Benchmarking the energy use of energy-intensive industries in industrialized and in developing countries

Improved energy efficiency is among the key measures for CO₂ emission abatement in the industry. Energy benchmark curves provide data measured at individual plants and they offer a basis to estimate the sectoral energy efficiency improvement potentials (IP) compared to a best practice technology (BPT) currently in operation worldwide. In this paper, we estimate the BPT energy use of 17 industry sectors based on such curves or energy indicators prepared at country-level. We compare BPT data with current energy use to estimate the IP. According to our analysis, BPT offers improvement potentials of 27 ± 8% worldwide. This is equivalent to 32.5 ± 9.6 EJ (exajoules) of final energy savings worldwide, of which three-quarters can be achieved in developing countries. Due to lack of benchmark curves and limited data availability for developing countries, our results include uncertainties. We used literature data at country-level and international energy statistics to fill data gaps and to develop energy indicators. Quality of these data should be improved and benchmark data needs to be collected for more sectors. By doing so, energy benchmarking could become a key tool to estimate energy saving potentials and energy indicators could serve as strong supplementary methodology.     

Approximation of theoretical energy-saving potentials for the petrochemical industry using energy balances for 68 key processes

We prepared energy and carbon balances for 68 petrochemical processes in the petrochemical industry for Western Europe, the Netherlands and the world. We analysed the process energy use in relation to the heat effects of the chemical reactions and quantified in this way the sum of all energy inputs into the processes that do not end up in the useful products of the process, but are lost as waste heat to the environment. We showed that both process energy use and heat effects of reaction contribute significantly to the overall energy loss of the processes studied and recommend addressing reaction effects explicitly in energy-efficiency studies. We estimated the energy loss in Western Europe in the year 2000 at 1620 PJ of final energy and 1936 PJ of primary energy, resulting in a total of 127 Mt CO₂. The losses identified can be regarded as good approximations of the theoretical energy-saving potentials of the processes analysed. The processes with large energy losses in relative (per tonne of product) and absolute (in PJ per year) terms are recommended for more detailed analysis taking into account further thermodynamic, economic, and practical considerations to identify technical and economic energy-saving potentials.     

Energy efficiency and carbon dioxide emissions reduction opportunities in the US iron and steel sector

This article presents an in-depth analysis of cost-effective energy efficiency and carbon dioxide emissions reduction opportunities in the US iron and steel industry. We show that physical energy intensity for iron and steelmaking (at the aggregate level, standard Industrial Classification 331, 332) dropped 27%, from 35.6 GJ/tonne to 25.9 GJ/tonne between 1958 and 1994, while carbon dioxide intensity (carbon dioxide emissions expressed in tonnes of carbon per tonne of steel) dropped 39%. We provide a baseline for 1994 energy use and carbon dioxide emissions from US blast furnaces and steel mills (SIC 3312) disaggregated by the processes used in steelmaking. Energy-efficient practices and technologies are identified and analyzed for each of these processes. Examination of 47 specific energy efficiency technologies and measures found a total cost-effective reduction potential of 3.8 GJ/t, having a payback period of three years or less. This is equivalent to a potential energy efficiency improvement of 18% of 1994 US iron and steel energy use and is roughly equivalent to 19% reduction of 1994 US iron and steel carbon dioxide emissions. The measures have been ranked in a bottom-up energy conservation supply-curve.     

