Sustainability 2023, 15, 5599. https://doi.org/10.3390/su15065599 www.mdpi.com/journal/sustainability Article Energy Assessment of a Tannery to Improve Its Sustainability Josep M. Morera, Emiliano Borri, Gabriel Zsembinszki, David Vérez, Gemma Gasa, Esther Bartolí and Luisa F. Cabeza * GREiA Research Group, University of Lleida, Pere de Cabrera s/n, 25001 Lleida, Spain * Correspondence: luisaf.cabeza@udl.cat Abstract: The tanning industry is one of the highly polluting sectors, and it is only in the last few years that studies on the energy improvement of tanneries started to proliferate in the literature. Even though the energy cost of a tannery is only a small fraction of the total cost, many tanners became aware of the importance of improving energy efficiency and reducing the environmental footprint to keep the business afloat and be more competitive in the market. This paper presents a study on increasing the sustainability of a tannery located in the region of Catalonia, Spain. Several measures to increase its energy efficiency and reduce its primary energy consumption were pro‐ posed and analysed including, among others, the implementation of solar thermal collectors and photovoltaic panels. A cost analysis of the most promising solutions was carried out and discussed. The results show that the tannery should invest between EUR 2 to 2.5 M to obtain the highest energy savings, with an estimated payback period between 5 and 7 years. However, acceptable energy sav‐ ings can be obtained with a lower investment cost of between EUR 1 to 1.5 M, with a shorter payback period of between 2 and 4 years. Keywords: tanning industry; energy efficiency; renewable energy; sustainability; cost analysis 1. Introduction Recently, evidence of global warming [1] has caused increased concern about climate change. Most governments are aware of the great danger that the continuous increase in the planet’s temperature represents for the future of their countries and have begun to reach agreements to implement measures to stop this increase and, if possible, reverse it [2]. One of the proposed solutions involves changing the current energy model, looking for new energy sources, and optimizing energy consumption [3]. In order to reverse the current situation of continuous temperature rise, the collabo‐ ration of the industrial sector, which consumes a large amount of energy, is essential [4]. Common consumer goods are manufactured thanks to this energy. Industry must con‐ tinue to provide the products it now makes, but at a lower energy cost. One of the industries that have traditionally been considered highly polluting is the tanning industry [5], a widespread industry in developing countries [6]. Nevertheless, recently, a very important effort has been made to improve the sustainability of compa‐ nies in this sector, called tanneries. Some of the studies carried out and their results have been reflected in publications edited by various organizations, such as the European Un‐ ion [7].Most of the corrective actions implemented and recommended are on generated wastes (solid and liquid). The studies carried out have made it possible to greatly improve the processes, and both the emission of waste and the risk of toxicity for workers have been greatly minimized [8]. It is estimated that the energy cost of a tannery is approximately 3% of the total cost [9]. The low economic impact of energy expenditure has meant that in most cases no ef‐ forts were made to reduce or optimize it. Citation: Morera, J.M.; Borri, E.; Zsembinszki, G.; Vérez, D.; Gasa, G.; Bartolí, E.; Cabeza, L.F. Energy Assessment of a Tannery to Improve Its Sustainability. Sustainability 2023, 15, 5599. https://doi.org/10.3390/su15065599 Academic Editor: Adam Smoliński Received: 16 February 2023 Revised: 13 March 2023 Accepted: 16 March 2023 Published: 22 March 2023 Copyright: © 2023 by the authors. Li‐ censee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and con‐ ditions of the Creative Commons At‐ tribution (CC BY) license (https://cre‐ ativecommons.org/licenses/by/4.0/).