**1. Introduction**

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Industrial energy efficiency is a key component in the transition of the economy towards in‐ creased sustainability. For an industrial company, there are four means to reduce energy costs: implementing energy-efficient technologies, energy carrier conversion, load management, and more energy-efficient behaviour. The European end-use energy efficiency and energy services directive promotes, among other things, the removal of existing market barriers and imper‐ fections that impede the efficient end use of energy [1]. Energy audits provide an important tool in reducing barriers to energy efficiency [2]. Furthermore, an initial, well-structured en‐ ergy audit is the first important step in a successful in-house energy management program in industry [3].

From the global perspective, industrial energy efficiency is one of the most important means of reducing the threat of increased global warming [4] as the industry accounts for about 80 percent of the world's annual coal consumption, 40 percent of the world's electricity use, 35 percent of the world's natural gas consumption, and around 10 percent of global oil consump‐ tion [5]. Of great importance are thus different means which promote energy efficiency for the industrial sector. In Europe, growing concern for increased global warming has led to the implementation of a number of policy instruments such as the EU Emission Trading Scheme (ETS) and the European Energy End-Use Efficiency and Energy Services Directive (ESD). From the industry's perspective, supply side policy instruments like the EU ETS will most likely result in higher European energy prices which will stress the industry to take actions toward increased energy efficiency. On the other hand, this may lead to competitive disadvantages compared to industries outside the EU [6].

© 2012 Rosenqvist et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 Rosenqvist et al.; licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The role and importance of energy audits varies from country to country. In a comparing study of factors influencing energy efficiency in the German and Colombian manufacturing indus‐ tries [7], firms and associations were asked about their view on energy audits. Among the German respondents 57 percent states that volontary audits is an important factor influencing the energy efficency in their country, while 61 percent of the Colmbian respondents states that volontary audits is an important or very important factor. When they were asked about their own measures and actions, 71 percent of the German respondents and 54 percent of the Co‐ lombian respondents stated that they would consider energy audits to increase energy effi‐ ciency performance.

Energy audits can also be described with the classification of energy audits from ASHRAE [13]. This classification involves three levels, defined in reference [14], and is similar to the audit procedure presented in reference [15]. The three levels presented in [13] are Level I (Walkthrough assessment), Level II (Energy survey and analysis), and Level III (Detailed analysis of

Industrial Energy Auditing for Increased Sustainability − Methodology and Measurements

The Level I walk-through assessment involves an assessment of the energy cost and effi‐ ciency by analyzing energy bills and a brief survey of the site. This first-level assess‐ ment targets low- or no-cost measures and presents a listing of capital improvements that need to be studied further. Level II, energy survey and analysis, includes a more detailed survey and analysis of the plant studied [13]. This is usually done by some form of detailed breakdown of energy use, either in activities and energy carriers or, as in this chapter, in unit processes. An energy audit with the method described in this

A unit process is defined by the energy service to be performed and industrial processes may

**•** Support processes − the processes needed to support the production processes but not

Disjointing Cooling Mixing Lighting

Cooling/Freezing Steam

Unit processes are a way to divide the energy use of an industry or other businesses into smaller parts. The unit process perspective also enables one to question the methods used for different processes. Air flows in ventilation systems are sometimes high because the ventilation system

**Table 1.** The unit processes used at Linköping University, divided into production and support processes.

Jointing Compressed Air Coating Ventilation Moulding Pumping

Heating Tap water heating Melting Internal Transport Drying Space Heating

Support processes

Administration

http://dx.doi.org/10.5772/51717

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chapter always involves the assessment at Level I and Level II.

**•** Production processes − the processes needed to manufacture the products.

thus be divided into two categories of unit processes:

Disintegrating

Packing

capital-intensive modifications).

**1.2. Unit processes**

Production processes

needed for production.

This audit method was developed in Sweden, in the Swedish manufacturing industry context. Evaluations of conducted energy audits in small and medium-sized manufacturing companies shows that the calculated technical potential for increasing energy efficiency performance varies from 16-40% of the total energy use. For electricity the calculated potential is up to 60% [8]. If the suggested measures are implemented and if the potential is reached or not depends on the barriers and driving forces for energy efficiency. The energy price can play an important role. For Swedish industry, energy prices have risen significantly in recent years. Between 2000 and 2006 electricity prices in Swedish industry almost doubled and oil prices rose by about 70 percent [9,10]. This trend has not declined. In January, 2010, prices on the Nordic electricity spot market arose to some 130 Euro per MWh. The electricity price increases were partly due to the deregulation of the European electricity markets as the deregulation has caused the national markets to converge and Sweden has for a long time enjoyed one of the lowest elec‐ tricity prices in Europe [11]. While the oil price increases may not create competitive disad‐ vantages for Swedish industry, the electricity price increases most likely will, as this is particularly related to the Swedish industry and the fact that the previously low electricity prices have resulted in a higher use of electricity in many Swedish industrial sectors compared to their European competitors.

The methodology described is primarily for a technical energy audit with the aim to make the energy use more efficient and sustainable. In the audit, organizational issues and the sur‐ rounding society are regarded mainly as means to reach the goal, and are important driving forces to implement changes.