Analysis of biomass-residue-based cogeneration system in palm oil mills

Palm oil mills in Malaysia operate on cogeneration system using biomass residue as fuel in the boiler. The boiler produces high pressure and temperature steam which expands in a backpressure steam turbine and produces enough electric power for the internal needs of the mill. The exhaust steam from the turbine goes to an accumulator which distributes the steam to various processes in the mill.The study were made on seven palm oil mills in the Perak state in Malaysia. The primary objectives of the study are to determine boiler and turbine efficiencies, energy utilization factor, oil extraction rate and heat/power ratio for various palm oil mills working under similar conditions and adopting same processes. The palm oil industry is one of those rare industries where very little attempt is made to save energy. The energy balance in a typical palm oil mill is far from optimum and there is considerable scope for improvement. Bench-marking is necessary for the components in the mill. Energy-use bench-marking can give an overview of energy performance of the mills. The calculations were done to get net gain in power when back pressure turbine is replaced by a condensing turbine.It was found that the boiler and turbine have low thermal efficiencies compared to conventional ones used in power plants due to non-homogeneity and non-uniform quality of the fuel. The extraction rate was around 0.188. The use of condensing turbine increase the power output by 60% and the utilization factor was found to be 65% for the cogeneration system.     

A Scandinavian chemical wood-pulp mill. Part 2. International and model mills comparison

The energy use at a Swedish chemical wood-pulp mill is compared internationally and for two model mills that aim to use the most efficient available technology. The international comparison is performed between Canadian and Scandinavian pulp-mills on a general level, and on a closer level among eleven Swedish and Finnish non-integrated sulfate pulp-mills, the type of mill considered in the case study. The two model mills that are used for comparison are one Swedish and one Canadian. The Scandinavian pulp-mills are somewhat more energy efficient than the Canadian mills. Still, the variation in energy use is remarkably large among the Scandinavian mills, which indicates that the energy-saving potential is great. If all Swedish freestanding sulfate pulp-mills became as energy efficient as the most efficient Scandinavian mill, electricity savings corresponding to nearly 1% of the national electricity use would be obtained. In the model mills comparison it was found that large amounts of heat could be saved, particularly in the evaporation plant.     

Estimating future costs of power-to-gas – a component-based approach for technological learning

Technological learning is a major aspect in the assessment of potential cost reductions for emerging energy technologies. Since the evaluation of experience curves requires the observation of production costs over several magnitudes of produced units, an early estimation of potential future technology implementation costs often presumes a certain degree of maturity. In this paper, we propose a calculation model for learning curves on the component or production process level, which allows to incorporate experience and knowledge on cost reduction potentials on a low level. This allows interchangeability between similar technologies, which is less feasible on a macro level. Additionally, the model is able to consider spill-over effects from concurrent technology usages for the inclusion of peripheral standard components for the assessment in an overall system view. The application of the model to the power-to-gas technology, especially water electrolysis, has shown, that the results are comparable to conventional approaches at the stack level, while providing transferability between different cell designs. In addition, the investigations made at the system level illustrate that the consideration of spill-over effects can be a relevant factor in the evaluation of cost reduction potentials, especially for technologies in an early commercial state with low numbers of cumulative productions.     

Preconditions and tools for cross-sectoral regional industrial GHG and energy efficiency policy—A Finnish standpoint

The aim of this paper is to develop an approach and tools for cross-sectoral regional industrial GHG and energy policies. These policies can be conducted at different levels of society. To achieve real results in energy efficiency improvements and in GHG reductions, the policies must be focused on the correct levels in society. In Finland, the province level seems to be a reasonable level for a policy targeted at industry. This paper proposes a category for the ways industry uses energy: building energy users, major users of electricity for process/production, major users of heat for process/production and direct combustion users. This approach gives opportunities for developing regional cooperation among different industries. The approach is also important between industries and society, so that there are integrated solutions which e.g. utilise district heating and biofuel potentials. The individual technologies like electric motors, pumps, fans, heat recovery equipment and boilers do not seem to have any significant potentials for improvements in energy efficiency by the EU target year 2020. However, there are opportunities but they are at system levels: how effectively the individual technologies are applied as a part of industrial systems. This fact supports the idea of energy use categorising.     

