What Is a Demand Ratchet Clause on a Commercial Energy Bill?
A demand ratchet clause sets a minimum demand charge each month based on a percentage of the highest peak demand a business recorded over a multi-month lookback window — often the trailing 11 or 12 months — rather than only on that month's own actual peak. That means one unusually high-demand month, even a single short spike, can keep inflating a business's demand charge for months afterward, regardless of how much lower actual demand runs in the meantime.
How a ratchet differs from a plain demand charge
A standard demand charge, as covered in our guide to demand charges, bills a business for its single highest burst of power draw during any short interval within that one billing month — nothing about it looks backward or forward to other months. A ratchet clause adds a second layer on top of that: your billed demand for the month becomes the greater of two numbers — your actual peak demand that month, or a set percentage of your highest peak demand from a defined lookback period, commonly the trailing 11 or 12 months. If that percentage-of-past-peak number is higher than your actual current-month peak, you're billed on the ratcheted number instead, not on what you actually used.
Why the lookback window matters
Say a business's demand spikes unusually high in one summer month — new equipment, an operational surge, or even a metering anomaly — and then usage returns to its normal, lower pattern for the rest of the year. Without a ratchet clause, that spike would only affect the one billing period it happened in. With a ratchet clause, that same spike can set an elevated minimum demand charge for every month inside the lookback window that follows, because the utility's tariff defines the billed demand as a percentage of the highest peak seen during that whole trailing period — not the current month's own number. The exact percentage and lookback length vary by utility and rate tariff, so the specific mechanics are worth confirming against your own utility's published rate schedule rather than assuming a one-size-fits-all figure.
Why utilities use ratchet clauses
The same infrastructure logic behind an ordinary demand charge extends to the ratchet: a utility has to build and maintain transformers, substations, and distribution capacity sized for a customer's highest possible demand, not their average. Once a customer has demonstrated they can draw that much power, the utility argues it has to keep that capacity available on standby every month, not just in the month the peak occurred — a ratchet clause is how some rate tariffs recover that standby-capacity cost across the full lookback period rather than only in the single billing cycle where the peak actually happened.
What this means for a business
Ratchet clauses are a commercial and industrial rate structure — they show up in tariffs for larger business accounts, not residential bills, and they matter most for businesses with seasonal or occasional high-demand events: a manufacturer running an unusual production surge, a facility doing planned equipment testing, or any business with one busy month that's well outside its normal pattern. Because a single spike can echo across most of a year's worth of bills, it's worth treating demand ratchet exposure as a planning consideration before it happens — staggering any planned high-draw activity, understanding your utility's specific ratchet percentage and lookback period, and reviewing monthly demand readings against prior peaks so an unusual month doesn't come as a surprise months later when the ratchet is still active.
Frequently asked questions
How does a demand ratchet clause work?
A ratchet clause sets your billed demand each month as the greater of your actual peak demand that month, or a set percentage — commonly in a range utilities define in their own tariffs, such as 70% to 90% — of your highest peak demand recorded over a lookback window, often the trailing 11 or 12 months. That means one unusually high-demand month can set an elevated minimum demand charge for every month within the lookback period, even ones where actual peak demand was much lower.
Why do utilities use demand ratchet clauses?
Utilities size transformers, substations, and distribution capacity to handle a customer's highest possible demand, not their average. A ratchet clause lets the utility recover the cost of maintaining that capacity across the months when it isn't being fully used, rather than only charging for it in the single month the peak actually occurred.
How can a business avoid a demand ratchet penalty?
The main lever is avoiding unnecessary demand spikes in the first place — staggering equipment startup, using soft-start controllers on large motors, and scheduling non-essential high-draw activity (testing, maintenance runs, seasonal equipment) for when it won't set a new, unusually high peak that then ratchets forward into future months' minimum billing demand.
See this on your own bill
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Running a business with seasonal demand swings?
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