Crawl, walk, run; A scalable approach for utilities to manage residential EV-charging demand

Utilities across the U.S. are seeking to get ahead of the electric vehicle (EV) growth curve. By 2030, the number of EVs on the road is estimated to be more than 20 million in the U.S. alone. While this exponential growth represents a significant amount of energy sales plus a decarbonization opportunity for utilities, it will also exacerbate the load balancing and management challenges that utilities already face today with the proliferation of renewables. However, as more customers install residential charging solutions that have the ability to capture charging behaviour and provide load management capabilities, the risks to the grid can be mitigated over time.

Electric utilities are using the opportunity to promote the adoption of EVs to deepen customer relationships by serving as trusted advisors. They are incentivizing adoption of EVs and EV charging solutions through rebates and special rates, educating their customers, and enabling the deployment of charging stations across their network.

Simultaneously, the same utilities are implementing EV management programs to mitigate the potential risks to the grid. Data from Chargepoint shows a spike in charging sessions beginning at 4pm, with peak charging time occurring between 6pm and 8pm. After 11pm, charging declines, with 2-5am the least common time of day to charge. All told, vehicles are plugged in 10 hours on average, while a full-charge requires two hours – creating a great deal of flexibility in charging load.  

Over 50 utilities across the U.S. have already adopted special Time-of-Use (TOU) rates that incentivize off-peak charging. Pioneering utilities are going a step further and launching programs that provide utility operators with direct control of customer-owned EV charging solutions in exchange for financial incentives to participate. These initiatives not only incentivize the adoption of EVs but also lay the foundation for mitigating the risks they pose to grid infrastructure and operations, ensuring the safe and reliable operation of a robust grid that supports an EV future.

Crawl, walk, run

Utilities are adopting a phased “crawl, walk, run” approach in the development of new managed charging solutions. Given the dynamic nature of the challenges and constraints that underpin the EV-utility relationship, utilities require solutions that create flexibility for the grid while enabling customer choice.

“- Crawl phase is to enable EV-specific time-of-use (TOU) rates
“- Walk phase is active event-based peak management
“- Run phase is holistic managed charging, that is, optimizing charging in an automated fashion, taking into account real-time grid and market constraints

Underlying all three phases is a robust data monitoring engine that gathers and analyzes EV charging data in real-time from all connected brands of EVs and smart EV charging solutions. This requires the system to have the ability to integrate with multiple EVs and EV charging cloud services platforms through open protocols or custom integrations. The data monitoring engine helps inform strategy and design of utility initiatives.

1. Crawl: TOU Rate Enablement

In order to prevent system coincident peaks resulting from clustered EV charging sessions, many utilities in the U.S. have implemented EV-specific rate structures designed to incentivize customers via rebates to move charging away from peak times. To operationalize TOU programs, utilities implement DERMS platforms that can not only gather EV charging data and track related incentives, but also market the rates to customers.

To ready itself for the adoption of 300,000 EVs, Baltimore Gas and Electric (BGE) deployed EnergyHub’s Mercury DERMS to lay the foundation for an EV-TOU rate. BGE is gathering and analyzing charging data to inform a TOU program that incentivizes off-peak charging by granting customers access to a preferred rate during certain portions of the day. This charging data is provided at a 15-minute granularity from customers’ Level 2 charging equipment (from Chargepoint and Enel X), aggregated by EnergyHub’s Mercury DERMS.

TOU programs can help inform customer engagement strategies for future scenarios, including the propensity of customers to participate. However, while TOU and critical peak pricing can be an effective first step to broadly shaping load, the coarse price signals they send are insufficient to prevent coincident charging and the distribution-level problems it creates. The next phase – peak load management – can more directly affect the charging patterns of EVs.

2. Walk: Peak Load Management

Data shows that TOU customers (or their smart charging solution) wait until the start of the off-peak period to begin charging. To manage this, utilities will need to take a more active control-based approach to peak management.

This phase entails customers providing utilities limited access to modulate the rate of charge in exchange for a financial incentive. This can take the form of a bill rebate or discount on charging equipment. Once the utility has access to EV chargers through a DERMS platform, it can schedule point in time events for peak reduction and load shifting by curtailing and intelligently staggering the charging of EV cohorts while ensuring customers get the charge they need.

In 2019, Eversource launched an innovative new EV management program gaining access to customer charging data and the ability to control residential charging at peak times. Eversource is further analyzing charging data to inform advanced load control strategies for future program years, such as managed overnight charging.

3. Run: Dynamic Load Shifting

Autonomous managed charging is a state of EV charging management that dynamically takes into account grid and market conditions and optimizes charging patterns multiple times a day in concert with other DERs stacking value for the utility. This could help meet utility needs such as congestion management, renewable firming, and voltage management.

In addition, the DERMS can also call upon inverter-based DERs to inject reactive power and tap into the operational flexibility of EVs for voltage management. 

Further, utilities bidding capacity in a wholesale market can use forward and real-time prices to arbitrage supply costs for EVs. This directly achieves the utility’s load and cost objectives, while respecting customer charging constraints.

Critical to the seamless execution of this phase is the integration of the DERMS with other utility systems that manage the physical infrastructure of the grid like the ADMS or EMS. Integration allows the DERMS to manage EVs in concert with other DERs and distribution assets to fulfill utility objectives.

Next steps

As utilities explore the crawl, walk, run approaches to manage charging, they should look to a solution that can scale and advance at their pace, such as the Mercury DERMS platform, which we built to support the dynamic and iterative nature of all EV programs. It enables customer choice, manages multiple brands and classes of DERs at scale, and integrates with complementary utility systems to unlock value across the utility value chain.

If utilities plan ahead and deploy a DERMS, they can benefit from the many opportunities provided by the growth of EVs and evolution of driver behavior. This will pave the way for them to achieve their strategic goals, extract operational grid value, and ultimately deepen relationships with their customers.

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The Clarion Energy Content Team is made up of editors from various publications, including POWERGRID International, Power Engineering, Renewable Energy World, Hydro Review, Smart Energy International, and Power Engineering International. Contact the content lead for this publication at Jennifer.Runyon@ClarionEvents.com.

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