Modeling an industrial energy system: Perspectives on regional heat cooperation

Through energy efficiency measures, it is possible to reduce heat surplus in the pulp and paper industry. Yet pulp and paper mills situated in countries with a heat demand for residential and commercial buildings for the major part of the year are potential heat suppliers. However, striving to utilize the heat within the mills for efficient energy use could conflict with the delivery of excess heat to a district heating system. As part of a project to optimize a regional energy system, a sulfate pulp mill situated in central Sweden is analyzed, focusing on providing heat and electricity to the mill and its surrounding energy systems. An energy system optimization method based on mixed integer linear programming is used for studying energy system measures on an aggregated level. An extended system, where the mill is integrated in a regional heat market (HM), is evaluated in parallel with the present system. The use of either hot sewage or a heat pump for heat deliveries is analyzed along with process integration measures. The benefits of adding a condensing unit to the back-pressure steam turbine are also investigated. The results show that the use of hot sewage or a heat pump for heat deliveries is beneficial only in combination with extended heat deliveries to an HM. Process integration measures are beneficial and even increase the benefit of selling more heat for district heating. Adding a condensing turbine unit is most beneficial in combination with extended heat deliveries and process integration. Copyright © 2007 John Wiley & Sons, Ltd.     

Addressing data center efficiency: lessons learned from process evaluations of utility energy efficiency programs

This paper summarizes the unique challenges related to addressing energy efficiency in the data center industry and lessons learned from original research and two process evaluations of energy efficiency programs with components that specifically target data centers. The lessons learned include: creating program opportunities specifically focused on data centers; clearly identifying target data centers able to implement energy efficiency programs; understanding decision making in these facilities; and effectively communicating the program opportunities to the target market. The growing energy use of data centers has drawn international attention from policy makers, regulators, industry consortiums, and electric utilities. Any program effective at improving the energy performance of data centers must include specific strategies and processes aimed at confronting a number of challenges specific to this industry, including: the concentrated and rapidly growing energy use of these facilities; the rapid pace of innovation; the extremely high reliability requirements; and the significant split incentives due to the typical data center management structure. The process evaluations covered in this paper are the Pacific Gas and Electric (PG&E) High-Tech program and the Silicon Valley Power (SVP) Public Benefits Program. While the PG&E evaluation was a more complete process evaluation, the SVP evaluation focused specifically on participation from co-location facilities. These process evaluations together included interviews with program participants, nonparticipants and utility staff and also included outreach to a large variety of industry stakeholders. In addition, the PG&E evaluation included detailed process-mapping used to identify the necessity and importance of all program processes. The insights gathered from these evaluations are not only applicable to US electrical utilities but can also be applied to any international organization looking to create incentives for energy efficiency or demand reduction in this industry.     

Building energy information systems: user case studies

Measured energy performance data are essential to national efforts to improve building efficiency, as evidenced in recent benchmarking mandates, and in a growing body of work that indicates the value of permanent monitoring and energy information feedback. This paper presents case studies of energy information systems (EIS) at four enterprises and university campuses, focusing on the attained energy savings, and successes and challenges in technology use and integration. EIS are broadly defined as performance monitoring software, data acquisition hardware, and communication systems to store, analyze, and display building energy information. Case investigations showed that the most common energy savings and instances of waste concerned scheduling errors, measurement and verification, and inefficient operations. Data quality is critical to effective EIS use, and is most challenging at the subsystem or component level, and with non-electric energy sources. Sophisticated prediction algorithms may not be well understood but can be applied quite effectively, and sites with custom benchmark models or metrics are more likely to perform analyses external to the EIS. Finally, resources and staffing were identified as a universal challenge, indicating a need to identify additional models of EIS use that extend beyond exclusive in-house use, to analysis services.     

Financial viabilities of husk-fueled steam engines as an energy-saving technology in Thai rice mills

Rice husk generated as a by-product of rice milling process can be utilized as an energy source for rice mills. The advantages of applying the steam engine as a power source for rice mills are discussed. An economic model was developed to find out the internal rate of return, IRR, on the investment in steam engine’s as an energy-saving technology in Thai rice mills. Based on the technical and economic data presented in this study, rice mills from 45 to 120 t d⁻¹ in size are financially feasible for investments in steam engines as an energy-saving technology for the mills. The maximum affordable husk prices at the different levels of mill use for various sizes of rice mill were analyzed and the economic performance of higher efficiency technology was also tested in this study.     

