The production of biofuels in Sweden has increased significantly in the past years in order to reduce fossil fuel dependence and mitigate climate impacts. Nonetheless, current methodological guidelines for assessing the GHG savings from the use of biofuels do not fully account for benefits from by-products and other utilities (e.g. waste heat and electricity) from biofuel production. This study therefore reviews the aggregated environmental performance of these multi-functional biofuel systems by assessing impacts and benefits from relevant production processes in Sweden in order to improve the decision base for biofuel producers and policymakers in the transition to a bio-based and circular economy. This was done by (1) conducting a mapping of the Swedish biofuel production portfolio, (2) developing future production scenarios, and (3) application of life cycle assessment methodology to assess the environmental performance of the production processes. Special focus was provided to review the potential benefits from replacing conventional products and services with by-products and utilities. The results provide evidence that failure to account for non-fuel-related benefits from biofuel production leads to an underestimation of the contribution of biofuels to reduce greenhouse gas emissions and other environmental impacts when replacing fossil fuels, showing the importance of their multi-functionality.

Energy savings result in economic and environmental benefits. Site-wide energy analysis of industrial systems considers all plant components, such as unit operations, heat exchangers, boilers, and turbines. This article presents the analysis of heat cascade through these components to reduce the overall energy consumption. As a consequence of the two first principles of thermodynamics, heat from hot utilities transferred to a process is gradually cascaded to the environment through process operations and exchangers. The enthalpy rate curves shift to ambient temperature through operations and exchangers; the difference between the outlet and inlet enthalpy rate curves of a system is equal to the flow rate of cascaded heat as a function of temperature. Reducing the energy consumption implies decreasing the flow rate of cascaded heat through process operations or exchangers in the entire temperature interval between the hot utility and the environment. Herein, the heat cascade is first analyzed to identify process operation modifications in order to reduce the utility consumption. Second, the heat cascade through a plant, including a boiler, a turbine, process operations, and exchangers, is represented on a single diagram for site-wide energy analysis. Third, the heat cascade through several processes is analyzed to integrate an industrial site. The proposed method provides benefits in comparison to foreground/background analysis and total site analysis, which are two commonly used approaches to identify energy-saving opportunities for industrial symbiosis. Analysis of heat cascade through individual operations and heat exchangers is simple and powerful, and its concepts can be used in software to identify energy-saving projects.

ABSTRACT Economic and environmental benefits result from increasing the energy efficiency of industrial systems. This article presents the application of bridge analysis concepts to improve the methodology of network pinch for heat exchanger network retrofit. In two simple examples, we compare bridge analysis with the network pinch approach, in terms of saving energy by heat exchanger network improvement. The first example is solved with both methods, while the second can only be solved by bridge analysis. In the first example, three different solutions are proposed, and the third solution leads to 3800 kW energy savings, i.e., the full savings capacity. In the second example, no heat can be saved using the network pinch approach, but two solutions are proposed using bridge analysis, which lead to 395 kW energy savings, i.e., the full savings capacity. Then, we discuss the advantages and limits of pinch analysis and the network pinch approach. Bridge analysis provides a broader perspective on pinch analysis, explains the natural presence of a pinch in a network, shows that removing cross pinch transfers is not necessary to save energy, and helps improve heuristics for creating new cooler‐heater paths in the network pinch procedure.

Journal of Industrial EcologyVolume 22, Issue 4 p. 943-966 FOREIGN LANGUAGE ABSTRACTSFree Access Chinese Abstracts Journal of Industrial Ecology Volume 22, Number 4 First published: 03 August 2018 https://doi.org/10.1111/jiec.12681AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume22, Issue4August 2018Pages 943-966 Translations 《产业生态学报》中文摘要 (JIE Chinese Abstracts) Resúmenes en Español de la Revista de Ecología Industrial (JIE Spanish Abstracts) RelatedInformation

