Time-of-Use Rate Programs for EV Charging in Indiana

Time-of-use (TOU) rate programs restructure electricity pricing so that the cost per kilowatt-hour varies depending on when consumption occurs, creating financial incentives to shift EV charging away from high-demand periods. Indiana's major investor-owned utilities offer distinct TOU and off-peak tariff structures that interact directly with EV charging load management decisions. Understanding how these programs are structured, which utilities offer them, and how they interface with home electrical infrastructure is essential for residential and commercial EV operators in the state. This page covers the definition and scope of TOU programs in Indiana, their operational mechanics, common deployment scenarios, and the boundaries that determine whether a given installation qualifies or benefits.

Definition and scope

A time-of-use rate program is a utility tariff structure under which the retail price of electricity is assigned to discrete time blocks — typically defined as on-peak, mid-peak, and off-peak windows — rather than charged at a single flat rate regardless of hour. Under Indiana utility tariffs filed with and approved by the Indiana Utility Regulatory Commission (IURC), these time blocks are established by each investor-owned utility through its general rate cases and tariff riders.

Indiana's primary investor-owned utilities — Duke Energy Indiana, Indiana Michigan Power (an AEP subsidiary), and Indianapolis Power & Light (AES Indiana) — each maintain tariff schedules that include EV-specific or general TOU options. Duke Energy Indiana's Schedule TOU-EV, for example, has historically separated on-peak windows (typically 2 p.m. to 9 p.m. on weekdays) from super off-peak windows (typically midnight to 6 a.m.) with price differentials that can exceed 3:1 between the most and least expensive periods, depending on the applicable tariff revision. Actual rates are subject to IURC-approved tariff filings and change with each rate case.

Scope of this page: Coverage is limited to Indiana-jurisdictional retail electric rates governed by IURC tariffs for residential and small commercial EV charging. Federal wholesale market rules administered by the Federal Energy Regulatory Commission (FERC) fall outside this scope. Municipal utilities and rural electric cooperatives operating under separate regulatory frameworks — such as Tipmont REMC or NIPSCO (a gas and electric combination utility regulated separately) — may offer TOU structures that differ materially from investor-owned utility schedules; those programs are not comprehensively covered here.

For a broader grounding in how Indiana's electrical regulatory environment governs EV infrastructure, see the Regulatory Context for Indiana Electrical Systems.

How it works

TOU programs for EV charging operate through four sequential mechanisms:

  1. Interval metering installation. A smart or advanced metering infrastructure (AMI) meter capable of recording consumption in 15-minute or 60-minute intervals is installed at the service point. Indiana utilities have deployed AMI meters across large portions of their service territories as part of grid modernization plans approved by IURC. Without interval metering, the utility cannot assign differentiated prices to specific consumption windows.

  2. Tariff enrollment. The customer or property owner applies to enroll in the applicable TOU schedule. Some schedules are optional; others are mandatory for customers who install qualifying EV supply equipment (EVSE) above a specified load threshold. Enrollment paperwork is submitted to the serving utility, not to a state agency.

  3. Load signal or price signal delivery. The utility communicates on-peak and off-peak windows through published tariff schedules, utility mobile applications, or — in more advanced deployments — direct signals to smart charger controllers via protocols such as OpenADR 2.0. EVSE that supports demand response can respond automatically.

  4. Billing settlement. The interval meter data is aggregated by time block, multiplied by the applicable block rate, and settled on the monthly bill. Customers who successfully shift the majority of their EV charging load to off-peak windows realize the full price differential benefit.

The electrical infrastructure requirements for TOU-optimized charging are explained in detail within the How Indiana Electrical Systems Works: Conceptual Overview, including circuit sizing and panel capacity considerations that affect whether a Level 2 charger can operate at full rated amperage during optimal off-peak hours.

Common scenarios

Residential Level 2 charging with overnight shift. A homeowner installs a 48-amp Level 2 EVSE on a dedicated 60-amp circuit (per NEC Article 625 requirements). The charger's built-in scheduling function is programmed to begin charging at midnight and complete the session before 6 a.m., capturing super off-peak rates. No additional permit beyond the original charger installation permit is required for the scheduling configuration itself.

Commercial fleet with demand charge exposure. A fleet operator running 10 Level 2 chargers at a depot encounters both TOU energy charges and peak demand charges measured in dollars per kilowatt of maximum 15-minute interval demand. Shifting charging to off-peak blocks reduces the energy component but does not eliminate demand charges unless all chargers are staggered through load management software. This scenario requires coordination between the TOU tariff structure and EV charging load management strategies.

Multifamily property with submetered EVSE. A property owner installs submetered EVSE in a parking structure. Each charging port is individually submetered, and residents are billed for actual consumption. TOU pass-through pricing requires that the submeter system be certified under NIST Handbook 44 (Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices) and that the billing methodology comply with Indiana's utility service rules. The Indiana Office of Utility Consumer Counselor (OUCC) provides guidance on lawful resale of electricity in shared-facility contexts.

Solar-integrated EV charging. A residential customer with a rooftop photovoltaic system pairs net metering credits with a TOU schedule. During on-peak hours, solar generation may offset grid draw; overnight charging draws from the grid at off-peak rates. This configuration is addressed in the Solar Integration for EV Chargers in Indiana resource.

Decision boundaries

Not every EV charging installation benefits from TOU enrollment. The decision turns on four primary variables:

1. Charging flexibility. TOU programs yield savings only when charging can be deferred to off-peak windows. Vehicles that must be available for unpredictable deployment (emergency fleet, medical transport) cannot reliably shift load and may realize minimal benefit despite enrollment.

2. Flat-rate vs. TOU comparison. Indiana utilities publish both flat-rate residential schedules and TOU options. The breakeven point depends on the ratio of on-peak to off-peak consumption. A household that charges exclusively overnight will likely benefit; one that charges primarily between 5 p.m. and 9 p.m. may face higher bills under TOU than under the flat tariff. Customers should request a utility bill analysis or use IURC-approved utility online calculators before switching schedules.

3. Electrical infrastructure readiness. A service panel operating near capacity may require a panel upgrade before a Level 2 EVSE can be added. The upgrade itself must be permitted through the local building department and inspected by a licensed electrical inspector operating under Indiana's adoption of the National Electrical Code. TOU scheduling does not substitute for infrastructure adequacy.

4. Tariff eligibility and meter type. Customers on legacy electromechanical meters are not eligible for TOU settlement until an AMI meter is installed. Enrollment requests submitted before meter upgrade completion will be queued pending hardware deployment by the serving utility. The Indiana Utility Regulatory Commission maintains docket records of each utility's AMI deployment commitments.

For a full overview of Indiana EV charging infrastructure programs and resources, the Indiana EV Charger Authority index provides a structured entry point to all technical topics covered on this site.

References

📜 2 regulatory citations referenced  ·  ✅ Citations verified Feb 28, 2026  ·  View update log

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