超超临界机组快速调峰磨煤机组合优化

基于磨煤机节能运行的控制需求,建立了某660MW机组磨煤机能耗模型,根据磨煤机实际运行状况建立相应的约束条件,并对标准粒子群优化(PSO)算法进行初始化改进、惯性权值改进和变异算子的引入后用于磨煤机组合出力的优化策略中.经试验确定各项参数后,对该策略进行Matlab仿真.结果表明:通过改进的PSO算法计算得出的磨煤机组合出力方式对磨煤机的节能运行起到了很大作用.     

Influencing factors in energy use of housing blocks: a new methodology,based on clustering and energy simulations,for decision making in energy refurbishment projects

In recent years, big efforts have been dedicated to identify which are the factors with highest influence in the energy consumption of residential buildings. These factors include aspects such as weather dependence, user behaviour, socio-economic situation, type of the energy installations and typology of buildings. The high number of factors increases the complexity of analysis and leads to a lack of confidence in the results of the energy simulation analysis. This fact grows when we move one step up and perform global analysis of blocks of buildings. The aim of this study is to report a new methodology for the assessment of the energy performance of large groups of buildings when considering the real use of energy. We combine two clustering methods, Generative Topographic Mapping and k-means, to obtain reference dwellings that can be considered as representative of the different energy patterns and energy systems of the neighbourhood. Then, simulation of energy demand and indoor temperature against the monitored comfort conditions in a short period is performed to obtain end use load disaggregation. This methodology was applied in a district at Terrassa City (Spain), and six reference dwellings were selected. Results showed that the method was able to identify the main patterns and provide occupants with feasible recommendations so that they can make required decisions at neighbourhood level. Moreover, given that the proposed method is based on the comparison with similar buildings, it could motivate building occupants to implement community improvement actions, as well as to modify their behaviour.     

Integration of a solar thermal system in a dairy process

Any analysis of the current energy world scenario draws on the combination of energy efficiency improvement and the use of renewable-type energies. The industrial use of renewable energies is not still well established as they present several problems that generate insecurity in this sector. Some of the renewable energy resources work intermittently (like the sun or wind) and the energy they provide is, often, of low intensity. Solar thermal technology has been successfully introduced in domestic applications and buildings. Many industrial processes work in temperature intervals where solar thermal technology would be able to supply an important amount of the total energy input at an acceptable price. Based on mathematical modeling, this work evaluates the viability of integrating a solar thermal system to the conventional energy structure of a dairy plant in the Atlantic side of Spain. Pinch methodology has been used to develop the integration of the solar subsystem in the energy installation of the plant. In order to determine the potential of the solar thermal energy, several hypotheses and scenarios were analyzed, based on real cases of the productive process. As a result, it could be stated that the solar thermal energy potential for the studied industrial process, operating at low and middle temperatures, was considerable, and must be taken into account as an energy option.     

Indicators for industrial energy efficiency in India

India accounts for 4.5% of industrial energy use worldwide. This share is projected to increase as the economy expands rapidly. The level of industrial energy efficiency in India varies widely. Certain sectors, such as cement, are relatively efficient, while others, such as pulp and paper, are relatively inefficient. Future energy efficiency efforts should focus on direct reduced iron, pulp and paper and small-scale cement kilns because the potentials for improvement are important in both percentage and absolute terms. Under business as usual, industrial energy use is projected to rise faster than total final energy use. A strong focus on energy efficiency can reduce this growth, but CO₂ emissions will still rise substantially. If more substantial CO₂ emissions reductions are to be achieved then energy efficiency will need to be combined with measures that reduce the carbon intensity of the industrial fuel mix.     

