Illinois Commercial Energy Procurement: Worked Example
By Illinois Commercial Energy editorial team
Reviewed by JakenEnergy commercial energy team
This is an illustrative model, not a client case study. The facility, usage, prices, and contract terms below are invented solely to demonstrate calculations. They are not current offers, market forecasts, or evidence of customer savings.
Scenario
An Illinois business is evaluating three electricity-supply paths for a 12-month period:
- Utility-supply benchmark.
- Supplier A: fixed energy price with capacity and transmission passed through.
- Supplier B: higher fixed price that includes energy, capacity, and transmission.
Illustrative annual usage is 1,200,000 kWh. The example excludes regulated delivery charges because the supplier choice does not eliminate them.
Assumptions
| Input | Illustrative value | Status |
|---|---|---|
| Annual eligible usage | 1,200,000 kWh | invented for model |
| Utility supply components | $0.091/kWh | invented benchmark |
| Supplier A energy | $0.067/kWh | invented offer |
| Supplier A modeled capacity/transmission | $25,200/year | invented estimate |
| Supplier A account fees | $1,200/year | invented fee |
| Supplier B bundled supply | $0.089/kWh | invented offer |
| Supplier B account fees | $0/year | invented fee |
None of these figures should be used for an actual procurement.
Base-case calculation
Utility benchmark:
1,200,000 × $0.091 = $109,200
Supplier A:
(1,200,000 × $0.067) + $25,200 + $1,200 = $106,800
Supplier B:
1,200,000 × $0.089 = $106,800
In this invented base case, A and B have the same modeled annual supply cost. A's headline energy price looks much lower, but the excluded capacity, transmission, and fees close the gap.
Stress case
Assume Supplier A's passed-through capacity/transmission total is $34,800 instead of $25,200:
(1,200,000 × $0.067) + $34,800 + $1,200 = $116,400
Supplier B remains $106,800 only if its contract truly fixes the stated components and no other adjustment applies. The stress case makes the risk tradeoff visible.
High-usage case
If usage rises 15% to 1,380,000 kWh, recompute every volumetric component and review volume-tolerance clauses. Do not simply increase total dollars by 15% when some costs are fixed, demand-based, or subject to bands.
What the decision memo should say
A sound memo would not say “Supplier B saves X%.” It would say:
Under the illustrative base assumptions, Supplier A and Supplier B have equal modeled supply cost. Supplier B has lower modeled exposure to the tested capacity/transmission increase, subject to confirmation that the executed price definition includes those components. Utility delivery charges and actual savings are outside this illustrative model.
Replace every invented value for a real account
For a live decision, use actual bills, interval data, service class, applicable utility rates, supplier proposals, contract language, capacity inputs, fees, taxes, and operating forecasts. Date every time-sensitive source. Mark missing items and avoid a precise conclusion until material gaps are resolved.
Why this is not a case study
A case study should be tied to a real, documented project with permission, dates, baseline, scope, and measured or reconciled results. Changing a business name while inventing the numbers does not make evidence. This worked example teaches the method and makes no performance claim.
Model publication date: July 19, 2026.