Indiana Michigan Power Rate Selection Guide
Indiana Michigan Power (I&M), an AEP subsidiary, serves about 615,000 electric customers across Indiana and southwestern Michigan. Michigan customers have full Green Button Connect My Data access via UtilityAPI, while Indiana customers rely on the online portal and authorization letters for data access.
Indiana Michigan Power Rate Schedule Comparison
| Schedule | Type | Rate | Best For |
|---|---|---|---|
| General Service (G.S.) | Commercial | Customer + energy charge; demand charge above threshold (see tariff) | Small to mid-size businesses |
| Large General Service (L.G.S.) | Commercial | Customer + energy + billing-demand $/kW (see tariff) | Larger commercial / demand-metered |
| Industrial Power (I.P.) | Industrial | Demand-dominated; contract-demand charges (see tariff) | Large industrial / high load factor |
| Large Load / Data Center | Industrial | Minimum-take + contract-term terms (Cause 46097) | Data centers / loads >70 MW |
Market Overview
I&M is a regulated AEP subsidiary. Indiana customers cannot shop for a competitive supplier; rates are set by the IURC. Michigan has a capped retail-choice program administered through Alternative Electric Suppliers, but most customers remain on bundled service.
Need to pull your actual usage data to compare rates? See the Indiana Michigan Power Data Access Guide →
Current Rate Schedules
I&M's Indiana base rates were approved by the IURC in Cause No. 45933 (order May 2024), implemented in two phases through January 2025; the settlement reduced the requested $116.4M increase to about $56.9M. C&I customers take service under General Service (G.S.), Large General Service (L.G.S.), and Industrial Power (I.P.) tariffs, each combining a customer charge, energy charge, and (for demand-metered classes) a billing-demand charge, plus rate-adjustment trackers (FAC, ECR, DSM, PJM, RAR). In February 2025 the IURC approved a modified large-load tariff (Cause No. 46097) for new/expanding loads above 70 MW at one site or 150 MW in aggregate. Specific cents/kWh and $/kW figures are set in the filed Indiana tariff book (IURC No. 20); consult it for exact current charges.
Effective: January 1, 2025 · Full Tariff Book →
| Schedule | Type | Applicability | Structure | Rate |
|---|---|---|---|---|
| General Service (G.S.) | commercial | Small and mid-size commercial customers for whom a residential rate is not available. | Monthly customer charge plus energy charge (cents/kWh); demand charge applies above a usage/demand threshold. Trackers apply. Exact charges in IURC No. 20 tariff book. | — |
| Large General Service (L.G.S.) | commercial | Larger commercial customers with demands above the General Service threshold. | Customer charge plus energy charge and billing-demand charge ($/kW); rate-adjustment trackers apply. Exact charges in IURC No. 20 tariff book. | — |
| Industrial Power (Tariff I.P.) | industrial | Large industrial customers taking high-load-factor primary or transmission service. | Demand-based tariff with customer charge, energy charge, and significant billing/contract-demand charges ($/kW); FAC and other trackers apply. Exact charges in IURC No. 20 tariff book. | — |
| Large Load / Data Center Tariff | industrial | New or expanding loads with contract capacity above 70 MW at one location or 150 MW in aggregate (each location >1 MW). | Modified industrial tariff approved February 2025 (IURC Cause No. 46097) with minimum-take and contract-term provisions designed for data center and large-load customers. Terms in the filed tariff/order. | — |
| General Service - Plug-In EV (G.S. - PEV) | ev | Commercial EV charging service. | EV-oriented commercial service offering; rates set in the filed Indiana tariff book. | — |
Rate Recommendations by Use Case
Mid-size commercial business (Indiana)
Indiana commercial sites typically take General Service or Large General Service. Verify the schedule fits your demand profile and manage peaks.
Indiana lacks retail choice, so optimizing schedule selection and demand is the main lever; interval data is viewable in-portal.
- Pull 13 months of billing history from the portal
- Watch billing-demand charges once you cross the demand threshold
- Track FAC and tracker filings for upcoming changes
Large industrial / manufacturing
High-load-factor industrial loads take the Industrial Power (I.P.) tariff, dominated by contract/billing-demand charges.
Demand and contract terms drive the bill; sustained high load factor and peak control yield the best unit economics.
- Maintain high load factor to spread demand charges
- Use interval data for coincident-peak management
- Engage I&M on contract-demand terms
Data center / very large load
New or expanding loads above 70 MW fall under the 2025 large-load tariff (Cause 46097) with minimum-take and term commitments.
Indiana created a dedicated structure to recover the cost of serving very large new loads and protect other ratepayers.
