Time of Use Demand Rates: When TOU Helps (and Hurts) Indiana Commercial & Industrial Facilities

Time of use demand rates can lower electricity costs for Indiana manufacturers and commercial operators who run significant load in off-peak windows — and raise them significantly for facilities that can't shift when or how they operate. Which outcome you get depends on three things: whether you qualify for the rate, whether your operation has real flexibility, and whether you have the visibility to see what your demand is actually doing against your specific tariff windows.

This post is for plant managers, facility managers, superintendents, COOs, and energy managers who've opened an electric bill, spotted a "peak vs. off-peak" section, and weren't sure what to do with it. It's also for anyone being pitched storage, automation, or solar with the promise it'll work well with a time of use rate — and who wants specific questions to push back with.

By the end, you'll know what time of use demand rates actually are at a decision-maker level, when they clearly help facilities like yours and when they don't, and the exact questions to ask a vendor to find out whether they actually know your tariff or are just waving their hands.

Watch this episode of The TEG Podcast on YouTube.

What Time of Use Actually Is

Most commercial and industrial operators run into three basic rate structures.

First, a straight usage rate: you pay a flat cost per kilowatt-hour, and your bill rises linearly with consumption. Second, a demand rate: you're charged for both how many kilowatt-hours you consume and how high your load peaks inside the billing period — that peak demand number drives a separate line item on your bill. Third — and this is where time of use lives — a time of use demand rate: a demand-based structure with additional provisions for when that demand occurs.

On a time of use demand rate, there are incentives or penalties based on whether your demand lands in what the utility has defined as a peak or off-peak window. That detail is what most articles gloss over: for commercial and industrial customers, time of use is usually not simply "electricity is cheaper at night." It's that the demand components of your bill are treated differently depending on when they occur.

Those peak and off-peak windows are not set by the industry at large. They are defined by one utility at a time — sometimes one rate at a time. The exact start and end times, which days they apply to, and which line items on your bill are affected are all written down in the tariff for your specific rate. Time of use is not a vague concept. It's a specific set of times and days that change how one or more lines of your bill are calculated.

Why Time of Use Exists on Paper vs. How It Works in Real Life

The stated objective from the grid side makes sense. When commercial and industrial operations ramp up during typical working hours, grid demand rises. When everyone goes home, residential load picks up. Utilities are trying to get you to use electricity during periods where the system has slack and pull back during periods where it's already strained. They do that with price signals.

On paper, if enough customers move demand away from crowded periods, you get less stress on the grid, fewer expensive peaker plants turning on, and a smoother load profile. That's the theory.

Where most writing on this goes wrong is in how it frames transparency and environmental benefit. You'll often see language like "time of use rates provide cost transparency" — as if having three different price periods automatically makes life clearer for a superintendent running a school system. That's only true in theory. In practice, the vast majority of commercial and industrial customers do not understand how these rates work and have very little ability to model their costs with clarity. The rate book is written in technical language. The terms and conditions are dense. Most operators don't have the time or the desire to become experts in reading tariffs.

There's a massive gap between the people who are abnormally interested in the grid and love drafting these rate structures — and the people who are trying to keep a plastics line running or keep classrooms comfortable. That gap is real, and it's the main reason time of use is so widely misapplied.

On the environmental side: advocates often connect lower grid strain with lower emissions. But demand timing does not correlate directly to emissions — kilowatt-hour consumption does. Time of use incentives, even when they work as intended, change when you use power, not how many kilowatt-hours you consume over the month. If sustainability goals are on your agenda, that's your call. But don't confuse a timing incentive with a guaranteed emissions reduction. Regulators and advocates position it that way. The billing math doesn't support it for most C&I facilities.

When Time of Use Actually Helps Facilities Like Yours

Time of use demand rates clearly help operators who either already operate heavily in off-peak periods or who can realistically shift meaningful load into those windows.

If you run two or three shifts, or if you have critical processes overnight, you have a much better shot at using time of use to your advantage. Facilities with around-the-clock loads — where you can sequence and automate so the heaviest demand events happen when the tariff says off-peak — are natural candidates.

But the conditions for time of use to pay off aren't soft. You need three things in place.

Qualification. Across Indiana, time of use is not available to everyone who wants it. Some general service rates have no time of use provisions at all. Others have limited off-peak incentives or only offer them at industrial service levels. Before any project conversation, the gating question is whether you even qualify for a time of use demand rate in your territory — and what the rules are for entering or leaving it.

