as a resource, which can feed into planning and engineering teams’ cost-effective infrastructure forecast scenarios and non-wire alternative opportunities related to EVs. Operations can use the new EV rates and non-wire alternatives to improve grid operations with additional batteries online while Customer teams can coordinate externally with impacted customers and vendors on upgrade requirements and advise customers in their efforts to ‘future proof’ their investments[2]. In times with heavy demand on the grid, these additional batteries could serve as a resource instead of a load that can help to prevent brownouts.
By collaborating internally on forecasting EV growth, utilities can identify where load is expected to grow, estimate the magnitude of the load, and establish timelines for expected growth. This collaborative effort ensures that all parties involved have a comprehensive understanding of the challenges and opportunities associated with EV integration.
Leveraging Hosting Capacity Analysis to Consider EVs as Both Load and Resource
Combining external outreach and internal collaboration with hosting capacity analysis can provide utilities with a valuable tool to consider EVs as both a load and a resource. Hosting capacity maps are often thought of as a tool for DERs. The California IOUs are using them to identify locations across every node of their distribution feeders that DERs can potentially be interconnected with minimal added costs or technical issues. This hosting capacity analysis treats DERs as a generation source inserted at every node of the distribution system under different circuit load conditions to determine the max DER potential at every node.[3] Similarly, this analysis can be performed on loads such as EV charging. Much like how potential DERs are modeled as generation sources at every node on every distribution feeder, EV charging load can be modeled at every node on every distribution feeder to determine the max load that can be installed at every node on every distribution feeder. The max EV charging load at every node on every feeder can be combined with EV forecasts to identify the required system upgrades to support the forecasted EV load growth and mitigate potential thermal, voltage, back feed, and protection issues. Proactively identifying and addressing potential grid constraints can allow for the grid to support increased EV loads as they come online instead of causing delays for the grid to be updated.
This same analysis can be used for EVs by modeling them as both a load and generation source. While this may add additional scenarios and computational needs, this analysis can reveal opportunities to leverage EVs as an energy source and defer potential grid upgrades through a non-wire alternative. These opportunities can be used to develop customer programs that incentivize vehicle-to-grid (V2G) use cases and incentivize customers to provide their EVs as resources at times of need. For example, hosting capacity analysis of EV load can show that forecasted EV growth will require conductor upgrades due to circuit overloads in the early evening hours. This may restrict the size of the forecasted EV charging load and may prohibit EV growth in the area or will require proactive grid updates to support the forecasted EV growth. However, if EVs are modeled as a load during most of the day and as a resource in the early evening, the max allowable EV charging load can be much higher outside the early evening hours with the EVs providing another source of energy during the early evening hours. This allows a larger EV charging load to be installed without any grid upgrades and with limitations only during the early evening. To promote the behavior of having EVs charge during the day and be available as a resource in the early evening, V2G programs and rates can be structured to incentivize people to charge during the day and allow for discharging when the grid needs additional power.
V2G programs not only allow for larger EV chargers but also for operational flexibility. EVs can be treated as a resource in hosting capacity analysis and in grid operations. This allows operators to pull energy from EV batteries during peak loading periods, which can prevent brownouts and other, more expensive programs from being called. By leveraging hosting capacity results, utilities can proactively identify required grid upgrades to support EV growth, shape rate and V2G programs to use EVs as a resource, and allow for operational flexibility by pulling energy from batteries in times of need.
Conclusion
Integrated, collaborative planning is an important tool for utilities, communities, and EV owners to effectively navigate the challenges and opportunities presented by the growing adoption of EVs. By engaging internal and external stakeholders, informing them about the potential of EVs as resources, and leveraging hosting capacity analysis, leading utilities have actively identified necessary grid upgrades, built infrastructure, and created rate plans that enable the near-seamless integration of EVs into the grid. By embracing this approach, leading utilities have positioned themselves at the forefront of the EV revolution, driving sustainability, reliability, and efficiency in the transportation and energy sectors.
Portions of this article were generated using generative AI tools.