Methodology for energy audits in the framework of the energy efficiency directive

The Energy Efficiency Directive 2012/27/EU (EED) was released in October 2012 and transposed in June 2014 by Member States. The Directive requires large companies to carry out an energy audit before December 2015, which has to be repeated every 4 years. A possibility for companies to be exempted from regular energy audits is to be or become certified by an approved energy management system (EnMS), most likely the international standard ISO 50001. In both cases it means that companies have to set plans and define actions to comply with European and national requirements that aim at improving their energy efficiency. Considering the differences across European countries regarding the awareness and involvement of the industrial sector in terms of energy management, a large number of companies still lack systematic and comprehensive systems to understand, monitor and improve their energy consumption in a cost-effective and sustainable way. This paper presents a methodology to carry out indicative energy audits in compliance with the European standard EN 16247-1 and including the ISO 50001 requirements of the energy planning phase (e.g. energy review, energy baseline and energy performance indicators). The proposed methodology follows a top down approach, starting from the energy bill and identifying major energy sources. It covers the evaluation of the actual system’s energy efficiency, identifies energy savings opportunities and presents an innovative approach for energy consumption monitoring via surrogate models of processes. It makes use of state-of-the-art techniques such as data reconciliation, heat integration via total site pinch analysis and statistical tools. Since natural gas and electricity usually take up the largest share of the total energy consumption in industry, the focus is put on these two energy carriers. One of the interesting aspects of the methodology concerns the data gathering and processing phases. Here the required data are targeted and classified in a systematic way in order to characterise the energy consumers and identify the areas of significant energy use presenting a potential for energy efficiency improvement. Once the energy review step is carried out, strategies for energy consumption monitoring should be developed. The methodology proposes an innovative approach to generate specific energy consumption models of industrial processes (surrogate models) that could be used to monitor units, online or offline, and detect deviations from expected behaviour

Methodology for efficient use of thermal energy in the chemical and petrochemical industry

The current European energy regulation, aligned with the European Union energy strategy and targets for the next decade, requires large industrial companies to regularly assess their energy performance and implement energy efficiency improvement measures. In many cases, these energy reviews fulfill minimum criteria for energy audits set by the legislation, and focus on the optimisation of the energy conversion units and utilities distribution. Opportunities for energy savings within production processes are missed, which can also lead to an inadequate hot and cold supply system. Existing methods for energy reviews in the petrochemical sector do not feature the holistic and systematic aspects required to deeply analyse and improve industrial sites down to the production units level. The lack of time and human resources, combined to the availability and reliability of data, are additional barriers preventing detailed studies to take place. This thesis presents a comprehensive methodology to carry out detailed energy review of petro- chemical plants, in accordance with energy management and auditing standards requirements. This methodology comprises three main steps: the energy consumption analysis, the targeting of the heat recovery potential and the identification and evaluation of energy saving opportunities to reach this target. A top-down approach is undertaken in the first step, with the objective of translating the raw energy consumption of the system into process units heating and cooling demand. In doing so the mass and energy flows are mapped and the efficiency of the entire energy chain is characterised in a structured way. The focus on the process requirements allows to understand how much, where and why energy is consumed. In this first step, guidelines and heuristic rules are defined to reduce the required time for data collection. A data consistency check in the form of key mass and energy balances ensures the validity of data and a good control of the energy flows of the system. In the second step, a novel methodology for the definition of the minimum approach temperature in pinch analysis is presented. By considering the characteristics of each process hot and cold stream individually, together with the economic parameters of the system, the heat recovery potential is refined and the minimum energy consumption targets are closer to what can be achieved economically. From the results of the pinch analysis, the objective of the third step is to reach the energy targets through the identification of energy saving opportunities. A bottom up approach is defined to look for options starting from the process operating parameters and heat integration towards the optimisation of the energy conversion and distribution system. Waste heat recovery through heat pumping being a recurring identified opportunity, a heat transformer system is proposed, coupling a mechanical vapour compression cycle to an organic Rankine cycle. Integrated to the polyethylene slurry production, this system allows to recover the residual reaction heat and produce steam without importing electricity from the grid. In doing so the energy consumption is reduced by 50%. The proposed methodology was developed, tested and refined on around 10 different petrochemical sites, enabling a comprehensive analysis of their energy performance and leading to the identification of promising energy saving opportunities to increase the energy efficiency of their production

