One bad half hour sets your demand charge for the month
Your kVA demand charges come from a single half hour. Ergon bills the highest 30-minute average at the connection point, once a month.
So it's the Monday restart that costs you. The compressors kick in, the ovens start heating, and nobody's watching the meter.
The bill shows the peak weeks later. By then the month's already locked in.
- kVA includes reactive power, so a poor power factor lifts the charge without lifting your kWh.
- Restarts often land right on 5pm, when the peak window opens.
What one Monday restart can cost you
- Your worst half hour each month is a Monday restart at 400 kVA.
- Normal running is 340 kVA.
- Network rate is an illustrative $20 per kVA per month, not a published Ergon price.
- Staggering holds the peak at 340 kVA in 10 of 12 months.
| Peak avoided | 60 kVA |
|---|---|
| Illustrative rate | $20 per kVA a month |
| Months avoided | 10 |
60 kVA x $20 x 10 months comes to about $12,000 a year of network demand charge avoided on these assumptions. Your tariff, season and site will change the real figure.
How the kVA demand charges warning works on your main board
- 1
A power meter reads the main board
Current transformers and voltage taps sit downstream of the utility meter and read kW, kVA and power factor.
- 2
A node sends it every few minutes
A LoRaWAN node reads every 1 to 5 minutes and sends by radio to a gateway near the board.
- 3
The system projects the half hour
It works out where the current half hour will finish, using the kWh so far and the load right now.
- 4
The shift lead gets a text
At about 90% of target you get a warning. At 100% you get an urgent one, in time to delay a start.
What we put on your main board
-
Three-phase power meter
Reads kW, kVA and power factor on the main board, downstream of the utility meter.
Reads every 1 to 5 min
-
Load clamps (optional)
Sit on the compressor bank, ovens and pumps so an alert shows which loads were running.
One clamp per big load
-
LoRaWAN node
Takes the meter readings and sends them by radio, with a buffer if the link drops.
Buffers readings offline
-
Site gateway
Sits near the board, collects the readings and passes them on to your phone.
Mains power, battery backup
-
4G backhaul
A second path out, so the warning still works if the site network drops.
Starlink where 4G is weak
What lands on the shift lead's phone
We set the targets from your bills and interval data, then tune them as the bills arrive.
-
Mon 5:08 pm
Main board half hour projected 405 kVA, target 380. Compressors and oven both running. Hold the next start.
-
Mon 5:14 pm
Urgent: projected 392 kVA, target 380. Drop a non-critical load before 5:30.
-
Mon 5:31 pm
Half hour closed at 366 kVA, under target. Highest so far this month: 371 kVA.
Messages go to the people you nominate, by SMS to any phone and by email, with the reading and the time in every alert.
Reading the bill versus watching the half hour
| Topic | Today | With monitoring |
|---|---|---|
| When you see the peak | Weeks later, on the bill | Inside the half hour, on your phone |
| Can you still act | No, it has already happened | Yes, delay or stagger a start |
| Which load did it | A guess from memory | Clamps show what was running |
| Power factor faults | Spotted when kVA climbs on the bill | Alert when power factor drops |
kVA demand charges on a plant main board
Compressors, ovens and pumps all want to start together after a shift change. Clamps show which one tipped the half hour.
Poor power factor lifts kVA without lifting kWh, so pair this with power factor correction failure alerts. Chasing air leaks? See compressed air leak monitoring.
For energy cost line by line, see sub metering. Running a gin? Read cotton gin demand charges.
What kVA demand charge monitoring costs
We fix the price after a short scoping call or site visit. It depends on the number of loads, the distance to the gateway and the backhaul. Ongoing support is available as a plan after handover.
Price a demand peak warningThe fixed price covers
- Power meter, current transformers, node and sensors
- Gateway and 4G or Starlink backhaul
- Installation and electrical work under licence 1513082
- Alert set-up and targets from your interval data
- Commissioning against your retailer's interval data, and shift lead training
- An ongoing support plan: we keep it running and tune targets as bills arrive
What this won't do
- It sends alerts and records. It doesn't shed load, and it isn't a kVA demand controller.
- Readings are indicative and won't match your billing meter exactly. We compare them during commissioning.
- It can't see a spike inside one minute, like a direct-on-line motor start.
- An alert only helps if someone acts on it. It doesn't replace your protection relays or safety systems.