Time-of-Use Pricing for Commercial Customers: How to Shift Load and Cut Energy Costs

What if you could pay half the price for the electricity you consume simply by running your operations at different times of day? That's not a hypothetical—it's the real opportunity available to Illinois commercial customers through time-of-use (TOU) pricing.

Electricity isn't a uniform commodity. The cost of generating and delivering electricity varies dramatically by time of day, day of week, and season. Peak demand periods—weekday afternoons in summer, winter mornings—require expensive peaker plants and stressed grid infrastructure. Off-peak periods use cheaper baseload generation running well below capacity.

Time-of-use pricing passes this real-time cost variation to commercial customers: higher rates when the grid is stressed, lower rates when it isn't. For businesses with operational flexibility to shift load—manufacturers, warehouses, food processors, commercial buildings with smart HVAC systems—TOU pricing can deliver electricity savings of 10-25% with no change in total consumption.

This guide explains exactly how TOU pricing works in Illinois, identifies the specific peak and off-peak hours that matter most, describes the practical load-shifting strategies your competitors are already using, and walks you through the steps to determine whether TOU pricing should be part of your energy cost reduction strategy.

What Is Time-of-Use Pricing and Why Illinois Commercial Businesses Can't Afford to Ignore It

The Foundation: Electricity Isn't One Price

In traditional flat-rate electricity pricing, you pay the same per-kWh rate regardless of when you consume electricity. This simplicity comes at a cost: businesses consuming electricity during expensive peak periods are subsidizing those consuming during cheap off-peak periods.

Time-of-use pricing replaces the flat rate with a schedule of rates that vary by:

Time of day (on-peak vs. off-peak hours)
Day type (weekdays vs. weekends)
Season (summer vs. winter vs. shoulder months)

The pricing structure reflects the actual cost of electricity production and delivery at different times—incentivizing customers to shift discretionary load to lower-cost periods.

TOU Pricing in Illinois: ComEd and Ameren Illinois

ComEd's Commercial Rate Options:

ComEd offers commercial customers several rate structures with time-differentiated components:

General Service (B/BM/BH): Standard commercial rates with demand charges but no TOU energy differentiation
Real-Time Pricing (RTP): Hourly prices reflecting actual wholesale market prices—maximum TOU complexity, maximum savings potential for sophisticated users
Peak Time Rebate: Credits for reducing demand during ComEd-declared peak events
Large Commercial TOU options: Available for customers above certain demand thresholds

For most small-to-mid commercial customers in ComEd territory, competitive electricity suppliers in Illinois's deregulated market offer TOU-aligned pricing that can be more advantageous than utility TOU tariffs—with supplier rates indexed to on-peak vs. off-peak market prices.

Ameren Illinois's Commercial Rate Options:

Ameren Illinois offers commercial customers:

Standard commercial rates with flat energy pricing
Opt-in TOU programs for qualifying commercial customers
Demand-side management programs that provide incentives for demand shifting

Why Illinois Businesses Are Leaving Money on the Table

Illinois commercial electricity markets have significant TOU price spreads: wholesale electricity prices on weekday summer afternoons (2-7 PM) often run 40-150% higher than overnight off-peak prices. For businesses on flat-rate contracts, this spread is invisible—you pay the blended average regardless of when you consume.

For businesses that can shift even 20-30% of their load to off-peak hours, TOU pricing can deliver substantial savings. The businesses already capturing this value include manufacturers with flexible production scheduling, warehouses and cold storage facilities, commercial buildings with programmable HVAC, and food processors with shift-adjustable production.

Peak vs. Off-Peak Hours: The Hidden Key to Slashing Your Commercial Energy Bill in Illinois

Standard TOU Definitions in Illinois

While exact hour definitions vary by supplier and rate schedule, the general framework for Illinois commercial TOU pricing is:

On-peak (highest rates):

Summer (June–August): Weekdays, 2 PM–7 PM
Winter (December–February): Weekdays, 5 AM–9 AM and 5 PM–9 PM
Rates typically 40-200% above off-peak

Shoulder/mid-peak (moderate rates):

Summer weekdays: 7 AM–2 PM and 7 PM–10 PM
Winter weekdays: 9 AM–5 PM
Rates typically 10-40% above off-peak

Off-peak (lowest rates):

All weekends and holidays
Overnight hours (typically 10 PM–7 AM weekdays)
Rates may be 30-50% below the average flat rate

Real-Time Pricing: Maximum Savings, Maximum Complexity

For sophisticated commercial customers, Real-Time Pricing (RTP) offers the maximum TOU price signal. RTP participants pay the actual day-ahead market price for electricity—updated hourly. In Illinois:

Average summer RTP price: $0.040–$0.060/kWh (off-peak hours)
Average summer on-peak RTP price: $0.070–$0.120/kWh (typical peak hours)
Summer scarcity event pricing: $0.200–$1.000+/kWh (extreme events)

Businesses with energy management systems capable of responding automatically to price signals—curtailing loads when prices spike, maximizing consumption when prices drop—can achieve savings of 20-35% compared to flat-rate contracts under RTP.

