**7. Conclusions**

Energy security is being tackled under the influence of energy in social life and in the economy, particularly in the liberalization of energy markets, in diversification and in resource efficiency, and in procedures that multiply competition in energy markets. More broadly, there are national and international measures to ensure stable energy supplies at affordable and stabilized prices, but also to guarantee the protection of critical energy infrastructure and to demonstrate state readiness to effectively respond to potential crisis. Since energy is one of the factors that determine the inputs into production and thus production costs, rising energy prices are multiplying pressures on producers, reducing profit. Therefore, it is necessary to secure energy resources in a liberalized market at acceptable prices in the interests of economic development.

From this point of view, the aim of this article was to summarize the information on EU and Slovak energy and environmental legislation, describe the current energy sources that are used for electricity production, current state of electricity production, consumption, and end user prices development. This information was also supplemented with information on heat production from energy sources and environmental consequences of lignite completed with information on the environmental consequences of electricity production using lignite (surface mining) as an energy source.

The data and charts used in the article come from publicly available sources.

**Author Contributions:** Conceptualization, J.J.; methodology, A.M., M.L. and M.T.; formal analysis, J.J., M.T.; resources, J.J., M.T.; data curation, A.M., M.L.; writing—original draft preparation, A.M.; writing—review and editing, A.M.; project administration, M.L..; funding acquisition, M.L.

**Funding:** This research was funded by the KEGA Grant Agency under the project KEGA 013TU Z-4/2017.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
