ISO 50001 · Step-by-Step Series · Energy Planning

ISO 50001 Clause 6: Energy Review, EnPIs, Energy Baseline and Objectives

Clause 6 is the technical core of ISO 50001:2018. This is where the Energy Management System (EnMS) stops being a statement of intent and becomes a set of data, indicators and measurable objectives: the energy review, Significant Energy Uses (SEUs), the energy baseline (EnB), energy performance indicators (EnPIs), and energy objectives, energy targets and action plans. This guide explains how to implement each element with real examples by industrial sector.

6.3 Energy review — the starting point of the entire EnMS

The energy review is the initial and periodic analysis that identifies where and how energy is used across the organisation. Under clause 6.3, the energy review must: analyse energy use and consumption based on measurement and other data; identify the areas of significant energy use; and determine the current energy performance of facilities, equipment, systems and processes related to the identified SEUs, as well as estimate future expected energy use and consumption.

The energy review is not a one-off exercise: it must be updated at defined intervals and whenever significant changes occur in facilities, equipment, systems or processes. In practice, most industrial organisations refresh their energy review annually.

The three steps of the energy review:

• Step 1 — Analyse energy use and consumption: gather bills, meter data and sub-meter readings for at least 12-24 months, broken down by energy source (electricity, natural gas, steam, compressed air, fuels).
• Step 2 — Identify Significant Energy Uses (SEUs): the equipment, systems or processes that represent a substantial share of total consumption, or that offer considerable potential for improvement.
• Step 3 — Identify improvement opportunities: prioritise actions with the highest energy-saving potential, considering technical and economic feasibility.

6.4 Energy baseline (EnB) — the point of comparison

The energy baseline (EnB) is the quantitative reference used to determine whether energy performance is improving. It is established from the information gathered in the energy review, corresponding to a specific period of time (typically 12 months, to capture seasonality and production variability).

Clause 6.4 requires the EnB to be adjusted (normalised) when the EnPIs no longer reflect the organisation's energy use and consumption, or when significant changes occur in relevant static or variable factors: process changes, operating pattern shifts, or changes to energy systems. Without this adjustment, comparisons can be misleading and lead to false conclusions about energy performance improvement.

Practical example: a ceramics plant sets its EnB using data from the previous 12 months: 8.2 GWh total consumption and 420,000 m² of fired product, giving an EnPI of 19.5 kWh/m². If production increases by 15% the following year due to a new line, the EnB must be normalised using a regression model that accounts for production volume, so that real energy performance — not just absolute consumption — can be fairly compared.

6.5 Energy performance indicators (EnPIs)

Energy Performance Indicators (EnPIs) are the quantitative values or measures of energy performance defined by the organisation (clause 6.5). They can be expressed as a simple metric, a ratio, or a more complex model. EnPIs allow the organisation to demonstrate improvement in energy performance against the EnB in an objective, auditable way.

The standard distinguishes between static factors (variables that affect consumption but rarely change, such as plant floor area or installed technology type) and relevant variable factors (which do change and must be built into the EnPI model, such as production volume, outdoor temperature or number of operating shifts).

6.2 Energy objectives, energy targets and action plans

Clause 6.2 requires the organisation to establish energy objectives and energy targets consistent with the energy policy, taking into account the identified SEUs and the improvement opportunities arising from the energy review. Each objective must be supported by an action plan defining: what will be done, what resources are required, who is responsible, when it will be completed, and how the results will be evaluated.

Ten examples of energy objectives and targets by industrial sector:

Frequently asked questions about ISO 50001 Clause 6

How often must the energy review be updated?

ISO 50001:2018 requires it to be updated at intervals defined by the organisation, and whenever significant changes occur in facilities, equipment, systems or processes. In industrial practice, an annual review is most common, typically aligned with management review, though the highest-consuming SEUs may need more frequent monitoring.

What is the difference between an EnPI and the energy baseline (EnB)?

The EnB is the fixed (or normalised) reference point against which performance is compared; the EnPI is the indicator calculated periodically to measure current performance and compare it with that reference. Without a well-defined EnB, the EnPI has nothing to compare against, and without a well-built EnPI, the EnB cannot demonstrate improvement.

When must the energy baseline be normalised?

Clause 6.4 requires the EnB to be adjusted when the EnPIs no longer adequately reflect the organisation's energy use and consumption, or when significant changes occur in relevant static or variable factors — for example, a plant expansion, a technology change, or a substantial shift in the production mix. Without this normalisation, energy performance comparisons lose validity.

Does every energy objective need an action plan?

Yes. Clause 6.2 requires that, to achieve energy objectives and targets, the organisation establish action plans that include the responsible person, resources, method and timeframe, as well as the process for verifying results. An energy objective without a documented action plan does not meet the requirements of the standard.

How are Significant Energy Uses (SEUs) identified?

The standard does not set a single percentage threshold; it is up to the organisation to define its own criteria (for example, processes or equipment representing more than a chosen share of total consumption, or offering considerable improvement potential). In industrial plants, 3 to 6 SEUs typically account for between 60% and 80% of total energy consumption, allowing management resources to be focused where they have the greatest impact.

IgeraIndustria Energy Team · Updated 2026-08-06 · ISO 50001 step-by-step series