Contract demand is the capacity agreed with the DISCOM, maximum demand is the peak recorded by the meter, and billing demand is the demand value used for charges. These are not the same as monthly units. A factory can have normal energy consumption and still suffer from a demand problem.
This is why owners should not treat demand as a technical footnote. Demand is where a few minutes of plant behaviour can affect the monthly bill.
What is the difference between CD, MD and billing demand?
Contract demand, often called CD, is the agreed demand level for the connection where such agreements apply. Maximum demand, or MD, is what the meter records as the peak during the billing period. Billing demand is the value charged as per the applicable tariff rule.
The tariff order decides how billing demand is derived. It may refer to recorded demand, contract demand or another rule-based value. Do not guess it from a WhatsApp explanation. Read the bill and current tariff.
The contract demand guide is the right starting point when the bill shows multiple demand fields.
How are peaks captured?
The meter records demand according to its configured method and billing rules. Owners do not need to memorise the internal meter algorithm, but they must understand that demand is time-based, not month-total-based.
Peaks often come from coincidence:
- compressors start as the shift begins
- a furnace heats while pumps and cooling tower are already running
- several machines restart after a power interruption
- maintenance tests run during production
- HVAC starts together after a lunch break
The plant team may say, “It happened only once.” The meter may still record the peak for billing review.
Why can one shift hurt the bill?
Shift start is a common demand trap. Operators want every line ready quickly. Utilities are started together. Motors, heaters, compressors and pumps all come alive.
The monthly kWh from that event may be small, but the demand peak may be large. This is especially painful when the plant already runs close to contract demand.
Use factory load profile explained to identify the exact time of the peak. Once the timestamp is known, the fix becomes operational: sequence starts, tune controls, avoid unnecessary trial runs during peak periods and review automation logic.
How is demand different from units?
Units measure energy over time. Demand measures the rate of draw during a period. A slow, steady load can consume many units without a sharp peak. A short combined start can create high demand without adding much energy.
That distinction matters in production discussions.
| Question | Energy view | Demand view |
|---|---|---|
| What did we use? | kWh or kVAh | kW or kVA peak |
| What drives it? | operating hours and load | coincident running |
| Who influences it? | production and utilities | scheduling and starting |
Both matter. Cutting useful production to reduce demand is usually bad business. Smoothing avoidable peaks is sensible.
How should demand be reviewed monthly?
Put demand review into the monthly bill process. Track contract demand, maximum demand and billing demand separately. Add notes for any new machine, major trial, outage restart or process change.
If maximum demand is creeping up, do not wait for a penalty or forced load extension. Investigate the time of peak and compare with operations.
Demand review should ask:
- Was the peak expected?
- Did it happen at shift start?
- Did any new load change the pattern?
- Was production output high enough to justify it?
- Is contract demand still suitable for the business?
This connects directly with load factor for production planning, because load factor links demand utilisation with energy use.
Tips from the field
- Record maximum demand from every bill in a separate column, not as a note hidden inside the PDF.
- Ask the plant team what was running at the time of peak before buying equipment to “solve” demand.
- Stagger compressor, furnace, pump and HVAC starts where the process allows it safely.
- Review demand immediately after commissioning a major machine because the first month often reveals the new peak behaviour.
- Do not reduce contract demand only because one low month looked comfortable; compare several normal operating months and future orders.
- Keep outage restart events in the tracker because restart sequences can create abnormal demand.
What should owners do with demand findings?
First, confirm the bill fields. Then identify the peak time. Then ask whether the peak was useful, avoidable or caused by a one-off event. Only after that should you consider automation, soft starters, VFDs, sequencing, load extension or contract demand revision.
Demand is not a punishment for using power. It is the electrical signature of how much capacity the plant asks from the system at once. Manage that signature and the bill becomes easier to control.
When should contract demand be revised?
Contract demand revision should be based on normal operations, near-term orders and site capacity. Do not reduce it after one weak sales month. Do not increase it blindly because a vendor is supplying a large machine.
Use bill history, load profile data and the production plan together. If MD is repeatedly close to the agreed level during healthy production, load extension may be sensible. If MD is high only because of avoidable simultaneous starts, fix scheduling first. If the plant is oversized after a business change, revision may reduce wasteful capacity cost where tariff rules permit.
This decision sits between engineering and finance, so both teams should see the same evidence.
When in doubt, run a review period before filing a change. Track peak timing, production level and upcoming orders. A rushed demand change can create fresh problems if the business pattern returns to normal or a new customer order lands soon after the paperwork is submitted.