*2.2. Energy Management in Manufacturing Companies*

Within DSR, unlike other tools, the customer takes care of power management, as it is necessary to know the current consumption and the possibilities of reducing it for quality DSR operation (see Energy managemen<sup>t</sup> below). It will no longer only be necessary to adjust production according to the current consumption, but thanks to the financial reward for "non-consumption" (or, conversely, "over-consumption"), it will be possible to influence the behavior of the consumers themselves. Thus, demand will be managed using a pricing policy, and, paradoxically, there may be situations where consumers consume more, but at a lower cost [18]. Moreover, as it turns out, DSR and managemen<sup>t</sup> through a clear pricing policy alone can have a much greater impact on RES uptake than other factors such as the customers' environmental sentiment [19]. This fact, on the other hand, is not so surprising, because in general, the reasons for increasing energy efficiency, which is closely linked to consumption, are mainly organizational (e.g., education, know-how), managerial (e.g., competence), or economic (e.g., cost reduction) [20]. One of the ways to deal with grid instability could also be so-called energy clusters or hubs, which would have more predictable energy consumption patterns and thus enable a more efficient use of RES [6,21].

However, ensuring energy-efficient production and implementing DSR in the manufacturing sector is significantly more complicated than, for example, in the residential and service sectors [21,22], given the difficulty of matching energy optimization with production requirements [23,24]. A large number of factors are involved in the whole process (see below). Energy managemen<sup>t</sup> should help companies cope with these requirements [25–27]. Scientific articles have mentioned several important areas to focus on in this context.

First and foremost is the importance of setting up a framework—a systematic approach using ISO 50001 and ANSI MSE 2000 (United States) [25,28,29]. Or also other standards (e.g., EN 16231) [26,30,31]. Next is respecting all key steps of the energy managemen<sup>t</sup> process. This includes, for example, the setting of KPIs, which is important, among other things, in terms of the actual optimization of energy consumption and the measurability of the effect [26,27,32]. Furthermore, the mapping and analysis of the whole system, focusing on energy managemen<sup>t</sup> (not only electricity, but also gas, water, and raw materials), on load curves and the possibilities of influencing them to shift the load from the peaks to the valleys as well as on the characteristics of the production program (batch sizes, production processes). This step should be implemented from the whole production plant down to the machine components. Various tools such as energy audits, value stream mapping, Sankey diagrams, etc., can be used for this purpose [26,29,33].

Without process analysis or knowledge of KPIs, it is not possible to address energy optimization, which includes activities such as process modification, modeling, planning, scheduling, forecasting, etc., to ensure energy-efficient production [26,27]. Energy optimization focuses on several key areas such as [21]:


Finally, it is of course necessary to simultaneously respect the energy (e.g., energy availability, regulations, prices), operational (e.g., current operation of some machines), safety, and other constraints (e.g., quality) [24,34]. In some cases, these can often be subtle limitations (e.g., switching off machines can compromise their thermal stability) [38].

As some of the factors may be variable [30] such as the electricity consumption of the technologies depending on the type of product or the electricity available from the grid, the optimization needs to focus on different scenarios taking these factors into account [38].

Moreover, it should be noted that only part of the electricity supplied to the enterprise is used for the realization of production processes [1]. Part of the energy is transferred to powering other devices (not directly related to technological operations) or the realization of auxiliary processes. According to the concept of lean manufacturing, these activities are called non-value-added but necessary operations. Their execution supports the realization of the basic process (i.e., it is necessary/required), but they do not translate directly into manufacturing a product for the customer. Especially in the engineering sector, the state of "processing" reaches a high percent share in energy consumption, however, depending on the technologies used in the industry, this share may not be significant/dominant [39,40].
