One bad half hour on Monday morning sets the whole month
Cotton gin demand charges come from a single interval. Ergon's tariff guide bills the highest 30-minute average kVA at your connection in the month.
Cleaners, stands, press and fans all come up together after a weekend. That half hour sets the charge, and you find out when the bill lands weeks later.
A gin only runs four to six months, but Queensland Country Life reported in 2017 that high-demand gins pay a large amount for every month they operate, even for one day.
- Starts stacked on top of each other add up their starting currents.
- A poor power factor lifts kVA without lifting kWh.
What one bad Monday can cost across a season
- An illustrative $20 per kVA per month. Check your own price list.
- Without a stagger, the monthly worst half hour is 1,900 kVA.
- Staggered starts hold it to 1,700 kVA over five months.
| Extra demand set by the bad start | 200 kVA |
|---|---|
| 200 kVA × $20 × 5 months | $20,000 |
About $20,000 a season on these assumptions. Your real figure depends on your tariff, authorised capacity and how the season runs.
What we put on the gin main board
We assume an independent power meter, because using the billing meter's pulse output needs written agreement from the retailer or network.
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Three-phase power meter
Reads kW, kVA and power factor on the main incoming supply, downstream of the billing meter.
Reads every 1 to 5 min
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Current transformers
Fitted on the incoming phases by our electricians with fusing, working under isolation.
Sized to your main board
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LoRaWAN node
Sends the meter readings by radio to the gateway.
No wifi needed
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Gateway
Sits near the switchboard and passes readings to the dashboard and SMS.
Starlink or 4G backhaul
How cotton gin demand charges get a warning at the main board
- 1
A meter reads the main board
A three-phase power meter with current transformers reads kW, kVA and power factor every 1 to 5 minutes.
- 2
A node sends it by radio
A LoRaWAN node passes the readings to a gateway near the switchboard. No wifi needed on the plant.
- 3
The system projects the half hour
It works out where the current half hour will finish. This is our own calculation, not a utility method.
- 4
The shift lead gets the text
At about 90% of your target, an SMS goes out. At 100%, an urgent one goes to the gin manager too.
What lands on the shift lead's phone on a Monday start
We set the target from your bills and interval data, then tune it as the season shows how the gin runs.
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Mon 6:15 am
Gin main board projected 1,680 kVA this half hour, 93% of the 1,800 target. Hold the next start.
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Mon 6:20 am
Urgent: projected 1,760 kVA, 98% of target. Press and fans still to come. Space them out.
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Mon 6:31 am
Half hour closed at 1,690 kVA, under target. Back to normal.
Messages go to the people you nominate, by SMS to any phone and by email, with the reading and the time in every alert.
The monthly bill versus a warning at 6:15 am
| Topic | Today | With monitoring |
|---|---|---|
| When you see it | On the bill, weeks later | Partway through the half hour |
| Retailer portal | Interval data a day or more behind | A reading every 1 to 5 minutes |
| Who knows | The office, after the fact | The shift lead, on their phone |
What gin demand monitoring costs
We fix the price after a short scoping call or a site visit. It depends on meter points, gateway distance and backhaul. Ongoing support is available as a plan after handover.
Price a demand warning for the ginThe fixed price covers
- Power meter, current transformers, node and gateway
- Starlink or 4G backhaul set-up
- Installation and electrical work under licence 1513082
- Alert set-up and a few days checked against retailer interval data
- An ongoing support plan: faults fixed, batteries and sensors replaced, targets tuned
Cotton gin demand charges across a short, heavy season
A gin runs from about April to August, so the charge starts in the first month. We install before the first bale.
The same meter shows what each motor group costs you. See gin energy monitoring for every motor group on the MCC. If kVA climbs without kWh, check gin power factor correction monitoring.
Running a mill or a receival site? Same method, different load list: mill drives, or aeration fans and conveyors. Have a look at gin compressed air monitoring, or the general warning before kVA demand charges are set.
What this won't do
- It doesn't switch load. A person acts on every warning, or we quote a controls change separately.
- It can't see a spike inside one minute, like a big motor starting direct-on-line.
- Readings are indicative. The billing meter is the reference for charges.
- It doesn't change authorised capacity, agreed demand or your tariff. Those are reviewed with your retailer.