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• Strategies for electrification of industrial sites to reduce fossil fuel use. • Energy, exergy, environmental and economic analysis of electrification scenarios. • Evaluation of an all-electric milk powder production with heat pump integration. • Comparison of scenarios with future energy prices and emissions. • Quantification of cost and emission reductions through heat pump integration. Denmark has the ambitious plan of being independent from fossil fuels by 2050 and to run the entire energy system based on renewable energy sources. One of the most likely scenarios is a bigger deployment of wind farms and a massive electrification of the industry and transportation sectors. In 2016, the industry sector accounted for 20% of the final energy use, which was by more than 50% covered directly with fossil fuels. Electrification is a promising way for decarbonizing this sector but it will require significant economic investments and changes of the infrastructures. In this work, several strategies for electrifying industrial processes, based on the integration of heat pumps and electric heaters are presented. They were compared using energy, exergy, economic and environmental performance indicators. The production of milk powder was taken as a case study, as current factories are energy-intensive and require high-temperature heat generated by natural gas combustion. The highest energy efficiency and lowest exergy destruction was found for a system using a central heat pump system, with energy savings of 65%. The implementation of decentralised heat pumps that exchange heat between process streams and electric heaters, results in smaller reductions of only 56%. These two systems are likely profitable based on the energy price forecasts from 2020, but the decentral system allows for a gradual implementation of the most cost-effective measures. [ABSTRACT FROM AUTHOR]

Abstract Energy, exergy and advanced exergy methods were used to analyse a milk powder production facility. While a conventional energy analysis is used to map the energy flows and to suggest possibilities for process integration through pinch analysis, an exergy analysis identifies the locations and magnitudes of thermodynamic irreversibilities. The advanced exergy analysis determines the real potential for thermodynamic improvements by dividing the exergy destruction into its avoidable and unavoidable parts, which relate to technological limitations, and into its endogenous and exogenous parts, which present the interactions between the different sub-systems. This analysis was based on factory data with which the complete production line (milk treatment, evaporators and dryers) and the utility systems were modelled. The results show the potential for optimisation and a comparison of the applicability of the different methods to the dairy industry. The pinch analysis and energy mapping showed that the potential for heat integration was small. The exergy analysis revealed the gas burner and spray dryer caused most exergy destruction, while the heaters had low exergy efficiencies. The advanced exergy analysis found the evaporators to have a high share of avoidable exergy destruction. However not all results from the advanced exergy analysis were practical. Highlights • Thermodynamic analysis of a milk powder production factory including the utilities. • Exergy and advanced exergy analysis of an industrial process with utilities. • Engineering evaluation and process integration study of the complete factory. • Comparison of methods for the analysis of industrial processes. [ABSTRACT FROM AUTHOR]

Highlights • Analysis of possible energy savings in the German chemical industry. • Uncertainty analysis of costs and potentials of energy saving measures. • Evaluation of marginal cost curves of energy savings with uncertainties. • Determination of important model parameters using sensitivity analysis. Abstract In 2014, 19.3% of Germany’s industrial final energy consumption could be allocated to the chemical industry. Energy efficiency measures with focus on the chemical industry could thus contribute to reaching the German goal of reducing greenhouse gas emissions. To achieve this goal, energy planners and industries alike require an overview of the existing energy efficiency measures, their technical potential as well as the costs for realizing this potential. Energy efficiency opportunities are commonly presented in marginal cost curves, which rank these measures according to specific implementation costs. Existing analyses, however, do not take uncertainties in costs and potentials sufficiently into account. The aim of this paper is to create a marginal cost curve of energy efficiency measures for the chemical industry in Germany, while quantifying the uncertainties of the results and identifying the most influential input parameters. The identification of energy efficiency measures and the quantification of the associated technical potentials and costs were identified based on literature data and own assessments. Based on these findings a cost curve was created for the current technical potential. This potential was found to be 24.4 PJ per year, of which 23 PJ had negative lifetime costs. To investigate the uncertainties of these results, Monte Carlo simulations were performed to quantify the standard deviations of the implementation potential and costs. Furthermore, a sensitivity analysis, based on Morris Screening and linear regression, was conducted in order to identify the most influential model input parameters. With the applied approach, it was shown that uncertainties have a non-negligible impact on the final energy saving potential and costs, as well as the shape of marginal cost curves. The standard deviation of the energy saving potential was found to be 3.1 PJ. Furthermore, it is possible to systematically prioritise efforts in refining data. [ABSTRACT FROM AUTHOR]

Industrial excess heat may often be utilised for district heating and thus replace existing expensive or CO 2 -emitting technologies. Previous works analysed the distribution of excess heat by temperature intervals and their geographical distribution relative to district heating areas. A more detailed analysis of the most suitable types of industries and the costs is required, allowing a targeted exploitation of this resource. This work extends the spatial and thermodynamic analysis, to account for the temporal match between industrial excess heat and district heating demands, as well as the costs for implementation and operation of the systems. This allows the determination of cost-effective district heating potentials, as well as the analysis of different industries and technological requirements. The results show that the temporal mismatch between excess heat and district heating demand and lack of demand, reduces the theoretical substitution potential by almost 30%. If heat storages are introduced, the total potential is reduced by only 10%. A majority of the excess heat can be utilised at socio-economic heating costs lower than the average Danish district heating price and the cost of solar district heating. Excess heat from oil refineries, building material and food production can be utilised at the lowest specific costs. [ABSTRACT FROM AUTHOR]