However, RTP also exposes businesses to price spikes. A business on RTP during an extreme heat event without load management capability can face electricity costs 10-20x higher than the flat-rate equivalent. RTP is appropriate only for businesses with robust energy management and genuine load flexibility.

The TOU Price Spread in Practice

Period	Typical Illinois TOU Rate	Vs. Flat Rate ($0.085/kWh)
Summer on-peak (2–7 PM weekdays)	$0.12–$0.15/kWh	41–76% higher
Shoulder hours	$0.08–$0.10/kWh	Similar to flat
Off-peak (nights, weekends)	$0.045–$0.065/kWh	24–47% lower

For a manufacturing facility consuming 500,000 kWh/month, shifting 20% of load (100,000 kWh) from on-peak to off-peak rates saves:

From $0.135/kWh on-peak to $0.055/kWh off-peak = $0.08/kWh savings
100,000 kWh × $0.08/kWh = $8,000/month = $96,000/year

That's a significant opportunity—without reducing a single kWh of total consumption.

Proven Load-Shifting Strategies That Illinois Businesses Are Using to Maximize Time-of-Use Savings

Strategy 1: Production Scheduling for Manufacturers

Manufacturers with energy-intensive processes—stamping, compression, heat treatment, mixing—that can be scheduled flexibly are ideally positioned to capture TOU savings through production timing.

Practical implementation:

Analyze which production processes have flexibility in their timing (vs. those tied to shift schedules, customer delivery windows, or continuous process requirements)
Schedule energy-intensive processes to overnight or weekend runs where operationally feasible
Build "energy-aware scheduling" into your production planning process—factor energy cost timing into the sequence of operations alongside labor and material inputs

Real-world example: An Elgin-area plastics manufacturer shifted 35% of their injection molding production from weekday afternoon to overnight runs after enrolling in a ComEd TOU-aligned competitive supply contract. Annual savings: $47,000 with no reduction in output.

Strategy 2: HVAC Pre-Cooling and Thermal Storage

Commercial buildings with significant HVAC loads can dramatically reduce on-peak electricity consumption through thermal pre-cooling:

Pre-cool aggressively during early morning off-peak hours (6-9 AM)—cool the building to 68-69°F before the on-peak window begins
Allow temperature drift during peak hours (2-7 PM)—let temperatures rise to 74-75°F as the building slowly warms
Resume cooling after the on-peak window closes (7 PM)
Repeat daily during summer peak months

For a large commercial office building, HVAC typically represents 35-50% of peak demand. Pre-cooling can reduce on-peak HVAC consumption by 40-60%—a significant TOU savings driver.

Advanced option: Ice thermal storage. Commercial ice storage systems freeze water overnight using cheap off-peak power, then use the stored cooling during peak hours—effectively shifting HVAC electricity consumption from peak to off-peak. Large commercial buildings have achieved 30-50% reductions in peak electricity costs through ice storage.

Strategy 3: Lighting and Plug Load Management

Automated lighting controls synchronized to TOU periods—dimming or cycling non-critical lighting during on-peak hours—provide modest but consistent TOU savings. For large warehouses, parking facilities, and common areas, automated peak-hour dimming can reduce lighting consumption by 20-30% during the highest-cost hours.

Plug load scheduling: Equipment with flexible operation timing—battery chargers (forklifts, vehicles, handheld devices), large printers, industrial cleaning equipment—can be scheduled to operate during off-peak periods using smart power strips, outlet timers, or energy management systems.

Strategy 4: Compressed Air and Refrigeration Cycling

Compressed air systems can be optimized for TOU savings by:

Building pressure during off-peak periods to a higher set point (tank pre-loading)
Allowing pressure to drop during peak periods without running compressors
Scheduling compressor maintenance and optimization tasks for off-peak periods

Refrigeration cycling: Cold storage facilities, grocery stores, and food processors can use pre-cooling strategies similar to HVAC—pre-cooling to lower temperatures before peak windows and allowing temperature to drift within safe ranges during peaks.

For a large cold storage facility, cycling refrigeration systems during summer peak hours can reduce on-peak electricity consumption by 25-40%—delivering thousands of dollars in monthly TOU savings. This load flexibility also directly reduces your Peak Load Contribution (PLC) for capacity charges; see our capacity charges guide for how these savings compound.

How to Get Started with Time-of-Use Pricing in Illinois: A Step-by-Step Guide for Commercial Customers

Step 1: Analyze Your Current Load Profile

Before choosing a TOU pricing structure, understand your consumption patterns:

Request your interval data from ComEd or Ameren Illinois—15-minute interval data is available through smart meters and shows exactly when your facility consumes electricity
Identify your peak consumption hours—when does your demand spike, and how well does it correlate with TOU on-peak periods?
Calculate your TOU exposure—what percentage of your consumption occurs during typical on-peak hours?