- Review Cause 46097 minimum-take and contract-term provisions
- Plan interconnection early given Indiana large-load interconnection rules
- Model trackers into total delivered cost
Multi-site portfolio incl. Michigan
Portfolios spanning both states should centralize data: Green Button Connect (UtilityAPI) in Michigan and portal/LOA access in Indiana.
Data access differs by state; a single ingestion approach for Michigan plus authorization-letter access for Indiana keeps reporting consistent.
- Authorize a UtilityAPI vendor for Michigan accounts
- Use LOAs for Indiana business accounts
- Standardize on 15-minute interval data where available
Historical Rate Trends
I&M's Indiana base rates have risen through periodic rate cases (2018, 2020, 2022, and the May 2024 order in Cause 45933) plus frequent tracker adjustments. The 2024 settlement cut the requested increase by roughly half.
May 31, 2024
IURC approved I&M base-rate settlement in Cause 45933, raising revenue ~$56.9M (down from a $116.4M request); residential bills rose about 5.2% (~$8.47/mo at 1,000 kWh) phased through Jan 2025.
+5.2% (residential, typical)February 1, 2025
IURC approved a modified large-load/industrial tariff (Cause 46097) for new/expanding loads above 70 MW (site) or 150 MW (aggregate), targeting data center demand.
n/aOverall trend: Upward. Base rates plus trackers have steadily increased; trackers alone made up about 20% of a typical bill as of July 2025. Large-load growth (data centers) is reshaping industrial tariffs.
Next expected change: Semi-annual Fuel Adjustment Clause (Cause 38702) and annual tracker updates; future base-rate case timing not yet set.
Cost Optimization Strategies
Because I&M C&I rates are demand-driven and layered with trackers, the biggest savings come from interval-data-driven peak management and choosing the correct schedule. Michigan customers can also leverage Green Button Connect for automated monitoring.
Peak demand management
For: L.G.S., Industrial Power
Use 15-minute interval data to flatten coincident peaks and reduce billing-demand ($/kW) charges, which dominate L.G.S. and Industrial Power bills.
Rate schedule verification
For: All C&I
Confirm the account is on the lowest-cost applicable schedule (G.S. vs L.G.S. vs I.P.) given load factor and demand; reclassification can lower charges.
Automated interval monitoring (Michigan)
For: Michigan C&I
Authorize a Green Button Connect vendor via UtilityAPI to automate 15-minute data ingestion for ongoing efficiency and M&V.
Tracker awareness
For: All C&I
Monitor FAC and other tracker filings (Cause 38702 and annual riders) to anticipate rate movements and budget accordingly.
To implement these strategies, you need your 15-minute interval data. Learn how to download Indiana Michigan Power interval data →
Frequently Asked Questions
Can a C&I customer in Indiana shop for a competitive electricity supplier?▾
No. Indiana is a fully regulated market with no retail choice. I&M's Indiana customers take bundled service under IURC-approved tariffs. Only I&M's Michigan service area has a (capped) Alternative Electric Supplier choice program.
How do C&I customers get 15-minute interval data programmatically?▾
Michigan C&I customers can authorize a third party through Green Button Connect via UtilityAPI for automated 15-minute interval, billing, and meter data. Indiana customers can view interval data in the Your Energy Usage portal but have no Green Button Connect or direct export; bulk data requires a Letter of Authorization.
What rate schedules apply to commercial and industrial accounts?▾
C&I accounts typically take General Service (G.S.), Large General Service (L.G.S.), or Industrial Power (I.P.), plus EV and large-load options. Demand-metered classes carry significant billing-demand ($/kW) charges. Exact charges are in the Indiana tariff book (IURC No. 20).
What is the new large-load tariff?▾
In February 2025 the IURC approved (Cause No. 46097) a modified industrial tariff for new or expanding loads above 70 MW at one location or 150 MW in aggregate, designed to serve data centers and other very large loads with minimum-take and contract-term provisions.
How far back does billing and usage history go online?▾
The online portal provides up to 13 months of billing and usage history. Smart-meter interval retention beyond that varies; contact I&M customer service for longer histories.
Automate Indiana Michigan Power Rate Analysis with Nectar
Nectar continuously monitors your Indiana Michigan Power rate options and alerts you when a better schedule is available. Save 10-30% on energy costs.
Nectar for Energy & Sustainability Teams
Managing utility costs for commercial or industrial buildings? Nectar offers a free rate analysis — we'll review your current rate schedules and identify where switching tariffs or shifting load can save 10-30%.
Get a Free Rate AnalysisNectar for Energy Brokers & Consultants
Advising clients on rate optimization? Nectar works with energy consultants who need reliable interval data and automated rate comparison tools.
Partner with Us