How to Budget for Commercial Energy Costs in Illinois

Energy is a line item that resists a single number — usage varies, demand shifts, and market prices move. The fix is to budget in components and scenarios so the number reflects the real risk instead of hiding it.

Budget in components, not a lump sum

Break the budget into parts with different behavior:

• Supply — the energy commodity. Under a fixed contract, the included components are forecastable for the term; under an index or block-and-index product, part of it varies.
• Delivery — utility distribution, metering, riders, and taxes, which follow published tariffs and are relatively predictable.
• Demand and capacity — for demand-billed accounts, demand charges and, in the ComEd/PJM zone, capacity are usage-driven and can move with operations.

Separating these is the same discipline as reading a bill in groups — see how to read a ComEd commercial electric bill.

Use scenarios, not a point estimate

Build low, base, and high cases that flex the moving parts — usage, demand, and any index/pass-through components. A range shows the exposure a single number hides, and it lets finance plan for the high case rather than be surprised by it. Represent estimates as estimates, not commitments.

Watch the renewal inside the budget year

If a supply contract expires mid-year, the post-renewal rate is unknown until the market is checked near that date. Model the contracted period and a renewal scenario separately, and align the budget with the renewal timeline so the decision isn't made under deadline.

A simple way to build the number

In practice, a workable commercial energy budget comes together in a few steps. Start from twelve months of actual usage by month, so seasonality is built in rather than averaged away. Apply the supply price the account is contracted for — or, for any period beyond the current contract, a range rather than a point, because that price isn't known yet. Add delivery using the utility's published tariff for the rate class, which is the most predictable part. For demand-billed accounts, layer in the demand charge from the account's own peak history, and, in the ComEd/PJM zone, the capacity component tied to its tag. Sum those by month, then flex usage and the unknown supply period up and down to produce the low, base, and high cases. The result is a budget that shows not just a number but the range around it and which drivers move it most.

Common budgeting mistakes

• Budgeting from a single "current rate." A rate quoted today applies to a specific account and delivery period; extending it across a whole year, or across an account it wasn't quoted for, bakes in an error.
• Treating a fixed supply price as a fixed bill. Delivery, demand, capacity, taxes, and any pass-throughs still move; only the contracted supply components are fixed.
• Ignoring the renewal cliff. A budget that assumes today's contracted rate continues past the expiration date understates the uncertainty in the back half of the year.
• Using one number instead of a range. A point estimate feels precise but hides the exposure; a low/base/high range is more honest and more useful for planning.

Revisit it, don't set it and forget it

A budget is a forecast, not a fixed truth, and it improves when it is checked against reality. Comparing actual bills to the budgeted figures each quarter shows where the estimate was off and why — usage ran higher than expected, a demand peak set a bigger charge, a pass-through moved — and that variance analysis sharpens the next cycle. The moments that most warrant a fresh look are a contract renewal, a change in operations (added equipment, a new shift, an expansion or closure), and any utility rate change that shifts the predictable delivery portion. Treating the budget as a living estimate, tied to the account's data rather than a one-time guess, is what keeps it useful across the year.

Ground it in the account's data

A credible budget starts from the account's actual bills and, for larger or variable loads, interval data — not a national average or a single "current rate." See commercial electricity and commercial natural gas for what drives each commodity, and fold the budget into the wider procurement and renewal calendar so the numbers and the decisions stay aligned.

Sources

• Illinois Power Agency — Electricity Supply Rates
• ComEd — Rates & Rules
• PJM — Reliability Pricing Model (capacity)

Scenarios support planning; they are estimates for a specific account, not guaranteed outcomes.