Flexibility. You must be able to change behavior or operations in line with the specific incentives and penalties in your rate. If your plant runs a single day shift and your heaviest loads must run between early morning and late afternoon, the question of whether you can shift to off-peak is already answered.

Visibility. Energy monitoring is essential for any demand-based strategy, but especially with time of use. You need to see your demand profile over time — and that profile needs to be compared against the peak and off-peak windows in your specific rate. Without that comparison, you're guessing.

For a manufacturer running multiple shifts who is motivated to invest in automation or storage and has access to real monitoring and tariff expertise, a time of use demand rate can be turned into a structural cost advantage. But notice what that list requires. None of it is soft.

When Time of Use Is a Terrible Idea (or Locks You In)

A plant running one shift in the middle of a defined peak window — with no appetite to move production or invest in automation — is not going to benefit because the utility happens to offer a time of use option. In that case, you've opted into more complicated billing with limited or no upside.

Time of use also costs you when you switch rates without a clear plan. In many Indiana utility territories, you cannot change your rate more than once every 12 months. That's not a lock-in from the peak and off-peak concept itself — it comes from standard rules that hold you to your rate choice for a full calendar year. Switch in without visibility and a real operational plan, and you may spend a year riding out an expensive experiment before you can make a change.

And time of use hurts badly when vendors get sloppy. Abstraction and approximation are never acceptable here. Peak and off-peak hours are specific. They're written in the tariff. They're not forgiving.

Solar is where this goes wrong most often. You'll see proposals claiming a solar project will reduce your peak demand — especially if the defined peak window lines up with sunny hours. On a clear day, solar can reduce what the grid sees as your demand in that moment. But utilities bill on the highest demand peak in the entire billing period. One cloudy day, or one day where operations look different, wipes out that solar effect from the billing math. Over 12 billing periods, solar alone will not reliably reduce billable demand in peak windows. The only way solar reliably addresses time of use demand charges is when it's paired with storage and a control system explicitly designed to shave demand events according to your specific tariff windows — and that's considerably more involved than most proposals make it sound.

Vendor Pitches, Red Flags, and Questions That Smoke Out BS

If a vendor is selling storage, control systems, or anything else supposed to work with your time of use demand rate, they must be able to operate at the level of detail the tariff demands. Here are the questions that separate vendors who actually know your rate from those pattern-matching to a generic pitch.

What are the exact peak and off-peak times for my specific rate? Not "it's usually daytime vs. nighttime." You want: on this rate, Monday through Friday, peak is from [exact time] to [exact time]. Off-peak is from [exact time] to [exact time]. And here's what weekends and holidays look like. The whole calendar, the whole clock.

Which days do those times apply to? The vendor should be able to say without hesitation: weekends are treated this way, Saturdays and Sundays are handled like this, holidays are treated like that — all for your specific rate, not a rate from another state or another customer's account.

What is the exact financial incentive? Is the difference between peak and off-peak 30%? 40%? Is it applied only to demand? To both energy and demand? Which line items on your bill are actually affected? They should be able to show you exactly how much more you pay per kilowatt — or per kilowatt-hour — in the peak window versus off-peak, and point to the specific language in the tariff that defines it.

Show me my tariff and point to where your project lines up. Pull up the tariff document. Show on the page where peak and off-peak windows are defined. Show the section describing the incentive structure. Show where those exact numbers have been built into their model for your facility. If they can't do that, they are not qualified to design a time of use project for you.

What You Can Do This Week

Step 1: Get your rate schedule and tariff in front of you. If you've never seen the full tariff sheet, find it. Pull it from the utility website, call your account rep, or ask whoever handles bills internally. You want the document that defines your rate, including any peak and off-peak provisions.

Step 2: Get your load profile, or at least interval data. If you have energy monitoring already installed, use it. If you don't, check whether your utility provides interval data downloads — many do. Even a basic graph of demand over time, overlaid against peak and off-peak windows, will tell you whether your operation is a natural off-peak candidate or not.

Step 3: Assess your operational flexibility honestly. How do your shifts run? Are there any processes that could move by an hour or two without disrupting your critical path, reliably and consistently? Do you have loads like refrigeration or compressors where you can pre-cool or sequence? Or is your production pattern rigid and locked into the defined peak window?

