• Energy Research

Primary aluminium production is a highly energy-intensive and greenhouse gas (GHG)-emitting process responsible for about 1 % of global GHG emissions. In 2009, the two most energy-intensive processes in primary aluminium production, alumina refining and aluminium smelting consumed 3.1 EJ, of which 2 EJ was electricity for aluminium smelting, about 8 % of the electricity use in the global industrial sector. The demand for aluminium is expected to increase significantly over the next decades, continuing the upward trend in energy use and GHGs. The wide implementation of energy efficiency measures can cut down GHG emissions and assist in the transition towards a more sustainable primary aluminium industry. In this study, 22 currently available energy efficiency measures are assessed, and cost-supply curves are constructed to determine the technical and the cost-effective energy and GHG savings potentials. The implementation of all measures was estimated to reduce the 2050 primary energy use by 31 % in alumina refining and by 9 % in primary aluminium production (excluding alumina refining) when compared to a “frozen efficiency” scenario. When compared to a “business-as-usual” (BAU) scenario, the identified energy savings potentials are lower, 12 and 0.9 % for alumina refining and primary aluminium production (excluding alumina refining), respectively. Currently available technologies have the potential to significantly reduce the energy use for alumina refining while in the case of aluminium smelting, if no new technologies become available in the future, the energy and GHG savings potentials will be limited.

The industry sector is a major energy consumer and GHG emitter. Effective climate change mitigation strategies will require a significant reduction of industrial emissions. To better understand the variations in the projected industrial pathways for both baseline and mitigation scenarios, we compare key input and structure assumptions used in energy-models in relation to the modeled sectors' mitigation potential. It is shown that although all models show in the short term similar trends in a baseline scenario, where industrial energy demand increases steadily, after 2050 energy demand spans a wide range across the models (between 203 and 451 EJ/yr). In Non-OECD countries, the sectors energy intensity is projected to decline relatively rapidly but in the 2010–2050 period this is offset by economic growth. The ability to switch to alternative fuels to mitigate GHG emissions differs across models with technologically detailed models being less flexible in switching from fossil fuels to electricity. This highlights the importance of understanding economy-wide mitigation responses and costs and is therefore an area for improvements. By looking at the cement sector in more detail, we show that analyzing each industrial sub-sector separately can improve the interpretation and accuracy of outcomes, and provide insights in the feasibility of GHG abatement.

The U.S. concrete industry is the main consumer of U.S.-produced cement. The manufacturing of ready mixed concrete accounts for about 75% of the U.S. concrete production following the manufacturing of precast concrete and masonry units. The most significant expenditure is the cost of materials accounting for more than 50% of total concrete production costs - cement only accounts for nearly 24%. In 2009, energy costs of the U.S. concrete industry were over $610 million. Hence, energy efficiency improvements along with efficient use of materials without negatively affecting product quality and yield, especially in times of increased fuel and material costs, can significantly reduce production costs and increase competitiveness. The Energy Guide starts with an overview of the U.S. concrete industry’s structure and energy use, a description of the various manufacturing processes, and identification of the major energy consuming areas in the different industry segments. This is followed by a description of general and process related energy- and cost-efficiency measures applicable to the concrete industry. Specific energy and cost savings and a typical payback period are included based on literature and case studies, when available. The Energy Guide intends to provide information on cost reduction opportunities to energy and plant managers in the U.S. concrete industry. Every cost saving opportunity should be assessed carefully prior to implementation in individual plants, as the economics and the potential energy and material savings may differ.

Energy-intensive industries across the EU-28 release unused heat into the environment. This excess heat can be utilized for district heating systems. However, this is the exception today, and the potential contribution to the decarbonization of district heating is not well quantified. An estimation of excess heat, based on industrial processes, and spatial matching to district heating areas is necessary. We present a georeferenced industrial database with annual production and excess heat potentials at different temperature levels matched with current and possible district heating areas. Our results show a total potential of 960 PJ/a (267 TWh/a) of excess heat when the exhaust gases are cooled down to 25 °C, with 47% of the 1.608 studied industrial sites inside or within a 10 km distance of district heating areas. The calculated potentials reveal that currently 230 PJ/a (64 TWh/a) of excess heat is available for district heating areas, about 17% of today’s demand of buildings for district heating. In the future, widespread and low-temperature district heating areas increase the available excess heat to 258 PJ/a (72 TWh/a) at 55 °C or 679 PJ/a (189 TWh/a) at 25 °C. We show that industrial excess heat can substantially contribute to decarbonize district heating, however, the major share of heat will need to be supplied by renewables.