This paper maps, categorizes, and quantifies all major point sources of carbon dioxide (CO2) emissions from industrial and combustion processes in Sweden. The paper also estimates the Swedish technical potential for electrofuels (power-to-gas/fuels) based on carbon capture and utilization. With our bottom-up approach using European databases, we find that Sweden emits approximately 50 million metric tons of CO2 per year from different types of point sources, with 65% (or about 32 million tons) from biogenic sources. The major sources are the pulp and paper industry (46%), heat and power production (23%), and waste treatment and incineration (8%). Most of the CO2 is emitted at low concentrations (< 15%) from sources in the southern part of Sweden where power demand generally exceeds in-region supply. The potentially recoverable emissions from all the included point sources amount to 45 million tons. If all the recoverable CO2 were used to produce electrofuels, the yield would correspond to 2-3 times the current Swedish demand for transportation fuels. The electricity required would correspond to about 3 times the current Swedish electricity supply. The current relatively few emission sources with high concentrations of CO2 (> 90%, biofuel operations) would yield electrofuels corresponding to approximately 2% of the current demand for transportation fuels (corresponding to 1.5-2 TWh/year). In a 2030 scenario with large-scale biofuels operations based on lignocellulosic feedstocks, the potential for electrofuels production from high-concentration sources increases to 8-11 TWh/year. Finally, renewable electricity and production costs, rather than CO2 supply, limit the potential for production of electrofuels in Sweden.

The present work is part of a cross-disciplinary Swedish research project on advanced tailor-made biofuels that aims at identifying drop-in biofuel options for the transport sector that combine excellent combustion properties with sustainable production pathways. The present paper addresses the methodology and primary results of the biofuel production pathway assessment for the diesel fuel alternatives identified within the project. The methodology is illustrated for 2-Ethylhexanol. Three alternative production pathways for 2-Ethylhexanol are analyzed: gasification-based, butanol-based and ethanol-based. The highest biomass to 2-Ethylhexanol conversion (33.9%, lower heating value basis) is achieved for the ethanol-based conversion pathway. The varying spectrum of by-products requires a sophisticated analysis necessary, as addressed in the present work. 2-Ethylhexanol as biofuel cannot outperform conventional biofuels such as e.g. ethanol from a well-to-tank energy performance perspective due to the additional conversion steps necessary. End-use phase benefits such as higher blend-in ratios or reduced pollutant emissions may change the well-to-wheel picture.

Eutrophication in the North and Baltic Seas is a major problem to the marine environment and the communities depending on it. To counteract this, the Swedish Marine and Water Authority suggested financial support for measures that increase the uptake of nutrients from the water by e.g. marine organisms and support for the utilisation of these organisms as value added products. In Sweden the use of biogas to replace fossil transportation fuels is widely adopted. The domestic biogas production corresponded to approx. 1.95 TWh (approx. 7010 TJ) in 2015 of which approx. 63% were upgraded for use as e.g. transportation fuel. Other uses are heat and electricity generation as well as industrial applications. To expand production, the biogas industry is searching for new substrates. In this paper the utilisation of the marine evertebrate organism Ciom intestinalis (tunicata), cultivated in the North Sea and used as feedstock for biogas and biofertilizer production is suggested and assessed. The greenhouse gas (GHG) emissions performance of the concept and it's consequences on marine eutrophication are investigated applying life cycle assessment. Results show that at full scale biogas production from C. intestinalis reduces GHG emissions by more than 65% compared to fossil transportation fuels. In addition, the results show that accounting for the system consequences of other products and services such as biofertilizer replacing mineral fertilizers and decreased marine eutrophication largely increase the environmental benefits provided by the concept. Approx. 3.7 g-N-eq/MJ(biogas) of nitrogen are removed from the marine environment during the cultivation of C intestinalis. (C) 2017 Elsevier Ltd. All rights reserved.

Summary Symbiotic linkages in industry clusters in the form of interconnected materials, energy and information flows, and close proximity provide unique opportunities to develop efficient environmental strategies. The purpose of our study is to examine the practical potential of applying a life cycle approach in strategy evaluations, as the environmental impact caused by industrial symbiosis systems outside the company gates has been scarcely addressed. This is done by evaluating two strategies for an industry cluster in Sweden: (1) to replace a share of the fossil feedstock used in the industry cluster with forest‐based feedstock and (2) to improve energy efficiency through thermal energy integration. The environmental impact reduction potential of the strategies is evaluated using life cycle assessment. The ratio between investment cost and reduced global warming potential is used as an indicator to evaluate the cost‐effectiveness of the strategies. Results demonstrate the importance of applying a life cycle perspective as the assessment outcome depends heavily on whether only on‐site consequences are assessed or if upstream and downstream processes are also included. 20% of the greenhouse gas emission reduction of the energy integration strategy occurs off‐site, whereas the forest strategy has the largest reduction potential off‐site, >80%.