Step 4: If you're already on a time of use rate, do a sanity check. Overlay your demand profile against the tariff windows. Are your highest demand events landing in peak periods or off-peak? If they're still in peak, any theoretical savings from that rate are probably not material. You may even be paying a premium compared to a standard demand rate.

Step 5: If you're in a deregulated market and hearing about block-plus-index plans or open market structures, the same discipline applies. Ask for specifics. Ask to see how a proposal plays out against your actual usage history, not a generalized promise or a scenario built on someone else's load profile.

The Bottom Line on Time of Use Demand Rates

Time of use is a winner when you qualify for the rate, run meaningful load in off-peak windows, have real operational flexibility, have monitoring in place, and either know your tariff well or have a trusted partner who does. It's a poor fit when your facility is locked into daytime operations, when you're relying on solar alone to manage peak demand charges, when you're switching rates without a plan, or when the only deliverable you've seen is a proposal with vague generalities instead of tariff-level specifics.

The one underlying concept to take with you: time of use demand rates are about the relationship between your demand pattern over time and your specific tariff windows. Until you can see that relationship mapped out clearly, you're guessing — regardless of what any vendor is telling you.

Frequently Asked Questions: Time of Use Demand Rates for Indiana Operators

Q: What is a time of use demand rate for commercial and industrial customers? A: A time of use demand rate is a billing structure where the demand components of your electric bill are priced differently depending on when your peak demand occurs. If your highest demand events land in off-peak windows as defined by your tariff, you pay less; if they land in peak windows, you pay more. For Indiana commercial and industrial customers, time of use demand rates are not simply "cheaper power at night" — they apply specific tariff-defined windows to demand line items on your bill, not just to overall energy consumption.

Q: Does my Indiana facility even qualify for a time of use rate? A: Not necessarily. Across Indiana, time of use is not available to all commercial and industrial customers. Some general service rates have no time of use provisions at all, and others only offer limited off-peak incentives at industrial service levels. The first step before any time of use project is confirming whether your specific rate in your utility territory includes time of use options — and what the rules are for switching in or out.

Q: When does time of use clearly help a manufacturer or industrial facility? A: Time of use demand rates deliver real savings when a facility qualifies for the rate, runs substantial load in off-peak windows, has the operational flexibility to shift or sequence heavy loads, and has energy monitoring in place to see demand behavior against the specific tariff windows. Without all three conditions — qualification, flexibility, and visibility — time of use typically adds billing complexity without meaningful savings.

Q: Can solar alone reduce my peak demand charges under a time of use rate? A: Reliably, no. Solar can reduce what the grid sees as your demand on a clear day during peak hours, but utilities bill based on the highest demand peak across the entire billing period. One cloudy day or one day with unusual operations eliminates the solar effect from the billing math. Solar only reliably addresses time of use demand charges when paired with storage and a control system explicitly designed to shave demand events according to your specific tariff windows.

Q: How long am I locked into a time of use rate if I switch? A: In many Indiana utility territories, you cannot change your rate more than once every 12 months. The lock-in doesn't come from the peak and off-peak concept itself — it comes from standard rules that hold you to your rate selection for a full calendar year. If you switch into a time of use rate without a clear operational plan and without visibility into your demand profile, you may spend a year riding out an expensive experiment before you can make a change.

Q: What questions should I ask a vendor pitching storage or controls based on time of use? A: Ask them to name the exact peak and off-peak hours for your specific rate — not industry averages, your rate. Ask which days and holidays those windows apply to. Ask what the precise financial difference is between peak and off-peak and which line items on your bill are affected. Then ask them to pull up your tariff document and show you exactly where their project model reflects those numbers. If they can't answer at that level of specificity, they are not qualified to design a time of use project for your facility.

If you're facing an actual time of use decision in the next few months — whether that's a rate switch, a storage pitch, or a controls proposal tied to peak and off-peak windows — the TEG Energy Decision Blueprint is built for exactly that situation. We pull your last 12 months of bills, your interval data, and your specific tariff, and we show you what your demand is actually doing against those windows before recommending anything. Visit tac-nrg.com to learn more about the TEG Energy Decision Blueprint.

Watch this episode of The TEG Podcast on YouTube for the full breakdown on time of use demand rates.

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