This paper gives a definition of collective self-consumption and introduces the current regulatory framework in some European countries. It proposes a review of relevant Demand Side Management (DSM) methods applicable to improve the collective self-consumption rate. It also introduces the concept of blockchain and its possible applications to collective self-consumption, with a focus on some current experimentations. Current blockchain applications include validation of measured data and energy transactions. New architectures propose a completely decentralized energy market and grid control based on the blockchain technology. However, a deeper analysis of the benefit of blockchain is required. The legal framework will also play a role on the future deployment of these applications.