Energy: Ever important - Part II

By Teemu Turunen and Jaana Kuorelahti, Metso's Paper and Fiber Technology

BRUSSELS, Nov. 21, 2011 (RISI) - Energy savings are not necessarily achieved merely by applying new technology. And efficient monitoring of energy efficiency can be affected by several factors. In many case, the users of the applications and equipment play the most important roles. Read Part I here.

Materials and methods

This article discusses two studies and their results related to the monitoring of energy efficiency. The first one deals with two conducted development projects in monitoring energy efficiency and the second one with an interview study on the needs of monitoring energy efficiency in the Finnish paper industry.

By analyzing the development projects in monitoring energy efficiency carried out in 2007 and 2010, it was studied what kind of factors are involved in the development of monitoring energy efficiency, which projects succeeded and which failed, and which issues require specific attention. The targets of the study were a line with older technology (Line 1) and one with new technology (Line 2).

The interview study conducted in the spring of 2011 investigated the needs for monitoring energy efficiency in the Finnish paper industry. The target of the study was to determine the needs for monitoring so that the system suppliers will be able to develop energy-efficient solutions to fulfill these needs. The study used a semi-structured theme interview with the background of the interviewee, energy efficiency, monitoring of energy efficiency, energy efficiency monitoring system and the role of the different parties as themes. The results of the interviews were analyzed by a theme analysis and were divided into five themes found in the interview material. The themes were the factors affecting energy efficiency, the current state of the measurement and monitoring of energy efficiency, the needs of developing the measurement and monitoring of energy efficiency, the material produced by the energy efficiency monitoring system and the utilization of the material, as well as the features of the energy efficiency monitoring system.

Figure 2 - Factors affecting energy efficiency on a papermaking line

Results

Line 1 was provided with an application for online monitoring of energy efficiency in the machine control system and a web-based energy efficiency reporting system utilizing the history database on the line. The technology supplier, a representative of the mill's head office and representatives of the line from different sectors were involved in the development project. Development meetings were held regularly during the project to discuss the state of the implementation, further procedures and development needs.

The online monitoring system included in the machine control system presented 23 different-level energy efficiency indicators, which could be calculated using the existing measuring instruments on the line. After the actual development project, the next investment target of the line was the development of measurement instrumentation. The modifications could be taken into account during the development project and the new indicators could be connected to the developed monitoring system. The energy efficiency indicators were added hierarchically as part of the operator displays of the machine control system. Due to the restrictions in the automation system, grade-specific monitoring was not included in the monitoring system although the possibilities of implementing it were discussed during the project. In addition to the actual monitoring, energy efficiency information windows for each indicator were developed to provide the operators with information on the indicators and the factors and parameters affecting these.

Correspondingly, the history database on the line was utilized in energy efficiency reporting with the most important process quantities collected to the database. A separate web application developed for searching reports could produce both grade-specific and time-specific reports. In addition to the consumption data, the reports contained explanatory information on the machine's production efficiency and water consumption. The reporting enabled actions such as filtering out the effect of production disturbances from the energy consumption data by means of a break signal.

Monitoring energy efficiency for Line 2 was installed as part of the automation system delivery in the mill project and the technology supplier's separate, internal development project was established for it. The purchaser of the package was interested in the online monitoring of heat use and so the reporting utilizing the database and the online monitoring of electricity consumption were excluded from the developed application. As this was a new product line delivery, the measurement instrumentation could be supplemented at the design stage. The measurement instrumentation became comprehensive in terms of heat use, enabling an extremely detailed calculation of thermodynamic indicators. A separate, hierarchical entity was created to display the indicators, which was placed as part of the machine control system exactly as in the case of Line 1. A traffic light display format, Fig. 3, which changes per each production grade and is automatically updated, as required, was used to display the indicators. In addition to the indicator displays, different balance formats were developed to display, among other things, the efficiency of the heat recovery cells.

Example of a monitoring display for line 2

Even though the energy efficiency reporting feature was not implemented for Line 2, a simple consumption reporting feature in a tabular form was created for the machine control system displays. However, there are not any technical obstacles which would prevent the implementation of the reporting feature at a later stage. As distinguished from Line 1, Line 2 was provided with different control packages boosting and optimizing the energy efficiency, such as grade-specific drying recipes and energy-efficient control of the hood operation mode.

The development project ended in the approval of the application and the actual implementation of the applications was left for the target mills to accomplish. Both technical problems and problems related to the practical operating procedures were discovered in the implementation of the applications after the project. The implementation of the reporting was hindered by the restricted web rights at the mill, so everyone requiring the reports was not able to utilize them. In addition, the energy efficiency reports were not used in weekly meetings, which is where they were mainly intended for. The monitoring system was not implemented for the practical operator level, and the operators did not receive any application training. A main user for the applications was not found at any stage from the line, which partly explains the defects in the implementation. The lack of grade-specific traffic lights and limit values on online displays partly hampered the commissioning of the application.

The feedback received from Line 2 proved to be ambiguous. First of all, the operation of the application was monitored by a remote connection and the information was found useful for the device manufacturer. Correspondingly, the staff of the target mill had not fully understood the content of the application, which had only a few users. These users used the application only occasionally and had not developed a consistent way of using it. As in the case of Line 1, the users on Line 2 had not been provided with a sufficient amount of support. Arranging user training either by the system supplier or the target mill is required as a further procedure.

Interview study

The interview study showed that the most significant obstacles for promoting energy efficiency were the lack of time and financial resources and indicators. Additionally, communication between, among other parties, the head office and the mill, or even within the mill itself, combined with the lack of commitment to promote energy efficiency were regarded as hindrances. According to the participants of the study, the best way to promote energy efficiency is to eliminate the bottlenecks mentioned above and improve the general attitude in terms of the issue. The study shows that the attitude can be changed through communication and different energy efficiency training courses. For example, briefings on energy efficiency at department and shift meetings, presentation of the progress in the company's energy efficiency issues in a staff bulletin and the energy sites on the intranet have proved to be efficient means of communication. Energy efficiency training should be illustrative enough and specifically tailored to the target line to best meet the requirements.

The study also showed that the monitoring of the use of energy varies in companies at the moment. The most typical practice is to follow the consumption numbers on a monthly basis. Old mills have several deficiencies in terms of promoting energy efficiency. The lack of indicators is a major obstacle and a few companies have deficiencies in reporting as well. Additionally, the several different automation systems in use cause problems in terms of comprehensive monitoring.

The monitoring system and the material produced by it must comply with the users' requirements. According to the participants of the study, it is important to have a vast range of features in the system and to be able to customize the system as per the needs of different users, Table 1.

The following features divided the views of the respondents:

• Showing energy costs to the operator.
• Shift-specific consumption monitoring and comparison.
• Alarms (e.g. from deviating consumption rates).

Nearly all of the respondents regarded showing the costs to the operator as a good thing. This means that the operator display shows the currency (e.g. euro) beside the energy consumption unit (e.g. MWh) to show the production consumption in a more illustrative manner. The respondents agreed that showing the currency increases cost-consciousness among the operators, who will at the same time see the financial influence of the changes in the process.

To be continued ... Read Part III here.

Teemu Turunen and Jaana Kuorelahti, Metso's Paper and Fiber Technology, teemu.p.turunen@metso.com

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