**1. Introduction**

## *1.1. General Factors Influencing Energy Price Increases*

The primary resource necessary for the operation of practically any economy is electricity. Electricity is supplied from generation units via transmission and distribution grids to the customers. The generating sources are primarily large system power plants. Renewable sources have still not become dominant, despite significant political pressure in recent decades and massive subsidies to support their installation and operation.

The significant increase in the number of small distributed sources has also not changed the structure of the power systems. The amount of renewable energy supplied to consumers has increased, but so have the problems of grid operators responsible for the security of supply and balancing the power system resources. So far, the main visible effect of the transformation of the electricity sector has been an increase in electricity prices for consumers. The electricity costs are distributed differently among various customer groups depending on political and regulatory decisions in individual countries.

In the past few years, additional factors driving up the operating costs of manufacturing companies have been the coronavirus pandemic and local and global political crises. The coronavirus pandemic led to the disruption of supply chains for materials, components,

**Citation:** Smagowicz, J.; Szwed, C.; D ˛abal, D.; Scholz, P. A Simulation Model of Power Demand Management by Manufacturing Enterprises under the Conditions of Energy Sector Transformation. *Energies* **2022**, *15*, 3013. https:// doi.org/10.3390/en15093013

Academic Editors: Bartlomiej Iglinski and Michał Bernard Pietrzak

Received: 25 March 2022 Accepted: 18 April 2022 Published: 20 April 2022

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**Copyright:** © 2022 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/).

and products. In the operation of manufacturing companies, this meant that there was an additional factor causing significant changes in electricity consumption. When production stops, electricity consumption drops temporarily. The contracted energy is not collected. When production is resumed, consumption rises significantly to make up for the earlier failure to produce. Politic crises can lead to a sharp increase in the price of primary fuels for electricity production. In the long run, they can also lead to changes in the energy policy of individual countries (i.e., the replacement of one primary fuel by another, usually more expensive one). This may mean an increase in the cost of electricity supply, which applies to both municipal consumers and manufacturing companies.

The automation and robotization of production processes is another factor leading to an increase in the energy costs of manufacturing companies. For several decades, along with the development and growth in the efficiency of processes, their energy intensity has also increased. With the noticeable trend of rising energy prices, the problem of reducing energy consumption has become significant for most companies. The undertaken actions aim to reduce the operating costs of enterprises, or at least stop their growth. However, it turns out that only a part of the electricity supplied to the enterprise is used directly for production processes. As in the case of thermal power plants, a significant part of this energy is wasted on thermal losses [1]. Companies are trying to reduce energy losses, and these actions should be aimed in different directions. On one hand, to reduce thermal losses of energy, and on the other hand, to lead to the best possible use of energy that goes into the production process.

### *1.2. Determinants of Energy Consumption Management in Enterprises*

With the development of automation and robotics, electricity is becoming a key resource for the execution of the production process, and its lack has already led and will lead in the future to the interruption/suspension of ongoing processes. Energy as a resource is used in the entire production area, starting from ensuring the operation of machinery, through running transport and storage systems, to ensuring proper working environmental conditions. This includes artificial lighting, maintaining a constant temperature, ventilation, etc. [2].

There are three basic levels of research identified in the literature, depending on the details of the analysis. The first level consists of a single workstation, usually a machine. The second is a production cell, a controlled cluster of interconnected machines. The third is the production system, a cluster of many production cells and areas that allow for handling activities within the entire enterprise. For example, it may include material and product storage areas and social areas. At each of these levels, a specific set of resources must be identified and the extent of electricity consumption must be determined [3,4].

For selected resources, consumption over time can be constant or variable. This factor is an important criterion when deciding on the running of technological operations as well as their financial implications for the company. The possibility of variable power consumption is more flexible for the entire process and allows for the operations to be adjusted to the company's capabilities. Constant power consumption in time usually means that power is drawn when the resource is working. This situation, however, requires a decision as to when the resource should be switched on, whether it is possible to ensure its continuous operation, and what this means for the company.

Another important aspect is the use of different technologies in the implementation of production processes that have different characteristics. For example, this may be related to the necessity of performing certain activities in a certain sequence or procedure. It can also be related to the maintenance of certain parameters of machine operation (temperature, humidity, pollution level, noise level). It turns out that even in the case of variable power consumption by a given resource, the company may not have such high flexibility. Due to the nature of the operation/technology used, the resource will be forced to maintain its operating parameters, consuming an adequate amount of power, incommensurately greater than the operation performed. For example, ensuring a high temperature of the furnace or

dryer during operation usually means a high power consumption throughout the entire period of operation of the machine, not only during the processing of the material/product, but also while waiting for the delivery of material to operate.
