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DIN publishes FAQ on energy-related performance according to ISO 50001:2018

Determination and presentation of the improvement of energy-related performance according to ISO 50001:2018


The improvement of energy-related performance is the central goal of energy management systems according to ISO 50001:2018. The standard requires proof of the continuous improvement of energy-related performance. According to the standard, this can be provided by means of energy performance indicators (EnPIs), in which the initial value (EnB, en: energy baseline) and the current EnPI value are determined at regular intervals for all EnPIs, normalized if necessary, compared and summarized. The following are questions from company practice which were submitted to and answered by the German Standards Committee with regard to the proof or presentation of the improvement.


of the working committee NA 172-00-09 AA “Energy efficiency and energy management” (in the DIN standards committee Fundamentals of environmental protection) to questions in connection with the improvement of energy-related performance according to DIN EN ISO 50001:2018-12:

1. Is a single index enough?

Excluding the borderline case of a company with only one energy source and significant energy use (SEU, en: significant energy use), several energy-related key figures are necessary for the operation of an energy management system (EnMS) and for the presentation of the improvement of the energy-related performance.

2. what makes an indicator an EnPI (methodology, influencing factors, normalization) ?

All indicators that show the actual energy-related performance are EnPIs. If the actual performance is not visible, e.g. due to distorting, significant influencing factors (weather, capacity utilization, etc.), we are not dealing with an EnPI.

Key figures that take into account the relevant variables and can thus be normalized are EnPIs also in the sense of ISO 50006. (See DIN EN ISO 50001:2018-12, 3.4.4 and DIN EN ISO 50001:2018-12, 6.4)

3. is a global indicator necessary, and must it improve?

In addition to EnPIs for the SEUs, key figures are required for the organization as a whole, because the addressee of all requirements of ISO 50001:2018 is “the organization”, which has to achieve and record improvements in its system and performance. The organisation-related (global) indicators should provide a general trend development, which should also be reflected in the specific indicators (of the SEUs and the measures).

4. do you need at least one EnPI?

for each SEU?
Yes, compare DIN EN ISO 50001:2018-12, 6.3 and 6.4

5. how are improvements outside the SEUs evaluated?

All improvements are incorporated into the overall view of the organisation. It is therefore essential to determine not only the energy-related performance of the individual SEUs but also the energy-related performance of the organisation as a whole. In this way, improvements or deteriorations in areas that are not SEUs can be identified and taken into account.

6. does the methodology for measuring performance need to be included in the action plans?

Yes. compare DIN EN ISO 50001:2018-12, 6.2.3

7. at what level is the improvement to be demonstrated in multi-site procedures?

The (multi-site) organisation as a whole must demonstrate its performance improvement (see answers to questions 1.-3.) The contributions of the individual sites must be available. It is not generally necessary for each site to demonstrate an improvement in energy-related performance on its own.

8 What and how must/can be measured? Measurement accuracy ?

ISO 50001:2018 does not give a detailed specification of what needs to be measured. However, data must be available on the following aspects (comparisons DIN EN ISO 50001:2018-12, 6.6):

“a) the relevant variables regarding SEUs;
b) the energy consumption in relation to SEUs and organisation;
c) operational criteria related to SEUs;

d) static factors, if applicable;
e) data specified in action plans.”

It is also possible that the data is not based on measurements. Should the organisation decide to use measurement, the accuracy and repeatability of the measurement shall be ensured.

“The organisation shall define and implement an energy data collection plan appropriate to its size, complexity, resources and measurement and monitoring equipment.”.

9. Are you free to define the SEUs?

The definition of the SEU should enable the organisation to establish a focus-oriented energy management. The criteria for the systematic definition of the SEUs are determined by the organisation itself. (compare DIN EN ISO 50001:2018-12, 3.5.6)

The organisation is therefore free to define the SEU, but must establish the relevant criteria. When defining the SEU, it must take into account its context. Since organizations or technical savings opportunities change over time, the SEUs must be reviewed at regular intervals and adapted if necessary.

10. how to deal with adjustments of the energy baseline (EnB, en: energy baseline) by ?

The baselines must represent suitable comparative figures. For this purpose, they may of course be changed and adapted according to ISO 50001:2018 under certain circumstances.

ISO 50001:2018 describes three cases in which an adaptation is mandatory. See DIN EN ISO 50001:2018-12, 6.5:

“The EnB(s) must be modified if one or more of the following cases occur:

a) the EnPI(s) no longer reflect the energy-related performance of the organisation
b) there were major changes in the static factors;

c) in accordance with a predetermined procedure.”