The introduction of sustainability criteria for solid biomass/biofuels on the European Union (EU) or global level may influence the EU pellets market, e.g., by limiting the eligible biomass supply potential or specific pellet chains. This assessment focuses on greenhouse gas (GHG) emission reductions and the issue of sustainable forest management (SFM) for pellets potentially used in Sweden (for residential and/or industrial use). The paper includes (1) a literature review of recent studies addressing the impact of sustainability requirements (for solid biomass and/or liquid biofuels) on the bioenergy market, (2) a characterization of SFM conditions in potential pellets export countries and their capacity to enforce respective legislation, and (3) an assessment of GHG emissions for heat and electricity for the Swedish market from selected potential wood pellet chains (including torrefaction) and related GHG emissions reduction compared to fossil fuels using a life cycle assessment perspective. Most of the assessed wood pellet value chains will most likely be able to meet stringent sustainability requirements from a GHG perspective. Thus, the impact of near‐term GHG emission reduction demands on the Swedish pellets market is limited. More specifically, we find that torrefaction may be advantageous for pellets imported over long distances (i.e., over approximately 18,500 km). We conclude that demand for SFM related to solid biofuels will not have a significant or long‐lasting effect on the market for Swedish pellets. The real impacts of sustainability requirements will however depend on levels of ambition as well as the methodologies and systems boundaries applied in future systems. WIREs Energy Environ 2016, 5:413–429. doi: 10.1002/wene.199This article is categorized under: Bioenergy > Economics and Policy Bioenergy > Climate and Environment

Biorefineries are a way to achieve the transition from our fossil feedstock based society towards the use of sustainable raw materials. Heat integration can help to increase the overall energy efficiency. Therefore integration of biorefinery concepts with industrial clusters can be advantageous. The chemical cluster investigated in this paper consumes a large amount of ethylene. The integration potential of a lignocellulosic ethanol plant and an ethanol dehydration plant is investigated. Based upon Aspen+ simulations integration opportunities at four different levels were identified using traditional Pinch Analysis and Total Site Analysis (TSA): (1) internal integration within each of the two separate processes; (2) heat integration of the two processes with each other; (3) heat integration of the processes with direct material flow from the upstream process to teh downstream process, and (4) integration of the two combined processes with an existing chemical cluster. Savings of up to 51 % utility steam by integrating the lignocellulosic ethanol production process with the ethylene dehydration and the chemical cluster were identified.

TSA (total site analysis) has shown to be an efficient tool for identifying heat integration measures in industrial clusters, leading to the optimal design of utility systems and energy bill reduction. In order to justify investments, any proposed utility system must be shown to be able to operate in all configurations that an industrial cluster can encounter, especially those relating to varying heat demand. Previous TSAs have generally been carried out using yearly means of heat exchange loads or using scenarios corresponding to specific operation modes of the sites. While these have been useful for designing systems under normal conditions, they are not fit for evaluating minima and peaks in utility demand. Carrying out a TSA on each possible configuration of a cluster is not feasible from a computational and results analysis point of view. A method is therefore proposed to represent the variability of data over long periods in a reduced form in order to carry out engineering studies.A methodology is proposed to identify typical operating periods of an industrial cluster made up of several production units. This algorithm exploits a multi-objective optimisation to identify n periods that delimit typical operating modes or multiple profiles.A TSA was previously carried out on the Stenungsund petrochemical cluster in Sweden, leading to the design of a utility system to significantly reduce the overall energy consumption of the cluster. The solution proposes that a common utility system would decrease the hot utility demand from 124 MWth to 70 MW. The multi-period analysis methodology is demonstrated by application to this case study in order to identify the resilience of the proposed solution when faced with variations in heat production and consumption. The multi-period analysis of the proposed utility system leads to the identification of a peak utility demand of 88 MWth rather than the previously identified 70 MWth. A Total Site Sensitivity Analysis leads to a better understanding of the contribution of each of the clusters units and feasibility of investments. (C) 2015 Elsevier Ltd. All rights reserved.