The Energy Efficiency Directive Impact on the Industry Sector: Importance of Energy Management

The Energy Efficiency Directive (EED) 2012/27/EU published in October 2012, sets out new requirements for European Member States on energy efficiency, acting on the energy chain from its production to end- use consumption. While improvement of the industry’s energy performance and increase in energy efficiency were mostly embedded in voluntary agreements or financial incentives, the EED requires large companies to undergo a first energy audit in December 2015 at the latest, to be repeated every four years. A possibility for companies to be exempted from this requirement is for them to be certified by an approved energy management system. Therefore this paper highlights the major importance of the development of a powerful and cost-effective energy management system within industries, in order to fulfil legally binding obligations, but also benefit from state aid or tax exemptions, included into national energy policies. While many techniques and tools are available for manufacturing companies to track their energy use and identify savings opportunities, there is still the possibility and need for the development of innovative tools to enhance the way energy is managed and tackle the energy efficiency gap that prevents identified energy savings from being carried out

Methodology for energy audits in the framework of the Energy Efficiency Directive

The Energy Efficiency Directive 2012/27/EU (EED) was released in October 2012 and transposed in June 2014 by Member States. The Directive requires large companies to carry out an energy audit before December 2015, which has to be repeated every 4 years. A possibility for companies to be exempted from regular energy audits is to be or become certified by an approved energy management system (EnMS), most likely the international standard ISO 50001. In both cases it means that companies have to set plans and define actions to comply with European and national requirements that aim at improving their energy efficiency. Considering the differences across European countries regarding the awareness and involvement of the industrial sector in terms of energy management, a large number of companies still lack systematic and comprehensive systems to understand, monitor and improve their energy consumption in a cost-effective and sustainable way. This paper presents a methodology to carry out indicative energy audits in compliance with the European standard EN 16247-1 and including the ISO 50001 requirements of the energy planning phase (e.g. energy review, energy baseline and energy performance indicators). The proposed methodology follows a top down approach, starting from the energy bill and identifying major energy sources. It covers the evaluation of the actual system’s energy efficiency, identifies energy savings opportunities and presents an innovative approach for energy consumption monitoring via surrogate models of processes. It makes use of state-of-the-art techniques such as data reconciliation, heat integration via total site pinch analysis and statistical tools. Since natural gas and electricity usually take up the largest share of the total energy consumption in industry, the focus is put on these two energy carriers. One of the interesting aspects of the methodology concerns the data gathering and processing phases. Here the required data are targeted and classified in a systematic way in order to characterise the energy consumers and identify the areas of significant energy use presenting a potential for energy efficiency improvement. Once the energy review step is carried out, strategies for energy consumption monitoring should be developed. The methodology proposes an innovative approach to generate specific energy consumption models of industrial processes (surrogate models) that could be used to monitor units, online or offline, and detect deviations from expected behaviour

Methodology for streams definition and graphical representation in total site analysis

The current regulatory framework in Europe regarding industrial energy consumption puts emphasis on regular energy assessments and increasing energy efficiency. Among the available strategies to identify energy savings opportunities, Total Site Analysis (TSA) can be a powerful method to generate utility savings in industrial sites or clusters, targeting for heat recovery and cogeneration potential. The grey box representation of the energy requirements focuses on process/utility heat exchanges when defining hot and cold streams. This representation is usually most suitable when carrying out a TSA on large industrial systems, as direct heat recovery schemes are rarely viable. Since its initial problem definition and solving in the 1990s, a high number of theoretical developments and practical applications have expanded the TSA knowledge. Still an important body of work on TSA techniques and case studies only addresses general aspects and issues that are encountered, and no in-depth explanation yet is found on how to consider specific types of heat consumers and producers. This paper presents a methodology for data collection and streams definition in TSA. It provides a step-by-step approach for defining the process and utility requirements of the main types of heat flows typically found in large industrial systems, including their graphical representations. Using the proposed definitions, it is possible to systematically build composite curves for the total site profiles