11. how to deal with “falling baselines” (see examples in ISO 50003)?

The baselines must represent suitable comparison parameters that allow the actual state to be compared with the expected state (based on the reference period). (Compare DIN EN ISO 50001:2018-12, 3.4.7)

In order to ensure adequate comparability, effects of relevant variables can be taken into account by normalisation in the EnBs. If a decline in the performance of an aggregate is expected over time, this can be taken into account in the determination of the normalised baseline depending on the time of observation, which ultimately leads to a baseline “falling” over time.

12 How to deal with non-achievement of objectives? (e.g. if a measure does not achieve the desired effect, a SEU “gets out of hand”)

The question arises whether the “non-achievement of objectives” is the consequence of a non-functional/non-effective EnMS or is due to other causes. In any case, such deviations must be identified and appropriate corrective measures (possibly also an improvement of the planning process) must be initiated or implemented. In the event of a system failure (significant non-conformity), corrective actions must be taken before a certificate is issued.

13. How do you deal with performance degradation around ?

See answer to question 12.

Continual performance degradation means the non-fulfilment of a requirement per se and also indicates that the EnMS is not working effectively. Depending on the severity of the non-compliance, a major non-conformity may be a major deviation that blocks a positive certificate decision until the problem is resolved, or a minor non-conformity that results in at least one corrective action, the effectiveness of which must be verified.

14 How should the design of combined heat and power plants be assessed when evaluating the improvement in energy-related performance ?

The inclusion of a CHP plant may in some cases result in increased energy use within the organisational boundaries, although the overall balance (primary energy consumption) improves. The installation of a cogeneration unit may count as a new/changed static factor, with the consequence that a new baseline has to be established, resulting in a new, not deteriorated but also improved energy-related performance.

15. can EnBs for the different EnPIs come from different time periods? If so, how does one proceed in such a case with the aggregation of savings that relate to different reference periods to ?

In order to demonstrate the improvement in energy-related performance, a comparison between the reference situation (represented by the EnB) and the actual situation (represented by the current EnPI values) shall be carried out. For the presentation of the improvement of the energy-related performance it is crucial that a consideration of the whole organisation takes place.

In addition, the developments of the SEUs and individual projects are also considered. The evaluation of the development can be done by an overall view without concrete aggregation across all projects, SEUs and others. If an organisation wishes to aggregate the individual developments, different reference periods must be taken into account in this procedure.

16. what is the relationship between the improvement of energy-related performance and the energy targets?

The improvement in energy-related performance shows the change compared to the situation in the reference period. The degree to which the targets have been achieved is determined by comparing the current EnPI values with the target values. It is conceivable that an improvement in energy-related performance compared to the baseline is present, although the target has not been achieved. In this case, the organization must determine how to deal with the “non-achievement” of the targets and what corrective measures are to be taken. In addition, it is conceivable that targets may be exceeded. Here too, it would be necessary to analyse what caused the overachievement in order to generate a learning effect (for example for the goal-setting process).

17. are (partial) deteriorations permitted if an improvement has been achieved in the overall view?

See answer to question 12.

18: What is the difference between improving energy-related performance and improving energy efficiency?

ISO 50001:2018 defines energy efficiency as one (possible) component of energy-related performance. See DIN EN ISO 50001:2018-12, 3.4.6:

In principle, a reduction in energy consumption can also be an improvement in energy-related performance. In practice, because of the required normalization, an improvement in energy-related performance is usually always an improvement in energy efficiency, because the output of an energy-consuming process is regularly the only or most significant relevant variable (with which normalization then also takes place).

Note: If there are no significant factors influencing energy consumption (and therefore no normalisation is required), absolute energy consumption can also be used as an EnPI.

19. if a certain level of improvement of energy-related performance is required ?

Above and beyond legal requirements, the organisation itself determines which requirements it wishes to meet and what level/objectives it wishes to set itself. The standard does not provide a concrete specification of the level of improvement (see application area ISO 50001:2018)

20. can there be an improvement even if the total energy consumption has increased?

Yes, as long as it can be demonstrated that efficiency has improved (see answer to question 18.). A comparison of the expected energy consumption based on the EnB and the actual energy consumption allows the improvement in energy-related performance to be shown.

Contact DIN and submit further questions:

If you have any further questions regarding the presentation of energy-related performance according to DIN EN ISO 50001:2018 or related standards, we would be pleased if you would forward them to the committee. Please send your questions to the coordinator of the committee Mrs. Hanna Schultz (hanna.schultz@din.de).


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The following information fits this report:

Module 1: 360° PDCA management as a continuous service

Module 2: Gap analyses of management systems

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