# Decarbonizing European Industry: A Novel Technology to Heat Supply Using Waste and Renewable Energy
## 1 Introduction  
Decarbonizing industrial production is crucial to achieving the European Union's climate change targets. This involves drastically reducing energy consumption and CO2 emissions and switching to renewable energy sources (RES) [1]. Furthermore, rising energy costs, relying on fossil fuels due to the global crisis, and increasing energy demand to reduce the carbon footprints of products are motivating companies worldwide to develop strategies to decarbonize process heat [2]. In recent years, the European Union (EU) underwent significant changes, with the transition from EU28, which included the United Kingdom, to EU27 following Brexit in 2020, impacting various policies and strategies, particularly in the areas of energy and industrial decarbonization. In the EU, roughly two-thirds of greenhouse gas emissions within the industrial sector are attributed to the utilization of fossil fuels to generate heat and electricity. The chemical, petrochemical, and non-metallic minerals industries are regarded as the largest consumers of energy, followed by the paper, pulp and printing, food, and steel industries [3]. Overall, energy production in all its forms is responsible for more than 70% of total greenhouse gas (GHG) emissions as depicted in Figure 1. As a result, the main contributors to GHG emissions in 2022 are related to the energy supply (26.60%), domestic transportation (23.10%), industry (19.60%),residential and commercial (11.50%), and agriculture (8.23%) [4]. An increase in energy consumption directly correlates with higher emissions, illustrating the close relationship between energy consumption and emissions [5]. Final energy consumption (FEC) includes all the energy provided to the different industrial sectors and serves as a measure of consumption at the FEC point [6]. The aforementioned five sectors account for around two-thirds of the total energy consumption in the industrial sector [7], mainly in the form of heat and electricity. The majority of the remaining energy consumption is related to heat generated from fuels (such as oil coal, and gas), renewables (such as biomass), and also combined heat and power (CHP) systems [8]. This includes both heating for spaces and heating for industrial processes. Odyssee-Mure data reveal that electricity constitutes roughly 30% of industrial energy consumption in the EU. Of this, 70% is allocated to heating, with temperatures exceeding 1000 \({}^{\circ}\)C in metal processing [9]. Figure 2 also illustrates an examination of final energy consumption by end-use in the EU27 in the year 2022, showing three main categories: transport (31%), households (27%), and the industry sector (25%) (see Figure 2). It should be noted that international aviation and marine bunkers are not included in the transport category [10]. However, the decarbonization alternatives leading the industrial transition include improving process efficiency and implementing novel processes to reduce end-use en  
Figure 1: Greenhouse gas emissions by sector in EU27 for 2020 [4]. Figure 2: Breakdown of final energy consumption by sector within the EU27 for the year 2022, represented as a percentage of the overall energy consumption, based on terajoules [10]. ergy consumption, using waste heat, and switching from fossil fuels to renewable energy sources and raw materials [11]. Conventionally, industrial processes and operations requiring high-temperature heating (HTH) ranging between 100 and 125 \({}^{\circ}\)C have been provided by low-pressure steam boilers, commonly fueled by fossil fuel energies or electrical heating systems that are not environmentally friendly [12]. Nevertheless, many industrial processes produce excess waste heat as a by-product, which is either free or requires cooling tower operation to dissipate it into the environment. This waste heat can be found at low temperatures and cannot be effectively reused in other processes in industries.