Energy Performance Contracts: A Guide for Illinois Businesses

An energy performance contract, or EPC, is a way for a business to fund efficiency improvements by tying the provider's compensation to the energy savings those improvements produce. The idea is appealing: upgrades pay for themselves out of a reduced energy bill, and the provider has skin in the game. But the value of an EPC depends entirely on how savings are defined, measured, and verified, and on the fine print of any guarantee. This guide explains how EPCs are structured, how savings are substantiated, and the questions an Illinois business should ask before signing. It does not quote any guaranteed-savings figures, because those depend entirely on your facility and the specific contract.

How an EPC Is Structured

In a typical EPC, a provider, often called an energy services company or ESCO, takes on a bundle of roles that a business would otherwise coordinate separately. The provider audits the facility, engineers a package of efficiency measures, installs them, and then measures the resulting savings over time. In many arrangements the provider also helps arrange financing, so the capital cost of the project is spread out and, in principle, covered by the reduction in energy spending.

This bundling is the defining feature. Rather than hiring an auditor, then a designer, then a contractor, then separately arranging a loan, the business contracts with one party responsible for the whole chain, and that party's compensation is linked to results. The structure aligns incentives, at least on paper, because the provider is motivated to deliver savings that actually materialize.

EPCs come in different flavors. A savings-guarantee structure has the provider commit to a defined level of savings and make up any shortfall. A shared savings structure splits the realized savings between the provider and the business according to an agreed formula. The details of which structure applies, and exactly how the numbers are defined, matter more than the label.

Why Measurement and Verification Is the Heart of an EPC

The central challenge of any performance contract is that savings are invisible. You cannot point a meter at "energy you did not use." Savings are the gap between what your energy use would have been without the project and what it actually turns out to be, and the counterfactual, the "would have been," has to be estimated.

This is why measurement and verification, universally abbreviated M&V, is the backbone of a credible EPC. An M&V plan does several things:

• Establishes a baseline. It documents your energy use before the project, typically using historical utility data and interval readings, so there is a defined starting point.
• Defines adjustments. Energy use changes for reasons unrelated to the project, weather, occupancy, production levels, operating hours. A sound M&V plan specifies how the baseline is normalized for these factors so that the project is not credited for savings that came from a mild winter, or penalized for a hot summer.
• Specifies the calculation method. It states exactly how post-project savings will be computed, what data will be collected, how often, and by whom.

Reputable EPCs follow a recognized M&V protocol, an established, published framework for calculating savings, rather than an ad hoc method invented for the deal. The reason is transparency: a recognized protocol makes the savings claim repeatable and auditable rather than a number the provider simply asserts. Before signing, a business should understand which protocol the contract uses and how it handles baseline adjustments, because that method is what turns a marketing promise into a substantiated claim.

Requesting and understanding your own demand and interval data is valuable groundwork here, because your historical usage is what the baseline is built from. The cleaner your understanding of your own load, the better you can evaluate the baseline a provider proposes.

How Savings Claims Should Be Substantiated

A savings claim in an EPC should be traceable, not just stated. When a provider tells you a measure will save a certain amount, you should be able to see the chain of reasoning: the baseline it is measured against, the engineering basis for the estimate, the adjustments applied, and the ongoing measurement that will confirm it.

Be cautious of any EPC that presents a single headline savings number without showing this chain. A defensible claim distinguishes clearly between:

• Estimated savings projected before the project, based on engineering models.
• Verified savings actually measured after the project through the M&V process.

These are not the same, and the gap between them is exactly the risk an EPC is meant to manage. A well-constructed contract makes that distinction explicit and defines what happens if verified savings fall short of estimates.

Keep in mind, too, that efficiency and price are separate levers. An EPC reduces how much energy you use, and sometimes your peak demand and commercial demand charges; it does not change the price per unit of the energy you still buy. That price is a procurement question, addressed through commercial energy procurement, and it should not be blended into the EPC's savings figure. A provider that folds an assumed rate change into its "savings" is mixing two different things.

Risks and Questions for an Illinois Business

An EPC is a long-term relationship, not a one-time purchase, and that brings real considerations.

• How is the baseline defined, and how are weather and occupancy adjustments made? This single question drives the credibility of every savings number that follows.
• Which M&V protocol governs the contract, and who performs the verification? Independent or transparent verification is stronger than the provider grading its own work.
• If there is a guarantee, exactly how is a shortfall measured and remedied? Understand the exclusions, the measurement period, and the provider's financial ability to honor the guarantee.
• What are my obligations over the contract term? Long contracts may constrain how you operate the building, and changes you make can affect measured savings.
• How does the financing work, and what happens if I sell or vacate the property? Understand who owns the equipment and what transfers with the building.
• How are utility efficiency incentives handled? Illinois utilities run efficiency programs whose terms and incentive amounts change over time and vary by utility. Confirm current details with your utility or the Illinois Commerce Commission, and clarify whether the EPC captures those incentives on your behalf or you retain them. Our guide to Illinois commercial energy rebates covers how these programs generally work.

An EPC can be a sound way to fund efficiency improvements while shifting some performance risk to a provider with the expertise to manage it. The structure lives or dies on the quality of its measurement and verification and the clarity of its guarantee. An Illinois business that understands how savings are defined and substantiated, rather than accepting a headline number, is in a far stronger position to judge whether a given contract is worth signing.

Sources

• Illinois Commerce Commission
• ComEd
• Ameren Illinois

This guide explains how energy performance contracts work and how savings should be substantiated. It does not quote guaranteed-savings figures, costs, or incentive amounts, and it does not promise any level of savings; your results depend on your facility, the specific contract, and current program terms.