Power is a pace; energy is a total
A 10 kW load running for one hour consumes 10 kWh. The same 10 kWh could be consumed by a 20 kW load in half an hour. The energy total is equal, but the power requirement differs. Utilities use tariff-defined demand measurements to recover particular service costs. The actual averaging interval and billing method vary. Do not assume an instantaneous equipment rating equals the billed peak, or that every commercial tariff includes the same demand charge.
The bill can show measured and billed demand
Measured peak is the load recorded under the meter and tariff method. Billed demand can be adjusted by a minimum, contracted capacity, power-factor rule, seasonal condition, or historical ratchet. A lower current peak therefore does not always reduce the invoice immediately. Find the utility rate class and applicable demand formula. Supplier energy pricing is a separate component, so a lower cents-per-kWh quote may leave the delivery demand charge unchanged.
Look for the pattern before buying a solution
Several loads starting together can create a peak: HVAC, kitchen equipment, compressors, production, charging, or other equipment. Interval data and operating schedules help locate the relevant overlap. Safe scheduling, controls, or other qualified measures may help, but essential service requirements remain. A battery or equipment replacement needs a tariff-specific economic model. Reducing total kWh does not guarantee demand savings if the same peak remains, and moving load can create another peak if not tested.
Hypothetical same-energy comparison
Business A uses an illustrative 10,000 kWh with 50 kW of billed demand. Business B uses the same kWh but has 100 kW of billed demand. At an assumed $12/kW-month demand rate, the modeled charges are $600 and $1,200 before energy and other items. The difference is $600 despite equal consumption. These are teaching values, not utility rates. Verify actual tariff rules, including any ratchet, before applying the concept to a real bill.
Practical review checklist
- Find the account’s rate class, demand unit, averaging interval, and price in the utility tariff.
- Compare measured peak with billed demand and identify minimum or look-back adjustments.
- Use interval data and site schedules to investigate large coincident loads safely.
- Calculate kWh and demand effects separately before approving a savings claim or equipment purchase.
Questions & answers
Can kWh go down while demand charges stay the same?
Yes. The billed peak, ratchet, or minimum can remain unchanged even when total consumption falls.
Where should I learn about ratchets and controls?
Use the detailed commercial demand-charge guide and the actual utility tariff to inspect measurement, history, and feasible load actions.
Sources & scope
Primary references reviewed October 15, 2026. These sources support the stated concepts; actual tariffs, program rules and signed agreements govern the account. Decision examples and operational worksheets are original educational analysis.
- DOE FEMP: Evaluating your utility rate options
Demand, ratchets, time-of-use rates, coincident peaks, and standby charges. - EIA: Delivery of electricity to consumers
Physical grid, transmission, distribution, and provider roles. - EIA: Electricity prices and factors affecting prices
Fuel, weather, generation, grid costs, and retail rate differences.