Why Measure Energy Consumption Continuously
A supplier's invoice shows total consumption for the month. It does not tell you which line or technology caused it, or exactly when it occurred. Continuous monitoring adds what invoices lack: the time profile, a breakdown by point of consumption and the link to production.
This makes it possible, for example, to identify consumption outside operating hours (weekends, night hours, breaks), detect peaks that increase reserved capacity, or assess whether consumption has actually fallen after a savings investment. The quickest savings often lie in the energy that machines use when nothing is being produced.
What to Measure
Start with what consumes the most and gradually add more metering points. A practical metering hierarchy is usually:
- Main meters at the point where energy enters the site (electricity, gas, heat). They are relevant for billing and are used for the energy balance.
- Metering at switchboards and sub-circuits for halls, lines and operations.
- Metering of significant energy uses: large technologies, compressors, furnaces, cooling, heating.
- Supplementary variables: production in units or tonnes, outdoor temperature, shifts, machine states.
Besides electricity, it may make sense to meter gas, heat, steam, compressed air and water. We typically collect data in quarter-hour intervals, which matches electricity billing and reveals the load profile.
How Data Is Collected
Meters are connected via gateways, which collect values (for example from electricity meters, gas meters or IoT sensors) and send them to the platform. It is important that the system can work with imperfect data: connection outages, out-of-sequence data or reset counters. Consumption should be calculated from the counter difference, not from an estimate based on instantaneous power, and every reading should carry a quality flag (measured, filled in, estimated).
The Energy Infra Scan platform follows these principles. It displays data in quarter-hour intervals and distinguishes measured from calculated data, so that an estimate is never passed off as a measurement.
Baseline and EnPI: How to Tell You Are Improving
Consumption on its own is misleading: it rises with production and changes with the weather. That is why specific consumption (kWh per unit or tonne) is calculated and compared with the baseline, i.e. with the expected consumption under the same conditions. The difference between actual consumption and the baseline shows whether you are improving and by how much.
These indicators (EnPI) are the foundation of ISO 50001. In addition, the data lets you set targets and verify whether measures have actually delivered savings after implementation.
How to Read the Data: From Load Profile to Measures
A practical analysis usually starts with simple views:
- Daily load profile: how power demand changes during the day and across shifts. A flat line at night indicates a constant base load that can be investigated.
- Working day versus weekend: a large difference indicates that many appliances remain in operation even with zero production.
- Comparison of shifts and lines: the same output with different consumption reveals differences in settings or operation.
- Consumption vs. production: points that deviate from the regression line are worth investigating.
Each finding becomes a specific action with a responsible person and a deadline. Once it is implemented, the same view is used to verify that consumption has genuinely fallen.
Peaks, deviations and alarms
Monitoring is not only for retrospective evaluation. Well-configured alerts warn you in good time about:
- quarter-hour peak approaching the reserved capacity, which may lead to an exceedance and higher charges,
- deviation from the usual profile, for example atypical consumption at weekends or at night,
- data outage from a meter or gateway, so that distorted figures are not used in calculations,
- power quality, if you measure it.
Typical sources of wasted energy that monitoring reveals
- Consumption outside operating hours. Machines, ventilation, lighting or heating run at weekends and at night because nobody switched them off.
- Compressed air leaks. The compressor runs continuously to maintain pressure in a leaking network, which shows up as increased consumption even without production.
- Equipment on standby. Furnaces, lines or pumps remain needlessly heated or running between shifts.
- Incorrect settings. Controls, time schedules or process parameters do not match actual operation.
- Simultaneous start-ups. Switching on large appliances at the same time creates peaks that increase the reserved capacity.
Such losses get lost in monthly invoices, but in quarter-hour data they are visible at a glance.
Data quality: what to watch out for
Monitoring is only useful if it can be trusted. The most common pitfalls are:
- Connection outages and out-of-sequence data. The system must be able to backfill delayed readings and mark what is measured and what is calculated.
- Counter resets and meter replacements. A negative or step increment must not be recorded as consumption.
- Instrument transformer ratios. An incorrectly entered ratio distorts all values; this is why the raw value before conversion is stored as well.
- Timestamps. Time is assigned by the gateway, not the meter, so that the data are comparable.
- Meter verification. Meters should be checked regularly and configuration changes recorded.
What you get from the data
- Savings: a list of places where energy is needlessly wasted and the verified impact of measures.
- Inputs for an energy audit and for ISO 50001 certification, without manually searching for data.
- Costs broken down by cost centre, line and product, plus invoice checking.
- Carbon footprint calculated from measured consumption and emission factors (more in the article on carbon footprint).
Custom solution or ready-made platform
Measurement can be built from in-house components, but this requires development, operation and maintenance: data collection, time-series storage, calculation of indicators, alerts and reports. A ready-made platform supplies these parts and the company can focus on interpreting the data. The Energy Infra Scan platform is built for manufacturing plants and follows the requirements of ISO 50001, so it works with EnPI indicators, baselines and materials for the auditor.
How to get started
You do not have to measure everything at once. We offer three levels: ISO Base (documentation and indicators to comply with the law without complex measurement), Start (automatic consumption monitoring from meters and IoT sensors) and Advanced (energy consumption and CO₂ emissions per product, order or line). You can find a comparison on the Products and services page.
Frequently asked questions
What is measured in energy monitoring?
Most often electricity at the main supply, in switchboards and at significant equipment, then gas, heat, compressed air or water, and supplementary variables such as production output and outdoor temperature.
How often is data collected?
Typically every quarter-hour, which matches electricity billing and shows the load profile including peaks.
What are the baseline and EnPI for?
The baseline defines expected consumption under comparable conditions, while an EnPI (for example kWh per unit) shows performance. Together they show whether you are genuinely improving or simply producing less.
Do I need monitoring to comply with the Energy Management Act?
The law requires an energy audit or ISO 50001 certification depending on consumption. Monitoring does not replace these obligations, but it provides data that make them considerably easier to fulfil.