Relevant process variables and energy efficiency

Submitted by Sérgio Grassi on Mon, 06/10/2019 - 14:48

Energy efficiency is a very important topic in energy and utilities management. In this article we will talk about the relevant process variables and how they are fundamental when applied to energy efficiency.


When it was created in 2011, ISO 50001 (ENERGY MANAGEMENT SYSTEM - REQUIREMENTS WITH GUIDELINES FOR USE) has done much to spread the implementation of effective energy management systems and consequently to promote more efficient use of the available energy sources. Therefore, the clear definition of what is a relevant process variable is very important, and how its proper use is vital to achieving continuously better energy performance.

Identification of relevant variables

According to ISO 50001, a relevant variable is a quantifiable parameter that significantly impacts energy performance and changes regularly, for example: product temperature, production rate, pressure, flow, climatic indicators.

Monitoring, measuring, and analyzing the key features of an organization's operations is a prerequisite for achieving meaningful results regarding energy efficiency. It should happen at planned intervals and contemplate at least:

  • The identification of processes with significant energy use and their relevant variables.
  • The EnPIs (Energy Performance Indicators).
  • The effectiveness of the action plans for achieving the goals and targets.
  • The evaluation of the actual versus expected energy consumption.

Energy Performance Indicators and the relevant variables

After analysis and identification of the relevant variables it is important to isolate those that are significant in terms of energy efficiency from the others that have little or no influence on the EnPI under analysis. Although organizations may already have the identification completed, an additional data analysis is generally required to determine the significance of these variables.

Read too: Don't fall into the trap: the fallacies of efficiency metrics

The routine monitoring of EnPIs and the complementary activity of correlating energy performance with the relevant variables is what leads to the expected results.

One very important factor that must be taken into consideration is the workforce. Labor turnover, lack of adequate training, or even lack of optimized operational procedures are often the causes of performance deviations and should be part of the process performance analysis.

Corrective actions related to the quality of the operational workforce (adequate admission, updated operational procedures, training, feedback, etc.) should be prioritized, mainly for the following reasons:

  • Do not involve investments in equipment and process changes.
  • The cost of the action is relatively low.
  • It is implanted in a short period of time.

During the process analysis, it is not uncommon to identify relevant variables that are not measured appropriately or that sometimes are not measured. In these scenarios it is always recommended to install these measurements, which will certainly have a financial return in a short period of time.

How a power and utilities management system can help in identifying the relevant variables

An effective energy management system begins by measuring the inputs and relevant variables of significant processes. These measurement data generate important information for the analysis. The analysis will generate behavioral actions, or even those aimed at equipment that seek to reduce consumption, costs, emissions and operational risks. The cycle of continuous improvement is repeated with new consumption verifications and planning of new actions.

A consumer measurement system integrated in a single digital platform, which allows online visualization throughout the site and generating important information for managers, is already a reality and is simply required to achieve the state of the art in energy management and utilities.

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Commercial Director, Viridis

Viridis’s Commercial Director. He has worked for 35 years at Vallourec in energy, maintenance, and industrial assembling. He managed the energy and utilities project at the Vallourec & Sumitomo (VSB) plant. He holds a BEng in Electrical Engineering and graduate degrees in Industrial Automation and Business Management. He is a member of CB-116, which developed the ABNT NBR ISO 50,001 – Energy Management standard. He was responsible for making Vallourec the first steel company in Brazil to achieve this certification. He is a member of the Board of Renewable Energy and Oil & Gas at FIEMG.

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