Toward Sustainable Smart Lighting. The "SSL-square" Concept

Artificial light production absorbs around 2 900 TWh corresponding 13,5% of the world’s electricity annual production in 2019. Even if this quantity is still very high, it should be noticed that till beginning of 2010’s electrical light sources were considered as responsible for an energy consumption of around 2651 TWh, which represented roughly 19% of world's total electricity consumption. This tendency suggests the beginning of a harnessing of consumption which can be explained by the increase of light system efficiency when keeping service level stable (measured in quantity of light). Today, the importance and use of the “legacy” lighting technologies is decreasing. During the last decade, SSLs-Solid-State Lighting based on components like LEDs, OLEDs and LDs, challenges conventional technologies. In particular, LED has turned into a game changer beating the conventional technologies in all aspects. It is therefore anticipated that in short term, all of electric lighting will be based on SSLs. Today, SSLs proceed to the projected conclusion: replacing all legacy technologies, this is a major change in the lighting market that is considered as a revolution.