Commercial Interval Data: Request, Validate, and Use It

Monthly bills show how much electricity a facility used; interval data shows when it used it. That timing can change supplier pricing, index exposure, peak risk, and the value of operational measures.

An interval file is not automatically analysis-ready. Confirm the source, units, timestamp convention, interval length, daylight-saving treatment, and completeness before calculating a load shape.

Download the interval-data validation checklist CSV.

Request data from the accountable source

For ComEd, use the customer's authorized account and data-access process. ComEd's Hourly Pricing FAQ provides official context for hourly usage and prices. For Ameren Illinois, customers can access usage history through Ameren.com; Ameren also describes Share My Usage for approved third-party access by residential and small commercial DS-2 and DS-3A customers.

Ameren's February 2026 RES Handbook states that authorized retail suppliers can request account-specific usage and that available historical reports may include kWh, demand, interval data, and revenues. Access rights and available fields depend on the customer, meter, authorization, and utility process.

Request:

• all meters and service points in scope;
• at least the intended pricing lookback period;
• native interval resolution, not a chart screenshot;
• CSV or other machine-readable format;
• time zone and daylight-saving convention;
• units and whether values represent interval energy or average demand;
• meter multipliers or loss-adjustment status;
• a file-generation date.

Validate before analyzing

For each meter, calculate the expected interval count. A non-leap year has 8,760 hourly periods; 30-minute and 15-minute files have proportionally more, subject to the source's daylight-saving convention. Do not “fix” a missing or duplicate daylight-saving interval until the utility's timestamp convention is known.

Run these tests:

1. Duplicate timestamps by meter.
2. Missing intervals and long gaps.
3. Negative values and whether export generation explains them.
4. Zero runs during normal operating periods.
5. Unit and multiplier consistency.
6. Monthly interval sums versus billed kWh.
7. Maximum interval value versus billed demand, accounting for definitions.
8. Meter additions, removals, and account changes.

Set a documented reconciliation tolerance. A difference should be investigated, not silently spread across intervals.

Convert interval energy to demand correctly

If a 15-minute interval contains kWh consumed during that interval, average kW for the interval is:

interval kW = interval kWh ÷ 0.25 hours

For 30 minutes, divide by 0.5; for hourly data, divide by 1. Confirm the file definition first because some exports already contain kW.

Procurement uses

Interval data supports:

• supplier load-shape pricing;
• on-peak/off-peak volume analysis;
• index-price backcasts using matched hourly prices;
• load-factor measurement;
• peak coincidence investigation;
• operating-hour and baseload diagnostics;
• evaluating blocks, collars, or other structured products.

Avoid choosing a product because it backtests well on one unusual year. Model weather or operating changes and show at least one stress case.

Operational uses

Plot a typical weekday, weekend, monthly peak day, and heat/cold extreme. Look for overnight baseload, simultaneous equipment starts, HVAC pre-start, compressed-air leakage, refrigeration cycling, and production schedule effects.

An observed pattern is a hypothesis, not proof. Confirm it with facility operators before assigning a cause or savings estimate.

Privacy and authorization

Usage data is customer-specific. Limit access, retain authorization, avoid emailing unprotected files when a secure channel is available, and remove account identifiers from shared analytical samples. A broker or supplier should explain who can access the data and how long it is retained.

Minimum analysis output

A defensible report includes the raw-file hash or preserved original, validation results, excluded intervals, reconciliation to bills, assumptions, load-shape charts, and a statement of what the data cannot establish. Keep transformed data separate from the source file.

Why interval data changes the answer

A monthly bill answers "how much" and "what was the single peak." Interval data answers "when," and for a commercial account "when" is where much of the cost is decided. Two facilities can consume the same annual kilowatt-hours yet face very different demand charges and capacity obligations because one concentrates its load into a few sharp peaks and the other spreads it evenly. Only interval data reveals that difference. It is what lets a supplier price a load accurately rather than with a cushion, what makes a time-of-use or block-and-index product evaluable rather than a guess, and what turns a demand-reduction idea into a testable hypothesis about specific hours. Without it, a larger account is being priced and managed on averages that hide its actual behavior.

Reconcile before you rely

The single most important discipline is reconciliation: the sum of the interval kWh across a billing period should tie back to the billed kWh on the bill for that period, within a small tolerance. If it doesn't, something is wrong — a units mismatch, a multiplier not applied, missing intervals, or a timezone/daylight-saving shift — and the data cannot be trusted for pricing until it's resolved. Preserve the raw export exactly as received (keep its hash or a read-only copy), do the reconciliation on a working copy, and document every excluded or corrected interval. A load-shape analysis built on unreconciled data can look convincing and still be wrong.

How this feeds the rest of procurement

Clean interval data is an input to nearly everything else: it sharpens the demand-charge review, it grounds the capacity/PLC discussion in the account's real peak behavior, and it makes the offer comparison and any structured-product decision defensible. It is most valuable for larger, demand-billed, or load-variable accounts; a small, steady account may not need it. Bring it into the broader procurement process rather than treating it as a standalone exercise.

Source check date: July 19, 2026. Utility portals and eligibility rules can change.