If 50%+ of your consumption falls during on-peak hours and you have limited flexibility to shift it, TOU pricing may actually increase your costs compared to flat rates. If significant load falls off-peak or can be shifted, TOU pricing is likely favorable.

Step 2: Identify Load-Shifting Opportunities

Audit your facility for flexible loads:

Which machines, systems, or processes can be rescheduled without operational impact?
What is the approximate kW demand of those flexible loads?
What are the operational constraints on shifting them (labor availability, process requirements, customer commitments)?

Quantify the potential shift: if you can move 150 kW × 8 hours of load from on-peak to off-peak daily during summer, the annual TOU savings potential at $0.08/kWh spread = $51,840/year.

Step 3: Evaluate TOU Options in Illinois's Deregulated Market

Illinois's deregulated electricity market gives you options beyond utility TOU tariffs:

Competitive suppliers offering TOU-indexed contracts: Several Illinois-licensed competitive electricity suppliers offer contracts priced on on-peak and off-peak indices rather than flat rates—providing TOU price exposure through your supply contract
ComEd's RTP program: Available for larger commercial customers; provides maximum price signal with corresponding volatility
Custom competitive contracts: For large commercial customers, custom supply contracts can be structured with specific TOU provisions tailored to your load profile

Work with a commercial energy advisor to identify which TOU structure best matches your load profile and operational flexibility.

Step 4: Implement Controls and Monitor Performance

Once you've selected a TOU pricing structure:

Deploy or program building controls to automate load shifting (building automation, programmable thermostats, interval-based equipment controls)
Establish baseline energy spend before TOU enrollment for performance comparison
Review monthly billing data to confirm expected savings are materializing
Adjust load-shifting schedules seasonally as TOU peak periods change

Conclusion: Time-of-Use Pricing Rewards Flexibility—And Illinois Businesses Have More Flexibility Than They Realize

For commercial businesses in Illinois, time-of-use pricing represents one of the most accessible energy cost reduction strategies available—particularly for facilities with production flexibility, programmable building systems, or cold storage operations. The combination of Illinois's deregulated electricity market (enabling competitive TOU-indexed supply contracts) and meaningful summer peak/off-peak price differentials creates genuine, quantifiable savings for businesses willing to shift a portion of their load.

The first step is understanding your current load profile—specifically, how much of your consumption occurs during on-peak hours and how much is operationally flexible. That analysis takes an hour with your interval data and reveals whether TOU pricing is a major opportunity or a modest one for your specific facility.

At Commercial Energy Advisors, we analyze Illinois commercial customer load profiles, identify TOU savings potential, and help businesses implement the supply contract structures and operational changes that capture those savings.

Call 833-264-7776 or request your free Illinois TOU savings analysis to find out whether your load profile qualifies for significant time-of-use savings.

Frequently Asked Questions

What is time-of-use pricing for commercial customers in Illinois?

Time-of-use (TOU) pricing charges different electricity rates based on when you consume electricity—higher rates during peak demand periods (typically weekday afternoons in summer) and lower rates during off-peak periods (nights, weekends). Illinois commercial customers can access TOU pricing through utility programs or competitive electricity suppliers in the state's deregulated market.

When are peak hours for commercial electricity in Illinois?

For most Illinois commercial TOU pricing structures, summer on-peak hours are weekdays from approximately 2 PM–7 PM (June–August). Winter peaks are typically weekday mornings and evenings. Off-peak periods include all weekends, holidays, and overnight hours (typically 10 PM–7 AM). Specific definitions vary by rate schedule and supplier.

How much can Illinois businesses save with time-of-use pricing?

Savings depend on your load profile and flexibility. Businesses that can shift 20-30% of load from on-peak to off-peak periods typically save 10-20% on electricity costs. A manufacturing facility shifting 100,000 kWh/month from summer on-peak ($0.13/kWh) to off-peak ($0.055/kWh) saves approximately $90,000/year with no change in total consumption.

What is Real-Time Pricing (RTP) and is it right for commercial businesses?

Real-Time Pricing uses hourly wholesale market prices for electricity—the maximum TOU price signal. RTP can deliver the highest savings for businesses with sophisticated energy management and genuine load flexibility, but exposes businesses to price spikes during extreme events. RTP is most appropriate for larger commercial customers with energy management systems capable of automatic load response.

What load-shifting strategies work best for Illinois commercial businesses?

Most effective strategies include: production scheduling to overnight/weekend hours (manufacturers), HVAC pre-cooling before summer peak windows (commercial buildings), refrigeration and compressed air pre-loading (food processors, cold storage), and automated lighting and plug load management. The right strategy depends on your specific operation and equipment.

Does Illinois's deregulated electricity market offer TOU pricing options?

Yes—in Illinois's deregulated electricity market, competitive suppliers can offer customized TOU-indexed supply contracts tailored to your load profile. For many businesses, competitive TOU supply contracts deliver better economics than utility TOU tariffs because the supplier pricing is benchmarked to actual wholesale market prices rather than regulatory tariff structures.

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