Despite past energy efficiency improvements and decarbonization efforts, the industrial sector is still responsible for 40% of global energy consumption and more than 43% of global CO2 emissions. It is shown that the role of energy efficiency in combination with increased recycling will be key in reducing industrial energy demand, achieving reductions of approximately one quarter by 2050. But how is the industrial sector represented in most long-term energy models, models widely used for policy assessment and for evaluating different decarbonization pathways? Not in adequate detail, as it is found that very few models capture industrial details while many represent the industrial sector as a whole. But even the more industry detailed energy models could profit by adding knowledge on key areas from bottom-up industry analysis and material flow analysis and improve their projections. Improvements assessed include the energy efficiency and material efficiency options, industry inter-linkages, and change in the approaches used for material demand projections. Results have pointed that i) cost-effective energy efficiency measures do exist, but they are commonly overlooked by models, ii) policies in one sector impact the CO2 emissions in another sector (e.g., the facing out of coal-fired power plants will limit the generation of by-products used for CO2 reduction in the cement industry) and, iii) demand projections can be drastically different when results from material flow analysis are used instead of the simplified and widely used approach of relating historical trends between economic activity and consumption levels.

AbstractIncreasing the energy efficiency in high energy demand sectors such as industry with a high reliance on coal, oil and natural gas is considered a pivotal step towards reducing greenhouse gas emissions and meeting the Paris Agreement targets. The European Commission published final energy demand projections for industry capturing current policies and market trends up to 2050. This Reference scenario for industry in 2050, however, does not give insights into the extent to which energy efficiency potentials are already implemented, in which sectors further efficiency can be achieved, to what extent or with which technologies. In this paper, the EU Reference scenario is broken down and compared to a Frozen Efficiency scenario with similar GDP developments but without energy efficiency. Through bottom-up analyses, it is found that with energy efficiency technologies alone, this Reference scenario for industry energy demands (10.6 EJ in 2050) cannot be achieved. That means that the EU Reference assumes higher energy efficiency than possible and too high an effect of current policies. In the Frozen Efficiency scenario, the energy demand reaches 14.2 EJ in 2050 due to the GDP development; 22% higher than 2015. Energy efficiency improvements and increased recycling can decrease industrial energy demand by 23% (11.3 EJ in 2050). In order to further reduce the energy demand, our analyses shows that the wide implementation of innovative in combination with electrification or hydrogen technologies can further decrease the 2050 energy demand to 9.7 EJ or 10.3 EJ, respectively.

The cost of energy as part of the total production costs in the cement industry is significant, typically at 20 to 40% of operational costs, warranting attention for energy efficiency to improve the bottom line. Historically, energy intensity has declined, although more recently energy intensity seems to have stabilized with the gains. Coal and coke are currently the primary fuels for the sector, supplanting the dominance of natural gas in the 1970s. A variety of waste fuels, including tires, steadily increase their share in fuel use. Between 1970 and 2010, primary physical energy intensity for cement production dropped 1.2% per year from 7.3 MBtu/short ton to 4.5 MBtu/short ton. Carbon dioxide intensity due to fuel consumption and raw material calcination dropped 24%, from 610 lb C/ton of cement (0.31 tC/tonne) to 469 lb C/ton cement (0.23 tC/tonne). Despite the historic progress, there is ample room for energy efficiency improvement. The share of wet-process plants decreased from 60% in 1970 to about 7% of clinker production in 2010 in the U.S. The remaining plants suggest the existence of a considerable potential, when compared to other industrialized countries. We examined over 50 energy-efficient technologies and measures and estimated energy savings, carbon dioxide emission savings, investment costs, and operation and maintenance costs for each of the measures. The report describes the measures and experiences of cement plants around the world with these practices and technologies. Substantial potential for energy efficiency improvement exists in the cement industry and in individual plants. A portion of this potential will be achieved as part of (natural) modernization and expansion of existing facilities, as well as construction of new plants in particular regions. Still, a relatively large potential for improved energy management practices exists.