EnPI (Energy Performance Indicator) is a value or ratio an organisation uses to measure how efficiently it uses energy. A typical example is electricity consumption per unit produced (kWh/unit).
What EnPI is used for
Kilowatt-hours alone say little: consumption grows with production and changes with the weather and the number of shifts. EnPI therefore relates consumption to what influences it (production, outdoor temperature, operating hours). Only such a value shows whether energy is being managed better or worse.
The ISO 50001:2018 standard requires an organisation to determine EnPIs suitable for its significant energy uses, monitor them and compare them with the baseline (EnB). The standard does not fix the number of indicators. The procedure for selecting and calculating them is described in the related standard ISO 50006.
Example from manufacturing
Illustrative numerical example: a welding shop consumes 120 000 kWh of electricity per month and produces 40 000 units. The EnPI is 3.0 kWh/unit. If the baseline was 3.2 kWh/unit, this is an improvement of roughly six per cent.
The following month, production doubles and consumption rises. Absolute kilowatt-hours look like a deterioration, but the EnPI may fall, which is the correct reading. Conversely, constant consumption while production falls is a warning sign.
How to monitor EnPI in practice
You need continuous data from meters and production data. The Energy Infra Scan platform calculates EnPI against the baseline and displays the cumulative deviation (CUSUM), so you can see when a saving took effect and whether it persists. More in the guide Energy consumption monitoring in manufacturing.
Frequently asked questions
What is the difference between EnPI and energy consumption?
Energy consumption is a measured value (for example in kWh). EnPI relates consumption to what influences it, such as production, and therefore allows a fair comparison between periods.
How many EnPIs must an organisation have?
ISO 50001 does not specify a fixed number. The organisation determines EnPIs that correspond to its significant energy uses and make it possible to track improvement in energy performance.