Citation: Uçal, E.; Yildizhan, H.; Ameen, A.; Erbay, Z. Assessment of Whole Milk Powder Production by a Cumulative Exergy Consumption Approach. Sustainability 2023, 15, 3475. https://doi.org/10.3390/ su15043475 Academic Editor: Mohammad Hossein Ahmadi Received: 14 November 2022 Revised: 21 January 2023 Accepted: 11 February 2023 Published: 14 February 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article Assessment of Whole Milk Powder Production by a Cumulative Exergy Consumption Approach Esmanur Uçal 1 , Hasan Yildizhan 2 , Arman Ameen 3, * and Zafer Erbay 1 1 Department of Food Engineering, Faculty of Engineering, Adana Alparslan Turkes Science and Technology University, Adana 01250, Turkey 2 Department of Energy Systems Engineering, Faculty of Engineering, Adana Alparslan Turkes Science and Technology University, Adana 01250, Turkey 3 Department of Building Engineering, Energy Systems and Sustainability Science, Faculty of Engineering and Sustainable Development, University of Gävle, 801 76 Gävle, Sweden * Correspondence: arman.ameen@hig.se Abstract: The production of food is a sector that consumes a significant amount of energy and encompasses both agricultural and industrial processes. In this study, the energy consumption of whole milk powder production, which is known to be particularly energy-intensive, was examined. The study used a cumulative exergy consumption approach to evaluate the overall production process of whole milk powder, including the dairy farm (raw milk production) and dairy factory (powder production) stages. The results showed that raw milk production dominated energy and exergy consumption and carbon dioxide emissions. An amount of 68.3% of the total net cumulative exergy consumption in the system was calculated for raw milk production. In the dairy factory process, the highest energy/exergy consumption occurred during spray drying, followed by evaporation and pasteurization. In these three processes, 98.3% of the total energy consumption, 94.6% of the total exergy consumption, and 95.7% of the total carbon dioxide emissions in powder production were realized. To investigate the improvement potentials in the system, replacing fossil fuels with renewable energy sources and using pasture feeding in animal husbandry were evaluated. While using alternative energy sources highly influenced powder production, pasture feeding had a high impact on consumption in raw milk production. By using renewable energy and pasture feeding, the exergy efficiency, cumulative degree of perfection, renewability index, and exergetic sustainability index values for the overall process increased from 40.5%, 0.282, -0.22, and 0.68 to 68.9%, 0.433, 0.65, and 2.21, respectively. Keywords: dairy; exergy; spray drying; carbon dioxide emission 1. Introduction Food production, which consists of many stages including agriculture and food pro- cessing, is one of the sectors with the highest energy consumption and includes several energy-intensive and/or low-efficiency processes. The most remarkable processes are the evaporation and drying applied for food preservation. While evaporation is employed to obtain concentrated liquid foods and drying is applied to produce solid foods, both are based on the removal of water via transferring latent heat. The energy consumption of these processes is estimated to constitute 15–25% of the total energy consumption in developed countries, and the most energy-intensive method among them is spray drying after freeze drying [1]. The major food sector using spray dryers is the dairy sector, and it was reported that evaporation and powder production in a typical German dairy plant consumed 32% of the total electricity and 58% of the total thermal energy. Similar values were obtained for the Dutch and Irish dairy industries [2–4]. The dairy sector uses spray dryers in the production of dairy powders; dairy powder production increased by an average of 2.2% annually between 2000 and 2018, and the total dairy powder production reached 12 million tons [5]. Sustainability 2023, 15, 3475. https://doi.org/10.3390/su15043475 https://www.mdpi.com/journal/sustainability