The utilization of solar energy based technologies has attracted increased interest in recent times in order to satisfy the various energy demands of our society. This paper presents a thorough review of the open literature on solar energy based heat and power plants. In order to limit the scope of the review, only fully renewable plants with at least the production of electricity and heat/hot water for end use are considered. These include solar photovoltaic and solar thermal based plants with both concentrating and non-concentrating collectors in both solar-only and solar-hybrid configurations. The paper also presents a selection of case studies for the evaluation of solar energy based combined heat and power generation possibility in Denmark. The considered technologies for the case studies are (1) solar photovoltaic modules, (2) solar flat plate collectors, (3) a ground source heat pump, (4) a biomass burner, and (5) an organic Rankine cycle. The various cases are compared on the basis of economic profitability and environmental performance. The results from the case studies indicate that it is economically and environmentally beneficial to invest in both small and large capacity solar-biomass hybrid plants for combined heat and power production in the Nordic climatic conditions. The results also suggest that the configuration with an organic Rankine cycle with solar thermal collectors and a biomass burner is particularly attractive for large capacity plants. [ABSTRACT FROM AUTHOR]

A detailed analysis of the Danish industry is presented in this paper using the energy and exergy methods. For the 22 most energy-intensive process industries, which represent about 80% of the total primary energy use of the industrial sector, detailed end-use models were created and analysed with data for the years 2006 and 2012. The sectoral energy and exergy losses, as well as the exergy destruction, were further established to quantify the potential for recovering and valorising heat otherwise lost. By also considering transformation processes occurring in the utility sector, the impact of using electricity and district heat in the industry is shown. The exergy efficiencies for each process industry were found to be in the range of 12–56% in 2012. However variations in the efficiencies within the sectors for individual process industries occur, underlining the need for detailed analyses. The exergy losses amounted to 3800 TJ for the same year. Meanwhile, the complete exergy losses, including the central production of heat and power, exceeded 8700 TJ. This analysis illustrates for the case study of Denmark how waste heat recovery potentials in the industrial sectors are found, by determining the sectors losses and exergy destruction. In addition the importance of applying a system analysis is shown, which corrects the site efficiencies for electricity and district heating use. The use of 22 industries, further highlights differences amongst industries belonging to the same sector. [ABSTRACT FROM AUTHOR]

Large-scale heat pumps (HPs), biomass CHPs and excess heat (EH) from industry and data centres are promising district heating (DH) sources. Electricity and thus power transformers (PTs) will be an important part of the future energy system, which opens the possibility to use the thermal losses occurring in PTs for DH. The present paper analyses high voltage PTs in Denmark as DH sources. First, we employ a thermodynamic model of PTs to determine the EH they produce. Subsequently, we analyse thermodynamic properties of heat exchangers and HPs necessary to utilise EH for DH. Finally, we perform a GIS analysis to link the PTs with specific DH networks. From the theoretical amount of excess heat from power transformers (EHPT) available for DH of 0.28 TWh per year, 0.12 TWh or 0.5% of Danish DH demand can reach the consumers. 0.07-0.21 GWh can reach the consumers below the average DH price. The entire EHPT potential can be utilised through HPs, working with an average COP of 4. The sensitivity analysis showed that the EHPT can supply up to 2.26% of the Danish DH demand. Therefore, EHPT is a relatively small DH source on the national scale but could be an important local option. [ABSTRACT FROM AUTHOR]

Numerous process integration techniques were proved to be highly effective for identifying and estimating potential energy savings in the industry. However, they require high time and effort to collect and analyse process data. As a result, they do not constitute the common practice in the industry and opportunities for increasing the energy efficiency of industrial processes are missed. The paper presents a method, termed the " Energy-Saving Decomposition ", which is based on Process Integration techniques. It is intended for expeditiously outlining and promoting energy efficiency in the industry. Two screening tools, based on mathematical criteria and engineering experience, are employed for reducing the problem dimension before applying conventional design procedures. The first step disregards streams based on their contribution to the overall energy-saving potential, calculated utilising a novel energy-saving decomposition technique. The most promising network is then selected based on its energy-saving potential and size. The second step reduces the problem complexity further, employing economic considerations. This novel method was exemplified by application to a dairy factory: the outcomes and the method itself were compared to conventional Pinch Analysis techniques. The results showed that the developed method can simplify and reduce the time consumption of conventional Process Integration methods significantly, while identifying the most encouraging saving opportunities. The automatic algorithm allowed for reducing the problem size from 62 process streams of the existing plant to 22 streams requiring a computational time of only 135 s. The final retrofit design proposed was the same obtained with conventional Pinch Analysis, achieving a 23% reduction in the plant final energy consumption. • A novel expeditious method for process integration retrofit studies is presented. • A novel decomposition of the energy-saving potential allows a reduction in problem size. • A case study proves that the problem size is reduced from 62 to 22 streams with no loss in favourable design options. • The method can be automated and is fast to compute, requiring a few minutes. [ABSTRACT FROM AUTHOR]