Photovoltaic energy: a key player towards a sustainable energy mix

The energetic issues are on the top of the political agenda in many countries, for environmental reasons, for its driving role in all the economic sectors, as well as for the energetic independency concerns. This problematic is stressed by the increasing weight of renewable intermittent power sources in the global mix. In particular, due to its high potential and the strong national policy support it beneficiated, solar photovoltaic energy is now a key player in the world energy mutation and the way it is integrated into the global mix should be carefully performed. To deeply understand the way the solar energy can penetrate and transform the forthcoming energy framework, we adopted a three-level strategy to provide some answers to the following questions: i/ how can we situate the photovoltaic power role in future energy mixes?; ii/due to its main drawback, intermittency, could we provide an optimal design of a system combining storage devices?; iii/ what is the efficiency of the incentive policies that are or have been implemented to accelerate its deployment? That is why, in a first part, the peculiar position of the solar photovoltaic energy in the energy mix is analyzed. After recalling the general issue of future global energetic mixes, we propose a brief description of the different photovoltaic technologies and their promising evolutions in terms of technical improvements and cost reductions. Then, we describe the fast growing photovoltaic market and its consequences both on the electricity mix and the industry sector. In the second part we investigate the problematic of integrating such intermittent energy in the electricity mix, by developing a multi-criteria optimization methodology which simulates a system composed of photovoltaic panels and storage devices. Applications on a real case in the Cirque de Mafate (L'île de la Réunion, France) are provided to illustrate the interest of our method. Finally, we question the efficiency of different public supports to the photovoltaic technologies in the most relevant countries. We focus on correlating the installed power capacity with the spent public money and the electricity prices. In these works, we put into relief the necessity to consider energy issues through the prism of technical basis. Indeed, solutions that cannot be efficient should not be implemented in the system. However, a solely technical treatment of energy challenges is obviously insufficient, since energy is core point for the economy, for the citizen and so for the politician. Such a combined approach needs to remain anchored on concrete data close to the reality of the technical devices and keeping in mind the financial feasibility of the proposed solutions, when designing a new energy landscape and thus a new societal model.