One power bill, and nobody knows which line ran it up
Without sub metering, the plant gets one bill for the whole site. Nobody can say what Line 2, the ovens or the compressor house cost last month.
On a demand tariff, one half-hour sets the demand charge for the month. A coincident start-up on a Monday can cost you until the next bill.
Ovens held at temperature and compressors left unloaded add kWh every hour, all year. They hide inside the total.
- The retailer data stops at the site boundary.
- An energy audit is a snapshot of one week.
- Handheld clamp readings go stale the day after.
- No energy cost per tonne, so quotes are a guess.
Worked example: what idle load costs out of hours
- 3,000 non-production hours a year
- 18 kW of avoidable idle load found
- Energy cost of $0.22 per kWh
- Illustrative only
| Idle energy | 18 kW x 3,000 h = 54,000 kWh a year |
|---|---|
| Cost of that energy | 54,000 kWh x $0.22 = $11,880 a year |
About $11,900 a year of idle load, before any demand charge saving. We can't promise it until we've surveyed your site.
How sub metering works on your switchboard
- 1
Meters go on each main feeder
Three-phase meters with current transformers sit on each line, oven and compressor feeder, and read kWh, kW and power factor.
- 2
Radio sends the readings
Each meter reports every 1 to 5 minutes by LoRaWAN. The meter keeps its kWh count, so a missed message loses nothing.
- 3
One gateway passes them on
The gateway sits outside the switchroom, so the steel cabinet doesn't block the signal. It uses site Ethernet, 4G or Starlink.
- 4
You see the balance and the tonnes
Main kWh less the sub-meters shows what's unmetered. A PLC or weighbridge count turns it into kWh per tonne.
What we put in your switchboard
We pick five to 10 feeders at the site visit, covering most of the load.
-
Three-phase energy meters
Read kWh, kW and power factor on each main feeder, with current transformers.
Reports every 1 to 5 min
-
Split-core CT nodes
Cover a feeder where a meter won't fit. Indicative only, not billing grade.
Reads every 5 to 15 min
-
Pulse counters
Read the pulse output on a meter you already have.
5 min count
-
LoRaWAN gateway
Sits outside the switchroom and collects every meter's readings.
Antenna outside the cabinet
-
4G, Ethernet or Starlink link
Carries the readings to your phone and dashboard.
Uses your site network or 4G
What lands on your phone when a line starts wasting power
We set the alert values from two to four weeks of your own readings.
-
Sat 2:10 am
Ovens feeder at 31 kW, 20% above its quiet baseline for 30 min. Check ovens and fans left on.
-
Mon 5:50 am
Site demand at 93% of this month's peak. Stagger the compressor and Line 1 start-up.
-
Sat 4:30 am
Ovens feeder back to 24 kW after a supervisor shut them down. Baseline restored.
Messages go to the people you nominate, by SMS to any phone and by email, with the reading and the time in every alert.
A monthly bill versus a reading every few minutes
| Topic | Today | With monitoring |
|---|---|---|
| Cost per line | One bill for the whole plant | kWh and kW on each main feeder |
| Idle load | Found in a one-off audit, if at all | SMS when night load steps up |
| Demand peak | Seen on the bill, weeks later | Warning as the half-hour nears the peak |
| Cost per tonne | A rough estimate | kWh divided by tonnes, every shift |
Sub metering in a Queensland plant
If your drives or relays already hold energy data, we use that first.
Idle baseload and peaks often trace back to the air system and the power factor. See compressed air leak monitoring, kVA demand charge warnings and power factor correction unit failure alerts.
We isolate and prove dead before we fit any meter or CT. Running a gin or mill? See cotton gin energy monitoring. If you on-charge a tenant, tell us at the site visit.
What sub metering costs
We fix the price after a short scoping call or a site visit. It depends on the number of meter points, the distance to the gateway and the backhaul. Ongoing support is available as a plan after handover.
Get a quote for sub meteringThe fixed price covers
- Meters, current transformers and nodes
- Gateway and backhaul
- Installation and electrical work under licence 1513082
- Alert set-up, baselines and commissioning against your main meter
- Training on the dashboard and alerts
- An ongoing support plan after handover
What this won't do
- It isn't billing grade. Your retailer meter is the authority on your bill.
- Meters used to bill others need pattern approval and verification under the National Measurement Act.
- Readings come every few minutes. They suit trends and alerts, not control or protection.
- It doesn't replace your retailer meter, protection relays, RCDs or safety systems.
- Metering doesn't save power by itself. Someone has to act on the alerts.