Estimation of global rebound effect caused by energy efficiency improvement

Rebound effect refers to the phenomenon that the actual reduction in energy use and emissions is less than the expected reduction caused by an energy efficiency improvement due to induced behavior adjustment of relevant economic agents. This article studies the global rebound effects on energy use and related emissions caused by an energy efficiency improvement. We adopt a global computable general equilibrium (CGE) model to design a scenario of energy efficiency improvement, which is compared to a business-as-usual (BAU) scenario to identify the global rebound effect. Our results show very large rebound effect on energy use (70%) and related emissions (90%) in 2040 at the global level with regional and sectoral differences. Important determinants, among others, are induced labor movement among economic activities and labor supply, and substitution elasticity between energy and other goods. Labor mobility has a marked impact on both rebound effects and on fuel mix. The global rebound effect is still considerable even with a low substitution elasticity between energy and other goods. The effect of capital accumulation over time contributes marginally to the global rebound effect as it is utilized to promote economic growth by using energy input more efficiently.     

Olefins from conventional and heavy feedstocks: Energy use in steam cracking and alternative processes

Steam cracking for the production of light olefins, such as ethylene and propylene, is the single most energy-consuming process in the chemical industry. This paper reviews conventional steam cracking and innovative olefin technologies in terms of energy efficiency. It is found that the pyrolysis section of a naphtha steam cracker alone consumes approximately 65% of the total process energy and approximately 75% of the total exergy loss. A family portrait of olefin technologies by feedstocks is drawn to search for alternatives. An overview of state-of-the-art naphtha cracking technologies shows that approximately 20% savings on the current average process energy use are possible. Advanced naphtha cracking technologies in the pyrolysis section, such as advanced coil and furnace materials, could together lead to up to approximately 20% savings on the process energy use by state-of-the-art technologies. Improvements in the compression and separation sections could together lead to up to approximately 15% savings. Alternative processes, i.e. catalytic olefin technologies, can save up to approximately 20%.     

Performance comparison of a group of thermal conductivity enhancement methodology in phase change material for thermal storage application

Phase change materials (PCM) are able to store thermal energy when becoming liquids and to release it when freezing. Recently the use of PCM materials for thermal energy storage (TES) at high temperature for Concentrated Solar Power (CSP) technology has been widely studied. One of the main investigated problems is the improvement of their low thermal conductivity. This paper looks at the current state of research in the particular field of thermal conductivity enhancement (TCE) mechanisms of PCM to be used as TES. This work considers a numerical approach to evaluate the performance of a group of TCE solutions composed by particular configurations of two of the principal TCE systems found on the literature: finned pipes and conductive foams. The cases are compared against a single PCM case, used as reference. Three different grades of graphite foams have been studied, presenting a charge time 100 times lower than the reference case for the same capacity. For fins two materials are analyzed: carbon steel and aluminum. The charge times of fin cases are from 3 to 15 times faster, depending on the amount and type of material employed. The internal mechanisms are analyzed to understand the results and locate possible improvement.     

Method for rating energy performance of public buildings

This paper discussed a comparative study of several state-of-art methods for determining building energy consumption benchmark. A new approach, which combined the idea of “building benchmark” and “operational benchmark” in its rating system, was proposed. A case study was conducted which applied the proposed approach to benchmarking an existing office building in Tianjin. Besides, the calculation of benchmarks of the reference building model and real building model using the rating method in eQUEST was also considered. Furthermore, the simulation results of the reference building model were taken as the baseline to divide real office buildings into different energy performance grades.     

Modeling and energy efficiency optimization of belt conveyors

The improvement of the energy efficiency of belt conveyor systems can be achieved at equipment and operation levels. Specifically, variable speed control, an equipment level intervention, is recommended to improve operation efficiency of belt conveyors. However, the current implementations mostly focus on lower level control loops without operational considerations at the system level. This paper intends to take a model based optimization approach to improve the efficiency of belt conveyors at the operational level. An analytical energy model, originating from ISO 5048, is firstly proposed, which lumps all the parameters into four coefficients. Subsequently, both an off-line and an on-line parameter estimation schemes are applied to identify the new energy model, respectively. Simulation results are presented for the estimates of the four coefficients. Finally, optimization is done to achieve the best operation efficiency of belt conveyors under various constraints. Six optimization problems of a typical belt conveyor system are formulated, respectively, with solutions in simulation for a case study.