The electric grid is shaped by network effects: in general, as more resources and users come online, the grid becomes more valuable and more reliable. At the same time, network effects can amplify weaknesses, sometimes leading to widespread failures when disruptions ripple through the system. 

Electric vehicles (EVs) illustrate these dynamics well. EV ownership tends to spread quickly. When one person gets an EV, their neighbors often follow, creating geographic clusters where EVs are purchased and charged close together. Even at modest adoption levels, this concentrated charging can strain multiple levels of grid infrastructure, overloading neighborhood transformers and power lines in ways that bulk grid charging cannot easily address.

Managed charging strategies focused on peak load reduction like passive time-of-use rates and demand response have proven their effectiveness in shifting EV charging away from bulk system peaks. But this has resulted in secondary peaks that are likely to overload grid assets, particularly in neighborhoods with high EV adoption. 

Figure 1 – Both TOU charging optimization and demand response can create severe secondary peaks that increase load on already stressed distribution assets.

In response, managed charging strategies have evolved to focus on distribution-grid impacts, targeting the secondary peaks caused by clustered EV charging. The challenge is that the grid has multiple interconnected layers, similar to how a tree branch splits into smaller branches. When you focus on individual assets or single points in the network, you might miss preventing overloads throughout the grid’s complex topology.

That’s where multi-level distribution load optimization comes in. This technology coordinates EV charging to deliver the energy drivers need while conforming to capacity constraints throughout the distribution network, delivering grid-aware managed charging that protects every piece of equipment between the power plant and the garage.

What is multi-level distribution load optimization?

Distribution load optimization (DLO) acts like a traffic controller to coordinate and enforce EV charging limits at multiple levels of the distribution grid simultaneously. DLO intelligently protects substations, feeders, service transformers, and other distribution assets all at once to ensure EVs charge within the limits of existing grid infrastructure.

Here’s how it works: 

• The system creates a map, showing what equipment each vehicle is connected to, ensuring that all grid assets serving a vehicle are considered.
• Charging schedules are generated for each vehicle to stay within the capacity limits of each piece of equipment in the chain— from substations, feeders, feeder sections (i.e. capacitor banks, voltage regulators, reclosers), down to the service transformer on your street. 
• The optimization service runs 24/7, constantly adjusting charging schedules  across multi-level load limits to protect the entire chain of grid infrastructure.
• EVs charge within the limits of grid infrastructure, while ensuring every driver’s car is ready when they need it.
• In the event of an unexpected change, like someone plugging in or leaving early, or customers overriding their managed charging schedule, the system quickly generates new schedules to keep the system balanced.

Figure 2 – EVs are connected to multiple levels of the distribution grid – feeders, feeder sections, and service transformers.

Several of EnergyHub’s EV clients are using distribution load optimization to protect feeders and service transformers while still avoiding charging during system-wide peak periods. Ameren Illinois is actively deploying the technology across their service territory to protect neighborhood transformers as more customers buy EVs.

Achieve multiple goals with one platform

This charging coordination can be layered with cost saving optimizations like wholesale cost optimization (WCO) and customer rate optimization (CRO). The result is a single system that delivers multiple benefits: protects distribution assets, delays expensive grid upgrades, reduces wholesale power costs, and lowers electricity bills for EV drivers. It’s one coordinated system that manages the complexity of modern grid operations while delivering tangible benefits across the board. Our DLO platform enables dynamic grid management, addressing new challenges before they become expensive problems. 

Results 

Multi-level distribution load optimization is live at utilities and is delivering industry-leading results and measurable benefits. Leading deployments show:  

• 95% off-peak charging, among the highest rates achieved by any EV program.
• 50%+ reduction in load on grid assets during the top 1% of system peak hours, extending hardware lifespan and lowering infrastructure upgrade expenses.
• 100% of drivers who plug in with enough time reach their desired state of charge, proving that grid optimization doesn’t compromise driver experience.

Results confirm that multi-level distribution load optimization protects the grid while keeping drivers happy—essential for successfully scaling EV managed charging programs.

Figure 3 – EVs are optimized simultaneously to protect all distribution assets they are connected to.

The next phase of distribution load optimization

Today’s system  uses static charging limits, but future versions will dynamically adapt load limits in real-time based on grid conditions throughout the day. Multi-level distribution load optimization provides a foundation for electric vehicles to be managed in concert with other distributed energy resources, like batteries, smart thermostats and commercial buildings, optimizing them together for even greater value. It’s paving the way for truly intelligent grid-aware virtual power plants that protect every level of the grid while maximizing value to consumers.