Electrification of processes and technologies for Danish Industry: Elforsk project 350-038 : Final Report

Abstract

The development of the Danish energy system tends towards significantly increasing production of electricity from renewable sources – in particular wind power. Hence, the energy system will be extensively electrified. 20 % of the energy is used in industrial processes, which may be an important focus area for electrification. The project has analyzed the potential realization of optimal substitution of process heating in industry based on combustion of fossil fuels with fully electricity-based heat. The main purpose of the project was to analyze and identify substitution of process heat from fossil fuels as currently used in industry with electricity-based heat. The project has analyzed how processes in specific industries are best converted to electricity-based heating, and as a consequence may increase efficiency and flexibility. Electrification can take place indirectly by conversion to fuels based on power-to-X, or directly by converting to electricity-based heating, by heat pumps or electric heating. This project focuses on the latter. Heat pumps are highly efficient, but are limited by e.g., temperature, while electric heating provides a potential for flexibility, in particular when using storage. The project includes detailed analyses of processes found in pectin production, milk powder production, brewing, plastics production and steam laundry. These cases may be seen as representative for a significant share of the manufacturing industry and involve options for process integration as well as high temperature processes. Throughout the project, a procedure for investigating electrification potential has been developed. This involves mapping the individual energy-demanding processes, analyzing the potential for heat recovery by process integration, assessing the potential for using alternative technologies, defining electrification scenarios, calculating electrified process scenarios with a focus on energy, economics and CO2 emission. The method has been continuously developed throughout the project but has been used on the basis of the same basic idea. The method has been used both for the overall analysis of the industry and for the individual cases. The presented analyzes show that electrification is possible and technically feasible for a significant part of the Danish industrial process heating needs. It has been found that the need for fuels can be reduced to 10 % of the current use, while the remaining use can be electrified. This in turn will reduce the need to about two-thirds of the current one. For some of the case studies, e.g. milk powder and pectin production, full electrification can take place through energy integration, use of mechanical steam compression, heat pumping and electric heating. Current heat pump technology allows temperatures up to 100 °C, but the technology needs further development for higher temperatures. From this perspective, the available low temperature sources for the heat pumps are also important, as temperature lift significantly affects the performance of the heat pump. The project has contributed with overall electrification plans for some of the cases, primarily pectin production. Part of this has involved assessment of technology from SAN Electro Heat for direct heating of processes that cannot use heat pumps and the need for further development of these. For Labotek, a new solution has been developed during the project for drying plastic granulate with recovery of excess heat. This solution is implemented in Labotek’s products and in operation in the industry. A further development of the solution with a heat pump has been analyzed and could provide further process improvement. The project has thus found a significant potential for electrification in Danish industry. The project also includes an analysis of bottlenecks in the conversion to electrification, which should be included in the picture. These are grouped as being economic, technical, organizational or risk-related. They include technical limitations in current heat pump technology and costs of conversion, but also requirements for security of supply and the company’s willingness to convert to a large extent and to use less well-known technology. For industrial production, the potential for sector coupling by using electricity flexibly is less clear. The industry will most often need to utilize the capacity for process heating fully with a high number of operating hours per year, but for batch processes and by investing in extra capacity, it is possible to utilize the potential for energy storage provided that it does not affect the final product, e.g. due to temperature changes. From an economic perspective the electrification is feasible for a number of the analyzed cases. However, full electrification will require further development of technology and frame conditions related to investment and operating cost as well as possible subsidies and taxation related to greenhouse gas emission. In this respect, it is important to keep in mind that electricity production in Denmark presently causes greenhouse gas emissions, and that sustainable electrification requires significant development of the electricity system.