The power sector is in transformation around the globe, thus opening the need to consider perspectives of related consequences and changes. Its main characteristic is a shift from a centrally organized system to one with many more market actors. A new organization, supported by technological advances, led to emergence of a prosumer (producer–consumer) system in which the same actor manages both the generation and consumption of its own electric energy, consequently creating an important and new social and business change. This paper is an analysis of the principles and perspectives of sharing economy in the electricity market, aiming to define its main current and foreseen facts and to provide recommendations for mitigations where thought to be needed. Special attention is paid to assessment of sustainability perspectives, based on its economic, social and environmental pillars. Since electricity generation and consumption have a vital role in stable and sustainable development and quality of life, any change introduced in the electricity market must be correspondingly assessed carefully and as quantitatively as possible. A method which can be used for analysis of the Shared Economy-Sustainability nexus was also presented. Four main perspectives are highlighted: regulation, technological challenges, market, and sustainability assessment.