Energy Audit: What it is and how to do it

Submitted by Acriziomar Alves on Wed, 10/14/2020 - 22:07
Energy Audit: What it is and how to do it


In order to generate gains in energy efficiency and promote sustainability in business and industrial processes, it is essential to perform an energy audit and to see how to apply it.


In energy and utilities management, when a process or operation is to be improved from an energy perspective, an energy assessment is a powerful tool.

Energy Audit is a definition used in ISO 500021 and is an analysis of the energy performance of a given process or operation, based on the PDCA methodology. It aims to provide clear and reliable information for decision making, always focusing on improving the energy performance of the object of study (area of interest in consumption and/or generation of energy).

In order for the audit to be conducted in an assertive manner and provide useful information, nothing could be natural than using a method with a precise sequence of steps.

PDCA Cycle and Energy Audit

Image 1 - PDCA Cycle 

(P) Planning of the Audit

A few crucial items are defined for starting the work, such as:

Team – It is advisable that people who will take part in the audit should have the appropriate education/training, have specific technical knowledge in the energy field, and be familiar with the target process/operation. There should also be a leader, who in addition to meeting the previous requirements, has expertise in management, especially of people.

Scope – The scope of the audit should be defined in advance, as well as the boundaries (the step of the operation or process that will be targeted) and the objective. These items must be clear clear so that the focus is not lost during the analysis.

Prioritization Criteria – This topic refers to the definition of the criteria for assessing and prioritizing the opportunities mapped, such as actions without investment (or with quick payback), greater reduction in consumption, rapid implementation, etc. These criteria will provide the basis and direction to the team responsible for the audit.

In addition to the aforementioned, it is recommended that the area in which the audit will be performed be contacted in advance and the schedule of the audit be evaluated together with them. In addition, line up access to data from the sector, whether they be KPIs (key performance indicators), operating procedures, flowcharts, manuals, etc.

(D) Data collection

In this step, all the data necessary for the future analysis should be collected, such as:

  • Energy matrix of the sector;
  • Pareto chart of the significant energy consumers divided by source (electric, gas, biomass, etc.);
  • History of consumption;
  • List of available meters;
  • List of relevant variables (which are those that impact energy consumption, such as temperature, flow, pressure, etc.
  • Prices of existing energy contracts and any previous audit (if available);

(D) Visit to the site

The main objective is to obtain more information about the process or operation, especially information that is not "on paper." In this way, ideally prior to the visit, the team responsible for the audit will perform a brief analysis of the data obtained previously (KPIs, Pareto charts, procedures, etc.)

The focus of the visit should be directed to identifying opportunities such as: “energy lost" in leaks and equipment switched on without reason; observing the behavior of operators in relation to energy consumption; showing possible technology changes; in addition to certifying that the operation is stable (using historical results as reference).

Whenever possible, talk to operators: draw up questions to be asked to each of them, especially those who operate significant consumers. Remember to note everything that is said during the visit; this information is of great value for the analysis.

(C) Data analysis

This refers to the search for and identification of energy gaps (opportunities) present in the sector diagnosed. To do this, start with those that can be identified more easily, such as waste, absence of procedures, and others. Evaluate the possible causes of waste, adherence to procedures, and verify that training is up to date.

In a second moment, dive into the data acquired. First be aware of the largest consumers identified by the Pareto chart. Compare the performance of the sector with another within the same institution or outside it. Correlate the variables relevant to them with their energy performance. Compare the correlation with what is observed in reality, assessing whether the operation has actually monitored the variables that impact consumption.

Make sure that the automatic controls present are good (permanent systemic error near zero). Check that the current set points are adjusted; the control may be good but the set point may not be. Compare the current indicators of the sector with respect to the applicability and significance to the process and/or operation, avoid "watermelon" KPIs (green on the outside and red on the inside; indicators that are numerically good but do not portray the reality of the operation), be critical. It is important to note that if necessary, the previous step should be repeated to obtain more data for analysis; the search for information is fundamental for a well-performed analysis. Finally, list the gaps observed so that they c an be reported later.

(A) Communication of the results

The report of the opportunities mapped during the audit can be made in a number of ways, whether by documents, presentations, or meetings. The fact is that some items should be present in this communication, such as: executive summary; main indicators analyzed; estimate of the gap found by energy consumption; difficulties encountered; suggestions for deeper analysis if necessary, and conclusions draw (proposed actions); among others. Starting from here, the area responsible will have a foundation to create an action plan, and the leadership will be responsible for executing and monitoring this plan.

Thus, with a well-developed and applied energy audit, important information is found for improvements from the perspective of energy consumption as well as of quality and productivity. After all, these pillars are complementary and should move together towards excellence.

  1. ISO 50002:2014 – Energy Audits – This standard includes requirements and guidance for the development of energy audits, which can be applied to any institution or organization independent of market segment, in addition to encompassing all forms of energy and its uses. Source: ABNT [back]
Energy Management Analyst, Viridis

Acriziomar Alves is an Energy Management Analyst at Viridis, working in Energy Management and Strategic Planning at Bayer. He holds a bachelor's degree from the Brazilian Federal University of Uberlândia in electrical engineering with a focus on power systems. Mr. Alves has participated in R&D projects with Petrobrás, with research directed toward the creation of computational models for power flow analysis and energy quality.

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