Glossary
FMCG and manufacturing

What is Maximum demand charges?

Definition

Maximum demand charges bill a commercial or industrial customer for the highest average power drawn over a short metering interval in the billing period, in kW or kVA, separately from energy in kWh.

Who pays them

Plants, hospitals, airports, campuses and large commercial buildings on demand-metered tariffs pay them. Finance sees a line on the bill, while operations controls the number through start-up sequencing and scheduling, which is why both teams need the same interval data.

How demand is measured: one tariff example

Each tariff sets its own interval and billing rules. Pacific Gas and Electric Schedule B-20, which serves customers with maximum demand of 1,000 kW or more, averages demand over 15-minute intervals and bills the highest of those averages in the billing month, allowing a 5-minute interval for customers whose use fluctuates severely. It also bills a separate maximum within the peak period. Other utilities use different intervals, contract demand limits or ratchets that carry a peak into later months, so the current tariff schedule is the reference.

How Aqueduct shows a peak forming

aQ EnergySmart reads interval kW and kVA at the main incomer and on feeders, and load disaggregation shows which feeders made each monthly peak. Where control is enabled, with owner approval, Smart Controls can stagger start-ups or hold back non-critical loads before a new interval peak is set, and command history records every action taken.

Questions

Maximum demand charges: common questions

A maximum demand charge is the part of a commercial electricity bill set by the site's highest short burst of power, not by total energy. One badly timed interval can set the charge for the whole billing period. Aqueduct's approach is on the peak demand management page.

It is the load a customer agrees with the utility in its supply agreement. Some tariffs bill a minimum share of it even in quiet months and add charges when actual demand goes over it.

It can, if it discharges during the intervals that set the peak. Sizing one needs interval data covering the seasons when peaks occur, not a single month.

See Aqueduct on your own facility.

Bring a site, a utility bill or a question. We will show you where the loss is.