# Decarbonizing European Industry: A Novel Technology to Heat Supply Using Waste and Renewable Energy
## 1 Introduction
In the recent European energy framework, utilizing recovered industrial waste heat (IWH) supplies a suitable opportunity to replace primary energy consumption with a cost-effective, low-emission energy source [13]. Numerous studies are available that investigated the potential of industrial waste heat from perspectives related to energy efficiency and policy perspective [14; 15]. The primary objective of these types of studies is to assess the recoverable waste heat and explore its possible applications. Sectors such as steel [16] and food [17] are examined for heat recovery, with proposals for technologies such as ORC for heat-to-power conversion [18] and heat pumps for intensification [19]. The field of research is dynamic due to the wide range of possibilities for waste heat utilization. However, concerning industrial waste heat, this potential is not only extensively unexplored but also unacknowledged. To promote the widespread adoption of recovered IWH, comprehensive assessments with extensive scope and detailed spatial resolution are essential. The optimal approach is to reuse this waste heat within the originating process, thereby avoiding scenarios where past investment decisions prevent additional energy efficiency improvements. Furthermore, when high-temperature heat demand coincides with the availability of nearby low-temperature waste heat, it presents an opportunity to utilize heat pumps. These devices are among the technologies that exist to recover industrial waste heat, enabling energy integration and improving the overall system efficiency [12]. Hence, with the rising share of electricity being generated from renewable sources, the use of an electric-powered industrial heat pump is a robust option for a more sustainable industrial sector. Technologically, heat pump prototypes currently under development can achieve temperatures of up to 200 \({}^{\circ}\)C and beyond [2]. Several research efforts are also focused on developing high-temperature heat pumps (HTHPs) capable of operating with sink temperatures ranging from 160 \({}^{\circ}\)C to 200 \({}^{\circ}\)C [20; 21], although their market implementation is expected to take several years. Enerin offers HTHPs utilizing helium (R704) as the working fluid and employing double-acting piston compressors within a Stirling cycle. This configuration enables adaptable operating conditions, high lifting capabilities, and the delivery of temperatures exceeding 200 \({}^{\circ}\)C [22]. Furthermore, Olvondo Technology's High-Lift HTTP system, implemented in the heat pumps at AstraZeneca in Sweden, was designed to operate within this temperature range [23]. [PERSON] and [PERSON] [24] assessed the potential applications of heat pumps by considering 15% of the overall industrial energy consumption in Europe. Nonetheless, the lack of progress in developing products for higher temperatures is often due to inadequate comprehension by manufacturers of heat pumps for applications of industrial processes, and market demand. To address these constraints, the EU funded the SUSHEAT project, whose main objective is to design a hybrid renewable heat upgrade system that aims to replace fossil fuel-based boilers in the European industrial landscape through three novel technologies: an advanced Stirling cycle-based HTHP capable of temperatures up to 250 \({}^{\circ}\)C, a bio-inspired phase change materials (PCM) TES system and a control and integration twin (CIT) system. Therefore, this study explores the potential application of the concept of the European SUSHEAT project to meet the industrial heat demand within the European industry. Section 2 introduces the SUSHEAT concept. Section 3 outlines energy consumption, heat demand, and industrial processes in the EU. Section 4 covers the Theoretical Potential (TP) of implementing the SUSHEAT system in the EU28. Section 5 focuses on waste heat in industries and heat pumps while Section 6 represents the environmental advantages of applying the SUSHEAT system in the EU 28. Lastly, Section 7 presents the conclusions of this study.