Increasing the share of energy from renewable sources in total energy consumption is a permanent concern for the Member States of the European Union. In this paper we propose to show the present situation of the renewable energy sector in the European Union, namely a statistical analysis of the gross consumption of renewable energy at the level of the European Union during 1990 - 2016, the evolution of the share of renewable energy in gross final consumption of energy in the EU 28 between 2004 and 2016 and a presentation of the renewable energy sector in EU28 member states in 2016.

Starting from the various interpretations of the concept of "informality", which can be associated with both negative aspects (underground economy, tax evasion, undeclared work, lack of productivity, lack of social protection, unfair competition) and positive aspects (a source for the poor, who have no alternative), this paper aims to review the main conceptual debates over the term "informality", opinions that can be synthesized in four currents or schools of thought, respectively: The dualist school, Structuralist School, Legalistic School and Voluntaristic School

The new stage of globalization, marked by deeper integration of work, creates new opportunities, both in terms of economic growth and job creation, but at the same time creates new challenges and problems in the labor market, such as: increasing labor market flows, exposing jobs to increased global competition and segmenting the labor market in formal and informal terms. It is known that the main feature of the informal labor market, whether we are talking about a developed economy or a developing economy, is flexibility, and the essential feature of a formal labor market is security. In any labor market, there is an increasingly fierce struggle between employers, who want more flexibility and employees, who want more security. Thus, was born the concept of "flexicurity". This paper aims to approach the flexicurity of the labor market through the formal / informal duality in the current context of globalization and to show the optimal combination of job flexibility and the security of the workers, who occupy those jobs.

This work proposes an incursion, from a theoretical point of view, in the specialized literature that has, over time, approached the labor market through the formal / informal duality.From the review of the specialized literature, I found that the studies on the duality of the labor market were based on aspects related to: the bureaucracy or the regulations existing on the two types of labor markets (formal/informal), productivity, rigidity, of the salaries practiced on the two types of markets, as well as the option of employees for formal or informal, depending on the cost benefit analysis.In this paper we intend to detail the models and theories with specialized literature is currently operating to characterize the labor market, through the formal/informal duality, respectively models based on the aspect of: bureaucracy /market regulations (Hart, Soto, ILO), productivity (Lewis), rigidity (Joshi, Hield), wages (Kuznets, Field) or employee choice (Maloney, Perry).

Since the 1970s when the term "informality" has penetrated into economic theory by designating everything that is not subject to the legal regulations of a state until today, the concept of informality has evolved from "simple business activities carried out by the poor population of economies in development "and up to the concept of" informal employment ", approached from the point of view of jobs or workers, and the" informal employment "approach taken from the perspective of the employer.Segmentation of the formal and informal workforce market is a specific feature of any labor market, whether we are talking about a labor market in a developed economy or one from a developing economy, with the difference that the motivation that pushes individuals towards informality is different, namely the instinct of survival in the developing economy and the "animal spirits" that Keynes himself spoke in developed economies.Informality can be considered as a consequence of the transition period to a market economy in the case of the countries that have undergone this transformation or even a consequence of capitalism in developed countries.Labor market informality is a reality recognized today by the entire scientific community, but still little understood, being a phenomenon that sometimes seems so natural and sometimes transcends our rational understanding. For this reason, there is a need for a better theorization of the concept of "informality" in order to be able to correctly quantify it and thus to have a true image of a dual economy: formal / informal.