Time-of-Use Rate Electrical Planning for EV Charging in Virginia

Time-of-use (TOU) rate structures charge electricity customers at different prices depending on the hour of day and season, creating direct financial consequences for when an EV charging session begins and ends. Virginia's two largest investor-owned utilities — Dominion Energy Virginia and Appalachian Power — both offer TOU-based rate options that apply to residential and commercial accounts. Understanding how these rate windows interact with EV charging load shapes is essential for minimizing operating costs and avoiding inadvertent demand charge exposure. This page covers the definition of TOU rate mechanics, the electrical planning decisions those rates drive, common installation scenarios, and the boundaries where TOU planning intersects with permitting and code compliance under Virginia law.

Definition and scope

A time-of-use rate is a utility tariff structure in which the per-kilowatt-hour (kWh) price varies across defined time blocks — typically an on-peak window, an off-peak window, and sometimes a mid-peak or shoulder window. The underlying logic is load management: by pricing peak-demand hours higher, utilities create a price signal that encourages customers to shift discretionary loads, such as EV charging, to hours when grid capacity is less constrained.

In Virginia, utility rate schedules are filed with and approved by the Virginia State Corporation Commission (SCC), the state agency that regulates investor-owned electric utilities under Title 56 of the Code of Virginia. Rate schedule filings are public documents accessible through the SCC's eDocket system. Dominion Energy Virginia's residential TOU options — including Schedule TOU-D and EV-specific pilots — and Appalachian Power's comparable offerings each carry specific on-peak windows, demand charge provisions, and enrollment eligibility criteria that govern how electrical systems should be sized and controlled. For a broader look at how Virginia's utility regulatory framework shapes EV infrastructure decisions, see Regulatory Context for Virginia Electrical Systems.

TOU planning does not eliminate the need for code-compliant dedicated circuits, proper breaker sizing, or permitted installations. The financial layer sits above — not instead of — the physical electrical infrastructure layer.

Scope and coverage limitations: This page addresses TOU rate planning as it applies to EV charging installations within Virginia, under jurisdiction of the Virginia SCC and Virginia-licensed electrical contractors following the Virginia Uniform Statewide Building Code (USBC). It does not cover federal rate regulation, interstate utility operations outside Virginia, commercial demand-response programs administered at the federal level by the Federal Energy Regulatory Commission (FERC), or any utility territory in an adjacent state. Installations in Washington, D.C., Maryland, West Virginia, Tennessee, North Carolina, or Kentucky — even if served by utilities with Virginia operations — fall outside this scope.

How it works

TOU rate planning for EV charging involves three discrete layers that interact with each other:

Rate window identification — Determine the exact on-peak and off-peak hours defined in the applicable utility rate schedule. Dominion Energy Virginia's residential TOU schedules have historically defined on-peak as weekday afternoon and early evening hours; exact windows are set in the current approved tariff on file with the SCC and are subject to change through rate case proceedings.
Load shape analysis — Quantify the daily EV charging load in kWh and the draw rate in kilowatts (kW). A Level 2 EVSE operating at 7.2 kW on a 40-amp, 240-volt dedicated circuit will consume approximately 7.2 kWh for each hour of active charging. Matching that draw profile against the rate window determines the cost differential between on-peak and off-peak charging sessions. Electrical load calculations for EV charging in Virginia provides the calculation methodology in detail.
Control mechanism selection — Select the scheduling or smart-charging technology that enforces off-peak charging. Options include EVSE-native scheduling (timer-based), networked EVSE with utility-integrated demand response, or home energy management systems. Smart EVSE integration is covered in depth at Smart EV Charger Electrical Integration in Virginia.

From a physical electrical standpoint, TOU-aware installations do not differ from standard dedicated-circuit installations in terms of NEC compliance requirements. Virginia has adopted the National Electrical Code (NEC) through the USBC, and Virginia NEC Code Compliance for EV Charging addresses the applicable articles. GFCI protection requirements at GFCI Protection for EV Charger Circuits in Virginia apply regardless of rate structure.

Common scenarios

Residential single-family with overnight off-peak window
The most common Virginia residential scenario involves a homeowner enrolling in a TOU schedule and programming a Level 2 EVSE to begin charging after the on-peak window closes — often at 9:00 p.m. or 11:00 p.m. depending on the applicable tariff. The panel upgrade considerations for this scenario are addressed at Residential EV Charger Panel Upgrades in Virginia. No additional permitting is required beyond the standard EVSE installation permit; TOU enrollment is a utility billing action separate from the building permit process.

Multifamily property with shared infrastructure
Multifamily properties face a more complex version of TOU planning because simultaneous charging by multiple residents can create aggregate peak demand that triggers demand charges even during nominal off-peak hours. Managed charging systems that stagger session start times are the primary mitigation. Multifamily EV Charging Electrical Infrastructure in Virginia addresses the subpanel and load management infrastructure required.

Commercial workplace installation
Commercial accounts on TOU schedules with demand charge components face a different cost structure than residential accounts. A workplace with 10 Level 2 chargers each drawing 7.2 kW represents a potential 72 kW instantaneous demand spike if all sessions start simultaneously. Demand charge mitigation through power management software is critical in this scenario. See Workplace EV Charging Electrical Design in Virginia for the design framework.

Solar-plus-EV charging integration
When a PV system is present, TOU planning can align self-generated solar production (typically peaking midday) with daytime charging to reduce grid draw during on-peak windows. The electrical interconnection requirements for this configuration are detailed at Solar Plus EV Charging Electrical Systems in Virginia.

Decision boundaries

TOU rate planning intersects with physical electrical decisions at four specific boundaries:

Panel capacity and TOU schedule eligibility — Some utility TOU schedules require a minimum service capacity or a smart meter (Advanced Metering Infrastructure, AMI) as a prerequisite for enrollment. A panel that cannot accommodate a 240-volt, dedicated EVSE circuit may need upgrading before TOU enrollment is practical. Electrical Service Entrance for EV Charging in Virginia addresses service entrance sizing constraints.
Circuit breaker sizing and continuous load rules — NEC Article 625 treats EVSE as a continuous load, requiring the branch circuit to be sized at 125% of the EVSE's rated amperage. A 48-amp EVSE requires a 60-amp breaker on a dedicated circuit. This physical constraint sets the upper bound on charging speed regardless of rate schedule. EV Charger Circuit Breaker Sizing in Virginia covers the calculation in detail.
Permitting and inspection obligations — TOU enrollment does not alter permitting requirements. Any new EVSE circuit installation in Virginia requires a building permit and electrical inspection under the USBC. The permitting process is outlined at Permitting and Inspection Concepts for Virginia Electrical Systems. Inspectors verify NEC compliance of the physical installation; utility rate enrollment is outside the inspector's scope.
Comparison: TOU-only vs. TOU-plus-demand-charge schedules — Residential TOU schedules in Virginia typically charge only on a per-kWh basis with no separate demand charge component. Commercial TOU schedules frequently include both a per-kWh energy charge and a per-kW demand charge billed on the highest 15-minute or 30-minute interval during the billing period. This distinction is critical: a residential customer optimizes by shifting session start times; a commercial customer must additionally limit the simultaneous draw rate. The Virginia EV Charging Incentives and Electrical Upgrades page covers financial programs that may offset upgrade costs associated with either scenario.

For a foundational orientation to Virginia's electrical systems as they relate to EV infrastructure, the Virginia Electrical Systems Conceptual Overview provides the structural context within which TOU planning operates. The full resource index is available at the Virginia EV Charger Authority home.

References

📜 2 regulatory citations referenced · ✅ Citations verified Feb 25, 2026 · View update log

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