ComEd's Time-of-Day Pricing Ties Bill Savings to Grid Emissions Reduction

ComEd has launched Time-of-Day Pricing, a rate structure that lets residential customers reduce both electricity delivery and supply charges by shifting their energy use to lower-demand periods of the day, developed in accordance with the Illinois Climate and Equitable Jobs Act. The programme also offers electric vehicle owners bill credits of $2 per vehicle each month for up to 24 months, capped at two vehicles per household. The launch follows a month of extreme high temperatures across July, a period that typically drives peak electricity demand and strains grid capacity.

 

Why Shifting Demand Reduces Pollution, Not Just Cost

 

The mechanism behind Time-of-Day Pricing ties directly to how electricity generation responds to demand spikes. When demand peaks during hot afternoons as air conditioning use surges, utilities often need to bring additional power plants online to meet that demand, and those marginal plants brought on for peak periods are frequently less efficient, more expensive to operate, and more polluting than the baseline generation running throughout the day. By pricing electricity higher during those peak windows and lower during off-peak hours, the rate structure gives customers a direct financial incentive to shift usage away from the periods when the grid is under the most strain and burning the dirtiest marginal generation.

That is why ComEd president and chief executive Gil Quiniones framed the programme around a dual benefit: customers lowering their bills while collectively helping defer the need to invest in new generation and grid infrastructure. Reducing peak demand across many households simultaneously can meaningfully reduce the pressure that drives utilities to build additional peaking capacity, infrastructure that is expensive to construct and often sits idle outside of high-demand periods, with those costs typically recovered from all ratepayers regardless of their individual usage patterns.

 

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How the Rate Structure Actually Works

 

The programme divides each day into four fixed pricing periods rather than varying prices continuously. Customers pay a moderate rate during the morning period from 6am to 1pm, the highest rate during the mid-day peak from 1pm to 7pm, a moderate rate again during the evening from 7pm to 9pm, and the lowest rate overnight from 9pm to 6am. That fixed-period structure differs from ComEd's separate Hourly Pricing programme, which charges a supply rate that fluctuates every hour based on real-time market prices; Time-of-Day Pricing instead gives customers predictable, known rates for each period, making it easier to plan when to run high-consumption appliances like dishwashers, laundry machines or EV chargers.

A customer's actual dollar rates vary depending on their home and heating type, which determines their delivery class, and participants can compare their current rate against the Time-of-Day structure using a rates comparison tool in their online account before deciding whether to enrol.

 

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Why the EV Credit Matters for Electrification

 

The $2 monthly per-vehicle credit for EV owners who enrol in delivery Time-of-Day Pricing is a targeted incentive layered on top of the general rate structure, encouraging exactly the customer segment whose electricity consumption is growing fastest and whose charging behaviour is most flexible to shift toward off-peak hours. EV charging is typically one of the most schedulable household electricity uses, since a car can charge overnight without any inconvenience to the owner, making EV owners a natural target for demand-shifting incentives that are harder to apply to less flexible uses like air conditioning during a heatwave.

Rob Kelter, managing attorney for the Environmental Law and Policy Center, framed the programme as helping customers avoid the need to activate power plants that both drive up prices and pollute the air on hot summer days, tying the environmental and financial arguments together directly. Enrollment and cancellation carry no cost, though customers who cancel their delivery Time-of-Day participation forfeit any remaining EV bill credits, and enrollment changes take two to three billing cycles to take effect. Whether the programme achieves meaningful demand-shifting at scale, and whether the EV credit proves large enough to influence charging behaviour among a growing base of EV owners, will determine how much this rate structure contributes to easing the peak-demand pressures driving both costs and emissions higher during Illinois summers.