## 1 Introduction  
Combating climate change is one of the five main themes of the Europe 2020 comprehensive strategy [1], adopted by the European Council in 2010, for smart, sustainable, and inclusive growth. The specific targets of the strategy consider that by 2020, greenhouse gas emissions to be reduced by 20%, 20% of electricity to be covered from renewable sources, and energy efficiency to be improved by 20%. However, the European Commission modified the targets set at the European Union (EU) level according to the document \"Towards a Sustainable Europe by 2030\" [2]. These targets refer to ensure at least 32% of the total energy consumption from renewable sources and energy efficiency of at least 32.5% in 2030, which will lead to exceeding the commitments made in within the framework of the Paris Agreement on climate change concerning to the reducing greenhouse gas emissions by at least 40% by 2030 compared to 1990 levels. If for the 2020 targets on greenhouse gas emissions and renewable energy, the EU is on track to achieve the target on the energy efficiency that may not be reached [3]. On 4 February 2020, Eurostat published a document [4] which stipulates that in 2018, the primary energy consumption in the EU was 4.9% above the efficiency target for 2020 and 22.0% away from the 2030 target, see Figure 1 adapted from [4]. It can highlight that since 1990, the primary energy consumption had a high variation between a maximum value recorded in 2006, with a gap by 15.2% from the 2020 target, and a minimum value recorded in 2014, representing a difference of 1.5% from the 2020 target. In December 2018, in the Official Journal of the European Union (L328), three normative acts related to the \"Clean Energy for All Europeans\" legislative package, with effect on 24 December 2018, were published. EU Directive 2018/2002 on energy efficiency establishes a common framework for measures to promote energy efficiency throughout the Union, to ensure that its main objectives are reached at least 32.5% by 2030 and to pave the way for future efficiency gains energy after this data [5]. The European Energy Regulatory Authorities supports the small and medium enterprises (SMEs) to use energy efficiently, including through special schemes, in compliance with state aid regulations. The support schemes for SMEs were established, including, if they have entered into voluntary agreements, to cover the costs of an energy audit and the implementation of cost-effective recommendations made in the following energy audits [6]. The EU Directive 27/2012 on energy efficiency [7] represents the base through which the small and medium enterprises (SMEs) are encouraged to participate in the energy audit programs. However, the SMEs have no obligation to follow energy auditing programs, although Article 8 of this Directive stipulates that \"the Member States must develop programs that encourage SMEs to undergo energy audits and to subsequently implement the recommendations from these audits\". Moreover, \"the member States may establish aid schemes for SMEs, including where voluntary agreements have been concluded, to cover the costs of an energy audit and the recommendations of energy audits, the costs involved being high, if it is decided to implement the proposed measures\" [7]. In this context, many industrial consumers become actively interested in the implementation of measures to reduce energy consumption because the energy efficiency is not only a tool to save money and resources but also a need for flexible adaptation to own needs. Supporting SMEs and the promotion of energy efficiency measures are essential for economic progress because about 23 million European SMEs represent 98% of the total number of businesses. The majority of SMEs are microenterprises with less than 10 people, having an annual turnover of up to 2 million euros [8]. The share of SMEs with less than 250 persons is very high, approximately 99.79, see Table 1 and Figure 2[9]. Figure 1: The primary energy consumption in the European Union (EU).