Depending on the type of commodity and its extraction processes, heat can also be an important energy need, for example, in the electro-winning of metals from ores (Philibert, 2017). In the past decade alone, the prices of crude oil and oil products saw a number of peaks. In 2008, prices reached an all-time high, followed by a fall, and another rise in 2011, remaining high until a new decline started in 2014, leading to record low prices in 2016. Given that energy costs can represent up to 30% of mining companies’ operating costs (Soliman et al.,