Continued growth of carbon dioxide (CO2) emissions from the shipping industry until 2050 and beyond is expected although of the recent decline. The global share of anthropogenic CO2 emissions from ships is only about 2 percent, but there is a risk that this share will increase substantially if no action is taken. What are the possibilities for decarbonisation of the shipping industry, then? Some of the measures discussed are energy efficiency, use of biofuels and use of hydrogen. In this paper a fourth option is scrutinised – use of electrofuels. Electrofuels is an umbrella term for carbon-based fuels, e.g. methane or methanol, which are produced using electricity as the primary source of energy. The carbon in the fuel comes from CO2 which can be captured from various industrial processes such as exhaust gases, the sea or the air. The production of electrofuels is still in its infancy, and many challenges need to be overcome before electrofuels are brought to market on a large scale. First, this paper gives an overview of the current status of electrofuels regarding technologies, efficiencies and costs. Second, as electrofuels production requires significant amounts of CO2 and electricity, the feasibility to produce enough electrofuels to supply all ships bunkering in Sweden, with regionally produced electricity and regionally emitted CO2, and the amount of CO2 that is required to supply all ships globally is evaluated in two case studies assessing supply potential.

The European process industry is facing major challenges to decrease production costs. One strategy to achieve this is by increasing energy efficiency. Single chemical processes are often well-integrated and the tools to target and design such measures are well developed. Site-wide heat integration based on total site analysis tools can be used to identify opportunities to further increase energy efficiency. However, the methodology has to be developed further in order to enable identification of practical heat integration measures in a systematic way. Designing site-wide heat recovery systems across an industrial cluster is complex and involves aspects apart from thermal process and utility flows. This work presents a method for designing a roadmap of heat integration investments based on total site analysis. The method is applied to a chemical cluster in Sweden.

Heat integration between chemical production facilities in an industrial cluster provides significant cost savings opportunities. While single chemical processes are often well integrated, site-wide heat integration based on Total Site Analysis (TSA) tools often identifies opportunities to further increase energy efficiency. However, further development of the TSA methodology is required to improve its applicability for identifying practical heat integration measures and providing key information for investment decision makers. The design of common site-wide heat recovery systems in an industrial cluster is a complex task in which a large number of aspects other than thermal process and utility flows must be considered. This paper presents a procedure for identifying site-wide heat recovery measures based on TSA. The proposed approach is illustrated for a chemical cluster located on the West Coast of Sweden, showing feasible site-wide heat recovery systems achieving up to 42 % of the maximum total site heat recovery target of 129 MW. A number of systems are suggested ranging from low complexity achieving a minor share of the heat recovery potential to complex, strongly interdependent systems demanding large investments and a high level of collaboration. Estimated pay-back periods for the proposed systems range from 3.2 to 4.2 years, while up to approx. 12 % of the cluster's CO2 emissions can be avoided.

This paper presents a study on the production of biofuels from algae cultivated in municipal wastewater in Gothenburg, Sweden. A possible biorefinery concept is studied based on two cases; Case A) combined biodiesel and biogas production, and Case B) only biogas production. The cases are compared in terms of product outputs and impact on global CO2 emissions mitigation. The area efficiency of the algae-based biofuels is also compared with other biofuel production routes. The study investigates the collaboration between an algae cultivation, biofuel production processes, a wastewater treatment plant and an industrial cluster for the purpose of utilizing material flows and industrial excess heat between the actors. This collaboration provides the opportunity to reduce the CO2 emissions from the process compared to a stand-alone operation. The results show that Case A is advantageous to Case B with respect to all studied factors. It is found that the algae-based biofuel production routes investigated in this study has higher area efficiency than other biofuel production routes. The amount of algae-based biofuel possible to produce corresponds to 31 MWfuel for Case A and 26 MWfuel in Case B.

Total Site Analysis (TSA) is a tool for quantifying energy savings targets in large industrial process clusters. Thereafter retrofit design tools can be used to identify efficient solutions in which the different process sites exchange excess energy with each other through the site utility system, thus reducing the overall need for external fuels/energy. Compared to energy efficiency investments identified for single companies, similar investments identified for clusters hold an inherent complexity; they assume joint investments and multi-party collaboration, which often constitute a barrier for implementation. Real Options Analysis (ROA) is a tool that can be used for helping managers to evaluate different investment options. However, previous research almost exclusively concerns single companies/actors and not the increased complexity of joint investments. This paper presents a novel approach, showing how ROA can be applied not only to handle uncertainties regarding market development but also reduce complexity associated with multi-party cooperation in a joint energy efficiency investments based on TSA. The approach is applied on a case study of a joint energy efficiency retrofit investment in a Swedish chemical cluster. Using ROA, the case study shows how the identified solution can divided into “investment packages” distributed over time, allowing for an initial investment by only two actors and permitting for an evaluation of both the cooperation and the market development before expanding the investment and the number of actors involved. Further, an economic assessment of the project is presented together with an analysis of the cost/benefit of gradually expanding the investment.